The Positive Benefits of Electrical Stimulation
In the 1980s, journalist and author Michael Hutchison published the results of his enquiries into the burgeoning field of neurotechnology – so-called “Mind Machines”. In “Megabrain” (1986), he devotes two whole chapters of the book to the discussion of the use of electricity to stimulate brain function: “We Sing the Mind Electric – Parts 1 and 2”.
The first of the two chapters describes his encounter with a TENS (transcutaneous electrical nerve stimulation) machine. Although commonly used in the control of pain, particularly during childbirth, Hutchison describes an unorthodox use of the TENS machine introduced to him by Joseph Light. Sitting in a café with electrodes stuffed down his socks, he finds himself talking excitedly to Mr. Light as the endorphins and other neurochemicals start flowing, stimulated by the current coursing through his body.
The second chapter discusses Hutchison’s further excursions into the effects of electricity on the brain, and his experimentations with cranial electrostimulation, or CES.
Few people in the 1980s had ever heard of “mind machines”, and “Megabrain” and its successor “Mega Brain Power” (1994), which continues the discussion of various brain stimulation methods, raised the public profile of such technologies and practically spawned a whole industry in light and sound machines, binaural beat tapes, and so on.
The use of electricity for the home user seemed less quick to catch on, although its study by clinicians has attracted considerable interest in recent years. There was a time when anyone researching such a topic would have found their grant money cut off, and perhaps it still has connotations of snake-oil salesmen attempting to persuade sceptical buyers that their latest “electrical healing device” would be a panacea cure. Or perhaps it still carries the stigma of the dangerously strong currents used by psychiatry in decades gone by. This is unfortunate, as safe and ethical uses of electricity can have a number of health and cognitive enhancing benefits.
The use of electrical stimulation actually has a long history. The ancient Egyptians used to zap themselves with small specimens of the Nile electric catfish to treat certain nervous diseases. In 43 A.D. the Greek physician Scribonius Largus used to prescribe his “seashore treatment”, whereby patients were advised to step on an electrical torpedo ray with one foot, while standing on wet sand with the other. Patients suffering from headaches and particularly gout would find their afflictions alleviated. In 1755 Charles Le Roy, a French physician, attempted to restore the sight of a blind patient by wrapping electrical wires around his head.
By the nineteenth century, with the continued improvement of the battery and the more widespread use of a variety of devices that generated pulsed or continuous current, people had become fascinated by electricity and what had come to be regarded as its almost mystical properties.
Electrical stimulation devices abounded, and literature can be found describing electrical cures for a variety of physical ailments.
While this sounds, on the surface of it, like pure quackery, there were also persistent reports of this use of electrical stimulation creating remarkable changes in the patient’s state of mind: trancelike states, euphoria, vivid mental imagery, and elevated mental states. There are even reports of depressed and anxious patients showing no sign of what we might now regard as a clinical condition after several treatments using this technology.
Because of the relative ease of building such a device, it was equally easy for a whole lot of charlatans to enter the field. Travelling medicine shows sprang up all over the place, promising to treat every possible condition. Giovanni Aldini, Luigi Galvani’s nephew, embarked on a travelling road show demonstrating the use of electricity to revive the dead!
Inevitably the currents, electrical waveforms and frequencies these devices delivered varied widely and, perhaps unsurprisingly, some volunteers got shocked or fried. These accidents, together with Aldini’s freak show, probably served to harm the reputation of electrical stimulation for an entire century to follow.
On the other hand, the medicos of the day became so concerned by the capability of electricity to boost a person’s mood or alleviate a patient’s pain without drugs or surgery, that they sought to have the entire practice “investigated”. A report eventually published in 1910 and widely publicised at the time, lambasted electrical healing as having no scientific basis, and banned its teaching from medical education.
Thus while the applications of chemistry and biology became mainstream in the field of medicine, a similar application of physics was dropped by wayside.
The notable exception, of course, was the use of ECT in psychiatry, a practice which only served to fuel the fears of a now already sceptical public.
While these misapplications may have cost science 100 years’ worth of potential research and progress in the use of electrical stimulation, fortunately this area is now gaining respectability for research again.
Over the last few years there has been a proliferation of published research papers into tDCS – transcranial direct current stimulation. This involves the use of a weak (1-2 ma) current delivered through the scalp of the volunteer by means of damp sponge-covered electrodes.
Its exact effect depends upon the polarity of the current. The anode, or “active” electrode, has an excitatory effect on the neurons underneath the electrode site, while the cathode, or “reference” electrode, has an inhibitory effect. Electrode placement, therefore, is critical and depends on what brain area the experimenter wishes to enhance or inhibit.
