Downloaded 18 times
More Related Content
![Frontal Lobe Syndromes [2014]](https://cdn.slidesharecdn.com/ss_thumbnails/fls2014zo-170704023944-thumbnail.jpg?width=640&height=640&fit=bounds)
Similar to Stroke & Balint's syndrome
![Stroke [uncensored] - by MHR Corporation](https://cdn.slidesharecdn.com/ss_thumbnails/mhr4-stroke-101129110104-phpapp01-thumbnail.jpg?width=640&height=640&fit=bounds)
Stroke & Balint's syndrome
- 1. Vascular lesions ofthe parietal cortex and their clinical implications for vision Vascular lesions of the parietal cortex and their clinical implications for vision
- 2. Overview • “Lesion” any localizedabnormal structural change in a bodily component • Interruption of tissue perfusion • Tumour Trauma Blood clots Stroke
- 4. Types of stroke •Ischaemic – 87% Obstruction of a blood vessel Thrombus – blood clot Embolus – fragment of clot stuck in another vessel • Haemorrhagic – 13% Haematoma – collection of blood outside vessels Compression of tissue Reduced blood flow Rosamond, W. et al., 2008
- 5. Frontal lobe stroke mostcommon ACT FAST • Facial weakness • Arm and leg weakness • Speech problems • Time to call 999 Unilateral damage Contralateral effect
- 6. Risk factors ofstroke • Transient Ischaemic Attack (TIA) “Mini Stroke” (<24 hours), 25% patients die within a year • Most likely candidates for stroke Diabetic women above the age of 55 Smokers twice as likely High cholesterol, alcohol intake and little exercise • Biggest risk factor? High blood pressure!
- 7. Risk factors ofstroke just a 10 mmHg increase in the middle aged individual can increase the risk factor of stroke by 40%! The danger in this is that such a small increase has no physiological signs associated with it and often goes unnoticed.
- 9. Gross anatomy ofthe brain • Left and right hemispheres Divided by central sulcus, connected by corpus callosum • Folds, grooves and clefts Gyri, sulci and fissures • Four lobes of the brain... Frontal Temporal Occipital Parietal
- 10. Arterial vasculature • Brainhas two main supplies R+L internal carotid arteries R+L vertebral arteries • Both form the circle of Willis on the ventral brain surface Plays a huge role in reducing the risk of stroke in individuals Netter, 2002 Vertebral Internal Carotid
- 11. • The circleof Willis reduces the probability of stroke Anastomosis of 3 arteries Blood can still flow along an alternate route in case of a blockage Not a likely preventative measure in the case of embolus formation of lacunar stroke Arterial vasculature Netter, 2002 Anterior Cerebral Middle Cerebral Posterior Cerebral
- 12. Parietal lobe vasculature •Anterior cerebral arteries Not associated with areas of vision Can be disregarded for this study • Middle cerebral arteries Continuation of internal carotids • Lacunar stroke Occlusion of one of the brain’s main penetrating arteries Netter, 2002
- 13. Border zone infarction •Areas where main arteries meet at their distal ends Blood at low pressure Tissue here susceptible to infarction when blood pressure is reduced (Image B) • Lacunar stroke Depicted in image C Caplan et. al., 1999
- 15. General symptoms of parietaldamage • Parietal lobe function Integration of sensory information & spatial sensation Dorsal pathway of vision • ‘Silent’ region of the brain No obvious visible symptoms as with frontal stroke • Contralateral neglect • Bilateral infarcts
- 16. General symptoms of parietaldamage • Parietal lobe function Integration of sensory information & spatial sensation Dorsal pathway of vision • ‘Silent’ region of the brain No obvious visible symptoms as with frontal stroke • Contralateral neglect • Bilateral infarcts
- 17. Contralateral neglect syndrome Purves et.al., 2008 • Failure to respond to a stimulus on the side contralateral to a lesion • Apraxia – motor deficits Reaching for objects, writing & drawing • Only affects the right parietal cortex Mediates attention to right and left So lesions on the left side are compensated for by right Right side affected and there is no compensation!
