Issues in brain mapping...EEG patterns of encephalopathies and altered state ...Professor Yasser Metwally
The document discusses the usefulness of electroencephalography (EEG) in evaluating brain function and various neurological conditions. It provides details on normal EEG patterns and how they change with age. Various abnormal EEG patterns are associated with different types of encephalopathies (diffuse brain dysfunction), including triphasic waves in metabolic encephalopathy and anterior theta-delta activity with superimposed alpha in sedative drug intoxication. EEG can also help assess severity of encephalopathy and prognosis based on degree of background slowing and reactivity.
Sebenernya "filosofi" merupakan topik yang "ketinggian" buat si cip yang masih berada dalam stage mengasah "teknik" interpretasi. Dalam perjalanannya, sang guru sudah menanamkan filosofi ke dalam benak si cip, bahkan sejak hari pertama. "Bad EEG is worse than no EEG at all". Dan beliau tidak bosan-bosannya mengulang.
Mungkin, hikmah yang terpenting dari mempelajari "filosofi" interpretasi EEG sejak awal adalah membuat kita menyadari limitasi diri kita dan instrumen yang kita gunakan, menjadi pengingat agar tidak berhenti belajar, dan kemudian dengan cara yang terbaik mendayagunakan seluruh knowledge, skill & technique yang kita punya..
Brain resting-state activity in patients with vision loss due to visual syste...Michał Bola
The document summarizes a study examining ongoing brain activity in patients with damage to the visual system. Nineteen patients with partial vision loss and thirteen control subjects underwent EEG recordings to characterize resting state visual cortex activity and relate it to perception. Results showed that in patients, resting high alpha activity in the visual cortex exhibited lower amplitudes and less complex, more noise-like temporal patterns compared to controls. Spontaneous cortical synchronization was also related to perceptual abilities, suggesting visual system lesions impair functional brain activity even in intact cortex.
Klasifikasi tipe kejang terbaru tahun 2017 oleh ILAE didasarkan pada "onset" kejangnya. Focal atau General. Kenapa kita harus tahu tipe kejang yang diderita ini focal atau general? Bagaimana kita tahu suatu kejang ini focal atau general? Apakah hanya berdasarkan "onset"-nya saja? Seberapa spesifik kah "focal" yang diperlukan untuk menentukan keputusan klinis kita? Apakah "focal" itu cukup sebatas mengetahui hemisfer kanan/kiri, atau sampai menentukan lobus yang terkait, atau gyrus, atau area yang lebih spesifik? Apa gold standar diagnosis topis sumber kejang? Apakah semiologi masih relevan dengan begitu berkembangnya teknologi imaging, EEG, genetika?
The document discusses various current applications of electroencephalography (EEG) technology both within and outside of clinical settings. It outlines EEG's predominant use in epilepsy and sleep disorder diagnosis clinically. It also explores recent developments that enable portable and cheaper EEG units, allowing novel consumer and research applications. Specifically, the document examines EEG's role in investigating sleep disorders, assessing brain death, monitoring anesthesia depth, cognitive engagement, brain development, and more. It explores EEG's growing use in cognitive science, neuroscience, and other research domains. Finally, it discusses emerging areas like brain-computer interfaces, closed-loop systems, and neuromarketing.
Amyotrophic Lateral Sclerosis (ALS) is the most common progressive neurodegenerative disorder reflecting
the degeneration of upper and lower motor neurons. Motor neurons controls the communication between nervous
system and muscles of the body. ALS results in the loss of voluntary control over muscular activities along with the
inability to breathe and the maximum life expectancy of affected individual will be 3-5 years from the onset of
symptoms. But the lifetime of affected people can be extended by early detection of disease. The usual methods for
diagnosis are Electromyography (EMG), Nerve Conduction Study (NCS), Magnetic Resonance Imaging (MRI) and
Magneto-encephalography (MEG). But some of these methods may erroneously result in neuropathy or myopathy
instead of ALS and some do not provide any biomarker. EEG is comparatively least expensive method and it
provides biomarker for ALS detection. ALS is always associated with fronto-temporal dementia (FTD). The spectral
analysis of EEG will reveal the structural and functional connectivity alterations of the underlying neural network
that occurs due to FTD and it can generate potential biomarkers for the early detection of ALS. A novel algorithm
has been developed by exploiting the Dual Tree Complex Wavelet Transform (DTCWT) technique and it can
overcome the short comes of existing methods for the analysis and feature extraction of EEG. Deterministic
biomarkers were obtained from spectral analysis of EEG and the proposed algorithm provided 100% accuracy for all
the test datasets.
a better understanding of sleep and coma may lead to new approaches to general anesthesia based on new ways to alter consciousness,29,97,98 provide analgesia,99,100 induce amnesia, and provide muscle relaxation.66
This document discusses various techniques for monitoring patients in the intensive care unit (ICU), including electroencephalography (EEG), somatosensory evoked potentials (SSEPs), brain oxygen monitoring, intracranial pressure (ICP) monitoring, and cerebral blood flow monitoring using transcranial Doppler ultrasound. It provides examples of how these monitoring techniques can be used to detect seizures, brain injury, vasospasm, and other conditions in ICU patients.
Issues in brain mapping...EEG patterns of encephalopathies and altered state ...Professor Yasser Metwally
The document discusses the usefulness of electroencephalography (EEG) in evaluating brain function and various neurological conditions. It provides details on normal EEG patterns and how they change with age. Various abnormal EEG patterns are associated with different types of encephalopathies (diffuse brain dysfunction), including triphasic waves in metabolic encephalopathy and anterior theta-delta activity with superimposed alpha in sedative drug intoxication. EEG can also help assess severity of encephalopathy and prognosis based on degree of background slowing and reactivity.
Sebenernya "filosofi" merupakan topik yang "ketinggian" buat si cip yang masih berada dalam stage mengasah "teknik" interpretasi. Dalam perjalanannya, sang guru sudah menanamkan filosofi ke dalam benak si cip, bahkan sejak hari pertama. "Bad EEG is worse than no EEG at all". Dan beliau tidak bosan-bosannya mengulang.
Mungkin, hikmah yang terpenting dari mempelajari "filosofi" interpretasi EEG sejak awal adalah membuat kita menyadari limitasi diri kita dan instrumen yang kita gunakan, menjadi pengingat agar tidak berhenti belajar, dan kemudian dengan cara yang terbaik mendayagunakan seluruh knowledge, skill & technique yang kita punya..
Brain resting-state activity in patients with vision loss due to visual syste...Michał Bola
The document summarizes a study examining ongoing brain activity in patients with damage to the visual system. Nineteen patients with partial vision loss and thirteen control subjects underwent EEG recordings to characterize resting state visual cortex activity and relate it to perception. Results showed that in patients, resting high alpha activity in the visual cortex exhibited lower amplitudes and less complex, more noise-like temporal patterns compared to controls. Spontaneous cortical synchronization was also related to perceptual abilities, suggesting visual system lesions impair functional brain activity even in intact cortex.
Klasifikasi tipe kejang terbaru tahun 2017 oleh ILAE didasarkan pada "onset" kejangnya. Focal atau General. Kenapa kita harus tahu tipe kejang yang diderita ini focal atau general? Bagaimana kita tahu suatu kejang ini focal atau general? Apakah hanya berdasarkan "onset"-nya saja? Seberapa spesifik kah "focal" yang diperlukan untuk menentukan keputusan klinis kita? Apakah "focal" itu cukup sebatas mengetahui hemisfer kanan/kiri, atau sampai menentukan lobus yang terkait, atau gyrus, atau area yang lebih spesifik? Apa gold standar diagnosis topis sumber kejang? Apakah semiologi masih relevan dengan begitu berkembangnya teknologi imaging, EEG, genetika?
