The Benefits of Closed-Loop Transcranial Alternating Current Stimulation on Subjective Sleep Quality

Abstract

Background: Poor sleep quality is a common complaint, affecting over one third of people in the United States. While sleep quality is thought to be related to slow-wave sleep (SWS), there has been little investigation to address whether modulating slow-wave oscillations (SWOs) that characterize SWS could impact sleep quality. Here we examined whether closed-loop transcranial alternating current stimulation (CL-tACS) applied during sleep impacts sleep quality and efficiency. Methods: CL-tACS was used in 21 participants delivered at the same frequency and in phase with endogenous SWOs during sleep. Sleep quality was assessed in the morning following either verum or sham control stimulation during sleep, with order counterbalanced within participants. Results: Higher sleep quality and efficiency were found after verum stimulation nights compared to control. The largest effects on sleep quality were found immediately following an adaptation night in the laboratory for which sleep quality was reduced. Conclusions: Applying CL-tACS at the same frequency and phase as endogenous SWOs may offer a novel method to improve subjective sleep quality after a night with poor quality sleep. CL-tACS might be helpful for increasing sleep quality and efficiency in otherwise healthy people, and in patients with clinical disorders that involve sleep deficits.

The Effects of Transcranial Electrical Stimulation of the Brain on Sleep: A Systematic Review

“…One that used high-definition direct current tES targeting the left prefrontal cortex in elders observed an increase in subjective sleep duration and sleep efficiency in the active group vs. a waiting list group (73). Similarly, a crossover study that tested slow alternating tES during sleep found higher sleep quality and efficiency after active vs. sham stimulation (72). A study that specifically investigated frontal stimulation in athletes observed a global improvement in subjective sleep after two consecutive active stimulation sessions in comparison to a group that received sham stimulations (71).…”

“…Fifteen studies investigated the impact of tES on subjective aspects of sleep in healthy ( 45 , 52 , 71 – 73 ) and clinical samples ( 41 – 44 , 46 , 48 , 66 , 74 – 81 ). Most used parallel arms ( 45 , 52 , 66 , 72 ) or crossover-controlled designs ( 41 – 43 , 46 , 71 , 73 , 74 , 78 , 80 , 81 ). The others were uncontrolled series or case reports.…”

“…A significant number of studies observed significant improvements of subjective sleep after tES in both healthy (71)(72)(73) and a large range of neuropsychiatric diseases (41, 48, 75-77, 79, 81). The positive results were observed across various rating instruments, suggesting large impact of tES on subjective components of sleep.…”

A novel closed-loop EEG-tDCS approach to promote responsiveness of patients in minimally conscious state: A study protocol

“…During sleep for instance, tACS was triggered during fast spindles to enhance motor memory consolidation [46]. The effects of closed-loop tACS in memory consolidation have been confirmed in other studies [47,48] and this setup has shown therapeutic benefits in sleep quality [49], and tremor suppression [50]. The field of closed-loop application of non-invasive brain stimulation is still subject to important challenges such as development of accurate and optimized triggering algorithms, translation to clinical use and correct identification of inputs to feed the system with.…”

Toward Predicting Human Performance Outcomes From Wearable Technologies: A Computational Modeling Approach

“…For example, if physical encumbrance and exertion is particularly influential for sustained performance across domains of interest, it may warrant increased investment in strength and endurance training, lower-extremity exoskeletons, or other approaches for reducing physical and physiological burden of continuous operations (Gregorczyk et al, 2010;Ozaki et al, 2013;Scribbans et al, 2016;Seo et al, 2018;Wei et al, 2020;Shepertycky et al, 2021). The same might be said for sleep or stress, identifying methods for increasing the quality or duration of naps and overnight sleep (Irwin et al, 2008;Ketz et al, 2018;Robinson et al, 2018), and/or reducing the intensity of stress responses (Stanley et al, 2011;Jaremko and Meichenbaum, 2013). As additional predictors are incorporated into the model, it will afford a more robust ranking and prioritization of cognitive and/or physical states that are most negatively impactful for performance and motivate research and development toward mitigating such impacts.…”