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 The experimental gadget, Nerivio Migra, is a patch with a battery,
electrodes and a computer chip that can wirelessly communicate with
mobile devices. It’s designed to stimulate nerves under the skin in
the arm and block pain signals from reaching the brain.
“All stimulation treatments given so far have been in the head,”
said lead study author Dr. David Yarnitsky, an advisory board member
for Theranica, the company developing the device.
“We worked on stimulation at a far away location, which makes the
treatment more convenient and more discrete so people can use it
even during working hours without anyone noticing,” Yarnitsky added
by email.
The study involved 71 people with episodic migraines who had two to
eight attacks a month and had not taken drugs to prevent the
episodes for at least two months.
Participants were typically in their mid-to-late 40s and had been
experiencing about five migraines a month. Most of them were female,
and more than half of them reported experiencing what’s known as
aura
Overall, participants had a total of 299 migraines during the study
period.
Researchers asked participants to put the device on their upper arm
as soon as possible after the start of a migraine and use it for 20
minutes. They were also asked not to take any medicines for
migraines for two hours after the start of the episode.
For the experiment, researchers randomly programed the devices to
give either placebo stimulation at a very low frequency or deliver
one of four levels of active electrical stimulation treatment.
The four active treatment programs were set at a pulse rate of 80 to
120 Hertz (Hz) with pulse widths of 200, 150, 100 and 50. People
feel less stimulation at lower pulse widths. At higher pulse widths
than this device used, people might feel their muscles contract.
When researchers excluded the lowest pulse width, they found 64
percent of people in the other active treatment groups had at least
a 50 percent pain reduction two hours after treatment, compared with
26 percent of people in the placebo group.
At the highest level of stimulation, 58 percent of the people who
started out with moderate to severe pain reported little or no pain
after treatment. So did 24 percent of people in the placebo group.
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The timing of treatment also mattered.
People who started using the device within 20 minutes of the start
of a migraine reported average pain reductions of 47 percent,
compared to a 25 percent reduction in pain for people starting the
device later.
Even though the study’s participants were not told whether they were
assigned active or placebo treatment, one limitation of the
experiment is that participants often stopped placebo treatments
before the recommended 20-minute course of stimulation was done, the
authors note in Neurology.
The technology known as transcutaneous electric nerve stimulation
(TENS) that was tested in the current study has been examined in
other devices for migraine pain for decades, said Dr. Jean Schoenen,
a neurology researcher at the University of Liege in Belgium who
wasn’t involved in the current experiment.
One shortcoming of the current study is that researchers didn’t
examine how long the pain relief lasts beyond two hours, Schoenen
said by email.
“Rapid and sustained relief is what patients want,” Schoenen added.
If the device works in larger trials and becomes widely available
for migraine patients, it might offer an alternative for people who
can’t tolerate migraine drugs or an option patients could try in
addition to medication when they don’t get enough pain relief from
drugs alone, Schoenen said.
“The percentage of attacks for which TENS is sufficient as sole
treatment and allows sustained pain relief remains to be
determined,” Schoenen cautioned.
SOURCE: http://bit.ly/2lsKXgQ Neurology, online March 1, 2017.
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