The document discusses various current applications of electroencephalography (EEG) technology both within and outside of clinical settings. It outlines EEG's predominant use in epilepsy and sleep disorder diagnosis clinically. It also explores recent developments that enable portable and cheaper EEG units, allowing novel consumer and research applications. Specifically, the document examines EEG's role in investigating sleep disorders, assessing brain death, monitoring anesthesia depth, cognitive engagement, brain development, and more. It explores EEG's growing use in cognitive science, neuroscience, and other research domains. Finally, it discusses emerging areas like brain-computer interfaces, closed-loop systems, and neuromarketing.
Amyotrophic Lateral Sclerosis (ALS) is the most common progressive neurodegenerative disorder reflecting
the degeneration of upper and lower motor neurons. Motor neurons controls the communication between nervous
system and muscles of the body. ALS results in the loss of voluntary control over muscular activities along with the
inability to breathe and the maximum life expectancy of affected individual will be 3-5 years from the onset of
symptoms. But the lifetime of affected people can be extended by early detection of disease. The usual methods for
diagnosis are Electromyography (EMG), Nerve Conduction Study (NCS), Magnetic Resonance Imaging (MRI) and
Magneto-encephalography (MEG). But some of these methods may erroneously result in neuropathy or myopathy
instead of ALS and some do not provide any biomarker. EEG is comparatively least expensive method and it
provides biomarker for ALS detection. ALS is always associated with fronto-temporal dementia (FTD). The spectral
analysis of EEG will reveal the structural and functional connectivity alterations of the underlying neural network
that occurs due to FTD and it can generate potential biomarkers for the early detection of ALS. A novel algorithm
has been developed by exploiting the Dual Tree Complex Wavelet Transform (DTCWT) technique and it can
overcome the short comes of existing methods for the analysis and feature extraction of EEG. Deterministic
biomarkers were obtained from spectral analysis of EEG and the proposed algorithm provided 100% accuracy for all
the test datasets.
a better understanding of sleep and coma may lead to new approaches to general anesthesia based on new ways to alter consciousness,29,97,98 provide analgesia,99,100 induce amnesia, and provide muscle relaxation.66
This document discusses various techniques for monitoring patients in the intensive care unit (ICU), including electroencephalography (EEG), somatosensory evoked potentials (SSEPs), brain oxygen monitoring, intracranial pressure (ICP) monitoring, and cerebral blood flow monitoring using transcranial Doppler ultrasound. It provides examples of how these monitoring techniques can be used to detect seizures, brain injury, vasospasm, and other conditions in ICU patients.
This document discusses critical care EEG monitoring. It provides information on the indications for EEG monitoring, including seizure assessment and brain death evaluation. It notes that about half of seizures in patients are identified within the first hour of monitoring, but up to 90% are identified within 24 hours. However, the duration of monitoring should be tailored to the individual patient. The document also discusses electrographic seizures versus clinical seizures and presents findings from a study which found that over 66% of events initially suspected to be seizures were actually non-epileptic based on EEG monitoring. It emphasizes that EEG monitoring is an important tool but remains labor-intensive.
This document outlines the surgical management of epilepsy. It discusses indications for epilepsy surgery including intractable seizures, side effects of medication, and quality of life issues. The goals of surgery are to eliminate or decrease seizures and prevent neurological deficits while improving quality of life. Extensive presurgical evaluation includes imaging, EEG, neurological assessments, and sometimes invasive monitoring. Surgery targets the seizure focus and may include resective procedures or disconnections. Radiosurgery and neurostimulation are also discussed as alternative options.
The Anesthetized Brain is less Vulnerable to ischemic injury than the awake brain.
EEG changes suggestive of severe ischemia are present.
Basic Methode Brain Protection are “ Corner Stone “
CPP, CBF, CBV maintained in “Normal Range”, MAP may increased up to 10 – 20 %.
Anesthetics Drugs may have Brain Protectection effect.
Volatile anesthetics do provide some Transient Protection (< 1,5 MAC)
Barbiturates, although long considered to be the gold standard.
Hypothermic methode are controversial, Hyperthermia should be avoided.
Insulin is Administered if glucose values exceed 180 mg/dl.
Close monitoring of BSL to ensure that Hypoglycemia does not develop
1. Amplitude integrated EEG (aEEG) is a device that measures background brain activity through electrodes placed on the scalp. It provides information on global brain function through a compressed timescale display.
2. aEEG is useful for predicting outcomes in conditions like hypoxic ischemic encephalopathy, seizures, and neurological disorders. Abnormal aEEG patterns correlate with adverse outcomes while return of normal patterns indicates better prognosis.
3. aEEG can help identify infants who benefit most from therapeutic hypothermia for hypoxic ischemic encephalopathy. More severe abnormalities on aEEG, like burst suppression, are associated with poorer response to cooling therapies.
This document discusses epilepsy surgery evaluation and outcomes. It notes that about one-third of epilepsy patients have seizures that cannot be controlled with medication. For these patients, surgical therapy can be an important treatment option. The goals of presurgical evaluation are to localize the epileptogenic zone and assess risk to brain functions from surgery. Evaluations may include brain imaging, video-EEG monitoring, neuropsychological testing, and in some cases invasive monitoring. Common indications for surgery include mesial temporal lobe epilepsy and lesions. Seizure freedom rates after surgery range from 50-90% depending on the specific diagnosis and evaluation findings. Outcome measures also consider cognitive and quality of life impacts.
This presentation describes the concept of temporal plus syndrome, pseudotemporal epilepsy and paradoxical temporal lobe epilepsy and how to differentiate them from temporal lobe epilepsy.
This document discusses studies using neuroimaging techniques like PET, SPECT, and fMRI to study cerebral metabolism, blood flow, and neuroreceptor functioning in schizophrenia. Early studies found abnormalities in frontal lobe activity and the anterior-posterior gradient in patients. Subsequent studies found greater differences between patients and controls when assessing brain activity during cognitive tasks rather than at rest. Tasks probing memory, language, and executive function have revealed impairments in associated brain regions in patients. The relationship between symptoms and metabolism in temporal and basal ganglia regions is still unclear. Neuroleptic-naive and first-episode patients have provided insights with fewer confounding factors.
di Paolo M. Rossini
Clinica Neurologica, Università Cattolica, Policlinico . Gemelli, Roma
Convegno "Le neuroscienze incontrano le altre discipline"
Padova, Palazzo del Bo
5 maggio 2011
Il convegno è promosso dall’Università di Padova e dal Dipartimento di Psicologia generale della stessa università, con il sostegno della Fondazione Sigma Tau e della Fondazione Giannino Bassetti.
The document summarizes EEG patterns seen in various encephalopathies. It describes diffuse slowing, triphasic waves, burst suppression, periodic epileptiform discharges (PLEDs, BIPLEDs, GPEDs), alpha coma, spindle coma and beta coma patterns. Specific patterns are seen in hepatic encephalopathy, uremia, Hashimoto's encephalopathy, NMDAR encephalitis, Creutzfeldt-Jakob disease, subacute sclerosing panencephalitis. Criteria for periodic discharges and electrocerebral inactivity seen in brain death are also outlined.
The neuromuscular junction is a chemical synapse between motor neurons and muscle fibers. Alterations in structure and function of the NMJ can cause disorders. Myasthenia gravis is an autoimmune disorder where antibodies attack acetylcholine receptors, damaging the postsynaptic membrane. Symptoms include fatigable weakness. Treatment involves cholinesterase inhibitors, immunosuppressants, IVIG, plasmapheresis, and sometimes thymectomy. Lambert-Eaton myasthenic syndrome is caused by antibodies against voltage-gated calcium channels, reducing acetylcholine release. It presents with proximal weakness and reduced reflexes.
