Left Cerebellar Stroke Deficits
A left cerebellar stroke produces ipsilateral motor deficits (left-sided ataxia, dysmetria, and coordination problems), along with cognitive and affective disturbances that are frequently missed by standard screening tools.
Motor Deficits (Ipsilateral to Lesion)
The left cerebellar stroke causes ipsilateral motor dysfunction affecting the left side of the body:
- Left-sided limb ataxia with dysmetria and intention tremor
- Left-sided fine motor impairment - difficulty with finger tapping and peg-placement tasks 1
- Truncal ataxia - a commonly missed finding on bedside examination that requires specific attention 2
- Gait ataxia and coordination problems
- Dysarthria with scanning or slurred speech
The anterior lobe (lobules III-VI) damage produces the most severe motor deficits, while posterior lobe lesions may spare motor function 1.
Cognitive and Affective Deficits (Cerebellar Cognitive Affective Syndrome)
Left cerebellar strokes frequently cause multidomain cognitive impairments that standard tools like MMSE miss 3. The cerebellar cognitive affective syndrome (CCAS/Schmahmann syndrome) includes:
- Executive dysfunction - impaired planning, set-shifting, abstract reasoning (associated with lobules VII-VIII damage) 1
- Language deficits - agrammatism, anomia, reduced verbal fluency (particularly with right Crus I and II extending through IX damage, though left-sided lesions affect language through crossed cerebro-cerebellar connections) 1
- Visuospatial impairment - difficulty with spatial processing 1
- Memory and concentration problems 3
- Affective changes - irritability, emotional lability, personality changes 3
Critical pitfall: Conventional screening (MMSE, even MoCA) underestimates these deficits. Use the CCAS Scale (CCAS-S) for proper assessment 3.
Hemispatial Neglect
Left cerebellar stroke can cause either contralesional (right-sided) or ipsilesional (left-sided) neglect in approximately 28% of cases 4. This occurs equally with left and right cerebellar strokes, contrary to the cerebro-cerebellar network hypothesis.
Posterior Circulation-Specific Deficits
- Hearing loss - occurs in up to 21% of posterior circulation strokes, particularly with anterior inferior cerebellar artery (AICA) territory involvement, usually accompanied by vertigo 5
- Intractable hiccups - may occur with posterior inferior cerebellar artery (PICA) territory infarction 2
- Vertigo, dizziness, nausea and vomiting - common presenting symptoms that make diagnosis challenging 2
Life-Threatening Complications
Decreased level of consciousness is the most reliable clinical indicator of dangerous tissue swelling 2:
- Acute hydrocephalus from fourth ventricle obstruction
- Pontine compression causing ophthalmoparesis, breathing irregularities, cardiac dysrhythmias
- Peak swelling occurs several days post-stroke, with deterioration typically within 72-96 hours (though can occur 4-10 days later) 2
Critical diagnostic pitfall: Initial CT is normal in 25% of cerebellar stroke patients 2. Maintain high clinical suspicion and obtain MRI when cerebellar stroke is suspected despite negative CT.
Examination Essentials
Focus specifically on:
- Speech quality (dysarthria, language deficits)
- Gait and truncal stability (don't just test limb coordination)
- Eye movements (nystagmus, ophthalmoparesis)
- Detailed cognitive assessment beyond standard screening
- Serial neurological checks for declining consciousness indicating edema