A number of studies can be found, covering such topics as treating diseases (e.g. alcoholism, depression, stroke and Parkinson’s disease), the study of physical changes in the brain such as the effects on various neurotransmitters and receptors, and observing the effect on sensory perceptions. Of particular interest were studies on the boosting general cognition, enhancing numerical ability (including in dyscalculics), and improving memory and reaction time.
The first question people tend to ask is, “Is it safe?” Reading through a number of papers, the only safety concern I saw specifically mentioned is possible skin burns resulting from poorly-applied electrodes. Perhaps of greater concern is the actual placement of the electrodes. While a basic tDCS device can be constructed with a few inexpensive parts (and instructions from amateur electronics hobbyists do pop up on forums and blogs!), the exact electrode placement is still very much at the experimental stage. You have to know what you are stimulating/inhibiting, and where to put the electrodes in order to target the correct brain area. Current must also be controlled to adjust for skin resistance.
Brain function under the anode is enhanced by approximately 20-40% with a current density of >40 µa/cm2 (260 µa per square inch). The cathode reduces brain function by 10-30%. While in some instances, such as with depression, the inhibitory effect may be desirable by the clinician, for the purposes of selectively enhancing brain function, anodal stimulation is the most common form of tDCS. Usually a relatively small anode (1” square) is placed over the region to be stimulated and a larger cathode (to allow the completion of the electrical circuit while dispersing its inhibitory effect) is used.
Mind Alive Inc. in Canada sell CES units with an add-on tDCS function, but because of the still-experimental nature of this technology and the fact that a certain knowledge of brain physiology and electrode placement is required to use them safely, the tDCS kits are usually only sold to clinical professionals.
The company’s owner and chief electronics developer held a training workshop last year at the Open University in Milton Keynes, UK, and used the lecturer in charge of the brain lab as a guinea pig to demonstrate the use of tDCS. He placed the cathode on the guy’s right shoulder, using his shirt to hold it in place, told him to close his eyes, and dabbed the anode on his forehead several times. “Can you see that? I’m stimulating the optic nerve.” He then placed the electrode somewhere near the top of the man’s head and held it in place with a stretchy fabric band. The session lasted for 20 minutes and then automatically shut off. He didn’t say much about what was happening, perhaps because the training session continued while he was sitting at the back of the room getting zapped, but there were obviously no ill effects, and after this demonstration, most the professionals in the room wanted to buy one!
There are two main theories as to what this electrical stimulation actually does. One theory suggests that the increased electrical flow assists the depolarization of neurons when they fire. The other suggests that the electricity stimulates additional production of neurotransmitters. Or it could be some combination of the two. Research is still ongoing, and the exact mechanism is far from understood.
Perhaps if the home user wishes to experiment with electrical stimulation, an easier option for the layperson to get started with is the CES device. No knowledge of electrode placement is necessary to use CES (sometimes referred to as transcranial alternating current stimulation). The device simply comes with a pair of electrodes which the user dampens and clips onto the ears. Some models of light and sound machine have an inbuilt CES function that synchronizes with the audiovisual stimulation.
CES is approved as a treatment for pain, depression and anxiety, and has also been shown to have positive effects in helping patients recovering from substance abuse and in the treatment of the addictive personality. Patients report feeling less anxious, more relaxed, and a general feeling of wellbeing, as CES appears to increase production of endorphins.
Studies have also been done showing CES as having beneficial effects for sleep. In fact, CES was originally known as electrosleep as it was thought to induce sleep. (I have found that when using CES before bed, although I feel little happening during use, subsequently sleep seems to be considerably less fitful.)
Aside from the health benefits mentioned above, CES is also used as a cognitive enhancer. Users have reported increased alertness, concentration and performance, and Michael Hutchison writes of a study that demonstrated improved learning of a psychomotor task. I put this last use to the test while learning to play the piano, wondering if it would take fewer repetitions of any given exercise before the muscle memory etc. would “take it”, and on these few crude self-experimentations, it did seem to make a slight difference. The effect of CES on the teaching of musical instruments is something I would like to specifically research in the future when circumstances allow.
Sessions are usually 20-40 minutes in length, and can be used daily or every other day.
On the technical side, CES uses a modified square wave (a pure square wave can sting slightly) to deliver the current. There are two frequencies that have been approved by the FDA: 100 Hz and 0.5 Hz. Therefore, manufacturers tend to build devices for commercial sale with these two settings only. The effects of other frequencies is, of course, an area ripe for future research.
As I hope has become clear, research into the various types of electrostimulation are ongoing, and most of the available literature shows that much of this technology is still at the experimental stage.
I should probably take care to say that no responsibility attaches to the writer or to WIN for any home-built devices or home experimentation using them. Nevertheless, I hope you are by now feeling as electrified as I am by these promising technologies!
© Gwyneth Wesley Rolph 2012.