Papalambros Nelly A, Santostasi Giovanni, Malkani Roneil G, Braun Rosemary, Weintraub Sandra, Paller Ken A, Zee Phyllis C
Center for Circadian and Sleep Medicine, Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago IL, USA.
Biostatistics Division, Feinberg School of Medicine, Northwestern University, ChicagoIL, USA; Department of Engineering Sciences and Applied Mathematics, Northwestern University, EvanstonIL, USA.
Front Hum Neurosci. 2017 Mar 8;11:109. doi: 10.3389/fnhum.2017.00109. eCollection 2017.
Acoustic stimulation methods applied during sleep in young adults can increase slow wave activity (SWA) and improve sleep-dependent memory retention. It is unknown whether this approach enhances SWA and memory in older adults, who generally have reduced SWA compared to younger adults. Additionally, older adults are at risk for age-related cognitive impairment and therefore may benefit from non-invasive interventions. The aim of this study was to determine if acoustic stimulation can increase SWA and improve declarative memory in healthy older adults. Thirteen participants 60-84 years old completed one night of acoustic stimulation and one night of sham stimulation in random order. During sleep, a real-time algorithm using an adaptive phase-locked loop modeled the phase of endogenous slow waves in midline frontopolar electroencephalographic recordings. Pulses of pink noise were delivered when the upstate of the slow wave was predicted. Each interval of five pulses ("ON interval") was followed by a pause of approximately equal length ("OFF interval"). SWA during the entire sleep period was similar between stimulation and sham conditions, whereas SWA and spindle activity were increased during ON intervals compared to matched periods during the sham night. The increases in SWA and spindle activity were sustained across almost the entire five-pulse ON interval compared to matched sham periods. Verbal paired-associate memory was tested before and after sleep. Overnight improvement in word recall was significantly greater with acoustic stimulation compared to sham and was correlated with changes in SWA between ON and OFF intervals. Using the phase-locked-loop method to precisely target acoustic stimulation to the upstate of sleep slow oscillations, we were able to enhance SWA and improve sleep-dependent memory storage in older adults, which strengthens the theoretical link between sleep and age-related memory integrity.
在年轻成年人睡眠期间应用的听觉刺激方法可以增加慢波活动（SWA）并改善睡眠依赖的记忆保持。目前尚不清楚这种方法是否能增强老年人的SWA和记忆力，老年人的SWA通常比年轻人低。此外，老年人存在与年龄相关的认知障碍风险，因此可能受益于非侵入性干预措施。本研究的目的是确定听觉刺激是否能增加健康老年人的SWA并改善陈述性记忆。13名年龄在60 - 84岁的参与者以随机顺序完成了一晚的听觉刺激和一晚的假刺激。在睡眠期间，一种使用自适应锁相环的实时算法对中线额极脑电图记录中的内源性慢波相位进行建模。当预测到慢波的上升状态时，发送粉红噪声脉冲。每五个脉冲的间隔（“开启间隔”）之后是一个大致等长的停顿（“关闭间隔”）。在刺激和假刺激条件下，整个睡眠期间的SWA相似，而与假刺激夜晚的匹配时间段相比，在开启间隔期间SWA和纺锤波活动增加。与匹配的假刺激时间段相比，SWA和纺锤波活动的增加在几乎整个五脉冲开启间隔期间持续存在。在睡眠前后对言语配对联想记忆进行测试。与假刺激相比，听觉刺激后单词回忆的夜间改善显著更大，并且与开启和关闭间隔之间的SWA变化相关。使用锁相环方法将听觉刺激精确地靶向睡眠慢振荡的上升状态，我们能够增强老年人的SWA并改善睡眠依赖的记忆存储，这加强了睡眠与年龄相关记忆完整性之间的理论联系。
