Working memory performance in patients with primary insomnia

Abstract

Objective To explore working memory performance in patients with primary insomnia. Methods 50 patients with primary insomnia,well matched with 50 healthy controls in both gender and age were assessed by Pittsburgh Sleep Quality Index, and delayed match working memory task which included visual-object, visual-verbal and visual-spatial tasks. The difference between groups was analyzed by independent-samples t test. Meanwhile, Pearson correlation analysis was performed to further assess the correlation between working memory performance and the Pittsburgh Sleep Quality Index in patients with primary insomnia. Results The error number of object working memory task and reaction time of spatial working memory task in primary insomnia group ((5.24±2.44) time,(1 392.10± 286.40) ms) were significantly impaired than healthy controls group ((4.18±2.31) time,(1 269.78±229.76) ms, t=2.232, P=0.028; t=2.356, P=0.020).Moreover, Pittsburgh Sleep Quality Index significantly correlated with the reaction time of spatial working memory task (r=0.487, P<0.01). Conclusion These data indicates that insomniac patients may suffer impaired working memory, especially the object working memory and spatial working memory. And the spatial working memory may strongly correlate to the sleep quality. Key words: Sleep initiation and maintenance disorders; Neuropsychology; Working memory