Neurological assessment - introduction

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Neurological assessment - introduction

  1. 1. Neurological assessment - introduction Why assess neurological function? This lecture aims to: Few neurological disorders originate in the foot but… Provide overview of purpose of neuro. Assessment You may be managing the sequelae of neuro. disorder in Outline aspects of neuro. assessment from podiatric the foot viewpoint Common example is peripheral neuropathy due to diabetes Describe process of each aspect of assessment Need to be able to determine risk and organise treatment in Make you aware of how to conduct the assessment and accordance with appropriate measures for that disorder what are normal values May recognise previously undiagnosed neurological Describe laboratory testing for neurological assessment disorders which manifest in lower extremity Should be part of a complete patient examination in situation of multiple or complex problem This lecture does not: Cover neuro anatomy in any great detail- you are expected to know this Cover neurological disorders of gait or otherwise - this is covered in 3rd year lectures Overview Neurological symptoms: Neurological examination different to any other: Headache Disorders of olfaction Observations are indirect Dizziness (smelling) Central nervous system cannot be visualised, palpated, Seizure like episodes Difficulty performing daily percussed etc. so it’s intactness deduced by functional Altered consciousness motor activities testing Personality change Difficulty with speech, Major part of exam is technique of stimulus-response swallowing or chewing Memory loss/confusion Gross findings can be observed directly, but stimuli testing Insomina, drowsiness and Weakness disorders of sleep very important Sensory phenomena or Must then correlate responses with pt. symptoms and Tremors and involuntary disordered sensations movements knowledge of nervous system pathology to come to Altered libido diagnosis Disorders of sight/hearing First impressions: Patient history Coming though the door: Like any other examination history is very important Stooping, flexed, rigid posture ?? Parkinsonism Especially so with neurological exam. Reel into door frame ?? Cerebella ataxia Detailed history of symptoms required Size and shape of pt. Most important to let pt use their own words Not dwarfism, excessive ht. Obesity, wasting and skeletal Must clarify what the patient actually means for example deformities Gait and posture WRITE DOWN WHAT YOU THINK I MEAN BY Try and observe without the pt. knowing ‘PINS AND NEEDLES’ Look for kyphosis, scoliosis etc Muscular weakness, footdrop, circumduction of limb, muscle spasticity etc. Try and correlate observations with known disorders 1
  2. 2. Patient history Patient history Could mean: Try and date the onset of symptoms - may be difficult Spontaneous tingling sensation - PARESTHESIA Slow evolving lesions can be compensated for Absense of sensation - ANESTHESIA Find out what makes it better / worse etc Decreased sensation - HYPOESTHESIA Get thorough personal and family history Unpleasant sensation with innocuous stimuli - ALLODYNIA Look for clues - disorders that can affect nervous system Similarly pts may complain of ‘weakness’ Surgical history Could mean number of things Obvious iatrogenic nerve damage True lack of power Nerve damage caused by tourniquets or positions of Easy fatigability stretch held for a long time Incoordination Social history VERY IMPORTANT TO ENSURE PT SYMPTOMS ARE Occupational or recreational pursuits UNDERSTOOD AS ACCURATELY AS POSSIBLE Exposure to toxic substances or environmental hazards Major sections of neuro. exam From podiatric viewpoint: MENTATION Suggested by Spadone, (1999) CRANIAL NERVES Natural observation of the patient MOTOR SYSTEM Formal sensory examination SENSORY SYSTEM Formal motor examination REFLEXES Integrated sensory-motor function examination (reflexes) CEREBELLAR FUNCTION OTHER SIGNS Sensory assessment: Sensory system: Evaluation of this system is least objective The sensory system allows the individual to interact with Must rely on their environment Patient report of what they feel Every sensation depends on impulses which are May vary with fatigue, suggestibility, attitude concerning recognised by receptors illness and rapport with examiner and ability to These impulses are then carried via afferent nerves to communicate the higher centres of the brain for interpretation Try and avoid tiring the patient with the examination Receptors are situated in: May need to break it up if too repetitive Skin Always explain carefully what you are going to do Subcutaneous tissue Can check reliability by repeating assessment on Muscles another occasion Tendons Periosteum Visceral structures 2
