The Science Behind Hibernate

Hibernate’s Deep Sleep Boost technology is scientifically supported by established acoustic entrainment research. This research has shown that acoustic entrainment increases neural activity and synchrony during deep sleep.  By doing so, a person feels more rested, alert, and refreshed throughout the next day. Deep Sleep Boost also assists the brain in moving more information from short-term to long-term memory.

Over the past decade we have learned more about our sleep and how it is tied directly to ones mental and physical health. A number of both scientific and clinicals studies have provide the evidence to support good sleep as being linked  to good health.

Below are a few references to speakers on the subject of sleep. Please take the time to listen and learn more about what quality sleep is and what it can do to improve your physical health, mental state, learning capacity, and memory. These videos are available on YouTube or Ted.Com

Matt Walker "Sleep is your Superpower"

Arianna Huffington "How to succeed get more Sleep"

Jeff Iliff "One more reason to get a good nights sleep"

The following six articles illustrate the scientific progression of sleep and brain activity experiments which scientifically support the Hibernate technology. The first study demonstrates that brain activity corresponding to an auditory illusion of low frequency beats can be recorded from the scalp. This indicates that human brain oscillations may be controlled by focused entrainment to promote increased brain functioning, laying the groundwork for subsequent inquiry into the causal role of brain oscillations. The plasticity of our brain, referring specifically to the ability of neurons to adapt their patterns to changes in certain stimuli, makes this engagement possible. In traditional auditory and visual stimulation, different patterns of signal stimulation (such as sinusoidal or square waves) have been used.  A possible advantage of haptic-based stimulation is that multi-modal entrainment methods combining haptic and audio/visual stimulation may achieve stronger or more robust entraining effect.

 

German Sport University comprehensively investigated whether sleep quality can be improved by auditory brainwave entrainment and whether this leads to enhancements of post-sleep psychophysical states.  Auditory stimulation with binaural beats improved perceived sleep quality and the post-sleep state.  Thus, brainwave entrainment during sleep seems to be a valuable method to support and improve sleep quality and post-sleep mental state of people in a non-wearable, timesaving and comfortable way. The slowly oscillating stimulation of potentials induced an immediate increase in slow wave sleep.  Slow Wave Sleep is characterized as the dreamless state of sleep. It is the deepest of all of the sleep stages and is likely the most important stage of the sleep cycle. There is converging evidence that auditory stimulation is a good choice for enhancing slow waves, because it is safe, easily controllable, and can be administered non-intrusively during sleep.  Evidence shows that acoustic stimulation could be used not only to enhance NREM slow waves, but also some features of REM sleep.  

"Cortical Evoked Potentials to an Auditory Illusion: Binaural Beats"

Background

Comprehensive investigation of sleep deprivation effects on psychophysical performance and well-being. Research investigating the effects of improved sleep quality is rare, including its relationship to athletic mental state and performance. 

 

Objective

To define brain activity corresponding to an auditory illusion of 3 and 6 Hz binaural beats in 250 Hz or 1000 Hz base frequencies, and to compare it to the sound onset response.

 

Methods

Event-Related Potentials (ERPs) were recorded in response to unmodulated tones of 250 or 1000 Hz to one ear and 3 or 6 Hz higher to the other, creating an illusion of amplitude modulations (beats) of 3 Hz and 6 Hz, in base frequencies of 250 Hz and 1000 Hz. Tones were 2000 ms in duration and presented with approximately 1 s intervals. Latency, amplitude and source current density estimates of ERP components to tone onset and subsequent beats-evoked oscillations were determined and compared across beat frequencies with both base frequencies.

 

Results

All stimuli evoked tone-onset P50, N100 and P200 components followed by oscillations corresponding to the beat frequency, and a subsequent tone-offset complex. Beats-evoked oscillations were higher in amplitude with the low base frequency and to the low beat frequency. Sources of the beats-evoked oscillations across all stimulus conditions located mostly to left lateral and inferior temporal lobe areas in all stimulus conditions. Onset-evoked components were not different across stimulus conditions; P50 had significantly different sources than the beats-evoked oscillations; and N100 and P200 sources located to the same temporal lobe regions as beats-evoked oscillations, but were bilateral and included frontal and parietal contributions.

 

Conclusions

Neural activity with slightly different volley frequencies from the left and right ears will converge and interact in the central auditory brainstem pathways to generate beats of neural activity that modulate activities in the left temporal lobe, giving rise to the illusion of binaural beats. Cortical potentials recorded to binaural beats are distinct from onset responses.

 

Significance

Brain activity corresponding to an auditory illusion of low frequency beats can be recorded from the scalp.

 

Pratt, Hillel, et al. 

Clinical Neurophysiology, vol. 120, no. 8, 2009, pp. 1514–1524., doi:10.1016/j.clinph.2009.06.014.

"Entrainment of Perceptually Relevant Brain Oscillations by Non-wearable Rhythmic Stimulation of the Human Brain"

Thut, Gregor, et al. 

