Sleep disorders are widespread, and it is estimated that one-third of adults worldwide are dissatisfied with their sleep. Furthermore, about 6-13% of the general population meet all the criteria for diagnosing a sleep disorder. Insomnia is a sleep disorder characterised by dissatisfaction with sleep quantity and/or quality. This dissatisfaction must be accompanied by difficulty falling asleep, staying asleep and/or waking up in the early morning. These difficulties must have occurred at least three nights per week in the last three months and caused distress or impaired functioning.
Insomnia is not only a problem but is also linked to various mental illnesses. 40% of insomnia symptoms co-occur with mental illness. Insomnia is also associated with numerous health problems, such as respiratory and heart disease. It is generally accepted that hyperarousal plays a significant role in insomnia.
Treatment options for sleep disorders
Currently, there are two main types of treatment: medication or cognitive behavioural therapy for insomnia (CBT-I). Medication is effective in treating insomnia, but its effect is mainly short-term. Unfortunately, long-term medication use causes unwanted side effects such as cognitive and motor coordination problems, physical dependence and rebound insomnia.
Several studies demonstrate the effectiveness of CBT-I in reducing insomnia symptoms, such as wakefulness after falling asleep and sleep efficiency. However, there needs to be more research proving that CBT-I leads to significant changes in sleep onset latency. It is also important to note that only 60% of people who receive CBT-I are considered good sleepers after treatment. CBT-I focuses mainly on behaviours and cognitions related to sleep. Since hyperarousal has been identified as a predisposing and maintaining factor in insomnia, a treatment such as neurofeedback would be recommended.
Neurofeedback for sleep disorders
Neurofeedback is a subcategory of
Biofeedback, a technique in which one learns to modulate, body functions, such as heart rate, through feedback. In biofeedback, various physiological parameters are used and fed back to the patient. The patient then uses this information to change their physiological functions. In the case of neurofeedback, brain waves are measured via sensors and fed back to the patient as audio-visual feedback.
Neurofeedback is based on the principle of operant conditioning. There are many different types of neurofeedback, but they all have in common that visual and/or auditory stimuli (video, music, etc.) are used as a positive reinforcement when brain activity matches the training target. Withdrawal or alteration of this stimulus is used as "negative punishment" to tell the person that their brain function is deviating from the training target. With this basic principle, neurofeedback can stimulate and attenuate certain brain waves.
The history of neurofeedback is closely intertwined with the history of sensorimotor rhythm, beginning with Sterman et al. This 1967 study led to the discovery of sensorimotor rhythm (SMR). This brain state occurs only during periods of motor silence. This EEG pattern strongly resembled the sleep spindles observed during sleep. These studies also found that cats could voluntarily induce this rhythm. These cats showed an increase in the density of sleep spindles and a decrease in sleep stage transitions, resulting in a prolonged sleep.
Since then, research on neurofeedback as a treatment for sleep disorders has often focused on controlling sensorimotor rhythms. In some studies, inhibition of higher frequencies, such as high beta frequencies (20-35 Hz), is used to reduce wakefulness, while in other studies, slower frequencies, from delta (less than 4 Hz) to alpha frequencies (8-12 Hz), are enhanced to promote deep relaxation.
SMR neurofeedback in the sensorimotor cortex improves sleep architecture, subjective sleep quality, sleep efficiency, total sleep time and physical quality of life. After only a few sessions, it was possible in scientific studies for patients to regulate SMR brain waves and thus reduce hyperarousal.
Audiovisual training systems
Audiovisual training systems (AVE) are another option. These stimulate the cerebral cortex using glasses and headphones programmed to deliver visual and auditory stimuli through synchronised lights and acoustic pulses. The stimuli are constant, repetitive and delivered at a predetermined frequency to excite the thalamus and neocortex, where the visual and auditory information is processed. This stimulation synchronises neural activity between the thalamus and neocortex and spreads to the rest of the cerebral cortex via thalamo-cortical-thalamic circuits. Studies have shown that daily 30-minute AVE sessions before bedtime over one month resulted in 63% of study participants no longer being diagnosed with insomnia. Significant improvement in daytime form and sleep quality was reported.
Thus, technological advances provide valuable additions to the current treatment options for sleep disorders.
Source: Lambert-Beaudet F, Journault WG, Rudziavic Provençal A, Bastien CH. Neurofeedback for insomnia: Current state of research. World J Psychiatry. 2021 Oct 19;11(10):897-914. doi: 10.5498/wjp.v11.i10.897. PMID: 34733650; PMCID: PMC8546766.
Comments