  3. 3. Sensory system: Altered sensations Abnormalities of sensation may be: Increased sensation: Increased sensation Usually manifested by pain Perversion Can result from excessive stimulation of sense organs, Impairment fibres or tracts Or loss of feeling Often a protective feature to avoid tissue damage Perversions of sensation: Paresthesia (tingling, pins and needles) Dysesthesia (disagreeable sensation caused by ordinary stimuli) Phantom sensations (sensations from absent body parts) May be irritation of receptors, fibres or tracts Altered sensations Purpose of sensory examination Impairment or loss of feeling “The sensory examination is performed to discover Lessening of acuity of sense organs whether areas of absent, decreased, exaggerated, Decreased conductivity of fibres or tracts perverted or delayed sensation are present. The quality Dysfunction of higher centres lowering the power of and type of sensation that is affected, the quantity and recognition or perception degree of involvement and the localization of the change should be dermined.” – DeJong, (1992) “To demonstrate clearly and consistently the limits of any area of abnormal sensation. To determine which modalities are involved within those limits. To compare the findings with known patterns of abnormal sensation.” – Bickerstaff & Spillane (1989) Definition of terms: What do you test? ANALGESIA - absence of pain sensation EXTEROCEPTIVE SENSATIONS: ANAESTHESIA - absence of sensation to touch Pain, light touch and temperature HYPESTHESIA - diminished sensitivity to touch HYPALGESIA - diminished pain sensation PROPRIOCEPTIVE SENSATIONS: Sense of position, passive movement, vibration and deep HYPERESTHESIA - increased sensation to touch pain sensation DYSESTHESIA - bizarre sensation or sensations elicited by a stimulus DISCRIMINATIVE OR CORTICAL SENSATIONS: PARESTHESIA - spontaneous abnormal sensations Stereognosis, graphesthesia, two-point discrimination such as pins and needles These assessments are not usually part of the podiatric HYPERPATHIA - exaggerated pain response, usually to assessment as any suggestion of a central nervous system lesion should prompt a referral a stimulus 3
  4. 4. Exteroceptive sensations: Assessment of pain Pain Equipment: Mediated by slow conducting, poorly myelinated fibres Pin or other sharp object, preferably with the other end Makes synaptic connection in posterior horn spinal cord blunt Second order neurone crosses within few segments Avoid using sterile needles because they very sharp and Axon ascends to the thalamus (spinothalamic tract) can often draw blood Third order neurone continues to the sensory (parietal) Safety pin OK or use disposable ‘Neurotips’ cortex Preparation of patient: So….. You are testing the integrity of above structures Explain to patient what you are going to do Expose the whole lower limb Test on uninvolved skin to allow patient to feel the stimulus Ask the patient “do you feel this” and “is it sharp” to determine that they can feel the difference Assessment of pain Give patient instructions that they must say “SHARP” or “DULL” in response to the stimulus when it is applied Get patient to close their eyes and keep them closed Alternate the use of sharp or blunt stimuli in a systematic and logical manner Also ask the patient if the stimulus feel different in different areas - move from impaired to normal sensation If you find an area of reduced or absent sensation you must endeavour to map out this region to see if it follows a dermatomal or peripheral nerve sensory pattern Can give clue to Peripheral nerve, sensory root, plexus, polyneuropathy or central nervous system involvement Exteroceptive sensations: Light touch Mediated by fast conducting, myelinated fibres Makes synaptic connection in posterior horn spinal cord Second order neurone crosses within few segments Axon ascends to the thalamus (spinothalamic tract) Third order neurone continues to the sensory (parietal) cortex So….. You are testing the integrity of above structures 4
