Audio-Visual Entrainment (AVE) 

Cranial Electrotherapy Stimulation (CES)

Cranial Electrotherapy Stimulation (CES), also known as Cranial Electrical Stimulation and Cranial Electrostimulation, has been categorized as a form of alternative medicine called "Electromedicine", that treats physical and psychological conditions with varying levels of electrical current. CES is the application of a very low level of alternating current (AC) to the brain by means of clips placed on the ears or electrodes taped to the skull or bony prominences of the head for treatment of anxiety, depression, insomnia, chronic pain, and substance addictions. A similar form of low amperage alternating current electrostimulation is called Microcurrent Electrotherapy (MET) or microTENS and is used to treat muscle tension and pain by massage and physical therapists.  

CES is approved in the United States by the Federal Drug Administration (FDA) within a category for medical devices using microcurrent levels of electrical stimulation across the head via transcutaneous electrodes for the treatment of anxiety, depression, and insomnia.

CES was originally developed in the Soviet Union in 1949, its primary focus being the treatment of sleep disorders—hence, its original designation as “electrosleep”. The treatment of insomnia was soon overshadowed by psychiatric applications for anxiety and depression.

The treatment of anxiety and depression with CES began in the United States in the early 1960s and it is currently routinely prescribed by thousands physicians and mental health practitioners in the US and Canada for a variety of brain-related psychiatric conditions, although it has yet to achieve full acceptance as a mainstream medical treatment. This is probably because sufficient information has not been made available to the majority of medical practitioners regarding the safety and efficacy of CES and the pharmaceutical industry spends a great deal of money every year promoting the use of medications instead of such alternative therapies as CES.

While there are over 150 published scientific research studies on the use of CES. The overwhelming majority of these studies support the safety and efficacy of CES in the treatment of a number of psychological disorders; particularly anxiety, depression and insomnia. Yet the majority of Canadian physicians in general medical practice are simply unaware of them. Unlike pharmaceuticals, there is no large industry promoting CES to physicians.

While CES is FDA-approved solely for the treatment of anxiety, depression and insomnia, there is scientific data showing promise in the treatment of other conditions such as pain, tension/migraine headaches, fibromyalgia, and substance dependencies (i.e., may reduce symptoms associated with alcohol, drug or tobacco withdrawal), as well as for calming agitated and aggressive patients with neuropsychiatric conditions.

Left to right, Mind Alive Inc. CESta device, Alpha-Stim 100 device, and Neurofitness LLC CES Ultra device.

How does CES work?

CES is a relatively simple treatment employing a small, battery-powered device that is similar in size and appearance to transcutaneous electrical nerve stimulators (TENS) devices commonly used in physical therapy for pain relief, but produce very different waveforms at a much lower current level. The CES device sends pulses of very low amperage (i.e., typically 100 microamperes to 5 milliamperes  ) electricity through thin wires attached to electrodes clipped to the ear lobes or stuck to the skin over the bony prominences just to the front of, or behind each ear. The frequency of the electrical pulses can be adjusted— usually from 0.5 Hz to 100 Hz— depending on the treatment effect desired. The devices of different manufacturers will typically differ in the specific waveforms and maximum amperage of the electrostimulation.

CES devices function differently from other biomedical electronics, such as deep brain stimulating electrodes (used to prevent seizures and hand tremors) and heart pacemakers. While those instruments require surgical implantation, CES operates non-invasively. CES is also quite different from electroconvulsive therapy (ECT) or electroshock therapy; a therapeutic modality sometimes used in hospitals to treat severe depression that is not responsive to medication. Where ECT uses a steady, strong electrical current applied directly to the scalp under anesthesia to cause a controlled brain seizure, CES applies a pulsing AC current that is over a thousand times weaker than ECT to the earlobes to induce changes in the excitability and average firing frequency of brain neurons but does not cause resting neurons to actually fire. CES is painless and non-invasive and many CES devices are designed for in-home use.