This document discusses various aspects of evaluating and surgically treating epilepsy. It begins by outlining when epilepsy surgery should be considered, such as when seizures persist despite adequate medication. The aim of presurgical evaluation is to accurately map the epileptogenic zone and completely resect or disconnect the area responsible for seizures. Noninvasive and invasive testing methods are described to localize the seizure focus. Common surgical approaches like temporal lobectomy and extra-temporal lobectomy are explained. Outcomes of different procedures and factors influencing prognosis are also summarized.
This document discusses epilepsy and anaesthesia. It provides definitions of seizures and epilepsy. It then discusses various factors that influence neuronal excitability like intrinsic factors related to ion channels and extrinsic factors like ion concentrations and synaptic remodeling. It explains the mechanisms of seizure initiation and propagation. It discusses the effects of various anaesthetic agents like inhalational agents, opioids, IV agents and local anaesthetics on seizures. It provides guidelines on perioperative management of anti-epileptic drugs. It also discusses status epilepticus, its treatment and refractory status epilepticus. The document concludes by covering various aspects of presurgical evaluation of epilepsy patients like neuroimaging, EEG, video-EEG, neuropsychological testing and WADA test
Evoked potentials, clinical importance & physiological basis of consciousness...Rajesh Goit
This document summarizes key aspects of electroencephalography (EEG), including its uses and physiological basis. EEG is used to diagnose epilepsy and study sleep disorders. It records electrical activity in the brain through scalp electrodes. Specific EEG rhythms like alpha, beta, theta, and delta waves are associated with different brain states. Evoked potentials are EEG responses to sensory stimuli and are clinically used to assess hearing, vision, and somatosensory pathways. Epilepsy is classified as focal or generalized seizures. EEG patterns in epilepsy include sharp waves in focal seizures and high-voltage discharges in generalized seizures. Non-rapid eye movement (REM) and REM sleep have distinct EEG signatures and functions in brain and body restoration.
Brainstem Auditory Evoked Potentials (BAEP) involves recording electrophysiological responses from the ear in response to auditory stimulation to assess the functioning of the auditory pathway. BAEP testing involves placing electrodes on the scalp to record waveforms representing activity in the auditory nerve and brainstem in response to click sounds. BAEP is useful for screening and monitoring conditions affecting the auditory pathway such as tumors near the cerebellopontine angle, multiple sclerosis, and coma. It can also be used for newborn hearing screening and evaluating stroke and tuberculous meningitis patients.
The document summarizes the history and technical aspects of conventional EEG. It discusses how EEG works to detect and amplify the brain's electrical activity, which is measured using electrodes placed on the scalp. Different electrode placements and montages are used to view brain activity from various regions and perspectives. While imaging techniques now provide anatomical details, EEG remains clinically useful for evaluating brain function in various neurological disorders.
Periodic Lateralized Epileptiform Discharges (PLEDs) are repeating waveforms seen on EEG that occur at regular intervals and are localized to one hemisphere. They are commonly seen after acute cortical injuries like stroke and infections. PLEDs are classified based on their pattern and presence of additional rhythmic discharges. They indicate unstable brain physiology resulting from seizures, injury or metabolic disturbances. While not strictly ictal, PLEDs are associated with increased risk of clinical seizures. Prognosis depends on the underlying cause, with acute severe strokes having the worst outcomes. Treatment involves antiepileptic drugs mainly if clinical seizures are present.
Deep brain stimulation (DBS)/Brain pacemaker has evolved as an important and established treatment modality for variety of advanced movement disorders and also for some psychiatry disorders.1Chronic DBS stimulation provides a non destructive and reversible means of disturbing the abnormal function of basal ganglia circuit. It can be adjusted as disease progresses or adverse event occur. Bilateral stimulation can be performed without a significant increase inadverse effects.Adverse events related to unintended stimulation of adjacent structures are readily reversible by altering the stimulus parameters.
- Epilepsy surgery in children can effectively control seizures and reduce risks of cognitive and behavioral issues associated with uncontrolled epilepsy. It is recommended for children with seizures uncontrolled by medication, especially those under 2 years old.
- Evaluation involves localization of the epileptic focus through EEG, MRI, PET, MEG and other tests. The goal is to identify and remove the minimum amount of brain tissue necessary to stop seizures without causing deficits.
- Common pathological substrates for surgery in children include cortical dysplasias, tumors, hippocampal sclerosis, and infections/injuries. Younger children are more likely to undergo hemispherectomies or multilobar resections.
This document discusses critical care EEG monitoring. It provides information on the indications for EEG monitoring, including seizure assessment and brain death evaluation. It notes that about half of seizures in patients are identified within the first hour of monitoring, but up to 90% are identified within 24 hours. However, the duration of monitoring should be tailored to the individual patient. The document also discusses electrographic seizures versus clinical seizures and presents findings from a study which found that over 66% of events initially suspected to be seizures were actually non-epileptic based on EEG monitoring. It emphasizes that EEG monitoring is an important tool but remains labor-intensive.
This document outlines the surgical management of epilepsy. It discusses indications for epilepsy surgery including intractable seizures, side effects of medication, and quality of life issues. The goals of surgery are to eliminate or decrease seizures and prevent neurological deficits while improving quality of life. Extensive presurgical evaluation includes imaging, EEG, neurological assessments, and sometimes invasive monitoring. Surgery targets the seizure focus and may include resective procedures or disconnections. Radiosurgery and neurostimulation are also discussed as alternative options.
The Anesthetized Brain is less Vulnerable to ischemic injury than the awake brain.
EEG changes suggestive of severe ischemia are present.
Basic Methode Brain Protection are “ Corner Stone “
CPP, CBF, CBV maintained in “Normal Range”, MAP may increased up to 10 – 20 %.
Anesthetics Drugs may have Brain Protectection effect.
Volatile anesthetics do provide some Transient Protection (< 1,5 MAC)
Barbiturates, although long considered to be the gold standard.
Hypothermic methode are controversial, Hyperthermia should be avoided.
Insulin is Administered if glucose values exceed 180 mg/dl.
Close monitoring of BSL to ensure that Hypoglycemia does not develop
1. Amplitude integrated EEG (aEEG) is a device that measures background brain activity through electrodes placed on the scalp. It provides information on global brain function through a compressed timescale display.
2. aEEG is useful for predicting outcomes in conditions like hypoxic ischemic encephalopathy, seizures, and neurological disorders. Abnormal aEEG patterns correlate with adverse outcomes while return of normal patterns indicates better prognosis.
3. aEEG can help identify infants who benefit most from therapeutic hypothermia for hypoxic ischemic encephalopathy. More severe abnormalities on aEEG, like burst suppression, are associated with poorer response to cooling therapies.
This document discusses epilepsy surgery evaluation and outcomes. It notes that about one-third of epilepsy patients have seizures that cannot be controlled with medication. For these patients, surgical therapy can be an important treatment option. The goals of presurgical evaluation are to localize the epileptogenic zone and assess risk to brain functions from surgery. Evaluations may include brain imaging, video-EEG monitoring, neuropsychological testing, and in some cases invasive monitoring. Common indications for surgery include mesial temporal lobe epilepsy and lesions. Seizure freedom rates after surgery range from 50-90% depending on the specific diagnosis and evaluation findings. Outcome measures also consider cognitive and quality of life impacts.
This presentation describes the concept of temporal plus syndrome, pseudotemporal epilepsy and paradoxical temporal lobe epilepsy and how to differentiate them from temporal lobe epilepsy.
This document discusses studies using neuroimaging techniques like PET, SPECT, and fMRI to study cerebral metabolism, blood flow, and neuroreceptor functioning in schizophrenia. Early studies found abnormalities in frontal lobe activity and the anterior-posterior gradient in patients. Subsequent studies found greater differences between patients and controls when assessing brain activity during cognitive tasks rather than at rest. Tasks probing memory, language, and executive function have revealed impairments in associated brain regions in patients. The relationship between symptoms and metabolism in temporal and basal ganglia regions is still unclear. Neuroleptic-naive and first-episode patients have provided insights with fewer confounding factors.
di Paolo M. Rossini
Clinica Neurologica, Università Cattolica, Policlinico . Gemelli, Roma
Convegno "Le neuroscienze incontrano le altre discipline"
Padova, Palazzo del Bo
5 maggio 2011
Il convegno è promosso dall’Università di Padova e dal Dipartimento di Psicologia generale della stessa università, con il sostegno della Fondazione Sigma Tau e della Fondazione Giannino Bassetti.
