Sleep-Related Declarative Memory Consolidation and Verbal Replay during Sleep Talking in Patients with REM Sleep Behavior Disorder

ObjectiveTo determine if sleep talkers with REM sleep behavior disorder (RBD) would utter during REM sleep sentences learned before sleep, and to evaluate their verbal memory consolidation during sleep. MethodsEighteen patients with RBD and 10 controls performed two verbal memory tasks (16 words from the Free and Cued Selective Reminding Test and a 220-263 word long modified Story Recall Test) in the evening, followed by nocturnal video-polysomnography and morning recall (night-time consolidation). In 9 patients with RBD, daytime consolidation (morning learning/recall, evening recall) was also evaluated with the modified Story Recall Test in a cross-over order. Two RBD patients with dementia were studied separately. Sleep talking was recorded using video-polysomnography, and the utterances were compared to the studied texts by two external judges. ResultsSleep-related verbal memory consolidation was maintained in patients with RBD (+24±36% words) as in controls (+9±18%, p=0.3). The two demented patients with RBD also exhibited excellent nighttime consolidation. The post-sleep performance was unrelated to the sleep measures (including continuity, stages, fragmentation and apnea-hypopnea index). Daytime consolidation (-9±19%) was worse than night-time consolidation (+29±45%, p=0.03) in the subgroup of 9 patients with RBD. Eleven patients with RBD spoke during REM sleep and pronounced a median of 20 words, which represented 0.0003% of sleep with spoken language. A single patient uttered a sentence that was judged to be semantically (but not literally) related to the text learned before sleep. ConclusionVerbal declarative memory normally consolidates during sleep in patients with RBD. The incorporation of learned material within REM sleep-associated sleep talking in one patient (unbeknownst to himself) at the semantic level suggests a replay at a highly cognitive creative level.研究目的 旨在明确快速眼动睡眠行为障碍（REM sleep behavior disorder, RBD）患者是否会在快速眼动睡眠期间说出睡前习得的语句，并评估其睡眠期间的言语记忆巩固能力。研究方法 18名RBD患者与10名健康对照者于晚间完成两项言语记忆任务：分别为来自自由提示选择性提醒测试（Free and Cued Selective Reminding Test）的16个单词，以及一段长度为220~263词的改良故事回忆测试（modified Story Recall Test）；随后接受夜间视频多导睡眠监测（video-polysomnography），并于次日清晨进行回忆以评估夜间记忆巩固效果。其中9名RBD患者以交叉设计完成改良故事回忆测试的日间巩固评估（即清晨学习/回忆、晚间回忆）。另有2名合并痴呆的RBD患者单独开展研究。通过视频多导睡眠监测记录睡眠期言语行为，并由2名外部评审员将患者的发声内容与习得文本进行比对分析。研究结果 RBD患者的睡眠相关言语记忆巩固能力得以维持（单词记忆提升量为+24±36%），与对照组（+9±18%，p=0.3）无显著差异。2名合并痴呆的RBD患者同样表现出优异的夜间记忆巩固效果。睡眠后记忆表现与各项睡眠指标（包括睡眠连续性、睡眠分期、睡眠碎片化程度及呼吸暂停低通气指数）均无关联。在9名RBD患者亚组中，日间记忆巩固效果（-9±19%）显著差于夜间记忆巩固效果（+29±45%，p=0.03）。11名RBD患者在快速眼动睡眠期间出现言语行为，平均发声词汇量中位数为20，占总睡眠期言语时长的0.0003%。仅1名患者的发声语句被评审员判定为与睡前习得文本存在语义层面（而非字面）的关联。研究结论 RBD患者的言语陈述性记忆可在睡眠期间正常完成巩固。1名患者（自身未察觉）在快速眼动睡眠相关的言语行为中出现了习得材料的语义层面整合，这提示睡眠期间存在高度认知创造性水平的记忆重放过程。