CES: A Practical Protocol for theTreatment of Pain
Cranial electrotherapy stimulation (CES) is the application of low-level, pulsed electrical currents (usually not exceeding one milliampere), applied to the head for medical and/or psychological purposes. It is primarily used to treat both state (situational) and trait (chronic) anxiety, depression, insomnia, stress related and drug addiction disorders, but it is also proving indispensable for treating pain patients.1-3
Drs. Leduc and Rouxeau of France were first to experiment with low intensity electrical stimulation of the brain in 1902. Initially, this method was called electrosleep as it was thought to be able to induce sleep. Since then, it has been referred to by many other names, the most popular being transcranial electrotherapy (TCET) and neuroelectric therapy (NET). Research on using what is now known as cranial electrotherapy stimulation (CES) began in the Soviet Union during the 1950s.
CES is a simple treatment that can easily be administered at any time. The current is applied by easy-to-use clip electrodes that attach on the ear lobes, or by stethoscope-type electrodes placed behind the ears. In the 1960s and early 1970s, electrodes were placed directly on the eyes because it was thought that the low level of current used in CES could not otherwise penetrate the cranium. This electrode placement was abandoned more than 20 years ago. Recent research has shown that from 1 mA of current, about 5 µA/cm2 of CES reaches the thalamic area at a radius of 13.30 mm which is sufficient to affect the manufacture and release of neurotransmitters.4
Most cranial electrotherapy stimulators are limited to 600 µA at 9 volts (0.0054 watts). To put this in perspective, this is about 11,000 times less energy output than a 60 watt bulb. Some people do not even feel this small amount of current.
Therapeutic effects are usually experienced during a treatment, but may be seen hours later, or as late as one day after treatment. Some people require a series of five to 10 daily treatments before an effect is seen. In severe depression CES may take up to three weeks to establish a therapeutic effect.
CES leaves the user alert while inducing a relaxed state. Most people experience a feeling that their bodies are lighter, while thinking is clearer and more creative. A mild tingling sensation at the electrode sites may also be experienced during treatment, and therefore, current should never be raised to a level that is uncomfortable. One 20-minute session is often all that is needed for at least a day, and the effects are usually cumulative. If the patient can only tolerate a small amount of current (5 For people who have difficulty falling asleep, CES should be used in the morning to avoid the possibility of increased alertness that may interfere with sleep.
Most people can resume normal activities immediately after treatment. Some people may experience an euphoric feeling, or a state of deep relaxation that may temporarily impair their mental and/or physical abilities for the performance of potentially hazardous tasks, such as operating a motor vehicle or heavy machinery, for up to several hours after treatment.
At present, there are more than 100 research studies on CES in humans and 20 experimental animal studies.5 No significant lasting side effects have ever been reported, but occasional self-limiting headache (one out of 450), discomfort or skin irritation under the electrodes (one out of 811), or lightheadedness may occur. A rare patient with a history of vertigo may experience dizziness for hours or days after treatment.
As in many areas of biology and therapy, the evidence of CES effectiveness is empirical. It is generally believed that the effects are primarily mediated through a direct action on the brain at the limbic system, the hypothalamus, and/or reticular activating system.6-8 The primary role of the reticular activating system is the regulation of electrocortical activity. Electrical stimulation of the periaqueductal gray matter has been shown to activate descending inhibitory pathways from the medial brainstem to the dorsal horn of the spinal cord, in a manner similar to b-endorphins.9-11 Cortical inhibition is a factor in the Melzack-Wall Gate Control theory.12 Toriyama suggested it is possible that CES may produce its effects through parasympathetic autonomic nervous system dominance via stimulation of the vagus nerve (CN X).13 Taylor added other cranial nerves such as the trigeminal (CN V), facial (CN VII), and glossopharyngeal (CN IX).14 Fields showed that electrocortical activity produced by stimulation of the trigeminal nerve is implicated in the function of the limbic region of the midbrain affecting emotions.15 Substance P and enkephalin have been found in the trigeminal nucleus, and are postulated to be involved in limbic emotional brain structures.16 The auditory-vertigo nerve (CN VIII) must also be effected by CES, accounting for the dizziness one experiences when the current is too high. Ideally, CES electrodes are placed on the ear lobes because that is a convenient way to direct current through the midbrain and brain stem structures.
From studies of CES in monkeys, Jarzembski measured 42 to 46 percent of the current entering the brain, with the highest concentration in the limbic region.17 Rat studies by Krupisky showed as much as a threefold increase in b-endorphin concentration after just one CES treatment.18 Pozos conducted mongrel dog research that suggests CES releases dopamine in the basal ganglia, and that the overall physiological effects appear to be anticholinergic and catecholamine-like in action.19 Richter found the size, location, and distribution of synaptic vesicles all within normal limits after a series of 10, one-hour treatments in Rhesus monkeys.20 Several studies in stump-tailed macaques and humans revealed a temporary reduction in gastric hypersecretion.21-24
A recent review by Kirsch of 106 human studies involving 5,439 subjects (4,058 receiving CES, while the remainder served as sham-treated or placebo controls)5 revealed significant changes associated with anxiolytic relaxation responses, such as lowered reading on electromyograms,7,25-28 slowing on electroencephalograms,29-35 increased peripheral temperature, an indicator of vasodilatation,6,26 reductions in gastric acid output,24 and in blood pressure, pulse, respiration, and heart rate.14,26
The efficacy of CES has also been clinically confirmed through the use of 27 different psychometric tests. The significance of CES research for treating anxiety has been reconfirmed through meta-analyses conducted at the University of Tulsa by O'Connor, and by Klawansky at the Department of Health Policy and Management, Harvard School of Public Health.36-37
Sixteen studies conducted follow-up investigations from one week to two years after treatment.6,26,38-51 All 16 reported that at least some of the subjects had a continued improvement after a single CES treatment, or a series of CES treatments. None of these 16 studies revealed any long term harmful effects.