  5. 5. Assessment of light touch Assessment of light touch Equipment: Give patient instructions that they must say “YES” or “NOW” in response to the stimulus when it is applied Small ball of cotton wool or feather or other soft light substance Get patient to close their eyes and keep them closed Also ask the patient where the stimulus is felt to avoid Preparation of patient: cheating Explain to patient what you are going to do If you find an area of reduced or absent sensation you Expose the whole lower limb must endeavour to map out this region to see if it follows Test on uninvolved skin to allow patient to feel the stimulus a dermatomal or peripheral nerve sensory pattern Ask the patient “do you feel this” and “what does it feel Always move from impaired to normal sensation like” to determine that they can feel the stimulus Can give clue to Peripheral nerve, sensory root, plexus, polyneuropathy or central nervous system involvement Assessment of light touch Exteroceptive sensations: Keep in mind Temperature sensation for hot and cold conduted via You must be systematic - keep a dermatome/peripheral same pathway as for pain nerve diagram with you when testing Keep in mind hot should not be too hot or it will stimulate Testing is very subjective - rely on patient communication pain fibres and understanding of what you are trying to achive Try and use just a light touch and be consistent in the amount of stimulus you supply Assessment of temperature Assessment of temperature Equipment: Give patient instructions that they must say “HOT” or “COLD” in response to the stimulus when it is applied Test tubes of ice or cold water and hot water, or metal canisters with hot and cold substances in them Get patient to close their eyes and keep them closed Preparation of patient: Also ask the patient where the stimulus is felt to avoid Explain to patient what you are going to do cheating Expose the whole lower limb If you find an area of reduced or absent sensation you Test on uninvolved skin to allow patient to feel the stimulus must endeavour to map out this region to see if it follows Ask the patient “do you feel this” and “what does it feel a dermatomal or peripheral nerve sensory pattern like” to determine that they can feel the stimulus - can they differentiate between hot and cold Always move from impaired to normal sensation Can give clue to Peripheral nerve, sensory root, plexus, polyneuropathy or central nervous system involvement 5
  6. 6. Assessment of temperature Proprioceptive sensations Keep in mind Most impulses carrying proprioception travel in posterior You must be systematic - keep a dermatome/peripheral columns of spinal cord nerve diagram with you when testing These sense organs are located in muscles, tendons Testing is very subjective - rely on patient communication and joints and understanding of what you are trying to achive Cold stimulus should be around 5 - 10 degrees C They respond to pressure, tension and stretching Hot stimulus should be around 40 - 45 degrees C Travel along heavily myelinated fibres to dorsal root ganglion In almost every instance, absence of sensation for one stimulus is accompanied by the absence of the other Then ascend on ipsilateral side to lower medulla where synapse occurs Fibres then ascend to thalamus Position/motion sense Position/motion sense These often tested together Heel to knee to toe test… Simple test of position of digit... This can also examine the pt. ability to detect position Patient should have their eyes closed and motion sense Examiner grasps hallux or lesser digit on MEDIAL AND Pt. is asked to close eyes and move their heel of one LATERAL ASPECT foot onto the knee and run it down the tibia to the toe Move digit up and down Pt should be able to discern between positions Position/motion sense Vibratory perception Romberg sign Use a tuning fork 128 Hz which produces strong Pt is asked to stand with feet together and eyes closed vibration Pt should be able to stand steadily with eyes open prior to Pt is asked to close their eyes testing with eyes closed Vibrating object is usually placed on bony prominences Ability to stand with eyes closed depends on integrity of the proprioceptive information from sensory endings in the foot e.g. apex of hallux, medial 1st MTPJ, lateral 5th MTPJ, ascending up the posterior column medial and lateral malleoli, anterior tibia It is thus a test of posterior column function Patient is asked if they can feel vibration or not Test is POSITIVE if pt. sways markedly and suggests a Can use tuning fork without vibration to test for cheating posterior column disorder Don’t press instrument into skin 6
  7. 7. Vibratory perception Bio-Thesiometer Instrument designed to quantify VPT (vibratory perception threshold) Delivers vibration via plastic post at fixed frequency of 120 Hz Amplitude gradually increased Can read off level at which vibration is first perceived Deep pain sensation Travels in proprioceptive pathways and is lost or diminished in patients with diseases of the posterior roots Test by squeezing the Achilles tendon Discriminative or cortical sensation Stereognosis Refers to sensory decisions requiring perception and Ability to identify an object by its feel, shape, texture and integration of sensory information at the parietal cortex weight Sensory pathways and proprioception must be intact With eyes closed object is placed in patients hand STEREOGNOSIS They should not transfer object to other hand GRAPHESTHEISA Try and limit auditory information prior to giving the test TWO-POINT DISCRIMINATION E.g. Don’t clink around with keys or search for coins in your pocket 7