Frontiers in Psychology, vol. 2, 20 July 2011, doi:10.3389/fpsyg.2011.00170.

Background

Driving brain oscillations by directly stimulating neuronal elements with rhythmic stimulation protocols has become increasingly popular in research on brain rhythms. Induction of brain oscillations in a controlled and functionally meaningful way would likely prove highly beneficial for the study of brain oscillations and their therapeutic control.

 

Objective

To review conventional and new non-wearable brain stimulation protocols regarding their suitability for controlled intervention of human brain oscillations.

 

Methods

We focus on one such type of intervention—the direct entrainment of brain oscillations by a periodic external drive. We review highlights of the literature on entraining brain rhythms linked to perception and attention and point out controversies.

 

Results

Behaviorally, such entrainment seems to alter specific aspects of perception depending on the frequency of stimulation, which can inform models of the functional role of oscillatory activity.

 

Conclusions

This indicates that human brain oscillations may be controlled by focused entrainment to promote increased brain functioning, laying the groundwork for subsequent inquiry into the causal role of brain oscillations. The reviewed studies collectively suggest that such rhythmic stimulation may alter one’s attention and perception by modifying communication in oscillatory networks through focused entrainment.

"Preliminary Study on Haptic-Stimulation Based Brainwave Entrainment"

Wang, Dangxiao, et al. 

2013 World Haptics Conference (WHC), 2013, doi:10.1109/whc.2013.6548470.

Background

Auditory or visual stimulation has been widely used for brainwave entrainment, i.e. to modulate brain electroencephalograms (EEG) signals into a specific target frequency band.

 

Objective

In this work, we study whether similar phenomena exists with haptic stimulation.

 

Methods

By using a Phantom desktop to provide a sinusoidal force stimulation to a human subject’s hand and using a Nexus EEG device for real-time brain signal monitoring, we test how the Sensory Motor Rhythm (SMR) signal and the Alpha signal of the subject responds to the haptic stimulation.

 

Results

Our experiments show that the energy level of SMR signal tends to increase considerably (on average 10~30% of 8 human subjects) after 10-15 minutes of haptic stimulation with a 15Hz stimulation signal, and the energy level of Alpha signal tends to decrease considerably (on average 10~30% of 8 human subjects) after 10-15 minutes of haptic stimulation with a 10Hz stimulation signal. 

 

Conclusions

These results may have potential application in training human concentration and/or relaxation practices.

"Brainwave Entrainment for Better Sleep and Post-Sleep State of Young Elite Soccer Players-A Pilot Study"

Abeln, Vera, et al. 

European Journal of Sport Science, vol. 14, no. 5, 2014, pp. 393–402., doi:10.1080/17461391.2013.819384.

Background

Comprehensive investigation of sleep deprivation effects on psychophysical performance and well-being. Research investigating the effects of improved sleep quality is rare, including its relationship to athletic mental state and performance. 

 

Objective

This study aims to investigate whether sleep quality of top athletes can be improved by auditory brainwave entrainment, and whether this leads to enhancements of post-sleep psychophysical states.  This pilot study aimed to improve sleep quality and perceived post-sleep psychophysical state of young elite soccer players via auditory brainwave entrainment.

 

Methods

In a pilot study, 15 young elite soccer players were stimulated during sleep over the course of eight weeks with binaural beats around 2Á8 Hz. Once per week after wake-up, participants completed three different questionnaires: a sleep diary, an adjective list for psychophysical and motivational state, and a self-assessment questionnaire for sleep and awakening quality. These fifteen student-athletes executed the same protocol sleeping on the same pillow, but without stimulation. 

 

Results

Subjective ratings of sleep and awakening quality, sleepiness, and motivational state were significantly improved only in the intervention group but did not impact their perceived physical state. In summary, eight weeks of auditory stimulation with binaural beats improved perceived sleep quality and the post-sleep state of athletes, whereas the physical effects may manifest in a time-delayed fashion.

 

Conclusions

It seems worthwhile to further study the long-run effects and consequences on physical and mental performance. The results of three different questionnaires showed that auditory stimulation had a positive effect on sleep and awakening quality and sleepiness, confirming the hypothesis. These results are in accordance with previous investigations about sleep extension (Ichikawa et al., 2008; Kamdar et al., 2004; Mah et al., 2011; Waterhouse et al., 2007). 

"Boosting Slow Oscillations during Sleep Potentiates Memory"

Marshall, Lisa, et al.

Nature, vol. 444, no. 7119, 2006, pp. 610–613., doi:10.1038/nature05278.

Background

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. However, oscillations in brain potentials are commonly considered to be mere epiphenomena that reflect synchronized activity arising from neuronal networks, which link the membrane and synaptic processes of these neurons in time.

 

Objective

Whether brain potentials and their extracellular equivalent have any physiological meaning per se is unclear but can easily be investigated by inducing the extracellular oscillating potential fields of interest.