The document summarizes EEG patterns seen in various encephalopathies. It describes diffuse slowing, triphasic waves, burst suppression, periodic epileptiform discharges (PLEDs, BIPLEDs, GPEDs), alpha coma, spindle coma and beta coma patterns. Specific patterns are seen in hepatic encephalopathy, uremia, Hashimoto's encephalopathy, NMDAR encephalitis, Creutzfeldt-Jakob disease, subacute sclerosing panencephalitis. Criteria for periodic discharges and electrocerebral inactivity seen in brain death are also outlined.
The neuromuscular junction is a chemical synapse between motor neurons and muscle fibers. Alterations in structure and function of the NMJ can cause disorders. Myasthenia gravis is an autoimmune disorder where antibodies attack acetylcholine receptors, damaging the postsynaptic membrane. Symptoms include fatigable weakness. Treatment involves cholinesterase inhibitors, immunosuppressants, IVIG, plasmapheresis, and sometimes thymectomy. Lambert-Eaton myasthenic syndrome is caused by antibodies against voltage-gated calcium channels, reducing acetylcholine release. It presents with proximal weakness and reduced reflexes.
This document discusses various aspects of evaluating and surgically treating epilepsy. It begins by outlining when epilepsy surgery should be considered, such as when seizures persist despite adequate medication. The aim of presurgical evaluation is to accurately map the epileptogenic zone and completely resect or disconnect the area responsible for seizures. Noninvasive and invasive testing methods are described to localize the seizure focus. Common surgical approaches like temporal lobectomy and extra-temporal lobectomy are explained. Outcomes of different procedures and factors influencing prognosis are also summarized.
This document discusses epilepsy and anaesthesia. It provides definitions of seizures and epilepsy. It then discusses various factors that influence neuronal excitability like intrinsic factors related to ion channels and extrinsic factors like ion concentrations and synaptic remodeling. It explains the mechanisms of seizure initiation and propagation. It discusses the effects of various anaesthetic agents like inhalational agents, opioids, IV agents and local anaesthetics on seizures. It provides guidelines on perioperative management of anti-epileptic drugs. It also discusses status epilepticus, its treatment and refractory status epilepticus. The document concludes by covering various aspects of presurgical evaluation of epilepsy patients like neuroimaging, EEG, video-EEG, neuropsychological testing and WADA test
Evoked potentials, clinical importance & physiological basis of consciousness...Rajesh Goit
This document summarizes key aspects of electroencephalography (EEG), including its uses and physiological basis. EEG is used to diagnose epilepsy and study sleep disorders. It records electrical activity in the brain through scalp electrodes. Specific EEG rhythms like alpha, beta, theta, and delta waves are associated with different brain states. Evoked potentials are EEG responses to sensory stimuli and are clinically used to assess hearing, vision, and somatosensory pathways. Epilepsy is classified as focal or generalized seizures. EEG patterns in epilepsy include sharp waves in focal seizures and high-voltage discharges in generalized seizures. Non-rapid eye movement (REM) and REM sleep have distinct EEG signatures and functions in brain and body restoration.
Brainstem Auditory Evoked Potentials (BAEP) involves recording electrophysiological responses from the ear in response to auditory stimulation to assess the functioning of the auditory pathway. BAEP testing involves placing electrodes on the scalp to record waveforms representing activity in the auditory nerve and brainstem in response to click sounds. BAEP is useful for screening and monitoring conditions affecting the auditory pathway such as tumors near the cerebellopontine angle, multiple sclerosis, and coma. It can also be used for newborn hearing screening and evaluating stroke and tuberculous meningitis patients.
The document summarizes the history and technical aspects of conventional EEG. It discusses how EEG works to detect and amplify the brain's electrical activity, which is measured using electrodes placed on the scalp. Different electrode placements and montages are used to view brain activity from various regions and perspectives. While imaging techniques now provide anatomical details, EEG remains clinically useful for evaluating brain function in various neurological disorders.
Periodic Lateralized Epileptiform Discharges (PLEDs) are repeating waveforms seen on EEG that occur at regular intervals and are localized to one hemisphere. They are commonly seen after acute cortical injuries like stroke and infections. PLEDs are classified based on their pattern and presence of additional rhythmic discharges. They indicate unstable brain physiology resulting from seizures, injury or metabolic disturbances. While not strictly ictal, PLEDs are associated with increased risk of clinical seizures. Prognosis depends on the underlying cause, with acute severe strokes having the worst outcomes. Treatment involves antiepileptic drugs mainly if clinical seizures are present.
Deep brain stimulation (DBS)/Brain pacemaker has evolved as an important and established treatment modality for variety of advanced movement disorders and also for some psychiatry disorders.1Chronic DBS stimulation provides a non destructive and reversible means of disturbing the abnormal function of basal ganglia circuit. It can be adjusted as disease progresses or adverse event occur. Bilateral stimulation can be performed without a significant increase inadverse effects.Adverse events related to unintended stimulation of adjacent structures are readily reversible by altering the stimulus parameters.
- Epilepsy surgery in children can effectively control seizures and reduce risks of cognitive and behavioral issues associated with uncontrolled epilepsy. It is recommended for children with seizures uncontrolled by medication, especially those under 2 years old.
- Evaluation involves localization of the epileptic focus through EEG, MRI, PET, MEG and other tests. The goal is to identify and remove the minimum amount of brain tissue necessary to stop seizures without causing deficits.
- Common pathological substrates for surgery in children include cortical dysplasias, tumors, hippocampal sclerosis, and infections/injuries. Younger children are more likely to undergo hemispherectomies or multilobar resections.
Cavernous carotid aneurysms are the most common type of extradural intracranial aneurysm. They are usually congenital and saccular in shape, arising from branches of the internal carotid artery within the cavernous sinus. About a quarter of cases are bilateral. Rupture can cause a carotid-cavernous fistula. Large unruptured aneurysms can compress nearby structures through mass effect as they expand upward and laterally within confined spaces of the skull. Cranial nerves are frequently compressed, which can impair eye movements or vision. On angiography, a thrombosed aneurysm may be difficult to detect due to surrounding tissue opacification.
The document discusses different types of headaches including primary and secondary headaches. Primary headaches include tension headaches, migraines, and cluster headaches where the headache is the main issue. Secondary headaches have an underlying cause like infection, trauma, or vascular issues. Treatment depends on the type with acute treatments like NSAIDs, triptans, or ergot derivatives for attacks and preventative medications for frequent headaches.
This document summarizes a case study of a 60-year-old male patient who presented with rapidly progressive left-sided hemiplegia and increased intracranial pressure. CT scans showed diffuse abnormalities in the left thalamus, internal capsule, and basal ganglia, as well as an enhanced lesion in the left thalamus. The diagnosis was determined to be a thalamic glioma. The author's website provides regularly updated case studies and references for further information.
This document summarizes a case report published by Professor Yasser Metwally in January 2010. It describes a 50-year-old male patient who presented with limited horizontal eye movement for 4 years. Imaging showed a posterior pontine glioma. The patient declined treatment and later presented with worsening symptoms. MRI revealed a diffuse brain stem glioma involving the pons, midbrain and crus cerebri. The patient died 2 days after hospitalization. The case report is accompanied by 5 figures illustrating the imaging findings.
