The Science at a Glance
Years of Research
Slow-Wave Sleep: the most restorative part of sleep
Human beings spend about one third of their lives sleeping. This is not an idle time, as often assumed, but a critical opportunity for our body (in particular our brain) to perform "house cleaning" tasks such as getting rid of toxins, strengthening memories and re-organizing and integrating new and old information, which increases creativity and problem solving. As we sleep we cycle through different stages of sleep that correspond to very distinct physiological states with different and complementary functions. The deepest stage of sleep is characterized by special electrical signals generated by the brain called "Slow Waves" because they are slower (around 1 cycle per second or 1 Hz) than the brain waves observed during waking (typically higher than 20 cycles per second).
These Slow Waves are an indication the brain is working in unison and in concert performing important restorative tasks. Hundreds of studies around the world have demonstrated that Slow Wave Sleep (SWS) is implicated in strengthening memory, enhancing the learning process, hormone and cardio-vascular regulation, the flushing of toxins from the brain and optimal mental health. For example; recent studies showed that beta amyloids, involved in Alzheimer's disease are disposed of during SWS. Also, a deficiency in SWS is co-morbid with many mental health conditions as PTSD, depression/anxiety and schizophrenia.
DeepWave Technologies' solution in this important area of human health and performance offers a powerful but non-invasive and natural way to measure and enhance slow wave sleep depth and efficiency. Our research shows that this improvement in SWS depth produces many benefits in particular memory strengthening and cognitive improvement in general.
NEUROSCIENCE OF SLEEP
Non Invasive Brain Stimulation to enhance Slow Wave Sleep
DeepWave Method Paper:
A brain-computer interface could potentially enhance the various benefits of sleep.We describe a strategy for enhancing slow-wave sleep (SWS) by stimulating the sleeping brain with periodic acoustic stimuli that produce resonance in the form of enhanced slow-wave activity in the electroencephalogram (EEG). The system delivers each acoustic stimulus at a particular phase of an electrophysiological rhythm using a phase-locked loop (PLL).The PLL is computationally economical and well suited to follow and predict the temporal behavior of the EEG during slow-wave sleep. Acoustic stimulation methods may be able to enhance SWS without the risks inherent in electrical stimulation or pharmacological methods. The PLL method differs from other acoustic stimulation methods that are based on detecting a single slow wave rather than modeling slow-wave activity over an extended period of time.
Acoustic Stimulation to enhance SWS:
Brain rhythms regulate information processing in different states to enable learning and memory formation. The <1 Hz sleep slow oscillation hallmarks slow-wave sleep and is critical to memory consolidation. Here we show in sleeping humans that auditory stimulation in phase with the ongoing rhythmic occurrence of slow oscillation up states profoundly enhances the slow oscillation rhythm, phase-coupled spindle activity, and, consequently, the consolidation of declarative memory. Stimulation out of phase with the ongoing slow oscillation rhythm remained ineffective. Closed-loop in-phase stimulation provides a straight-forward tool to enhance sleep rhythms and their functional efficacy.
SLEEP AND MEMORY
There is compelling evidence that sleep contributes to the long-term consolidation of new memories. This function of sleep has been linked to slow (<1 Hz) potential oscillations, which predominantly arise from the prefrontal neocortex and characterize slow wave sleep. Our findings indicate that endogenous slow potential oscillations have a causal role in the sleep-associated consolidation of memory, and that this role is enhanced by field effects in cortical extracellular space.
SLEEP AND LEARNING
While asleep, people heard sounds that had earlier been associated with objects at specific spatial locations. Upon waking, they recalled these locations more accurately than other locations for which no reminder cues were provided. Consolidation thus operates during sleep with high specificity and is subject to systematic influences through simple auditory stimulation.