 

Methods

Here we show that inducing slow oscillation-like potential fields by transcranial application of oscillating potentials (0.75 Hz) during early nocturnal non-rapid-eye-movement sleep, that is, a period of emerging slow wave sleep, enhances the retention of hippocampus-dependent declarative memories in healthy humans. The slowly oscillating potential stimulation induced an immediate increase in slow wave sleep, endogenous cortical slow oscillations and slow spindle activity in the frontal cortex. Brain stimulation with oscillations at 5 Hz—another frequency band that normally predominates during rapid-eye-movement sleep—decreased slow oscillations and left declarative memory unchanged.

 

Results

By stimulating the scalp with a gentle electric current during sleep after learning, memory was enhanced by 8% in a word-learning task in volunteer medical students.  The slowly oscillating potential stimulation induced an immediate increase in slow wave sleep.  Slow Wave Sleep is characterized as the dreamless state of sleep. It is the deepest of all of the sleep stages and is likely the most important stage of the sleep cycle.  Neuron activity during Deep Sleep involves processing and transferring. Growth Hormones are released for tissue repair and Memory consolidation for daytime alertness.

 

Conclusions

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.

"Enhancement of Sleep Slow Waves: Underlying Mechanisms and Practical Consequences"

Bellesi et al. 

Frontiers in Systems Neuroscience, vol. 8, article 208, 2014.

Background

Even modest sleep restriction, especially the loss of sleep slow wave activity (SWA), is invariably associated with slower electroencephalogram (EEG) activity during wake, the occurrence of local sleep in an otherwise awake brain, and impaired performance due to cognitive and memory deficits. Recent studies not only confirm the beneficial role of sleep in memory consolidation, but also point to a specific role for sleep slow waves. Thus, the implementation of methods to enhance sleep slow waves without unwanted arousals or lightening of sleep could have significant practical implications. Slow Wave Enhancement is a possible way to improve the restorative functions of sleep. 

 

Objective

Review the evidence that it is possible to enhance sleep slow waves in humans using transcranial direct-current stimulation (tDCS) and transcranial magnetic stimulation. Since these methods are currently impractical and their safety is questionable, especially for chronic long-term exposure, we then discuss novel data suggesting that it is possible to enhance slow waves using sensory stimuli. We consider the physiology of the K-complex (KC), a peripheral evoked slow wave, and show that, among different sensory modalities, acoustic stimulation is the most effective in increasing the magnitude of slow waves, likely through the activation of non-lemniscal ascending pathways to the thalamo-cortical system. In addition, we discuss how intensity and frequency of the acoustic stimuli, as well as exact timing and pattern of stimulation, affect sleep enhancement. Finally, we discuss automated algorithms that read the EEG and, in real-time, adjust the stimulation parameters in a closed-loop manner to obtain an increase in sleep slow waves and avoid undesirable arousals.

 

Methods

The effect of somatosensory and auditory stimulation was assessed by Tononi et al. (2010). While the change observed with somatosensory stimulation was minor, acoustic stimulation was particularly efficacious in enhancing sleep slow waves. Specifically, using an intermittent stimulation in which tones were played in blocks of 15 s spaced out by stimulation-free intervals, slow waves appeared remarkably large and numerous during the stimulation blocks (Figure 1A; Riedner et al., 2012).

 

Results

By reviewing the relevant literature, we pointed out several features (intensity, sound frequency, timing, and entrainment) of the acoustic stimulation that may play an important role in regulating the efficacy of the stimulation. Specifically, we indicate that stimulation intensity should be tuned according to sleep depth, because there is a threshold below which the stimulation intensity is effective in enhancing slow waves and above which it causes arousal. Changing the sound frequency could counteract the occurrence of habituation and hitting the thalamo-cortical system at convenient times could maximize the enhancing effect.

 

Conclusions

There is some evidence that acoustic stimulation could be used not only to enhance NREM slow waves, but also some features of REM sleep (Drucker-Colin et al., 1983; Arankowsky-Sandoval et al., 1986, 1992; Vazquez et al., 1998; Amici et al., 2000). The increased REM duration following acoustic stimulation was later confirmed by another group of researchers showing longer REM periods also for stimulations occurring during NREM sleep (Amici et al., 2000). In humans, an increase in both REM sleep duration and sleep efficiency occurs when acoustic stimulation is started at the beginning of REM sleep, whereas a disruptive effect with a larger number of awakenings has been reported when the stimulation starts near the end of a REM episode (Salin-Pascual et al., 1991). Increased REM sleep duration was also correlated with a pronounced decrease in the density of REMs (Mouze-Amady et al., 1986), and to a better retention of memories in a Morse code learning task (Guerrien et al., 1989). Nevertheless, despite several reports indicating that acoustic stimulation lengthens REM sleep, the behavioral impact of this manipulation requires further investigation.

Additional Relevant Articles

  • Fino, E, et al. "(Not So) Smart Sleep Tracking Through the Phone: Findings from a Polysomnography Study Testing the Reliability of Four Sleep Applications." J Sleep Res. 2020 Feb 29(1);e12935. doi: 10.1111/jsr.12935. Epub2019 Oct 31.