Acute and Chronic Sleep Restriction, Total Sleep Deprivation, Recovery and More
Our sleep restriction studies, both observational and interventional, focus on investigating sleep deprivation and its neurobehavioral effects. We mostly focus on understanding how partial sleep deprivation impacts cognitive performance and brain function, also developing countermeasures to mitigate these performance deficits. One goal for many of our sleep restriction studies is practical implications for astronaut safety and mission success. Multiple studies have specifically addressed sleep challenges faced by astronauts, investigating countermeasures for neurobehavioral deficits that could occur during space missions where sleep loss and high workload intersect. More recently, the lab has evolved toward developing and evaluating sleep optimization technologies, including "SmartSleep" systems designed to improve sleep efficiency and restorative quality. For example, the OASIS project uses auditory stimulation during sleep to enhance cognitive performance, a technological solution that could benefit both space travelers and the general population.
Observational Studies on Sleep Loss
Adequate sleep is essential for general healthy functioning. Our laboratory has conducted protocols involving chronic sleep restriction, followed by a varied number of recovery nights. Restricting sleep below an individual's optimal time in bed (TIB) can cause a range of neurobehavioral deficits, including lapses of attention, slowed working memory, reduced cognitive throughput, depressed mood, and perseveration of thought. Neurobehavioral deficits accumulate across days of partial sleep loss to levels equivalent to those found after 1 to 3 nights of total sleep loss. A causal role for reduced sleep duration in adverse health outcomes remains unclear, but laboratory studies of healthy adults subjected to sleep restriction have found adverse effects on endocrine functions, metabolic and inflammatory responses, suggesting that sleep restriction produces physiological consequences that may be unhealthy.
Read more here: Neurobehavioral Effects of Partial Sleep Deprivation
Interventional Sleep Protocols
NASA's OASIS Project sought to understand whether auditory stimulation during sleep periods could be optimized to improve cognitive performance. The SmartSleep device, developed by Philips Healthcare, was tested in a double-blind, placebo-controlled laboratory study in our laboratory to determine what effect it has on daytime cognitive performance and on emergent awakenings from sleep in a chronic sleep restriction paradigm (i.e., 5h/night for 4 nights). This study is the first to evaluate slow-wave activity enhancement and its effects on performance and sleep inertia during sleep using a chronic sleep restriction paradigm to evaluate whether slow wave sleep enhancement via the SmartSleep stimulus algorithms benefits daytime cognitive performance during a period of chronic sleep restriction as commonly observed during spaceflight.
Learn about the study here: Evaluation of SmartSleep Technology for Improving the Efficiency and Restorative Quality of Sleep in Healthy Adults
Thirty-six individuals with current depression and 10 euthymic controls underwent a baseline night of sleep followed by 36 h of total SD and one night of recovery sleep in the laboratory. Participants completed the Cognition battery and a self-report survey of wellbeing twice after each protocol night. Depressed individuals had similar – if not faster – performance on Cognition subtests relative to healthy controls at baseline and reported worse wellbeing. SD had pronounced effects on both speed and accuracy across Cognition subtests, with all participants becoming slower, less accurate, and less efficient overall; no differences between depressed and healthy controls were observed. Performance returned to pre-deprivation levels after recovery sleep. These results suggest that currently depressed individuals exhibit the same decrements in cognitive performance after acute SD as non-depressed individuals, which is a critical consideration for future research aimed at elucidating the mechanisms that underlie SD's antidepressant effects and potential therapeutic applications.
Read more here: Effects of acute sleep deprivation and recovery sleep on cognitive performance in depressed individuals
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