Brain Areas Affected by Stroke

What are the areas affected by ACA stroke?

Medial primary motor area, medial primary sensory area, Posteromedial superior frontal gyrus and corpus callosum

Medial Primary Motor Area Weakness

Contralateral LE weakness or paralysis (hemiparesis or hemiplegia)

Medial Primary Sensory Area Weakness

Contralateral sensory loss (somatosensation, proprioception) in LE

Posteromedial superior frontal gyrus Weakness

Houses parts of SMA, results in apraxia (difficulty w/ motor planning), working memory deficits, behavioral changes (apathy), and urinary incontinence (micturition area affected)

Corpus Callosum Weakness

Interhemispheric communication, difficulty w/ bimanual tasks, Seizures, poor balance/coordination, disconnection syndrome

Areas affected by MCA stroke?

PMC, Primary sensory cortex, Broca's, Wernicke's Parietal Association Cortex, Premotor Cortex, Internal Capsule (motor, somatosensation, and optic fibers), FEF and Striatum

PMC Weakness

Contralateral hemiparesis, UE and face, and difficulty with fine motor tasks (grasp, manipulation), also force and execution

Primary Sensory Cortex Weakness

Loss of Contralateral sensory info from UE and Face (Poor stereognosis, 2-point discrimination, proprioceptive feedback)

Left Broca's area Weakness

Broca’s (Expressive) Aphasia: Non-fluent, effortful speech, good comprehension, difficulty planning movement of speech

Right Broca's area weakness

Issues w/ non-motor aspects of speech (social cues, analogies, prosody, discourse processing)

Wernicke's Area Weakness

Wernicke’s (Receptive) Aphasia: Fluent but nonsensical speech, poor comprehension, inability to determine meaning of speech

Parietal Association Cortex Weakness

Sensory guidance of motor behavior and spatial awareness

Non-dominant hemisphere (right):

Hemispatial neglect (left side of body/space)

Body awareness of disorder (anosognosia)

Dominant hemisphere (left): ideomotor Apraxia (cannot perform a motor action to command) or constructional apraxia (difficulty appreciating the structure or arrangement of objects by looking at them)

Premotor Cortex Weakness

Difficulty planning movement (Apraxia) and anticipation for externally-driven movements based on sensory input (PMA), along with intuition of self-paced movement based on memory and internal goals (SMA)

Internal Capsule (Posterior Limb, Optic Fibers and Genu) Weakness

Posterior Limb: Loss of voluntary motor control through corticospinal and sensory info through thalamacortical tracts

Genu: Loss of activation of CN Nuclei resulting in loss of facial muscle activation, loss CN V, IX/X and Upper Vll (Bilateral) or Lower Vll and Xll (Contralateral)

Optic Fibers: Loss of visual field info from thalamus to cortex with potential visual field deficits

FEF Weakness

Loss of output to Superior colliculus, caudate, cerebellum and brainstem nuclei: loss of voluntary saccadic eye movements, ipsilateral eye deviation towards lesion,

Striatum Weakness

Inability to initiate, terminate, and change amplitude of movement (Tremors, rigidity, bradykinesia, postural instability)

Areas affected by PCA Stroke:

Primary visual cortex, visual association cortex, VPL of thalamus, sub thalamic nucleus, cerebral peduncle and CN lll

Primary Visual Cortex Weakness

Contralateral homonymous hemianopsia or cortical blindness

Visual Association Cortex Weakness

Dorsal: Optic Ataxia

Ventral: Visual Agnosia and Prospagnosia

VPL of Thalamus Weakness

Relay contralateral sensory loss (spinothalmic, dorsal column) to post central gyrus

Thalamic Pain Syndrome (intense burning or dysesthetic pain after initial numbness)

Subthalamic Nucleus Weakness

Part of indirect basal ganglia pathway – inhibits movement (inability for indirect pathway to work resulting in erratic movement, hyperkinetic disorder)

Hemiballismus: wild, involuntary flinging movements of contralateral limbs

Cerebral Peduncle Weakness

corticospinal and corticobulbar tracts deficits, Contralateral hemiparesis or hemiplegia

CN lll Weakness

Loss of Eye movement (medial, superior, inferior rectus; inferior oblique), pupil constriction, levator palpebrae)

Loss of ipsilateral motor control of eyes, ipsilateral pupil constriction and ipsilateral eyelid elevation

Areas affected by AICA Stroke?

Corticospinal tract, CN Vll, Cn Vlll, Vestibular nuclei, Middle cerebral pedicle, and spinothalmic tract

AICA is also known for ?

Lateral Pontine Syndrome

Corticospinal Tract

CL voluntary motor loss in extremities and trunk

CN Vll Weakness

Ipsilateral loss to anterior 2/3 of tongue, function to lacrimal gland, submandibular gland, and sublingual gland and loss of motor function for facial muscles

CN Vlll Weakness

Ipsilateral loss of balance (unsteady gait and mvt of head), loss of hearing and impaired VOR

Vesibular Nuclei Weakness

Head and trunk positioning dysfunction (medial and lateral vestibular= ipsilateral), diminished VOR and impaired vestibulospinal and vestibulocollic reflex

Middle Cerebellar Peduncle Weakness

Afferent input from contralateral brain loss from cerebellum to cortex from pons, loss of motor efferent copy (ataxia=intention tremor)

Spinothalamic Tract

Loss of Nociception, crude touch, and temperature on C/L side of body (excluding face)

Areas affected by PICA Stroke

Spinothalmic, Spinal trigeminal, nucleus ambiguous, Inferior cerebellar peduncle, and sympathetic fibers

PICA stroke is also known as?

Wallenberg Syndrome

Spinal trigeminal weakness

Loss of nociception and temp sensory function on Ipsilateral side of face

Nucleus Ambiguus Weakness

Dysphagia, dysarthria, dysphonia, deviated uvula, soft palate not raising, all ipsilateral

Sympathetic Fibers Weakness

Ipsilateral Horner’s Syndrome:

Ptosis

Miosis

Vasodilation

Anhidrosis

Inferior Cerebellar Peduncle Weakness

Saccades, smooth pursuits and coordinated eye movement impacted

Reticular Formation: ARAS dysfunction

Loss of climbing fibers to convey error signal, and impaired mossy fibers to convey magnitude

Dorsal Spinocerebellar/Cuneocerebellar: Loss of what actually happened, ipsilateral ataxia

Lateral vestibular: Loss of ipsilateral postural control

Areas affected by Basilar artery stroke?

Corticospinal tracts, long cranial nerves and ARAS

Basilar artery infarct is also known as ?

"Locked in syndrome"

Corticopsinal Tract Weakness

Could affect one or side or bilateral (hemiplegia or quadriplegia resulting in spasticity)

ACST: Impaired contralateral/ipsilateral voluntary trunk and proximal movement

LCST: Impaired contralateral voluntary limb movement

Long Cranial Nerve Weakness

All ipsilateral impairments

CN V: Facial sensation and muscle of mastication

CN Vl: Lateral rectus, VOR, abduction

CN Vll: Muscles of facial expression, glands, and taste 2/3 if tongue

CN Vlll: Hearing, impaired balance

Why can all of the following CN be affected by an basilar artery infarct?

All run alongside the pons and receive blood supply by the pontine arteries

ARAS Weakness

Consciousness disorder