This document provides a summary of age dependent epileptic syndromes and focuses on primary generalized epilepsy and benign Rolandic epilepsy. It discusses the key characteristics of each condition including typical age of onset, common seizure types and EEG patterns. The summary concludes that these conditions are age determined and often seen in childhood, with seizures typically remitting by late adolescence.
Topic of the month.... The role of gamma knife in the management of benign br...Professor Yasser Metwally
This document discusses the use of radiation therapy to treat benign intracranial tumors. It provides an overview of the different radiation therapy strategies including stereotactic radiosurgery (SRS), stereotactic radiotherapy (SRT), and fractionated radiation therapy. It describes the key factors in determining which strategy to use such as tumor location, needed dose, and tolerance of surrounding tissues. The document also reviews different radiation sources and delivery methods including 3D conformal radiation therapy and intensity-modulated radiation therapy (IMRT).
A 22-year-old male presented with increased intracranial pressure, meningeal irritation signs, and bilateral papilledema. MRI images showed enhancement of the leptomeninges and pachymeninges, ventricular dilation, and periventricular lesions. He was diagnosed with lymphomatous meningitis affecting both the leptomeninges and pachymeninges.
Research section. Cervical spondylitic myelopathy, Clinico-radiological appro...Professor Yasser Metwally
Research section. Cervical spondylitic myelopathy, Clinico-radiological approach: Correlation with the Hemorheological parameters and vascular risk factors
http://yassermetwally.com
http://yassermetwally.net
This patient presented with transverse myelitis involving the cervical spinal cord, with a history of previous transverse myelitis in the dorsal region and left optic neuritis. MRI showed longitudinally extensive lesions involving the cervical and dorsal spinal cord and left optic nerve enlargement. This clinical and radiological picture is consistent with neuromyelitis optica (NMO), also known as Devic's disease, an inflammatory disorder that predominantly involves the optic nerves and spinal cord. NMO can be difficult to distinguish from multiple sclerosis but tends to cause more severe episodes of optic neuritis and transverse myelitis.
This document summarizes an MRI study of a 40-year-old female patient with multiple sclerosis. The MRI shows lesions throughout the brain characteristic of multiple sclerosis, including periventricular lesions and lesions perpendicular to the ventricles. Some lesions enhance with contrast, indicating active inflammation, while others do not, representing chronic inactive lesions. The MRI findings of disseminated lesions in both time and space support a diagnosis of chronic multiple sclerosis.
The document lists 5 different types of ancient Egyptian pyramids: the false pyramid, the red pyramid, the stepped pyramid, the stepped pyramid again, and the bent pyramid.
This document discusses sodium channel dysfunction and various related disorders. It begins by describing the physiology and pharmacology of voltage-gated sodium channels. It then discusses several sodium channelopathies involving muscle channels, cardiac channels, and brain channels. Specific channelopathies covered in more detail include generalized epilepsy with febrile seizures plus, severe myoclonic epilepsy of infancy (Dravet syndrome), and familial hemiplegic migraine. The document examines the genetic basis and functional properties of disease-causing mutations in the SCN1A gene associated with these conditions. Key findings include that GEFS+ mutations tend to cause gain of function through increased persistent sodium current, while SMEI mutations generally cause loss of function through
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80-Year-Old Woman With Dementia And ParkinsonismMonica Waters
An 80-year-old woman presented with a 4-year history of progressive memory loss and a 3-year history of gait deterioration. On examination, she showed signs of dementia, parkinsonism, and upper motor neuron dysfunction. Brain imaging showed diffuse cerebral atrophy, most pronounced in the medial temporal lobes. Based on the clinical features and test results, the diagnosis was probable Alzheimer's disease. Neuropsychological testing supported impaired memory, language, and cognitive function consistent with AD.
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4. Specific EEG patterns like lateralized periodic
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ABSTRACT
Background
Autism Spectrum Disorder is a neurodevelopmental disorder and symptoms are considered to be due to brain deregulation and dysfunction in multiple regions of the brain. There is no cure for autism and the management guidelines are defined to reduce the symptoms and reinstitute normal functioning in life. Neurofeedback is one of these methods in treating children with Autism. Several studies have shown that individuals with autism are able to alter their brain activity in specific frequency bands through the use of neurofeedback which induces prolong changes in autism symptoms, cognitive functioning and long-term changes in EEG. Neurofeedback is a way of training the brain to use more productive patterns of brainwaves which teaches the brain to self-regulate, strengthening neural pathways while increasing mental endurance and flexibility
Objective
To observe the effect of Neurofeedback Treatment in Children with ASD in areas of speech, language, communication, sociability, sensory ,cognitive awareness, health, physical and behaviors
Methods and Materials
It is a descriptive longitudinal study with purposive sampling done from January 2018 to March 2020 among children diagnosed with ASD who underwent Neurofeedback training for at least 80 sessions. 70% were boys 30% were girls. Assessment was done by Autism Treatment Evaluation Checklist. Data were analyzed by SPSS 21
Result
The study showed Improvements in all ATEC Evaluation Categories in Speech, Language, and communication39.1%, Sociability53.7%, Sensory and Cognitive awareness56.8%, and in Health, Physical, and Behaviors58%
Conclusion
The study shows marked improvement in all 4 specific Areas of evaluation of ATEC after Neurofeedback training of children with Autism. Since Autism has no specific cure and neurofeedback has its efficacy without any untoward effects may be used as a treatment option for Autism
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Electrical status epilepticus in sleep (ESES) is an electroencephalographic pattern showing significant epileptiform discharges during sleep. Two clinical syndromes associated with ESES are continuous spike wave in slow-wave sleep (CSWS) and Landau-Kleffner syndrome (LKS). CSWS often presents with global regression and loss of language or cognitive skills, while LKS primarily involves language regression. Treatment of ESES focuses on antiepileptic drugs and corticosteroids, with the goal of resolving seizures and discharges to improve long-term neuropsychological outcomes.
This lecture is all about the recognition of an abnormal EEG, its characteristics, its appearance and all about how to differentiate the abnormal activity with normal EEG background.
Autoimmune encephalitis in children, when to suspect.Subhankar Mishra
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2) Key presenting symptoms in pediatric AE can include altered mental status, seizures, movement disorders, and neuropsychiatric or behavioral changes.
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This document summarizes information about refractory epilepsy. It begins by defining refractory epilepsy as persistent seizures under antiepileptic drug treatment. It then discusses predictive factors of refractory epilepsy like epileptic syndrome, response to previous drugs, age at onset, and structural brain abnormalities. The document outlines evaluation and management approaches including optimizing medical treatment, surgical options like resection or palliation procedures, and other therapies like the ketogenic diet.
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ISO/IEC 27001, ISO/IEC 42001, and GDPR: Best Practices for Implementation and...PECB
Denis is a dynamic and results-driven Chief Information Officer (CIO) with a distinguished career spanning information systems analysis and technical project management. With a proven track record of spearheading the design and delivery of cutting-edge Information Management solutions, he has consistently elevated business operations, streamlined reporting functions, and maximized process efficiency.
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Date: May 29, 2024
Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
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Issues in brainmapping...EEG in dementias and hereditary encephalopathies
1. Version 11 A Monthly Publication presented by Professor Yasser Metwally March 2009
INTRODUCTION: EEG IN DEMENTIA AND HEREDITARY ENCEPHALOPATHIES
EEG has been employed clinically for some time as a measure of brain function in the hope of determining and differentiating certain
functional conditions of the brain. It is used in patients who suffer from cognitive dysfunction, either a general decline of overall brain
function or a localized or lateralized deficit. This article addresses primarily the clinical use of EEG in evaluation of dementias and
encephalopathies. In addition, aspects of digital EEG and other newer developments are discussed briefly at the end of the article.
Definition of dementia
Criteria from Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) should be used in the diagnosis of dementia.
