Patent Application
20060205994
Sleep disorders are increasing in their incidence and prevalence in the general population and pose enormous public health issues. An effective therapy for the most common sleep disorders could bring massive public health benefits in terms of physical health, psychological well-being, and productivity. Indeed, sleep disorders have been strongly associated with depression and anxiety.
The normal sleep cycle is divided into two main phases each embodying characteristic physiological constellations.
Sleep centers in the nervous system regulate the rhythm of circadian sleep/wake cycles. The suprachiasmatic (SNC) nucleus of the anterior hypothalamus receives impulses from retinal nerves and other special senses. The SNC projects nerve fibers into the hypothalamus which, in turn, has influence over locomotor activity, food and water intake, body temperature, and hormone levels. It is apparent, therefore, that sleep functions actively weave into the spectrum of basic bodily functions.
In one of these phases, a salient feature is the emergence of rapid eye movement (REM). This phase is called REM sleep. In the other phase, eye movements are relatively absent. This phase is called non-REM, or NREM sleep. During the course of the night, there are several periods of alternating REM and NREM sleep phases.
REM periods are associated with, in addition to eye motions, EEG rhythms found in the waking state such as alpha waves (8 to 12 cycles per second), the inhibition of muscle activity, the engagement of the autonomic nervous system as expressed in blood pressure and heart rate fluctuations, and with dreaming. 20% to 25% of sleep time is devoted to REM sleep. In normal sleep, an initial NREM phase of approximately 70 to 100 minutes duration is followed by the first REM period. Depending upon total sleep time, this cycle is repeated 4 to 6 times during the night.
NREM cycles do not show the characteristic horizontal and vertical eye motions found in REM sleep. In the beginning of the nightly sleep cycle, alpha waves begin to give way to low-voltage, theta, 4 to 7 cycles per second brain waves. This is identified as stage 1 sleep.
Stage 2 sleep usually occurs less than a minute later, but may be delayed for several minutes. 12 to 14 cycle spindle tracings appear with occasional slow triphasic waves, known as K complexes.
Soon thereafter, cycles ranging from 4 to 0.5 cycles per second appear. These are known as delta waves. When occupying less than 50% of the tracing, this is designated as stage 3 sleep. When delta waves account for more than 50% of the EEG tracing, stage 4 is achieved. Taken together, stages 3 and 4 are known as delta sleep or slow wave sleep (SWS).
In the transition from full wakefulness to somnolence, drowsiness, slumber, and finally sleep, waking EEG patterns give way to stages 1 through 4 NREM sleep. Delta sleep provides the most recuperative, highly quality sleep.
Individuals afflicted with initial insomnia have difficulties transitioning from the waking state to stages 1 and 2, and on to stages 3 and 4.
This invention aims to assist in the therapy of the most common manifestation of sleep dysfunction, namely the difficulty in falling asleep, so-called initial insomnia.
This invention proposes to prompt sleep-generating brain waves in brain sleep centers by stimulating sensory organs such as the skin, the visual senses, and the auditory senses with delta rhythms.
The delta wave prompting, importantly, is preferably individualized. Indeed, individuals show important variations in their preferences for the frequencies and the properties of the vibrations, and their translation into sound and color.
The invention's rationale is based upon electroencephalographic (EEG) studies that have delineated, with ever-increasing precision, the architecture of normal and abnormal sleep patterns. It is also inspired by a unifying principle applicable to the nervous system: Every neuron in the nervous system finds connections to every other neuron.
This principle forms the foundation of this invention. Specifically, a stimulus applied to the skin, such as a vibration, will travel through nervous system networks, eventually impacting upon and resonating into all cortical and subcortical structures, including the sleep centers.
The initial stages of sleep show characteristic brain wave configurations, namely slow waves and delta waves. Encephalographically-speaking, individuals afflicted with initial insomnia have difficulties in making the transition from waking brain wave patterns to patterns associated with the onset of normal sleep.
The present invention seeks to encourage this transition using vibrational prompting. In addition, the apparatus and method also comprise optional auditory, visual, and electrophysiological stimulation to impel the waking brain into adopting theta, and eventually, delta brain wave configurations.
