Is sleep‐related verbal memory consolidation impaired in sleepwalkers?

SummaryIn order to evaluate verbal memory consolidation during sleep in subjects experiencing sleepwalking or sleep terror, 19 patients experiencing sleepwalking/sleep terror and 19 controls performed two verbal memory tasks (16‐word list from the Free and Cued Selective Reminding Test, and a 220‐ and 263‐word modified story recall test) in the evening, followed by nocturnal video polysomnography (n = 29) and morning recall (night‐time consolidation after 14 h, n = 38). The following morning, they were given a daytime learning task using the modified story recall test in reverse order, followed by an evening recall test after 9 h of wakefulness (daytime consolidation, n = 38). The patients experiencing sleepwalking/sleep terror exhibited more frequent awakenings during slow‐wave sleep and longer wakefulness after sleep onset than the controls. Despite this reduction in sleep quality among sleepwalking/sleep terror patients, they improved their scores on the verbal tests the morning after sleep compared with the previous evening (+16 ± 33%) equally well as the controls (+2 ± 13%). The performance of both groups worsened during the daytime in the absence of sleep (−16 ± 15% for the sleepwalking/sleep terror group and −14 ± 11% for the control group). There was no significant correlation between the rate of memory consolidation and any of the sleep measures. Seven patients experiencing sleepwalking also sleep‐talked during slow‐wave sleep, but their sentences were unrelated to the tests or the list of words learned during the evening. In conclusion, the alteration of slow‐wave sleep during sleepwalking/sleep terror does not noticeably impact on sleep‐related verbal memory consolidation.