Unilateral thalamic stroke does not decrease ipsilateral sleep spindles

Study Objectives: To measure the sleep spindle characteristics in patients with unilateral thalamic stroke. Design: A prospective study of patients with thalamic stroke and age-matche d healthy controls. Setting: Department of Neurology of a University Hospital Participants: Thirteen patients (mean age: 67 years, SD: 13,44) with an iso lated, unilateral acute thalamic stroke and 18 healthy age-matched voluntee rs. Interventions: A polysomnogram recording from 14 scalp EEG electrodes perfo rmed during 2 consecutive nights, the second or third week after the stroke . Only the sleep of the second night was analyzed. Measurements and results: Sleep spindles were counted during two separate 1 0-minute epochs of stage II. Spindles appearing synchronously in both sides with similar amplitude were called "bilateral." Spindles with twice the am plitude in one side than the other were "right" or "left-side predominant". There were 8 patients with posterolateral, 3 with global and 2 with anteri or lesions, Eight were right and 5 left-sided. The number of spindles was s imilar in patients (39.8 +/- 23.4 in 20 minutes) than controls (26.07 +/- 2 9.07; p=0.173). Spindles with a centroparietal (34%) and centroparieto-occi pital localization (22%) were the most frequent, In controls approximately 66% of the spindles had a bilateral and symmetric distribution over the sca lp, 23% of the spindles were predominantly left-sided and 5% were predomina ntly right-sided. In patients, bilateral spindles decreased (p<0.0001) but asymmetric spindles did not change. Conclusion: Unilateral acute thalamic stroke does not decrease sleep spindl es ipsilaterally; rather, it seems to produce a bilateral diminution in the ir number.