Clinical dementia is a fairly broad-based decline of brain function; most definitions center on the patient’s intellectual decline and memory
dysfunction. This is, however, a fairly simplistic approach; dementia is much more than these fundamental deficits. Some of the dementias
have distinguishing features. The process that constitutes normal aging is still an ongoing debate. As our understanding and testing
procedures develop, more people are being classified as suffering from some type of dementia.
In 1998, Widagdo et al performed a quantitative EEG (QEEG) study of age-related changes during cognitive tasks. This study revealed no
conclusive differences between the young and the elderly. Cognitive decline, unlike normal aging, is associated with alterations in the
temporospatial characteristics of EEG. The diagnosis of the initial stages of dementia is based mainly on neuropsychological testing and
clinical suspicion. The EEG findings are nonspecific.
EEG findings in dementia
In early dementia, the resting alpha frequency declines. Most authors agree that the lower limit of normal alpha frequency is 8.5 cycles per
second. Medications can slow the posterior dominant rhythm; therefore, medication effect should always be excluded. In assessing the
frequency of the alpha rhythm, alerting maneuvers are essential in order to ensure that the patient is in the best awake state and not drowsy.
Computerized methods, such as EEG spectral analysis, coherence, and complexity (ie, correlation dimension), have been demonstrated to
correspond to cognitive function.
Stevens et al recorded EEGs during 2 resting conditions (eyes closed and eyes opened) and 2 tasks (mental arithmetic and a lexical decision).
The goal of the study was to evaluate which temporal and spatial EEG descriptors change with cognitive decline and normal aging. The EEGs
were analyzed by using EEG microstates. The primary findings were a significant increase in the number of ultrashort EEG microstates and a
reduction in the average duration of EEG microstates in cognitively impaired and demented patients. Cognitive impairment was associated
with a reduction or loss of EEG reactivity. In contrast, no alterations in temporal or spatial EEG descriptors were found in normal aging.
Cognitive tasks did not add to the information already obtained during the resting states. The reduction in EEG microstate duration correlated
with loss of cognitive function.
Therefore, temporospatial analysis of the EEG record is a useful indicator of cortical dysfunction in dementia and correlates with degree of
cognitive impairment. Apparently, temporospatial analysis may be useful in distinguishing patients with dementia from those experiencing
normal aging. These data are largely preliminary; whether they contribute additional information to the clinical data in evaluating dementia is
unclear.
Definition of encephalopathy
Encephalopathy represents a brain state in which normal functioning of the brain is disturbed temporarily or permanently. Encephalopathy
encompasses a number of conditions that lead to cognitive dysfunction. Some of these conditions are multifactorial and some have an
established cause, such as hepatic or uremic encephalopathy. Because the EEG patterns in most dementias and encephalopathies demonstrate
few specific features, they are discussed together. Some notable exceptions include Creutzfeldt-Jakob disease (CJD) and subacute sclerosing
panencephalitis (SSPE); however, no specific patterns exist for most dementias and encephalopathies. Other conditions, such as hepatic and
renal encephalopathies, carry distinguishing features; nevertheless, similar patterns may be seen in a fairly wide range of illnesses under
certain conditions.
2. EEG findings in encephalopathy
In general, the most prominent feature of the EEG record in encephalopathies (if there is a change) is slowing of the normal background
frequency. A gradual and progressive decline over the course of the disease may be noted if serial EEGs are performed. Disorganization of the
record may develop gradually. Reactivity to photic or other type of external stimulation may be altered. If a QEEG is done, it may show a
frequency shift or decreased interhemispheric coherence of background frequencies. Some conditions are associated with an increase in
seizure frequency, and in such cases, epileptic activity may be recorded.
In a given context, the EEG can play a clinically useful role, especially since functional MRI, positron emission tomography (PET), and
single-photon emission computed tomography (SPECT) are either still in an experimental stage or require special settings not widely
available.
Use of digital EEG data
Although in the following sections digital EEG data are cited frequently, these data represent primarily digital analysis of clinical EEG
recording. The referenced data are presumed to be based on an EEG recording that is read by a clinician; presently, it is recorded by using
computerized technology for ease and also for availability for further analysis. A variety of mathematical transforms are available after the
initial clinical interpretation—for example, coherence, Fourier transform, wavelets, and microstates (see Digital EEG). These allow for
further comparisons with norms and control groups but should be interpreted in conjunction with the primary EEG reading.
EEG FINDINGS IN DEMENTIA
Alzheimer disease
EEG is the only clinical diagnostic instrument directly reflecting cortical neuronal functioning. Although the EEG may be normal or
minimally disturbed in a number of patients in the initial stages of Alzheimer disease (AD), an abnormal EEG usually is recorded later in the
course. A large percentage of patients with moderately severe to severe AD exhibit abnormal EEGs.
In 1981, Stigsby reported diffuse increases of delta and theta frequencies, as well as decreases in the alpha and beta frequency ranges in AD.
Frontal slowing was more prominent. The slowing was more prominent anterior to the sylvian fissure, while the blood flow was more
decreased posterior to the sylvian fissure. These findings may be explained by the fact that the EEG reflects the functional decline of the
anterior structures, while the flow decrease correlates more with the structural damage of the parietal lobe. The frontal slowing probably
reflects the loss of functioning of the frontal cholinergic system.
Wada et al showed that EEG coherence provides a measure of functional correlation between 2 EEG signals. They examined intrahemispheric
EEG coherence at rest and during photic stimulation in 10 patients with dementia of the Alzheimer type. In the resting EEG, patients with AD
had significantly lower coherence than gender- and age-matched healthy control subjects in the alpha-1, alpha-2, and beta-1 frequency bands.
EEG analysis during photic stimulation demonstrated that the patients had significantly lower coherence, irrespective of the stimulus
frequency. The changes in coherence from the resting state to the stimulus condition showed significant group differences in the region of the
brain primarily involved in visual functioning. The patients had significantly lower coherence of their EEG reactivity to photic stimulation at 5
and 15 Hz over the posterior head regions.
These findings suggest that patients with AD may have an impairment of interhemispheric functional connectivity in both nonstimulus and
stimulus conditions. This suggests a failure of normal stimulation-related brain activation in AD. Jelic et al found a positive correlation
between levels of tau protein in the cerebrospinal fluid (CSF) and EEG alpha/delta ratio. In a subgroup with high CSF tau levels, a strong
relationship between EEG alpha/theta and alpha/delta power was found. No such correlation was found in healthy controls and mildly
cognitively impaired individuals with elevated CSF tau levels.
Locatelli et al used EEG coherence to evaluate the functionality of cortical connections and to get information about the synchronization of the
regional cortical activity. They studied EEG coherence in patients with suspected AD. Alpha coherence was decreased significantly in 6
patients. Significant delta coherence increase was found in a few patients between frontal and posterior regions. The group with AD
demonstrated a significant decrease of alpha-band coherence in the temporo-parieto-occipital areas. This was expressed to a greater extent in
patients with more severe cognitive impairment. They theorized that these abnormalities could reflect 2 different pathophysiological changes:
(1) the alpha coherence decrease could be related to alterations in corticocortical connections, whereas (2) the delta coherence increase
suggests lack of influence of subcortical cholinergic structures on cortical electrical activity.
Strik et al studied EEG microstates in AD. The microstates of the resting EEG of patients presenting with mild or moderately severe dementia
of the Alzheimer type demonstrated a significant anteriorization of the microstate fields, and the duration of sustained microstates was
reduced. These differences were more important than the diffuse slowing. The measurements of microstates may be useful in the early
diagnosis of AD. Muller et al conducted a study comparing SPECT and QEEG. They concluded that QEEG may be as useful as SPECT brain
scanning in staging the disease; however, the correlation with clinical status was weak.
