IEEE Spectrum - North American - March 2017 - 11

ybrain

memory improvement for people with
Alzheimer's disease, and craving reduction for smokers and alcoholics.
Ybrain may not be the first to enter the
all-important American market; New
York City-based Soterix Medical may
beat it. Soterix chief technology officer Abhishek Datta says that its tDCS
system for depression was approved
for clinical use in Europe in late 2015,
and he says more than 30 European
clinics now use it. The company is currently pursuing approval in Canada and
the United States. At the moment, the
Soterix treatment is not quite as user
friendly as Ybrain's. Although the company offers a take-home version of its
tDCS system, Datta says most European
patients are receiving their stimulation
at a clinic under a doctor's supervision.
Ybrain hopes its slick, consumerfriendly design will make at-home
treatment the norm. "It's designed for
home use," says Lee, "so physicians can
electronically prescribe the device and
patients can bring it to their homes."
To make the medical gadget easy to use
and fail-safe, Ybrain's designers kept it simple. "The device has just a power button,
no interface," Lee says. "The patient turns
it on and puts the device on their head,

and it automatically starts the stimulation
based on the doctor's prescription." If the
doctor prescribed one 20-minute session
per day at 2 milliamperes, for example,
the gadget wouldn't allow more stimulation than the prescribed limit.
Though companies are pushing ahead
with commercialization, many scientific
questions must still be answered about
tDCS. Neuromodulation experts agree that
it can alter the brain in meaningful ways-
but they're still figuring out which medical conditions will truly benefit from these
alterations. An article recently published
in the journal Clinical Neurophysiology
reviewed the evidence on tDCS effectiveness across a range of disorders; for most,
the article said that there haven't yet been
enough rigorous trials to draw conclusions.
However, that article singled out tDCS
treatment for depression as "probably
effective." Considering the World Health
Organization's estimate that some
350 million people around the world
suffer from depression, many researchers and clinicians think that depression
might be the first killer app for tDCS.
Andre Brunoni, a neuroscientist and
psychiatrist at the University of São Paulo,
provided strong evidence of tDCS's utility
for depression in a 2013 study he coauthored that compared tDCS to a standard antidepressant medication. That
study found electric and pharmaceutical therapies to be equally effective, and
it found that patients who received both
treatments together fared best of all. But
Brunoni says he's not ready to forge ahead
with tDCS in his clinical practice; he's
BAnD oF AID: Ybrain's transcranial directcurrent stimulation headband [left] is
designed for home use. A doctor programs
prescriptions, including amperage and
duration of treatment, into the device's
processing modules [above].

still waiting for answers to many crucial
questions that will define its practical
use. "We don't know the best 'dose' to
use for tDCS," he says. "What's the best
amount of current to use? What's the
optimal number of sessions? There are
a lot of parameters to explore."
If such issues are resolved, Brunoni
says tDCS may offer several advantages
over both antidepressant drugs and
another device-based depression treatment, transcranial magnetic stimulation
(TMS), which is performed using a large
and comparatively expensive machine at
a clinic. Because tDCS treatment is relatively cheap, Brunoni says, private medical plans would likely prefer it. Safe and
reliable devices from companies such
as Soterix and Ybrain will allow home
use "with almost zero risk," he says. And
treatments can be short-term, beginning
with an intense phase-for example, two
weeks of daily sessions-followed by less
frequent "maintenance" stimulation sessions. Brunoni says this timing offers a
big advantage over antidepressant drugs,
which require treatment for at least nine
months and can cause unpleasant side
effects throughout that period (like
weight gain and sexual problems).
While hopes are high for tDCS depression treatments, some experts are cautious.
Mark George, an eminent neurologist and
psychiatrist who directs the Brain Stimulation Laboratory at the Medical University of South Carolina, in Charleston, says
he's not yet ready to prescribe tDCS to his
clinically depressed patients. He invokes
Hippocrates: "First, do no harm." While
there's ample evidence that tDCS is safe
when used correctly, George notes that
physical safety isn't the only consideration. The depressed patients he sees are
desperate, despondent, and looking to
him for salvation.
"Hope is fragile," George says, "and
you want to be very careful with what
you throw out there for your patients.
You want to go with your best shot. And
right now, I don't see tDCS as your best
shot." -eliza str ick l a nd

NEwS

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MAR 2017

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