- 18. Contralateral neglect syndrome Purves et.al., 2008 the saccadic eye movements of a “normal” individual. In free viewing of this “interesting scene”, the entire field is scanned If we introduce a right hemisphere lesion, the right visual field is observed, while the patient ignores the opposite side of the world
- 19. Bilateral posterior parietal infarcts Purveset. al., 2008 • The left and right brains are affected Right brain compensates for left field BUT Left brain cannot sense right field Severe right field neglect • Bálint’s syndrome Lesions at the parieto-occipital border Psychic paralysis of visual fixation Optic ataxia Simultagnosia
- 20. Simultagnosia • The patientperceives whole objects But can only see a single object at once Regardless of object size or spatial orientation • NOT like tunnel vision Where the visual field constricts single
- 22. Simultagnosia (Rafal, 2001) The patientwas presented with a comb, which he could identify correctly. When a spoon was placed in front of the comb, the patient still only reported the comb to be visible When the spoon was moved. The patient could see the spoon only, and not the comb When both the spoon and comb were moved, the patient only reported to see “what looks like a blackboard with some writing on it” When the examiner turned round, he saw a blackboard behind him
- 23. Simultagnosia Robertson and Grabowecky,unpublished observations (Rafal, 2001) S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S A L I P Y B G H C F X T I U C W R W S J H N S U V Q Z U C U E L X Q J Z B R Q P F S M N G Y S F S B G VTHE ALPHABETTWICE! In a more recent study, the question that needed clarifying was what exactly an “object” was to the patient. An image was constructed of several small letter Ss that were arranged to make an overall H shape This image was presented to a subject, who reported to only seeing the local S On repeated testing over several months, he only reported seeing the global H shape twice! When the H shape was constructed from many different letters The subject reported to seeing “the alphabet”
- 25. RehabilitationTreatment • Remedial approach Re-trainthe damaged CNS with general daily activities • Functional approach Use a person’s strengths and abilities to compensate • Multicontext approach Targeted strategies within varied environments
- 26. References • BUPA (2007)The British United Provident Association Limited, England, accessed 1 March 2009, <http://www.bupa.co.uk/about/asp/history/index.asp> • Caplan, L.R., Hurst, J.W., Chimowitz, M.J. (1999) Clinical Neurocardiology, Informa Health Care, 14 • Al-Khawaja, I., (2001) Neurovisual rehabilitation in Balint's syndrome, J Neurol Neurosurg Psychiatry, 70, 416 • Moore, K.L., Dalley, A.F. (2006) Clinically Oriented Anatomy, 5th Edition, Lippincott Williams & Wilkins, 921- 932 • Mensah, G.A. (2008). Epidemiology of stroke and high blood pressure in Africa. Heart, 94, 697-705. • Netter, F.H. (2002) Interactive Atlas of Human Anatomy, CD-ROM, 3rd Edition, Saunders • Purves, D., Augustine, G.J., Fitzpatrick, D. et al. (2008), Neuroscience, 4th Edition, Sinauer Associates Inc, 668-671 • Rafal, R. (2001), Handbook of Neuropsychology, 2nd Edition, Elsevier Science, Vol. 4, 121-139 • Rosamond, W., Flegal, K., Furie, K., Go, A., Greenlund, K., Haase, N., Hailpern, S.M., Ho, M., Howard, V., Kissela, B., et al. (2008). Heart disease and stroke statistics--2008 update: a report from the American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Circulation 117, e25-146.
Editor's Notes
- #3 What is a lesion? – any localised abnormal structural change in a bodily component A lesion results in the interruption of blood flow and thus an interruption of tissue perfusion It can result from tumour, trauma, and most commonly by blood clots Interruption of perfusion can lead to stroke
- #5 Ischaemic strokes are responsible for roughly 87% of deaths. Ischaemia is the death of a tissue due to obstruction of a blood vessel, which can be due to either a thrombus (formation of a blood clot in situ), or an embolus (clot fragment breaks off and gets stuck elsewhere in the body)
- #6 The most common type of stroke is of the frontal lobe and the mnemonic ACT FAST has been used in many advertising campaigns: facial weakness, arm and leg weakness, speech problems, time to call 999. Here we can see the damage is forming on the right side of the brain, while the symptoms are expressed contralaterally
- #7 Transient Ischaemic Attacks (TIAs) are known as mini-strokes because their effects only last under 24 hours, whereas a stroke causes long-term irreversible damage. It is a major risk factor for stroke as 25% of patients die within a year of suffering a TIA. The most likely candidate for a stroke is a woman above the age of 55 who suffers from diabetes mellitus, probably due to the fact that women have a longer average lifespan than men. Smokers are twice as likely to suffer a stroke, and three major influences on stroke are high cholesterol, alcohol intake and little exercise But the biggest risk factor is a high blood pressure...
- #8 In fact, just a 10 mmHg increase in the middle aged individual can increase the risk factor of stroke by 40%! The danger in this is that such a small increase has no physiological signs associated with it and often goes unnoticed! So keep that heart healthy!
- #10 The brain is divided into a left and right hemisphere, that are separated by the central sulcus and connected by the corpus callosum, which allows communication between the two hemispheres. The brain has many folds, grooves and clefts on its surface, known as gyri, sulci and fissures and these help to distinguish four main lobes of the brain with different purposes Frontal lobe – planning and long term memory storage Temporal lobe – auditory processing, ventral visual pathway for object recognition Occipital lobe – primary visual processing area Parietal lobe – integration of sensory information, dorsal visual pathway for object positioning in space We will concentrate on the parietal lobe in this lecture
- #11 The brain has two main arterial supplies; the right and left carotid arteries, and the right and left vertebral arteries. Both these paired vessels branch from the aortic arch. The vessels form the circle of Willis on the ventral brain surface; the internal carotid most anteriorly, and the vertebral most posteriorly. This structure plays a huge role in reducing the risk of stroke in individuals...
