Despite a rather exhaustive search of the literature and Internet, there is a scarcity of information comparing Cranial Electrotherapy Stimulator (CES) devices to one another in terms of mechanism of action or efficacy. While Cranial Electrotherapy devices may have markedly different waveforms, they all seem to have similar benefits for as of yet scientifically unclear reasons.
Cranial Electrotherapy Stimulation (CES) essentially consists of applying a very low current that is usually pulsed at 0.5 to 500 Hz to the temples, mastoid processes, or the earlobes. It is thought to modulate neurotransmitter systems in the brain including the serotonergic system. There are a few devices on the market which the FDA allows to promote for the treatment of anxiety, depression, and insomnia. The FDA approval essentially was secondary to a “grandfather” clause that allowed them in based on evidence of efficacy as the regulations were becoming much more stringent for newer devices (and medication approval). CES devices require a prescription in the United States. While some individuals sense an immediate benefit, generally the devices must be used about 20 to 40 minutes per day, at least a few times per week, for about a month to really appreciate efficacy.
While Cranial Electrotherapy has been around for many years and several devices have “FDA Approval” there is a marked difference between the operating frequencies, duty cycles, and consequently waveforms among the various devices. For example, the Fisher Wallace Stimulator has a 15,000 Hz square wave carrier modulated at 15 Hz and 500 Hz. The Alpha-Stim SCS is modulated at 0.5 Hz, and the CES Ultra operates at 100 Hz. In addition there are several devices which do not have or have not sought FDA approval such as the Sota Bio-Tuner which similarly connects to the mastoid area or clips to the ear lobes like the CES devices, and provides 6 different output modes with a base frequency of 1,000 Hz, pulse modulated at 111.11 Hz, but also with options to be further modulated at 0.5Hz or 7.83 Hz. The Bio-Tuner has more power output than some of the FDA approved units, and if the Fourier frequency spectrum is analyzed, actually overlaps in power and frequency with the FDA approved devices.
The research I have seen concerning the efficacy of CES is relatively good, and my clinical experience has also been good (I have also seen good results with the Bio-Tuner). Cranial Electotherapy seems to be relatively safe, however CES may be contraindicated if one has a pacemaker, is pregnant, or has a seizure disorder. It may also cause some dizziness and nausea among other side effects but is generally well tolerated.
The FDA approved devices all seem to have adequate scientific evidence to back up their claims of having efficacy for anxiety, depression, and insomnia. This is well documented in the literature and also via links on the websites which market and sell the respective devices.
Because devices like the Bio-Tuner are not FDA approved, like nutritional supplements they can not be marketed to claim that they are intended to cure or treat any disease. They can be described as being used for wellness, health, well-being, and relaxation however. And in fact, while there are many testimonials as to the benefits of the Bio-Tuner and other such devices, there is only limited scientific research backing it up for those particular devices.
Thus, despite a rather exhaustive search of the literature and Internet, there is a scarcity of information on the rational for why any of these devices should work differently from one another at any of the frequencies, while researchers might speculate that there is a similar mechanism of action, despite markedly different waveforms. Nevertheless, there is compelling evidence that applying current to the head as these units do, is of some benefit.
Further discussion of these devices, their comparisons, including their costs, and links to their websites may be found on my website Psychiatry Alternatives.