As with most medications for psychological problems, the actual mechanism by which CES works remains unclear but it is increasingly being viewed as an adaptogen, in that CES reduces stress that underpins many emotional disorders. Research to date suggests a number of possible mechanisms of action, including direct action on the brain at the level of the limbic system, the reticular activating system and the hypothalamus, increased release of various neurotransmitters and endorphins in the brain, increased parasympathetic nervous system dominance, and changes in blood flow and the electrical rhythms (EEG) of the brain. Rat studies have reported a three-fold increase in endorphin levels with only a single relatively brief exposure to CES. Some researchers have reported rapid increases in serotonin in humans, a brain neurotransmitter associated with relaxation and calmness, and decreases in cortisol, one of the primary stress-related hormones in patients treated with CES. As well, CES is known to increase levels of the brain neurotransmitters norepinephrine and dopamine, both associated with alertness and feelings of pleasure. Interestingly, serotonin, norepinephrine and dopamine are the same neurotransmitters that most antidepressant medications attempt to activate.

Animal studies indicate that 40-45% of the CES current actually enters the brain, with the highest levels of current recorded in the thalamus--the primary communication link between deep brain regions and the outer cortex. The thalamus is also a brain structure that appears to pay an important role in the pathophysiology of anxiety and in transmitting pain-related signals from the body up through the brain to the cortex. Medications that are effective in reducing anxiety and some forms of pain appear to reduce activity in the thalamus.

CES has also been demonstrated to increase brain electrical patterns known as “alpha rhythms”. Increases in the amount and power of alpha waves in the brain are associated with meditation and increased feelings of relaxation and calm focus. As well, Kennerly (2006) also reported a reduction in very slow Delta and high frequency Beta brainwaves. Reduction in high frequency brain activity between 20-30 Hz correlates with reductions in anxiety, ruminative thought, and obsessive-compulsive behaviour (Demos, 2005). Using QEEG and LORETA analysis techniques, Kennerly also reported that the electrical impulses generated by CES reached all cortical and sub-cortical areas of the brain. 

The figure above shows the change in EEG relative power across the clinical frequency bands for an individual following a single 30-minute stimulation session using an Alpha-Stim 100 device. Note the increases in 8-12 Hz Alpha centrally and Gamma in the auditory cortices.  

To view a YouTube video of David Siever, CEO of Mind Alive Inc. lecturing on Cranial Electrostimulation at the March 2011 Annual Conference of the Association for Applied Psychophysiology and Biofeedback in New Orleans, GOTO: http://www.youtube.com/watch?v=PDK68rpM7k0&feature=related 

What does CES feel like?

Applied to the ear lobes or to the mastoid, just behind the ear, CES causes the patient to experience nothing more than a faint tingling sensation. As the treatment continues, the tingling tends to disappear and most patients begin to feel less anxious, less distressed, and more relaxed and, yet, mentally alert and focused. Patients with positive response to CES generally sleep better and report improved concentration, increased learning abilities, enhanced recall and a heightened state of well-being after one or a series of CES treatments. Most people can resume normal activities immediately after a CES session. Others may experience a mild euphoric feeling, or a state of deep relaxation that may temporarily and minimally impair their mental and/or physical abilities for the performance of potentially hazardous tasks, such as motor vehicle operation. In some cases, this may last for up to several hours after treatment. Users may do other things during treatment such as read, watch TV, engage in conversation, or work on a computer.

CAUTIONARY NOTE: Until you have experienced CES for yourself and are certain of how you will react to treatment, it is best that you do operate a motor vehicle or other motorized equipment or engage in potentially hazardous activities immediately after treatment.

Most patients are left feeling relaxed and alert after a CES session— in what psychologists call an “alpha state”. This state differs from pharmaceutical treatments in that people report feeling that their bodies are lighter and more relaxed and their minds more alert and clear. The results tend to be cumulative and long lasting.

What are the adverse effects of CES?

Unlike the United States, where CES devices are sold by prescription only, there are no specific restrictions in Canada on the purchase or home-use of CES devices by the consumer. Canada Health does not recognize CES for the treatment of any medical condition and, therefore, no one selling CES devices can make any direct claims for their effectiveness in treating any medical condition. That said, no one is actually proscribed from using a CES device to treat any condition.

CES has a proven track record of safety, especially in comparison to alternative pharmaceutical treatments for the same conditions. There have been no reports of lasting adverse effects, significant side-effects, or any serious contraindications to CES treatment. CES treatment has not been shown to interact negatively with any medications and may be used adjunctively with psychoactive medications.

