hemiataxia
Loss of coordination affecting one side of the body, typically indicating a cerebellar or brainstem lesion. Distinguished from bilateral ataxia by its unilateral presentation.
Full Definition
Hemiataxia describes incoordination and loss of smooth, controlled movement that affects only one side of the body. This condition typically results from lesions in the cerebellum, cerebellar connections, or brainstem structures that control motor coordination on the contralateral side. Patients with hemiataxia demonstrate impaired fine motor control, dysmetria (overshooting or undershooting targets), and difficulty with coordinated movements on the affected side while maintaining normal coordination on the opposite side. The condition is often seen in cerebellar strokes, multiple sclerosis plaques affecting cerebellar pathways, or space-occupying lesions in the posterior fossa. Clinical examination reveals positive finger-to-nose and heel-to-shin testing on the affected side.
Usage
Usage note: Not to be confused with hemiparesis, which involves weakness rather than coordination problems.
In Context
- "Examination revealed hemiataxia on the right side with preserved strength." — Neurological examination findings
- "The patient's hemiataxia improved following surgical resection of the cerebellar lesion." — Post-operative follow-up note