Reference — Neurology
Stroke Syndromes Reference
Stroke territory syndromes for nurses — left hemisphere, right hemisphere, brainstem, cerebellar, and lacunar stroke: description, motor deficits, cognitive/language findings, and nursing priorities for each territory.
Educational use only. This material supports nursing education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional policy, or medical direction. Always follow facility protocols and current provider orders.
Key principle: Motor and sensory pathways decussate (cross) in the brainstem — so a lesion in one hemisphere causes deficits on the OPPOSITE side of the body. Cranial nerve deficits are ipsilateral to the lesion (nuclei are in the brainstem, not yet crossed).
Quick Comparison
| Territory | Key Motor Finding | Key Cognitive/Language Finding |
|---|---|---|
| Left Hemisphere | Right hemiplegia | Aphasia (Broca, Wernicke, or global) |
| Right Hemisphere | Left hemiplegia + left neglect | No aphasia; spatial neglect, anosognosia |
| Brainstem | Crossed: CN deficit + contralateral limb weakness | Dysarthria, dysphagia; no aphasia |
| Cerebellar | Ipsilateral ataxia — no weakness | Dysarthric speech; nystagmus; no aphasia |
| Lacunar | Pure motor OR pure sensory — no cortical signs | No aphasia, no neglect, no visual field cut |
Syndrome Detail
Left Hemispheric Stroke
Left MCA (middle cerebral artery) most common
The left hemisphere contains the dominant language centers in most right-handed individuals (and ~70% of left-handed). Left hemisphere strokes produce right-sided motor deficits and aphasia.
Motor Deficits
- Right-sided hemiplegia or hemiparesis (arm ≥ leg for MCA territory)
- Right facial droop (lower face — UMN pattern)
- Right-sided sensory loss
Cognitive / Language
- Broca aphasia: non-fluent, effortful speech; reading/writing impaired; comprehension relatively preserved
- Wernicke aphasia: fluent but meaningless speech ('word salad'); comprehension severely impaired
- Global aphasia: both expression and comprehension severely impaired (large MCA territory)
- Dyslexia, dysgraphia, dyscalculia
Nursing Focus
- Communication board and augmentative devices for aphasia
- Swallowing assessment — dysphagia risk
- Right-sided fall risk and skin protection
- Speech-language pathology referral
Right Hemispheric Stroke
Right MCA most common
The right hemisphere controls visuospatial processing, attention, and prosody (emotional tone of speech). Right hemisphere strokes can be deceptively subtle — the patient often lacks insight into their own deficits (anosognosia).
Motor Deficits
- Left-sided hemiplegia or hemiparesis
- Left facial droop
- Left-sided sensory loss
Cognitive / Language
- Left-sided spatial neglect (hemispatial neglect): patient ignores left visual field and left side of body
- Anosognosia: patient unaware of their own deficits — significant fall and safety risk
- Constructional apraxia: inability to draw or copy shapes
- Impaired prosody: speech sounds monotone; emotional affect flattened
Nursing Focus
- Approach patient from RIGHT side (they ignore left)
- Place call light, food, and important items on RIGHT side
- Fall prevention — patient may attempt to get up not recognizing left weakness
- Cue patient to look left during meals and ADLs
Brainstem Stroke
Posterior circulation: vertebral arteries, basilar artery, PICA, AICA, SCA
Brainstem strokes produce 'crossed' neurological findings — ipsilateral cranial nerve deficits with contralateral limb motor/sensory deficits. The brainstem also controls vital functions (breathing, BP, heart rate) and maintains consciousness.
Motor Deficits
- Crossed findings: CN deficits ipsilateral + limb weakness contralateral
- Quadriplegia possible (basilar artery occlusion)
- 'Locked-in syndrome': paralysis of all voluntary muscles except vertical eye movements and blinking
Cognitive / Language
- Dysarthria — slurred speech (CN IX/X/XII involvement)
- Dysphagia — aspiration risk (CN IX/X)
- Diplopia (double vision) — CN III, IV, or VI
- Nystagmus — vestibular nuclei involvement
- Vertigo, nausea
Nursing Focus
- Airway is priority — brainstem controls respiration
- Swallowing assessment — high aspiration risk
- Hemodynamic monitoring (BP instability, arrhythmias)
- ICU-level monitoring for basilar artery occlusion
Cerebellar Stroke
PICA (posterior inferior cerebellar artery) most common; also AICA and SCA
The cerebellum coordinates movement, balance, and speech. Cerebellar strokes produce ipsilateral ataxia — coordination deficits on the SAME side as the lesion. They are commonly missed because there is NO weakness.
Motor Deficits
- Ipsilateral limb ataxia: wide-based gait, falls, inability to perform tandem walking
- Dysmetria: overshooting/undershooting on finger-to-nose test
- Dysdiadochokinesia: inability to rapidly alternate hand movements
- Truncal ataxia: unable to sit upright without support
Cognitive / Language
- Dysarthria: scanning or ataxic speech — irregular, slurred
- Nystagmus: horizontal nystagmus is common
- Nausea and vomiting
- No aphasia (cerebellum does not contain language areas)
Nursing Focus
- Fall prevention is highest priority — severe ataxia
- HINTS exam (Head Impulse, Nystagmus, Test of Skew) to differentiate from peripheral vertigo
- Large PICA strokes can cause brainstem compression and herniation — monitor for LOC decline
- Aspiration risk due to dysarthria and dysphagia
Lacunar Stroke
Small penetrating arteries (lenticulostriates); associated with chronic HTN and DM
Lacunar strokes are small, deep infarcts in the basal ganglia, thalamus, internal capsule, or pons. They characteristically produce pure motor or pure sensory deficits WITHOUT cortical signs (no aphasia, no neglect, no visual field defects). MRI is more sensitive than CT for detection.
Motor Deficits
- Pure motor hemiparesis: weakness face/arm/leg on one side without sensory or cognitive deficits
- Pure sensory stroke: hemisensory loss without weakness
- Ataxic hemiparesis: ipsilateral ataxia + mild weakness
- Dysarthria-clumsy hand syndrome: dysarthria + hand clumsiness
Cognitive / Language
- No aphasia
- No visual field cuts
- No hemispatial neglect
- Multiple lacunar strokes over time → vascular dementia
Nursing Focus
- Risk factor management: aggressive blood pressure control, diabetes management, smoking cessation
- These patients may appear minimally affected but are at risk for future strokes
- Antithrombotic therapy per provider order
- Assess baseline and monitor for deficit progression
Related Resources
Standards & sources
Fact-checked Jun 21, 2026This page is written to align with American Heart Association / American Stroke Association (AHA/ASA) · American Association of Neuroscience Nurses (AANN). It is an educational summary, not a citation of any single document — always verify specific doses, values, and protocols against current guidelines and your facility policy. How we source content →