Adverse-effects reported in research to date have been mild and time-limited and include... dizziness/nausea (<1%), skin irritation or mild electrode burns (<1%), and headaches (<1%). In rare cases, CES may trigger temporary paradoxical reactions of hyperexicitability, increased anxiety, and sleep disturbances. There have been a few reports of persons suffering from posttraumatic stress disorder (PTSD) experiencing more vivid and sometimes disturbing dreams at night. This latter adverse-effect may be ameliorated  by not using CES too close to bedtime.

That said, labeling of CES devices contains precautions seen on all electromedical devices against use by pregnant women and persons with implanted medical devices such as cardiac pacemakers. Due to the relaxing effect of CES treatment, patients are cautioned in the use of hazardous machinery or driving. Despite the known safety of CES, it is advisable to only use CES to treat clinical conditions under the direction and supervision of a health professional and to keep your primary care physician informed.

What is the evidence for the effectiveness of CES?

Research studies of CES that been published to date reveal significant changes associated with relaxation responses such as reduced muscle tension, positive changes in brain wave activity, increased vasodilation, reductions in gastric acid output, and reductions in blood pressure, pulse, respiration, and heart rate. CES research has also shown significant reductions in clinical depression (Gilula & Kirsch, 2005), anxiety (Klawansky, et al., 1995) and specific fibromyalgia symptoms (Lichtbroun, et al., 2001; Taylor, et al., 2011).

More than 25 clinical research studies examining the efficacy of CES for the treatment of depression have been published, with over 80% of these studies reporting significant clinical improvements in the symptoms of depression (Gilula & Kirsch, 2005).

A recent meta-analysis of 22 placebo-controlled CES research studies involving a total of 1075 patients found that the average treatment effect beyond that attributable to placebo was 57% (Gilula & Kirsch, 2005). This compares very favourably with the often claimed 40-60% average treatment effects beyond placebo for antidepressant medications.

The book— Cranial Electrotherapy Stimulation— by Dr. R.B. Smith (2007) reviews the results from over 100 studies involving over 4000 subjects and reports that CES is highly effective in the treatment of insomnia, anxiety, depression, drug abuse, anxiety and cognitive dysfunction with an average of 67% of patients reporting significant improvement in their symptoms.

CES has also been shown to improve sleep and memory consolidation during sleep (Born, et al. 2006; published in Nature).

How is CES treatment actually done?

Although CES devices are relatively inexpensive (generally about $300-$500) and anyone in Canada can purchase a CES device for home use from a local or internet speciality store, it is best to use CES under the advisement or supervision of a qualified health care professional when treating a clinical condition such as an anxiety disorder, depression, insomnia, or chronic pain or associated symptoms.

In all cases, the health care professional will need to see you for at least one or two appointments to assess your condition, evaluate your initial response to the CES treatment within the safe and controlled environment of their office, and show you how to properly use the device. In some cases, the health care practitioner will offer a series of regular CES treatments in his/her office; often in conjunction with other treatments such as counselling or psychotherapy. In other cases, the health practitioner will provide you with a CES device for use at home for a period of time or will encourage you to purchase your own device for use at home.

While there certainly may be situations in which it is both practical and sensible to include CES treatments as part of regular clinical visits, in most situations it is far more cost-effective for the patient to use CES on a daily basis at home for a period of time and only see the health practitioner in the clinic for follow-up and any other related treatments.

In the treatment of anxiety or depressed mood, the research has generally shown that approximately 30-60 minutes of CES daily for a period of 2-4 weeks is effective in alleviating symptoms for extended periods of time. However, some people find that their symptoms will slowly return over time and that they benefit from one or more follow-up series of CES treatments. Others find that regular use of the CES device for 30-60 minutes a few times a week will effectively maintain treatment gains indefinitely or successfully manage chronic anxiety, depressed mood, insomnia, pain, or stress.

What results can I expect?

Individual results may vary dependent on a variety of factors, including the severity and chronicity of the condition or symptoms being treated, what medications are being taken (if any), the presence of other concurrent medical factors or comorbid conditions and, ultimately, your level of motivation. Some disorders can be successfully treated in 10-20 sessions; others require more extensive treatment. In the case of more chronic conditions, CES may be required on a regular basis indefinitely to manage symptoms.

For those patients with more severe acute or chronic conditions there may be extra benefit to combining CES with counselling or psychotherapy as well as other forms of neurotherapy such as Audio Visual Entrainment (AVE) therapy or certain biofeedback therapies such as Heart Rate Variability (HRV) biofeedback.

