Advances in Cranial Electrotherapy Stimulation
Cranial electrotherapy stimulation (CES) is the use of low-level microcurrent applied through the head to the brain for medical and psychiatric/psychological purposes. Although CES is primarily used for the management of anxiety, insomnia, and depression, there is a growing body of evidence that suggests that it will play a role in pain management over the coming decades.1
Indeed, in a recent report from the office of the army surgeon general, CES was included as a complementary and alternative (CAM) tier II modality.1 In one Veteran’s Administration study of patients with severe head and neck cancer pain, CES was effective even in patients in whom morphine failed to provide adequate control of their pain.2 More recently, VA studies have shown CES to be highly effective in the management of patients with chronic pain with such refractory conditions as spinal cord injuries and in refractory populations such as patients with Parkinson’s disease (PD).
Modern pain theorists are looking more toward the cerebral cortex to provide an additional basis for understanding pain-related disorders. The successes of CES for pain management may contribute to our understanding of the centrally mediated mechanisms of pain. At the very least, it is rapidly becoming an evidence-based intervention for pain management.
An open, clinical trial in pain management was undertaken to assess the effectiveness of CES and microcurrent electrical therapy (MET) using the same device on the body.3 Twenty patients with refractive chronic pain in a Korean hospital were studied. Patients ranged in age from 18 to 75 years (mean age, 44 years) and included 15 women. Treatments were scheduled for 1 hour per day, 5 days a week, for 3 weeks. The current used ranged from 100 to 300 microamperes and often varied from day to day. Although of those completing the study, 3 of 20 patients obtained no relief from this treatment, 6 obtained complete relief, and an additional 8 patients received significant relief of 33% to 94%.
When length of time they had the pain was evaluated, it was found that patients who had been in pain for 2 and 4 months improved by 94% and 100%, respectively. The researchers concluded that the combination of CES and MET is an effective treatment for patients with chronic pain as well as for pain of shorter duration.
A recent double-blind crossover study of CES for chronic pain in patients with spinal cord injury (SCI) was conducted in the United Kingdom.4 Treatments were applied twice daily for 53 minutes on 4 consecutive days. After a washout period of 8 weeks, all subjects returned to treatment and were crossed over to the opposite condition (active to sham and sham to active).
Pain levels were significantly lower (P=.0016) in CES-treated subjects than in sham-treated subjects (P=.50). After crossover, sham subjects also showed significant improvement (P<.005). Subjects receiving CES reported using significantly less analgesic medication (46% of the average pre-treatment level; P<.05) and significantly less (53% of the average pre-treatment level; P<.05) combined antidepressant and anxiolytic medications. No significant differences were found between groups in plasma assays. However, there were marked differences (P<.05) between groups in salivary cortisol concentrations in the first arm, and salivary cortisol was also lowered significantly (P<.05) in the sham group from active CES after crossover to active treatment. The authors added that no adverse reactions were reported and that subjects reported a feeling of relaxation that coincided with lower blood pressure.
Another randomly controlled study examined the effects of daily, 1-hour active (N=18) or sham (N=20) CES treatments for 21 consecutive days on pain intensity and interference activities.5 Subjects consisted of 38 veterans (6 months to 60 years after their SCI) who were receiving care at a Department of Veterans Affairs SCI Center. Treatments were self-administered at home. The active CES group reported significantly decreased daily pain intensity (P=.03) compared with the sham group. The active CES group also showed significantly decreased pain interference (P=.004). The average change in daily pain intensity from pre- to post-session was significantly larger (P=.03) for the active CES group (mean = –0.73) than the sham CES group (mean = –0.08).
After the double-blind phase, the sham group was offered the opportunity to cross over to an open-label phase with an active CES device for another 21 consecutive days. The 17 sham CES participants who subsequently participated in the open-label phase reported significant post-session pain reduction (P=.003). None of the changes in the pain intensity subscale items was statistically significant for any of the 3 groups. However, in paired t-tests for the active CES group, 7 of the 10 individual pain interference subscale items significantly changed and reflected small to moderate effect sizes. This included general activity (Cohen’s d = 0.67), self-care (Cohen’s d = 0.58), sleep (Cohen’s d = 0.53), social activities (Cohen’s d = 0.51), normal work (Cohen’s d = 0.45), enjoyment of life (Cohen’s d = 0.42), and recreational activities (Cohen’s d = 0.38). A paired t-test within the active CES group showed that the composite pain interference score for both groups decreased significantly (mean change = 14.6, P=.004, Cohen’s d = 0 .50). Neither the individual BPI pain interference subscale items nor the composite pain interference score changed significantly in the sham group (mean change = –4.7, P=.24). After crossover into the open-label phase, pain interference with sleep decreased significantly (Cohen’s d = 0.40). Changes were greater in the 3 participants in the active group who had nontraumatic SCI.
The researchers concluded that CES can effectively treat chronic pain in people with SCI and may lower the burden of long-term pharmacologic management.
To further test that conclusion, the VA researchers conducted a comprehensive, 3-year, multi-site study following a similar protocol with the addition of a 6-month arm to determine if the longer treatment period increased the results in pain reduction.6 The number of days during the follow-up in which the device was used ranged from 5 to 186 (mean = 88.6, standard deviation [SD] = 58.5). For participants who used the device at least once during the 6-month follow-up period, the total number of days the device was used was significantly inversely correlated to depressive symptomatology (10-Item Center for Epidemiologic Studies Depression Scale [CES-D-10], N = 38, r = 0.41, P=.011) and perceived stress (10-Item Perceived Stress Scale [PSS-10], n = 38, r = 0.41, P=.011). People with less depressive symptomatology and less perceived stress were likely to use the device more often than those with more depressive symptomatology and stress. Frequency of use was not significantly related to demographic characteristics or measures of pain, changes in pain, or health obtained either at study entry or at the beginning of follow-up.