- #12 The structure is essentially an anastomosis of three main arteries; the anterior cerebral, the middle cerebral and the posterior cerebral. Because the structure forms an enclosed structure, if a blockage were to result in one of the communicating vessels, blood could still flow to all parts of the brain in the other direction. Although this is a good preventative measure against thrombus formation, it is not so effective in defence against embolus formation or lacunar stroke, which we will come back to later.
- #13 The anterior cerebral arteries provide perfusion to the parietal lobe, but since they do not extend to the parietal areas associated with vision, they can be disregarded for the purpose of this study. The middle cerebral arteries are a direct continuation of the internal carotids, and these supply the parietal areas associated with vision Lacunar stroke is the occlusion of one of the brain’s three main penetrating arteries.
- #14 The cerebral areas perfused by the distal ends of the arteries contain blood which is under a much reduced pressure, and on a systemic reduction in blood pressure, such as in cardiac arrest, these areas can be most extensively effected, which can cause bilateral visual defects, which will be discussed later... Image C also shows the effect of a lacunar stroke on the middle cerebral artery, which usually results in contralateral visual defects.
- #16 Once again, the function of the parietal lobe is to integrate sensory information and spatial sensation, and contains the dorsal pathway of vision concerned with recognising an object’s position in space It is often referred to as the “silent” region of the brain because there are no obvious visual symptoms produced as with frontal stroke, which may cause muscle weakness and slurred speech. Parietal damage can be categorised into two main disorders: contralateral neglect and bilateral infarcts.
- #17 In parietal lobe strokes: Intellectual function is not normally inhibited BUT It causes focal neurological symptoms which are behavioural or perceptual in nature. Defective two point discrimination may occur, As well as muscle wasting Reduced proprioception and inco-ordination And astereognosis – the inability to recognise an object through touch alone
- #18 Contralateral neglect syndrome is the failure to respond to a stimulus on the side of the visual field that is contralateral to the brain lesion. The most common symptom is apraxia, which may manifest in activities such as reaching for objects, writing and drawing, where the contralateral side is neglected... But this only affects the left side of the visual field, which is controlled by the right parietal cortex. The right parietal cortex normally mediates the attention of both the right and the left visual fields, so when the left hemisphere of the brain is affected, the right hemisphere compensates for it. However, if the right hemisphere is affected, there is no compensation, and the left visual field is completely lost...
- #19 Taking a step back... Here we have an image showing the saccadic eye movements of a normal individual. In free viewing of this “interesting scene”, the entire field is scanned. If we introduce a right hemisphere lesion into his brain, the right visual field is observed, while the patient ignores the opposite side of the world. This, however, does not just apply to the contralateral visual field, but can also involve the contralateral side of an object. When asked to copy this image of a house, the patient only draws one side With these lines, a patient was instructed to bisect them at the halfway interval, and only bisected half of what he actually saw, while on this clock face, the numbers are all placed in the correct order, but only across one side of the object!
- #20 When both sides of the brain are affected by a bilateral infarct, Bálint&apos;s syndrome results. The right hemisphere of the brain still compensates for the left visual field, but the left brain cannot ‘see’ the right field. This causes severe right field neglect Lesions that are located at the parieto-occipital border zone result in Bálint&apos;s syndrome, which is characterised by: Psychic paralysis of visual fixation – patient cannot look towards a fixed point Optic ataxia – inability to co-ordinate movements based on visual input Simultagnosia– only the stimuli falling on the macula (the fovea and its periphery) are recognised We are going to take a closer look at simultagnosia
- #21 In simultagnosia, the patient can see whole objects, but can only see a single object at once regardless of its size or orientation in space. This is not like tunnel vision, where the visual field itself gets smaller.
- #23 To help understand this, here is a dialect from Dr. Rafal’s findings: The patient was presented with a comb, which he could identify correctly. When a spoon was placed in front of the comb, the patient still only reported the comb to be visible When the spoon was moved. The patient could see the spoon only, and not the comb When both the spoon and comb were moved, the patient only reported to see “what looks like a blackboard with some writing on it” When the examiner turned round, he saw a blackboard behind him
- #24 In a more recent study, the question that needed clarifying was what exactly an “object” was to the patient. An image was constructed of several small letter Ss that were arranged to make an overall H shape This image was presented to a subject, who reported to only seeing the local S On repeated testing over several months, he only reported seeing the global H shape twice! When the H shape was constructed from many different letters The subject reported to seeing “the alphabet”
- #26 There is no cure to restore the permanent damage caused by a stroke, so treatment involves rehabilitation, which can be done in three different ways: Remedial approach tries to encourage the patient to practice routine daily activities Functional approach tries to use an individual strengths to compensate for areas of weakness Multicontext approach tries to encourage the patient to complete multiple targeted strategies within many different situations