3. Siennicki-Lantz et al studied the relation of cerebral white matter lesions to AD. Cerebral blood flow (CBF) in white matter correlated with
systolic blood pressure and multichannel EEG in senile dementia of the Alzheimer type. The presence and functional significance of white
matter lesions in the aging brain or in dementia and their relation to blood pressure is an unsettled issue. White matter lesions occur in both
cerebrovascular disease and AD. Probably, the white matter lesions in hypertensive patients are not related to but simply are coexistent with the
AD. Their influence on overall expression of the degree of dementia is unclear; intuitively, however, the lesions should be causing additional
cognitive dysfunction.
They observed significantly lower CBF in the white matter (WMCBF) in patients with AD than in controls. This was more obvious in the
posterior cerebral region (ie, parieto-temporo-occipital area). QEEG from the posterior cerebral regions correlated with WMCBF. Systolic blood
pressure was significantly lower in the AD group and was correlated positively with WMCBF in the posterior and anterior brain regions.
Epileptiform activity may occur more frequently in patients with AD than in the general population; clinical tonic-clonic seizures can occur.
Bilateral synchronous periodic epileptiform discharges (BiPEDs), such as triphasic waves (TWs), may be recorded in AD, usually in the late
stages (for more information on TWs, see Triphasic Waveforms). These findings are not specific for AD because they most often are observed in
metabolic disorders, particularly hepatic encephalopathy and other degenerative diseases, such as CJD. While good correlation exists between
severity of EEG abnormalities and cognitive impairment, epileptiform discharges or TWs are not predictive factors for seizures. EEG often can
be useful in evaluating dementia in order to exclude a superimposed reversible metabolic etiology, and to confirm CJD when the dementia is
rapidly progressive.
To investigate the relationship between QEEG band powers and CBF, Rodriguez et al studied 42 patients with suspected AD and 18 healthy
controls who were elderly. They tried to differentiate patients with AD from the controls by QEEG and CBF measurements. Regional CBF and
QEEG were correlated with one another, especially in the right hemisphere. Significant correlations were found between Mini Mental State
Examination (MMSE) scores and relative power of the 2- to 6-Hz and the 6.5- to 12-Hz bands on either side and between MMSE scores and left
regional CBF, while the correlation between MMSE scores and right regional CBF was less strong.
Employed together, QEEG and regional CBF sensitivity was 88% and specificity 89%, with a total accuracy of 88.3%. QEEG alone showed an
accuracy of 77% in the whole group and of 69% in those with mild AD, and regional CBF alone an accuracy of 75% in the whole group and of
71% in those with mild AD. This study suggests that QEEG and regional CBF measurements used together are reasonably accurate in
differentiating AD from healthy aging.
Lehtovirta et al studied the relation of apolipoprotein E (ApoE) to EEG changes. ApoE sigma-4 allele is a risk factor for late-onset AD and is
proposed to have an impact on cholinergic function in AD. Because the cholinergic system has an important role in modulating EEG, an
impairment of the cholinergic system may have a relation to the EEG slowing that is characteristic of AD progression. The QEEG of 31 patients
with AD was recorded at the early stage of the disease and after a 3-year follow-up. Patients with AD were divided into several subgroups
according to the ApoE sigma-4 allele (ie, 2 sigma-4, 1 sigma-4, and 0 sigma-4). These subgroups did not differ in clinical severity or duration of
dementia. The AD patients carrying the sigma-4 allele had more pronounced slow-wave activity than AD patients without the sigma-4 allele,
although the disease progression rate did not change. These differences in EEG may suggest differences in the degree of the cholinergic deficit
in these subgroups.
The typical electrophysiological correlates of myoclonus in AD are similar to those of cortical reflex myoclonus, with a focal, contralateral
negativity in the EEG preceding the myoclonic jerk. The electrophysiological correlate of polymyoclonus that can be seen in AD and other
pathological states is a bifrontal negativity in the EEG that precedes the myoclonic jerk. This new type of electrophysiological correlate of
myoclonus may reflect activity of a subcortical generator.
Pick disease
Pick disease, which is a frontotemporal dementia, is much less common than AD. The age of onset is earlier than that of AD. The EEG is less
abnormal than in AD, especially in the early stages. Posterior alpha rhythm is more preserved. Theta and delta are increased. Frequency analysis
may demonstrate a difference at a time when simple visual reading may not pick up a clear abnormality. The major feature of Pick disease is a
decline in judgment and insight with relative early preservation of memory. Because EEG correlates poorly with the clinical symptoms,
impressive EEG changes are not observed in this condition. Blood flow measurements correlate with thinking processes; Ingvar demonstrated
these changes in 1977. Stigsby demonstrated a decrease in anterior blood flow in patients with Pick disease. Because the anterior cholinergic
system is relatively preserved in Pick disease, the EEG changes are not prominent frontally.
Huntington chorea
Huntington chorea is a combination of a movement disorder and a dementia, which is dominated by cognitive impairment, psychotic features,
and memory impairment. The EEG changes show gradual and progressive slowing over time. The amplitude also attenuates as the disease
progresses. About 30% of the patients have very-low-voltage EEGs with amplitudes below 10 microvolts. Hyperventilation as a rule does not
increase the background voltage as it usually does in healthy subjects. About 3% of the patients show epileptiform activity; they tend to be
juvenile cases. The EEG has not been proven to be of any predictive value in identifying future affected family members. Genetic testing is far
more useful.
4. Progressive supranuclear palsy
In progressive supranuclear palsy (PSP), usually the degree of dementia is not severe. The EEG may be normal initially but eventually shows
increasing delta and theta activity. The delta may be rhythmic with frontal accentuation. Gross et al showed a decrease in background frequency
down to 6-7/s and delta activity over the temporal regions. Sleep may show poor spindle development. Rapid eye movement (REM) sleep may be
reduced or absent. These changes probably reflect the involvement of the locus ceruleus and the pontine raphe nuclei.
Parkinson disease
The EEG is frequently normal. In advanced cases, however, marked slowing is noted. Sleep may be markedly abnormal with frequent
awakenings, prolonged sleep latency, reduced REM sleep, periodic leg movements, etc. Wszolek et al studied patients with rapidly progressive
familial parkinsonism and dementia with pallidopontonigral degeneration (PPND). The patients had PPND linked to chromosome 17q21-22; 11
EEGs of 9 patients were studied. EEGs revealed normal findings early in the disease and diffuse slowing that became more prominent with
disease progression. Electromyograms (EMGs) and nerve conduction studies (NCSs) showed no abnormalities. Visual evoked potentials (VEPs)
and sensory evoked potentials (SEPs) were normal. The clinical neurophysiologic study findings were consistent with a cortical and subcortical
degenerative process.
With clinical deterioration, progressive decline is seen in the mean parietal frequency and background rhythms. Theta and theta-delta mixture
may be recorded bilaterally in the posterior head regions. After stereotactic surgery, focal theta or delta slowing may be observed.
Binswanger disease
Binswanger disease usually demonstrates slowing of background and a nonspecific pattern; however, Kuroda et al reported some other patterns.
They described a 72-year-old patient with von Recklinghausen disease exhibiting akinetic mutism within 6 months of the onset of dementia. The
EEG demonstrated periodic synchronous discharges (PSDs) suggesting CJD. The CT brain scan findings represented diffuse cerebral atrophy.
Autopsy findings revealed diffuse subcortical white matter disease and marked arteriosclerotic changes of the subcortical arterioles.
The cortex was relatively spared, and the pathologic diagnosis confirmed Binswanger disease. Binswanger disease, therefore, can present with
PSD and should be included in the differential diagnosis of dementia. On the other hand, Dziaiek et al described a group of 15 patients with
Binswanger subcortical atherosclerotic encephalopathy who showed different EEG appearance. The EEG records were pathological in most
cases, with varying degrees of slow activity that was distributed symmetrically.
