The important thing to note here is that Cefaly has been approved through the “de novo premarket review pathway, a regulatory pathway for generally low- to moderate-risk medical devices”. The safety study referenced by STX-Med for approval involved over 2,000 patients of which only 4.3% reported any adverse reactions, all of which were mild and reversible following discontinuation of treatment. This study did not examine the effectiveness of the headset in any way other than a vague outcome of ‘patient satisfaction’.
The study that did involve efficacy had only 67 patients in the trial, but some of the outcomes showed promise. The researchers compared sham neurostimulation against the standard Cefaly stimulation. There was no control without a device.
The STS generates biphasic rectangular impulses with an electrical mean equal to zero and the following characteristics: pulse width 30 µs for sham and 250 µs for verum, frequency 1 Hz for sham and 60 Hz for verum, maximum intensity 1 mA for sham and 16 mA for verum. The daily sham or verum neurostimulation sessions lasted 20 minutes.
Patients maintained a diary and recorded headache frequency and severity.
Primary outcome measures were 1) change in monthly migraine days between the run-in month and the third month of treatment; and 2) percentage of “responders,” i.e., of subjects having at least 50% reduction of monthly migraine days between run-in and third month of treatment.
Secondary outcome measures were 1) change in monthly migraine days between run-in and the average 3 months of treatment; 2) change in monthly migraine attack frequency; 3) change in monthly frequency of any headache; 4) change in mean headache severity per migraine day; 5) change in monthly acute antimigraine drug use and in associated symptoms per migraine headache between run-in and third month of treatment; and 6) percentage of patients stating at the end of the trial that they are very satisfied, moderately satisfied, or not satisfied with the treatment.
My statistics are rusty, but the number of total comparisons would increase the possibility of a false positive, and the inclusion of study dropouts using data up to the time they left the study seems questionable to me. Perhaps someone with a grasp of the relevant stats could leave a comment to help clarify the appropriateness of the analysis.
There were a number of reasons that patients were excluded from the study:
Exclusion criteria were use of a preventive antimigraine treatment in the previous 3 months, failure on well-conducted preventive drug treatments, medication overuse headache (ICHD-II 8.2), frequent/chronic tension-type headache (ICHD-II 2.2/2.3), and other severe neurologic or psychiatric disorders
In the end, the number of migraines was decreased in the active treatment group, as was the amount of medication required. There was also an increase in the number of patients who reported a 50% decrease in attacks.
A third study describing the sedative effect of Cefaly used a slightly different protocol in an attempt to control for the patient’s ability to sense the electric current by using controls and sham neurostimulation.
We performed a double-blind crossover sham-controlled study of 30 subjects to assess the effect on vigilance of different protocols of supra-orbital TNS. Each subject was tested in 4 different experimental conditions: without neurostimulation device (blank control: BC), with a sham neurostimulation (Sham control: SC), with a low frequency neurostimulation (LFN) and with a high frequency neurostimulation (HFN)
Results are compatible with decreased vigilance and arousal studies, but show no indication of inducing or improving sleep. Sedation may help some patients with migraine, but decreased arousal during sleep has been associated with sufferers.
The primary Cefaly site lists only the 3 studies described here, while the Canadian site, at least at the time of this writing, still contains the entire list of irrelevant studies with the misleading headings I discussed in my previous article. I’m not going to comment on the testimonials except to say that my degree of skeptism of any treatment is directly proportional to the number of testimonials used in advertising.
These studies show the possibility of Cefaly as a partial prophylactic for some types of migraines, but but no indication it is useful as a treatment for an ongoing attack.