ataxichemiparesis

Ataxichemiparesis, sometimes written as ataxic-hemiparesis, is a neurological syndrome characterized by the simultaneous presence of ipsilateral limb ataxia and hemiparesis. It most often results from small subcortical infarcts, commonly lacunar strokes, that disrupt pathways carrying both motor commands and cerebellar afferents. The clinical picture is typically unilateral, with the upper limb more prominently affected than the lower limb, and may include mild facial weakness.

The underlying lesion usually involves the posterior limb of the internal capsule or nearby subcortical white matter, where corticospinal fibers are intermingled with cerebellar and corticopontine fibers. This yields combined weakness and incoordination on the same side of the body. Additional features can include dysarthria, limb dysmetria, and dysdiadochokinesia. Sensory findings are often minimal or absent, helping distinguish ataxichemiparesis from some other stroke syndromes.

Diagnosis relies on clinical assessment supported by neuroimaging. Magnetic resonance imaging (MRI) typically reveals a small subcortical infarct in the internal capsule or adjacent white matter; CT may be normal early after onset. Vascular risk assessment is important, as most cases are associated with small vessel disease and risk factors such as hypertension and diabetes.

Management follows standard acute ischemic stroke protocols when appropriate, including antiplatelet therapy and risk factor control, along with early rehabilitation. Prognosis varies with lesion size and location but many patients experience substantial recovery with targeted therapy, though residual motor and coordination deficits may persist.