The graphs above show data from studies conducted by Neurofitness LLC using the CES Ultra device.

To view a brief YouTube video on the use of the AlphaStim CES device to treat depression, GOTO: http://www.youtube.com/watch?v=tsaeTlzvHwk&feature=related  

For more information on purchasing CES devices…

Mind Alive Inc. in Edmonton manufactures and sells a number of different CES devices  GOTO: www.mindalive.com

Optimum Health in Edmonton is the Canadian distributor for the AlphaStim 100 Microcurrent Stimulator  GOTO: www.optimumhealth.ca

Neurofitness LLC in Seattle manufactures the CES Ultra device  GOTO: www.cesultra.com

Transcranial Direct-Current Stimulation (tDCS)

A non-invasive and safe neurostimulation therapy for the treatment of
depression, obessive-compulsive disorder, migraine, and chronic pain. 

Transcranial direct current stimulation (tDCS) is a new form of neurostimulation that may be used to safely treat a variety of clinical conditions including depression, obsessive-compulsive disorder, migraine, and central and neuropathic chronic pain. TDCS can also relieve the symptoms of narcotic withdrawal and reduce cravings for drugs, including nicotine and alcohol. There is some limited evidence that tDCS can be used to increase frontal lobe functioning and reduce impulsivity and distractibility in persons with attention deficit disorder. TDCS has also been shown to boost verbal and motor skills and improve learning and memory in healthy people. Finally, there is quite an extensive literature on the use of tDCS within stroke rehabilitation programs.

Among the various techniques of brain stimulation, tDCS stands out as one of the simplest in design. It involves the application of a weak (very low amperage), non-alternating electrical current to the scalp by means of surface electrodes to generate an electromagnetic field that selectively modulates the activity of neurons in the cerebral cortex of the brain.

A battery-powered current generator capable of delivering small currents (usually less than 10 milliamperes) is attached to two sponge-based electrodes. The sponge electrodes are soaked in a saline solution, applied over the hair to the scalp, and held in place by non-conducting elastic bands affixed around the head. Current is injected through the scalp and skull to change the membrane potentials of neurons in the underlying cortex, resulting in real-time neurological effects.

Illustration of transcranial DC stimulation device.

The exact mechanism of tDCS is not clear but extensive neurophysiological research has shown that direct current (DC) electricity penetrates the skull and outer layers of the cortex to modify neuronal cross-membrane resting potentials and thereby influence the level of neuronal excitability and modulate firing rates. Importantly, tDCS only modulates neuronal activity and does not actually stimulate action potentials.

Direct current appears to modulate spontaneous neuronal activity in a polarity-dependent fashion. For example, stimulation with the positive pole (anode) placed over a selected cortical region will increase the exicitability of the underlying neurons while stimulation with the negative pole (cathode) will decrease neuronal exicitability under the electrode. It has been shown that anodal stimulation results in sub-threshold depolarization of the underlying neuronal membranes; increasing their electrotonic potential and making these neurons more easily excited. Cathodal stimulation of the neurons will result in hyperpolarization and a decrease in electrotonic potential of the neuron membrane with a resultant decrease in excitability. The amount of depolarization/polarization and the duration of the change in neuronal excitability is dependent on the current density and duration of the stimulation of the stimulation.

Anodal stimulation is associated with a decrease in GABA concentration and cathodal stimulation is associated with decrease in both glutamate and GABA. Dopaminergic mechanisms may be involved in NMDA-induced after-effects. Anodal stimulation increases oxyhemoglobin concentration and associated regional cerebral blood flow in the stimulated area.

In this manner, tDCS may be used to increase cortical brain activity in specific brain areas that are under-aroused or alternatively decrease activity in areas that are overexcited. Research has shown that the effects of tDCS can last for an appreciable amount of time after exposure. Stimulation of less than 5 minutes have little carry over effect once stimulation has stopped, whereas stimulation lasting longer than 20 minutes can have after-effects lasting for a couple of hours or more. Similarly, when stimulation is repeated on a daily basis for periods of 5-10 days, there is a clear increase in the length of treatment effects often lasting a number of weeks or even months. These long-term effects of tDCS likely involve NMDA-receptor dependent mechanisms.

