Evolution of neurological, neuropsychological and sleep-wake disturbances after paramedian thalamic stroke

The clinical features and natural course of paramedian thalamic stroke is poorly known. The aim of this study was to characterize the evolution of neurological, neuropsychological, and sleep-wake deficits after paramedian thalamic stroke.

Forty-six consecutive patients, aged 48.4+/-16.6 years, were studied. Fourteen had bilateral, 16 left-sided, and 16 right-sided lesions. Assessment included neurological examinations, estimation of sleep needs, formal neuropsychological tests (n=27), and polysomnographies (n=31). Functional outcome was followed up over 1 year in 31 patients with the modified Rankin Scale and Barthel index.

Oculomotor palsy (76% of patients), mild gait ataxia (67%), deficits of attention (63%), fluency and error control (59%), learning and memory (67%), and behavior (67%) were common in the acute stroke phase. Outcome was excellent with right-sided infarcts but mostly incomplete with bilateral and left-sided lesions. This was mainly related to persistent frontal lobe-related and cognitive deficits found in 100% bilateral and 90% left-sided, but only 33% right-sided strokes. Initially, hypersomnia was present in all patients associated with increased stage 1 sleep, reduced stage 2 sleep, and reduced sleep spindles. Sleep needs improved in patients with bilateral and almost disappeared with unilateral lesions after 1 year. Sleep architecture remained abnormal with the exception of sleep spindles that increased.

Whereas neurological deficits and hypersomnia recover to large extent in patients with paramedian thalamic stroke, the frontal lobe-related and cognitive deficits, which are mainly linked with bilateral and left-sided lesions, often persist. As such, stroke outcome is better in right-sided than bilateral or left-sided infarcts.