However, researchers have found functions for delta stimulation beyond those related to sleep, as you have seen in the studies above. Stimulating delta in people who are wide awake has been shown to have additional benefits such as increasing relaxation and relieving certain types of pain.
The first two studies highlighted in the infographic above were cited in Dr. Tina Huang's landmark overview of brainwave stimulation, "A Comprehensive Review of the Psychological Effects of Brainwave Entrainment."
The third study, on improved sleep, was conducted by David Siever, one of the leading experts in the field today.
Below you'll find the full details of this incredible research
In this study, 15 patients with acute muscle contraction headaches were given just 5 minutes of delta stimulation at 1 to 3hz. All but one of the patients reported complete relief of their headache in that short time.
4 of the patients were also treated in a placebo-controlled trial- none of the 4 responded to the placebo, but all 4 experienced headache relief when given actual delta photic stimulation.
This experiment included an additional 6 patients who were suffering from chronic muscle contraction headaches- and again, all but one patient experienced complete headache relief after 5 minutes of delta stimulation.
The study reached the conclusion that "slow wave photic stimulation appears to be effective in the treatment of acute and chronic muscle-contraction type headaches."
Solomon GD. Slow wave photic stimulation in the treatment of headacheâ€”a preliminary report. Headache. 1985;25(8):444-446.
108 patients who were scheduled to undergo general anaesthesia for elective surgery were recruited for this controlled study. About an hour before their operation, the subjects were asked to complete a State-Trait Anxiety Inventory (STAI) questionnaire. The STAI is a well validated and widely used test for measuring subjective feelings of anxiety. Scores for the STAI range from 20 to 80, with a higher score corresponding to higher anxiety levels.
Subjects were separated into one of three groups. One group listened to a 30 minute audio track including music and binaural beats stimulating delta activity. Another group listened to exactly the same music, but without the binaual beats. The third group received no specific intervention, and participants were allowed to read or watch television.
At the end of the 30 minutes, participants completed the STAI questionnaire for a second time. The group who listened to delta binaural beats experienced the greatest reduction in anxiety scores, a 26.3% drop. By comparison, the group who only listened to music lowered their scores by 11.1% on average, and the "no intervention" group lowered their scores by just 3.8%.
This is one of a number of studies that has successfully shown that the effect of audio brainwave stimulation is not just a placebo, nor is it the same relaxing effect that one may get from simply listening to relaxing music. These carefully executed and peer reviewed studies give evidence for a very distinct benefit specific to this form of therapy.
Padmanabhan R, Hildreth AJ, Laws D. A prospective, randomised, controlled study examining binaural beat audio and pre-operative anxiety in patients undergoing general anaesthesia for day case surgery. Anaesthesia. 2005;60(9):874-877
The 49 participants were randomly distributed into three groups. One group would receive brainwave stimulation. The second would receive standard and alternative medical therapies such as prolotherapy, neural facial therapy, and acupuncture. And the third would receive nutritional supplements, consisting of amino acids, vitamins, minerals, and herbs.
The brainwave stimulation group listened to a 30 minute delta session every night while in bed. The delta stimulation was delivered through a pair of headphones (using isochronic tones), and the participants either removed the headphones when the session ended, or simply fell asleep with the session still playing.
All of the participants completed the SCL-90 survey before treatment, and after one month. When survey scores from all three groups were compared, it was found that more patients from the brainwave stimulation group (58%) experienced improvements in sleep and reductions in fatigue than did patients in any other group.
Siever, D. (2002) "The Rediscovery of Audio-Visual Entrainment Technology.