The behavioral effects of tDCS are dependent on the location and electrovalence of stimulation. Anodal tDCS of the premotor cortex, for instance, increases the excitability of the ipsilateral motor cortex and inhibition of the contralateral motor areas.  

tDCS may sound similar to electroshock or electroconvulsive therapy (ECT) used in psychiatry but it is quite different. ECT is a medical procedure done under anaesthesia and applies electrical currents as much as a thousand times greater than tDCS. ECT induces action potentials in resting neurons throughout the brain resulting in massive neuronal firing and brain seizure. ECT drastically affects the functioning of the entire brain and can result in significant adverse effects, including memory loss. Transcranial DC stimulation uses only very small electric currents that cannot set off a seizure and is far more selective in its effects. No instances of epileptic seizures caused by tDCS have been observed in humans. tDCS only influences the area of the cortical brain directly beneath the electrode.

tDCS may work in a way that is somewhat similar to transcranial magnetic stimulation (TMS) but is still quite different. In TMS, the brain is penetrated by a powerful pulsed magnetic field that causes all the neurons within the targeted area of the brain to fire in concert. After TMS stimulation stops and depending on the frequency of the magnetic pulses, the targeted region of the brain is either turned off or on. TMS devices are quite expensive and bulky which makes them difficult to use outside a hospital or large clinic. TMS can also set off seizures, as well as temporary motor paralysis, so must be medically monitored. Where tDCS is quite different from TMS is that it only affects neurons that are already active— it does not cause resting neurons to fire. Moreover, the effects of tDCS appear to be limited to the cortex of the brain, whereas TMS can penetrate to deeper brain structures.

How is tDCS Administered?

Transcranial DC stimulation may be done in the neurotherapist's office with the client sitting in a comfortable chair. The basic treatment consists of a series of five 20-minute sessions over five consecutive days. Sometimes a second series of five treatments may be necessary to obtain maximum improvement in symptoms being treated.

Illustration of a patient being treated with tDCS.

While the client is seated in a chair, two 5 cm x 5 cm non-metallic conductive rubber electrodes are placed on selected locations of the scalp and covered by saline soaked sponges and held in place by elastic headbands. After the electrodes are properly placed, a tDCS device powered by a 9-volt battery is used to send a steady electrical current of between 1.0 and 2.0 milliamps through the electrodes and into the cortex for 20-30 minutes. Dependent on the size of the electrodes used, current densities are maintained at a safe and comfortable level of 30-40 microamps per square-centimeter for the active electrode.

The electrode attached to the positive (anode) pole of the battery will excite neuronal activity in the cortex under it, whereas the electrode attached to the negative pole (cathode) of the battery will inhibit neuronal activity in the cortex under it.

The procedure does not elicit any pain. Persons receiving tDCS generally report nothing more than a mild tingling or itchy feeling from under the electrode during the stimulation. These sensations disappear immediately after the current is turned off.

Treatment with tDCS is relatively inexpensive, easy to administer, non-invasive, painless, and safe.

To view a YouTube video of a lecture by David Siever, CEO of Mind Alive Inc., on Transcranial DC stimulation at the Association for Applied Psychophysiology & Biofeedback conference in New Orleans in March 2011, GOTO: http://www.youtube.com/watch?v=f3eAU5aXQ9E&feature=related 

Numerous studies verify that low-intensity tDCS is safe for humans and that it is linked with only rare and relatively minor adverse effects. The most common side-effects observed with tDCS are mild tingling (71%), moderate fatigue (35%), sensations of light itching (30%), slight burning sensation (21%), and mild pain (16%). Less commonly, some subjects report headache (12%), temporary trouble concentrating (11%), nausea (3%), and sleep disturbance (1.0%). Reddening or irritation or very mild burn of the skin under he electrodes has also been reported, more commonly with increasing numbers of treatments closer together in time. No seizures have ever ben reported in humans. The safety of tDCS use in pregnant women and young children has not been investigated and remains unknown. 

