Human Research Program
OASIS: Optimizing Auditory Stimulation to Improve Cognitive Performance Using SmartSleep
Project Description
Simply put, individuals who do not get enough sleep do not perform well when awake. Although physical rest is an important part of the benefit gained from sleep, adequate sleep is essential for optimal brain function. Not surprisingly, inadequate sleep is a great concern for astronauts during spaceflight missions. Astronauts often get less nightly sleep than they should (< 7 hours) and may be forced to get little sleep for prolonged periods. Unfortunately, taking sleeping pills is often counterproductive. In addition to other unwanted side effects, like addiction and increased tolerance with prolonged use, sleep medications often lead to daytime grogginess and a lack of mental alertness, the opposite of the mentally refreshed feeling sleep is supposed to provide. Our group has spent over a decade developing a technique to optimize sleep without using medications. We designed a system that capitalizes on two of the most important things the brain needs to do during sleep - produce slow waves and monitor the environment. Slow waves are the dominant rhythm of the brain when it is in its deepest and most restorative sleep state. When the brain goes offline during sleep, slow waves work to actively restore the brain in preparation for the next day. However, the act of going offline during sleep is dangerous for the brain because it can no longer do one of its primary functions - protect the body. Therefore, even during deep sleep, the brain subtly monitors the surrounding environment, most effectively by listening for sounds. The device we developed takes advantage of this fact and actively monitors the brain during sleep to reliably detect slow waves. When slow waves are detected, auditory stimuli are played at a frequency that results in a robust increase in slow waves, the most important restorative rhythm of sleep. However, the overall benefits of enhancing sleep slow waves with auditory stimulation has not been adequately tested. Largely, this is because an adequate system for nightly stimulation has not been available. While several research groups have recently demonstrated improved memory retention in the laboratory after playing appropriately timed sounds during slow wave sleep, these effects were demonstrated using a different stimulation protocol than the one we developed and typically did not show an overall increase in sleep slow waves across the night. This suggested that other than improved memory, the stimulation might not affect the other known restorative benefits of sleep. Assessing the cognitive effects of tone-enhanced sleep is also challenging in the laboratory due to the variability in sleep, between different people, and even night-to-night within the same person. On any given night in the laboratory, sleep might be better and subsequent cognitive performance might improve but this will have nothing to do with the stimulation and will have more to do with chance. Maximizing the sleep enhancing benefit of a system means adapting to and accounting for an individual and his/her changing sleep patterns and testing the subject for longer periods of time, not just a few nights. The ability to enhance sleep with a wearable device that is comfortable, easy to use, and continuously adapts to an individual is a truly exciting prospect. The proposed study will be the first to assess the ability of different ways of playing auditory tones during sleep to enhance slow waves and improve cognitive performance over a long-term period (8 weeks). We will record and stimulate subjects in their home environment using the recently developed, commercially available wearable device and test subject performance throughout each day using a short-term test battery developed particularly for astronauts. This proposal represents the vital first steps towards optimizing auditory stimulation during sleep to enhance long-term cognitive performance using a device that is easily translatable to spaceflight.
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Anticipated Benefits
Individuals who do not get enough sleep do not perform well when awake whether in space or on Earth. Although physical rest is an important part of the benefit gained from sleep, adequate sleep is essential for optimal brain function. Unfortunately, taking sleeping pills is often counterproductive. In addition to other unwanted side effects, like addiction and increased tolerance with prolonged use, sleep medications often lead to daytime grogginess and a lack of mental alertness; the opposite of the mentally refreshed feeling sleep is supposed to provide. The ability to enhance sleep with a wearable device that is comfortable, easy to use, and continuously adapts to an individual is a truly exciting prospect. Taking advantage of SmartSleep headband technology, an innovative, non-invasive, closed-loop brain stimulation and recording technology, this is the first ever study to directly evaluate the ability of various auditory stimulation protocols to enhance sleep and cognitive function in an ecological, “at-home” sleep environment over the course of several weeks. This study has the potential to transform sleep health during spaceflight and on Earth by (1) determining how distinct methods of auditory slow-wave enhancement impact neurobehavioral performance daily and (2) advancing individualized sleep enhancement to meet the next day task demands. The insights gained from this immense data set will help us to further improve and individualize sleep enhancement and provide further insights into the link between sleep quality and cognitive performance in a way previously unachievable.
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Project Library
Primary U.S. Work Locations and Key Partners
| Organizations Performing Work | Role | Type | Location |
|---|---|---|---|
| Translational Research Institute for Space Health (TRISH) | Lead Organization | Academia | Houston, Texas |
| University of Pennsylvania | Supporting Organization | Academia | Philadelphia, Pennsylvania |
| University of Wisconsin-Madison | Supporting Organization | Academia | Madison, Wisconsin |
Primary U.S. Work Locations
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Wisconsin
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