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Stroke Factors in Rehabilitation Anthony Munson, M.D. Medical Director, Christiana Care Stroke Program Outline Stroke Basics Neuroanatomy Neuroimaging Stroke symptoms Stroke syndromes Subacute complications Ischemic Stroke Two subtypes by general mechanism: – Thrombotic More common Current theory: Atherosclerotic plaque “cracks”, exposing an inner, thrombogenic surface that then triggers clot formation – Embolic Material from elsewhere that travels to the cerebral circulation and blocks a vessel supplying blood to an area of brain Can be thrombus, fat, infectious material, foreign objects, or even air Hemorrhagic Stroke Intraparenchymal – Most commonly the basal ganglia, thalamus, brain stem, and cerebellum Intraventricular (extension) – Possibility of obstructive hydrocephalus – Can require neurosurgical intervention Stroke Risk Factors Ischemic – – – – – – – – Smoking Hypertension Atrial fibrillation Elevated cholesterol Clotting disorders Endocarditis Diabetes mellitus Drug abuse Hemorrhagic – – – – – – – Hypertension Amyloidosis Vascular malformation Trauma Drug abuse Ischemic stroke Metastatic disease NEUROANATOMY Anatomy and Physiology Vascular tree – Anterior circulation CCA ICA ACA MCA – Posterior circulation Vertebral PICA Basilar SCA AICA PCA Imaging (MRA) Vascular Territories The Brain Homunculus NEUROIMAGING Non-enhanced CT (NECT) Advantages Fast! Sensitive for acute hemorrhage Widely available Less Expensive Disadvantages Radiation dose Not sensitive for acute ischemia Less sensitive for subacute or chronic hemorrhage Non-enhanced CT (NCET) CT Angiogram Advantages Allows visualization of the actual vessels More sensitive for arterial dissection Can identify aneurysms or other vascular malformations Disadvantages Radiation dose is much higher than NECT Contrast required Requires 18g or larger IV in the arm CT Angiogram Non-enhanced MRI Advantages More detailed scan of the brain parenchyma Able to differentiate conditions that mimic stroke Able to identify smaller lesions and infarcts DWI exquisitely sensitive for acute ischemia Disadvantages Longer study Limitations due to magnetic field (no pacemakers) More difficult for patients to tolerate Less forgiving of patient motion Less readily available Non-enhanced MRI DWI ADC MRA / MRV Advantages Allows visualization of the actual vessels Can identify aneurysms or other vascular malformations Disadvantages Same as non-enhanced MRI Additional time in the scanner Neuroimaging - Stroke CT DWI T2 - FLAIR MRA STROKE SYMPTOMS Motor Deficits - Weakness Various terms (weakness, plegia, paresis, palsy) all describe loss of strength Vascular anatomy determines the deficits – ACA = leg weakness >> arm or face – Cortical MCA = face and arm > leg – Deep MCA = all three equally affected Motor Symptoms Spasticity – Velocity-dependent increase in tone – Seen with many types of upper motor neuron dysfunction (cortex to spinal cord) – Abnormal regulation of stretch reflex Apraxia (actually cognitive) – Inability to perform a previously learned task despite preserved strength, vision, and coordination – Caused primarily by injury to the motor planning areas (MCA territory) in the dominant hemisphere Other motor symptoms Myoclonus – Seen most often with large strokes or diffuse brain injury (hypoxia), as well as metabolic syndromes Tremor – Ventral intermediate nucleus of thalamus Hemiballismus – Subthalamic nucleus Chorea / Athetosis Sensory Symptoms Usually described by modality – – – – – Light touch Pinprick Proprioception (position sense) Vibration Temperature Most sensation areas in the brain are mixed modality, as opposed to the spinal cord where they are separated into two different tracts Sensory deficits and rehabilitation Light touch, pinprick, temperature – Need training regarding safety Proprioception – Significant gait deficits Wide base, decreased stride length, foot slap – Loss of ability to type, operate devices without visual input Aphasia Broca’s / Motor / Expressive Wernicke’s / Sensory / Receptive Transcortical – Same as above but repetition is spared Anomia Global STROKE SYNDROMES Stroke Syndromes - ACA Contralateral motor and sensory deficits – Primarily involves the leg, although occasionally arm and rarely face Apraxia Personality changes Ipsilateral eye deviation Abulia (inability to make decisions) Bowel and bladder dysfunction Tendency to speak in whispers Distractibility Lack of spontaneity Akinetic Mutism Stroke Syndromes - MCA Complete occlusion (either side) – – – – Contralateral hemiplegia Contralateral hemianesthesia/hyperesthesia Homonymous hemianopsia Deviation of the head and eyes toward the side of the lesion Stroke Syndromes - MCA Dominant hemisphere – Receptive aphasia (Wernicke’s area) – Expressive aphasia (Broca’s area) – Apraxia Inability to perform a previously learned task despite preserved strength, vision, and coordination – Gerstmann’s syndrome asomatognosia (right-left confusion) dyscalculia finger agnosia dysgraphia Stroke Syndromes - MCA Non-dominant hemisphere – – – – – – – – – Amorphosynthesis Anosognosia Hemi-neglect Extinction Topographic memory deficit Confabulation Constructional apraxia Allesthesia Aprosody, lack of intonation in speech, and affective agnosia Stroke Syndromes - MCA Non-dominant hemisphere (testing) – – – – Clock drawing test Famous people flash cards Puzzle pictures “Cookie theft” picture Stroke Syndromes - MCA Stroke Syndromes - PCA Contralateral homonymous hemianopsia Dominant hemisphere – dyslexia – color anomia – alexia without agraphia Non-dominant hemisphere – prosopagnosia Anton’s syndrome Lacunar / Brainstem syndromes Pure motor hemiplegia Pure sensory syndrome Sensorimotor syndrome Ataxia hemiparesis Dysarthria - clumsy hand syndrome Wallenberg syndrome Brain Stem / Cerebellar Brain Stem – Symptoms vary widely, due to significant function packed into a small volume – One of the few places that can cause loss of consciousness or sudden death from stroke – Locked-in syndrome Cerebellar – Ataxia – Vertigo – Dysmetria – Dysdiadochokinesia – Speech abnormalities Alien Hand syndrome Frontal version – Reaching, grasping and other purposeful movements in the contralateral hand – Trouble releasing objects once grasped Parietal / Occipital version – “parietal hand” – avoidance of palmar contact – Hand often levitates in the air on that side with fingers extended Callosal version – Non-dominant hand performs “purposeful”, often oppositional movements Other stroke syndromes Balint syndrome – Asimultagnosia – Optic ataxia – Loss of voluntary eye movement Foreign Accent syndrome Acalculia Kluver-Bucy syndrome SUBACUTE COMPLICATIONS Post-Stroke Depression Incidence of 5 - 60%, depending on study (most common statistic seems to be 40%). The strongest predictors of PSD were: – history of depression, – increased severity of stroke – post-stroke physical or cognitive impairment. Under-appreciated in the caregivers of stroke patients as well.