To see a brief YouTube video on transcranial DC stimulation, GOTO: http://www.youtube.com/watch?v=1RMV0yxxMh8 

To see a much longer and more academic YouTube video on research with Transcranial DC Stimulation to treat aphasia, GOTO: http://www.youtube.com/watch?v=gSBsQj9HwQg&feature=related 

Transcranial DC Stimulation to Treat Depression

Fregni, et al. (2006) reports on a randomized, sham-controlled, clinical trial of tDCS in the treatment of 10 patients diagnosed with major depression. Level of depression was evaluated before and after treatment by means of the Hamilton Depression Rating Scale (HDRS) and Beck Depression Inventory (BDI). Patients were randomly assigned to one of two groups, an active treatment group that received 1.0 mA anodal (+) DC stimulation over the left dorsolateral prefrontal cortex (DLPFC) and cathodal (-) stimulation over the contralateral supraorbital area (just above right eyebrow) versus a sham treatment group that received the identical treatment but with the tDCS device turned off. Both groups received 20 minutes of actual or sham stimulation once a day for five consecutive days. All patients remained blind to treatment conditions and the treatment was well-tolerated with no significant adverse effects. Four of the five patients in the active treatment group were treatment responders whereas none of the five patients receiving sham were treatment responders. The active treatment group showed a significantly greater reduction in depression scores on the post-treatment HDRS and BDI as compared to the sham treatment group (70% vs 30% respectively).

Fregni, F., Boggio, P., Nitsche, M., et al. (2006). Letters to the Editor: Treatment of major depression with transcranial direct current stimulation. Bipolar Disorders, 8:203-205.

Boggio, et al. (2008) followed up and expanded on Fregni’s earlier small clinical trial by examining the effects of 2.0 mA tDCS treatment on major depression with a larger group of 40 unmedicated patients. In this study, the patients were randomly assigned to one of three groups in a 2:1:1 ratio: active treatment (n = 21), active control (n = 9), and sham treatment (n = 10). As with Fregni’s study, all patients were evaluated pre- and post-treatment using the HDRS and BDI depression scales but this time the scales were administered at the beginning of treatment (baseline), immediately after treatment, and at 15 and 30 days post-treatment.

All patients received ten 20-minute treatment sessions over a period of two weeks. The active treatment group was treated with anodal (+) tDCS over the left DLPFC. The active control group was treated with anodal (+) tDCS over the occipital cortex. The sham group was treated exactly as the active group but with the electricity turned off. In all cases, the cathode (-) was placed over the right eyebrow.  

Treatment response was defined as a 50% or greater reduction in HDRS scores from baseline. Remission was defined as HDRS scores below 7. On average, the active treatment group obtained a 40% reduction in HDRS scores with treatment as compared to 21% and 10% for the active control and sham groups respectively.

The results of this study demonstrated that ten brief sessions (10 x 20 minutes) of cortical stimulation with tDCS is associated with clinically significant reductions in depression scores on clinical symptom rating scales that is specific to the site of stimulation and lasts for at least 30 days post-treatment. Moreover, 10 days of tDCS treatment resulted in only minimal and temporary adverse effects in less than 15% of the patients that did not carry on beyond the end of treatment.

An even more recent study by C.K. Loo and colleagues (Loo, Sachdev, Martin, et al., 2010) in Australia demonstrated very similar improvement in 40 depressed subjects with only ten tDCS treatment sessions.

References

Boggio, P., Amancio, E., Correa, C., et al. (2009). Transcranial DC stimulation coupled with TENS for the treatment of chronic pain: A preliminary Study. Clinical Journal of Pain, 25:691-695.

Boggio, P., Nitsche, M., Pascual-Leone, A. (2005). Correspondance: Transcranial direct current stimulation. British Journal of Psychiatry, 186:446-447.

Boggio, P., Sultani, N., Fecteau, S., et al. (2008). Prefrontal cortex modulation using transcranial DC stimulation reduces alcohol craving: A double-blind, sham-controlled study. Drug & Alcohol Dependancy, 92(1-3):55-60.

Fregni, F., Boggio, P., Nitsche, M., et al. (2006). Letters to the Editor: Treatment of major depression with transcranial direct current stimulation. Bipolar Disorders, 8:203-205.

Fregni, F., Gimenez, R., Vallc, A., et al. (2006). A randomized sham-controlled, proof of principle study of transcranial direct current stimulation for the treatment of fibromyalgia. Arthritis & Rheumatism, 54(12):3968-3998.

Fregni, F., Pascual-Leone, A., et al. (2007). Technology Insight: Non-invasive brain stimulation in neurology - Perspectives on the therapeutic potential of rTMS and tDCS. Clinical Practice in Neurology, 3(7):383.