Circulatory encephalopathy
Atherosclerosis
Plachinda et al studied the correlations of cognitive disorders and the EEGs of elderly patients with circulatory encephalopathy. They explored
the possibilities of using EEG for evaluating intellectual-mnemonic disorders in elderly patients with cerebral atherosclerosis. Ninety-five
patients (aged 60-74 years) with atherosclerotic encephalopathy but without stroke were included in the study. Statistical analysis of the data
demonstrated a correlation between psychological test results and EEG readings and computerized EEG data. In cerebrovascular disease, focal
slowing is far more frequent than in nonvascular dementia; therefore, EEG can be useful in distinguishing the 2 conditions.
Multi-infarct dementia
No specific EEG pattern is associated with multi-infarct dementia. Some background slowing may be observed, especially in advanced disease.
These changes are less prominent and do not show the progressive course observed in AD. Research is very scanty. Edman et al found a
significant relationship between the increase in EEG slow-wave activity and increases in severity of the parietal brain syndrome. A somewhat
lower significance was found for the relation between the increase in slow-wave activity and increases in the degree of dementia. These results
suggest that the EEG deterioration mainly reflects the progressive and gradual decline of parietal brain function.
Iznak et al used QEEG to reveal the specific features of and study amplitude-frequency parameters in patients with mild dementia of different
origins compared to healthy elderly individuals. They found that alpha rhythm was suppressed in AD and vascular dementia and that alpha
rhythm was slower and theta activity higher in AD. Patients with AD were characterized by desynchronized EEG.
Transient global amnesia
A variety of records have been reported from normal to even epileptiform potentials in transient global amnesia (TGA). Nonepileptiform
activity, such as bitemporal delta or bioccipital theta, has been reported. Kushner described patients with normal activity, one with occasional
epileptic activity, and one with asymmetric alpha depression, while 2 patients had intermittent rhythmic slowing. TGA caused by a seizure is
uncommon, and is believed to be caused by a vascular etiology or spreading depression. Patients with Korsakoff syndrome often have abnormal
EEGs with theta-delta slowing.
5. EEG IN HEREDITARY ENCEPHALOPATHIES
Action myoclonus
Action myoclonus consists of arrhythmic muscular jerking induced by voluntary movement. It can be made worse by attempts at precise or
coordinated movement (ie, intention myoclonus) and may be elicited by sensory stimuli. The effective stimulus for action myoclonus is thought to
be feedback from muscle afferents, although it may be related to activity in the motor cortex relayed to the reticular formation preceding or
coinciding with voluntary movement. The condition usually is associated with diffuse neuronal diseases, such as posthypoxic encephalopathy,
uremia, and the various forms of peripheral neuroepithelioma, although action myoclonus may be limited to one limb in some cases of focal
cerebral damage. It is caused by hyperexcitability of the sensorimotor cortex (ie, cortical reflex myoclonus) or reticular formation (ie, reticular
reflex myoclonus), or both.
Autopsied cases have failed to reveal a clear pathology. Theories include loss of inhibitory mechanisms involving serotonin and possibly GABA
transmitters. Myoclonus may be seen in degenerative disorders of the nervous system. It may be associated with tonic-clonic seizures or
dementia. Myoclonus has been described in cases with Lafora inclusion bodies and cerebral storage diseases, as well as system degenerations:
cerebellodentatorubral, pyramidal, extrapyramidal, optic, auditory, posterior columns and gracile and cuneate nuclei, spinocerebellar pathways,
motor neurons of cranial nerves and anterior horns, and muscle fibers.
Action myoclonus usually responds to sodium valproate or clonazepam, and some patients with posthypoxic action myoclonus may improve with
serotonin precursors.
Ramsay-Hunt and Unverricht-Lundborg syndromes
The clinical distinction between Ramsay-Hunt syndrome and Unverricht-Lundborg syndrome (ie, Baltic myoclonus) is unclear because cerebellar
signs are found in patients described under both syndromes. Some have proposed that the names could be joined and referred to as Unverricht-
Lundborg-Hunt disease. Some authors have suggested that the condition be known as systems degeneration type of progressive myoclonus
epilepsy. Presently, the cause of the condition (or spectrum of conditions) is not known.
Mitochondrial encephalopathy with lactic acidosis and stroke (MELAS) and myoclonus, epilepsy with ragged red fibers (MERRF)
Isozumi et al described a 50-year-old woman with subacute dementia and myoclonus whose CT scan revealed brain atrophy and EEG revealed
PSDs. She initially was thought be suffering from CJD but dramatically recovered over 5 months. Based on further investigations, the final
diagnosis was mitochondrial encephalomyopathy. In general, the EEG changes were described as background slowing, multifocal epileptiform
discharges, and photosensitivity.
Poststereotactic surgery
Patients developed EEG slowing of different degrees about 50% of the time.
Alpers disease
This clinicopathological entity, consisting of progressive neuronal degeneration (ie, Alpers disease) of childhood with liver disease, has been
studied by Boyd et al. The onset is in early childhood and consists of intractable fits and progressive dementia. EEG studies have been carried out
in 12 children with this condition. The EEGs were similar and demonstrated abnormal patterns with high-amplitude, slow activity, as well as
smaller polyspikes. The flash VEP was usually abnormal and often asymmetrical. In the appropriate clinical setting, the neurophysiologic
features may aid the clinician in diagnosis of this autosomal recessive inherited disorder.
Adrenoleukodystrophy
Multifocal paroxysmal discharges, hypsarrhythmic pattern, and prominent arrhythmic delta are present in temporo-occipital areas. Epileptic
discharges usually do not occur in adrenoleukodystrophy.
Zellweger syndrome
This is characterized by diffuse slowing.
Infantile neuroaxonal dystrophy
This condition is characterized by a high-voltage, 14- to 22-Hz activity that is not reactive to environmental stimuli.
Hallevorden-Spatz disease
In this disease the EEG is normal to slow.
6. Neuronal ceroid lipofuscinosis
In the infantile form, the EEG is slow and early, and posterior spikes may be present. Photic response is excessive and evokes high-voltage spikes
that are polyphasic. The EEG abnormalities in the juvenile form are not as marked.
Gaucher disease
In patients with type III disease, posterior spikes and sharp waves, diffuse spike and waves, and photomyoclonic and photoparoxysmal responses
may be present.
Metachromatic leukodystrophy
Diffuse slowing progresses to high-voltage generalized delta activity. Epileptic activity is rare; however, hypsarrhythmia may be observed.
Tay-Sachs disease
EEG is generally slow. Generalized or multifocal spikes accompany the seizures.
Rett syndrome
This is a progressive encephalopathy observed in girls. AI-Mateen et al reported 15 cases of Rett syndrome. The course is slowly progressive; it
occurs only in girls and is characterized by early deterioration of higher brain function with dementia, autistic behavior, loss of purposeful use of
the hands, and deceleration of head growth. When affected girls are aged 2-4 years, epilepsy may develop with minor motor seizures. Additional
features may include an extrapyramidal disorder with dystonia and choreoathetosis, and lactic acidemia. A precise biochemical marker of this
disorder has not been identified.
According to McIntosh et al, Rett syndrome consists of a progressive encephalopathy and psychomotor deterioration in young girls who have
appeared clinically normal until age 6-18 months. The incidence is similar to phenylketonuria and autism in females. When the child is at least 6
months old, head growth decelerates in association with severe dementia, autism, apraxia, stereotypic quot;hand washingquot; movements, and loss of
previously acquired skills. Other signs include breathing dysfunction, seizures, EEG abnormalities, and growth retardation. It appears to be
sporadic in occurrence.
The EEG may demonstrate slowing, a variety of nonspecific patterns, and epileptiform discharges. The epileptic activity may include multifocal
spikes, slow-wave spikes, and paroxysmal delta slowing with spikes that may appear in sleep; in certain cases, however, sleep may attenuate the
EEG abnormalities. Background flattening occurs to some degree, corresponding with the stage of dementia and cognitive decline. Rolandic
spikes may be elicited by noise.
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