Neurophysiological prompting is a process by which an external stimulus acts as an inducer for a desired physiological response. In this case, the desired response is the generation and the maintenance of delta sleep waves.
In order to facilitate the transition from the waking state to sleep, this invention uses vibrational prompting synchronized to theta and delta wave frequencies. This vibrational prompting may be supplemented or supplanted by auditory, visual, and subliminal or para-subliminal electro-physiological stimulation.
The ability to perceive vibrational stimulation is called pallesthesia. Receptors in the skin and deeper tissues, including Pacinian corpuscules, relay their messages to the dorsal columns of the spinal cord, making their way to the thalamus and from there to somesthetic cortical areas for detailed recognition.
Along this trajectory, communications are made with multiple areas of the brain, including deeper structures. These include the hypothalamic sleep centers. In addition, once having reached the somesthetic cortex, vibrational impulses freely extend their reach into other cortical areas including the frontal, temporal, and occipital lobes. For example, it is appreciated that vibrations applied to the skin may be perceived visually.
Synesthesia is the phenomenon which describes such cross-sensory perception. The significance of this cross-sensory phenomenon is that, for example, a vibrational stimulus applied anywhere on the body will, given adequate time and repeated applications, create neural reverberations into many areas of the nervous system. If this vibrational stimulus is given a delta frequency, the effect will eventually make its way into brain sleep centers, which will be prompted to mimic this sleep-inducing rhythm.
The apparatus generates a desired brain wave frequency through a microprocessor unit. The frequency may be selected by the user, or may be predetermined. Thus, the unit frequency setting may be set anywhere from 8 to ½ cycles per second. Some individuals find that inducing theta waves (8 to 4 cycles per second) automatically paves the way for delta wave production. Others will prompt delta waves from the start.
Other options are possible. The unit, for example, may emit a sequential progression of frequencies which mimic the transition from the waking state (descending from 12 to 8 cycles per second), to stage 2 sleep (descending from 8 to 4 cycles per second), then on to delta sleep, from 4 to ½ cycles per second. Each of these stages may be programmed as to their respective durations.
The frequencies generated by the microprocessor are capable of driving different modalities of stimuli, either individually, or in combination. Among them:
Thus, the invention provides an apparatus and method designed to assist in the transition from wakefulness to sleep by means of theta and/or delta brain wave rhythmic prompting via vibrational stimulation applied to the skin. The apparatus is capable of supplementing or supplanting the vibrational stimulation with visual, auditory, and electrophysiological stimulation.
According to a preferred embodiment of the invention, the apparatus may comprise:
A preferred embodiment of a method may provide:
Other features and advantages of the present invention will become apparent from the following description of embodiments of the invention which refers to the accompanying drawings.
The programmable microprocessor has a variety of functions. Foremost is the rhythm function programmed through control (5a). The rhythm selection is shown on the LCD display (3). The rhythm control may select a fixed rhythm, or may select a sequence of rhythms, such as a rhythm progression from alpha (12 to 8 cycles per second), to theta (8 to 4 cycles per second), on to delta (4 to ½ cycles per second), for example.
The respective rhythms may be generated for variable corresponding lengths of time. The timer control (5f) programs the desired time parameters of the unit including automatic shut off and re-start.
The apparatus presents as a flat pad made of pliable and electroconductive material, such as, for example, carbon silicone. It is thin and comfortable enough to rest one's head upon it. Yet, it may be apposed to any part of the body. In the illustration in
The function of the sleep pad of greatest therapeutic value is believed to be its vibrational capacity. However, in addition, it has the capacity, predicated upon individual choice or therapeutic preference, to express rhythmic light, rhythmic sound, and rhythmic electrophysiological stimuli.
The sleep pad is provided with an energy source, a battery,
The microprocessor may be programmed to:
Although an embodiment of the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it will be obvious to those skilled in the art that certain changes and modifications may be practiced without departing from the spirit and scope thereof as described in the specification and as defined in the appended claims.