Iyer, M., Mattu, U., Grafman, J., et al. (2005). Safety and cognitive effects of frontal DC brain polarization in healthy individuals. Neurology, 64(5):872-875.

Lefaucheur, J-P., Antal, A., Ahdab, R., et al. (2008). The use of repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) to relieve pain. Brain Stimulation, 1:337-344.

Loo, C., Sachdev, P., Martin, D., et al. (2010). A double-blind, sham-controlled trial of transcranial direct current stimulation for the treatment of depression. International Journal of Neuropsychopharmacology, 13(1):61-69.

Mori, F., Codeca, C., Kusayanagi, H., et al., (2009). Effects of anodal transcranial direct current stimulation on chronic neuropathic pain in patients with multiple sclerosis. The Journal of Pain, December 2009.

Nitsche, M. & Paulus, W. (2000). Excitability changes induced in the human motor cortex by weak transcranial direct current stimulation. Journal of Physiology, 527(3):633-639.

Reidler, J., Zaghi, S., Fregni, F. (2011). Neurophysiological effects of Transcranial Direct Current Stimulation. In: R. Coben & J.R. Evans (eds.)(2011). Neurofeedback and Neuromodulation Techniques and Applications. Chapter 12, pp.319-349. New York, NY: Academic Press.

Rigonatti, S., Boggio, P., Myczkowski, M., et al. (2008). Letters to the Editor: Transcranial direct current stimulation and fluoxetine for treatment of depression. European Psychiatry, 23:74-76.

Roizenblatt, S., Fregni, F., Gimenez, R., et al. (2007). Site-specific effects of transcranial direct current stimulation on sleep and pain in fibromyalgia: A randomized, sham -controlled study. Pain Practice, 7(4):297-306.

Transcranial DC Stimulation for Chronic Pain

(CBS) There's new hope for people suffering from chronic pain, and that's the focus of our new series, "Easing the Pain." For the first installment, CBS News medical correspondent Dr. Jon LaPook examines a way to cut pain without using medication - instead, it employs an ancient technique: applying electricity. 

When Detective Thomas Tobin was busting bad guys for the New York City Police, he never imagined that his toughest adversary would turn out to be... pain.

"What I usually have constantly is a dull aching crushing pain like deep in my bones, as if my shin is in a vice or somebody is standing on my foot," he told CBS News medical correspondent Dr. Jon LaPook.

I all started 10 years ago after an operation for a knee injury.  "It was life-changing. I went from working constantly to not working at all," he said. For years, his only relief was a cocktail of prescribed medications. "I take about 35 pills a day," he said. "Every day."

Now he's trying something that might seem shocking: an electrical current applied to his head - part of a clinical trial at Beth Israel Medical Center in New York. It's called tDCS, Transcranial Direct Current Stimulation. A small electrical current seems to work by affecting pain centers deep within the brain, somehow muffling the perception of pain. The main side effect so far is slight scalp irritation.

Tobin doesn't feel a shock, just a tingling sensation.

"In some way that nobody understands and still seems rather magical, pain might be reduced," said Dr. Russell Portenoy.

The idea dates back 2,000 years, when a Roman physician found he could relieve gout and headache by placing an electric fish on the scalp.

Since then, the technique has been refined. "It's very early," Portenoy said. "And we don't know how effective it will be. We think it will be very safe."

Thirty years ago, electrodes were surgically implanted deep within the brain. Years later, on the surface. This new approach places them right on the scalp. This kind of surface stimulation has shown promise in small studies of patients with fibromyalgia and spinal cord injury.

"The idea is when you get the treatment and it is successful and the pain gets better then you can start cutting down the on the medication, and see how low you can go" said Dr. Richard Cruciani.

Every few months, Tobin gets treatments 20 minutes a day for five days. He says his pain drops significantly after therapy and then slowly returns over time. "I am in a lot less pain today and now it just feels as though I have a sunburn that is a few days old," he said.

This therapy is being tested at several centers around the world and more study is needed, but this new variation on an ancient concept is promising -- using electricity to try to zap the perception of pain.

Could this could work for all kinds of pain?

"That's the hope," says Lapook. "Whatever the cause, it dials down the pain on the brain center. With chronic pain you have to throw the kitchen sink at it. That means integrative medicine, acupuncture, massage, medication in as low doses as possible.

To see this CBS News video, GOTO: tDCS for Pain