  8. 8. Graphesthesia Two point discrimination Ability to identify letters or numbers written on the skin Ability to detect that a stimulus consists of two blunt with a blunt point. points when applied Patient closes eyes - letters or numbers are traced out Use dorsum of foot on the palm of the hand, thigh or lower leg Ability to discriminate between two points varies with If peripheral sensation is lost graphesthesia will be different parts of body absent Fingertips - possible less than 5mm separation Foot probably 5cm Depends on the integrity of light touch From podiatric viewpoint: Formal motor examination Suggested by Spadone, (1999) This will be covered in lectures on musculoskeletal Natural observation of the patient assessment Formal sensory examination Keep in mind you are looking for: Strength, spasticity, tone and weakness of muscles Formal motor examination Atropy Integrated sensory-motor function examination (reflexes) Fasciulations Reflexes Reflexes require the integrated function of: Muscle fibres Sensory afferents to spine Spinal internuncial neurones Motor efferents from spine Extrafusal muscle fibres Decreased reflexes can be caused by: Lesions of lower motor neurone Primary sensory neurone Lesions of spinal cord segment Increased reflexes can be caused by: Lesions of upper motor neurone 8
  9. 9. Reflexes Should be about same magnitude throughout body and equal on left and right Patient should be relaxed Extremity should be hanging loosely or resting comfortably Any muscle tension may alter reflex Minimal reflexes can be exaggerated by asking patient to forcefully contract muscle group not involved in the exam - ‘JENDRASSIK REINFORCEMENT’ - indicate the reflex was obtained with augmentation in your records Patellar reflex The ankle jerk - achilles reflex Peripheral nerve - FEMORAL Peripheral nerve - TIBIAL Spinal segment - L2 - L4 Spinal segment - S1-S2 Patellar tendon should be lightly tapped with reflex A little difficult to elicit hammer Position pt. with limb externally rotated and slight knee Important that pt. is relaxed initially flexion Look for extension of lower leg and/or visible contraction Slightly dorsiflex patient’s foot to put provide tension of the quadriceps Strike achilles tendon and look for p.flexion of foot and contraction of calf muscles ALTERNATIVE - mobile pt. could kneel on chair with both feet projecting over the edge - can then strike tendon from above. Exaggerated reflexes: Absent or diminished reflexes: Excessively brisk Reduced reflex may occur in normal individuals but Movement sudden and short - often seen in lesion of the become normal on reinforcement upper motor neurones (pyramidal system) True reduction or absence can occur from: Excessively prolonged Break in any part of reflex arc, sensory, anterior horn cell, Cerebella lesions - large amplitude slow speed peripheral motor nerve, muscle itself Myxoedema - movement slightly retarded Cerebral or spinal shock which occurs after cerebral or Clonic: spinal injury Rigidity, spasticity or muscle contracture splint a joint so Muscle which has been stretched goes into clonic no movement can occur. Can occur in advanced spastic contraction - common in knee and ankle reflex - usually paraplegia or very anxious patients means pyramidal system disease 9
  10. 10. Superficial reflexes: Plantar reflex Many superficial reflexes - Position pt. with knee slightly flexed and thigh externally Applied with light scratch with sharp point until response rotated is obtained Outer aspect of foot lying on couch These reflexes are polysynaptic - depend on intact Warn pt. of test corticospinal pathway Outer aspect of sole firmly stroked with a blunt point Abnormal response usually indicates functional or such as key or end of percussion hammer anatomical lesion of the corticospinal, pyramidal or Move the object forwards and then inwards toward upper motor neuron system middle of foot across mets. Stimulus must be firm but not painful Normal result Babinski response Watch for movement of hallux and then lesser toes EXTENSION of the great toe at MTPJ Hallux should flex at MTPJ Usually the lesser digits will open out in a fanwise At same time lesser toes will also flex and close together manner and are dorsiflexed Movement is usually slow Can indicate a disturbance of the function of the pyramidal system NOTE… this is a normal response in children less than 1 or 2 years of age Babinski response may also been seen in patients who are in a comatose state 10

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