newyorker | What does this part of the brain do, again?” I asked, pointing to the electrode on my right temple.
“That’s the right inferior frontal cortex,” said Vince Clark, the
director of the University of New Mexico Psychology Clinical
Neuroscience Center, in Albuquerque. “It does a lot of things. It
evaluates rules. People get thrown in jail when it’s impaired. It might
help solve math problems. You can’t really isolate what it does. It has
emotional components.”
It was early December, and night was falling, though it was barely
five. The shadows were getting longer in the lab. My legs felt
unusually calm. Something somewhere was buzzing. Outside the window, a
tree stood black against the deepening sky.
“Verbal people tend to get really quiet,” Clark said softly. “That’s
one effect we noticed. And it can do funny things with your perception
of time.”
The device administering the current started to beep, and I saw that
twenty minutes had passed. As the current returned to zero, I felt a
slight burning under the electrodes—both the one on my right temple and
another, on my left arm. Clark pressed some buttons, trying to get the
beeping to stop. Finally, he popped out the battery, the nine-volt
rectangular kind.
This was my first experience of transcranial direct-current
stimulation, or tDCS—a portable, cheap, low-tech procedure that
involves sending a low electric current (up to two milliamps) to the
brain. Research into tDCS is in its early stages. A number of studies
suggest that it may improve learning, vigilance, intelligence, and
working memory, as well as relieve chronic pain and the symptoms of
depression, fibromyalgia, Parkinson’s, and schizophrenia. However, the
studies have been so small and heterogeneous that meta-analyses have
failed to prove any conclusive effects, and long-term risks have not
been established. The treatment has yet to receive F.D.A. approval,
although a few hospitals, including Beth Israel, in New York, and Beth
Israel Deaconess, in Boston, have used it to treat chronic pain and
depression.
“What’s the plan now?” Clark asked, unhooking the electrodes. I could
see he was ready to answer more questions. But, as warned, I felt
almost completely unable to speak. It wasn’t like grasping for words;
it was like no longer knowing what words were good for.
Clark offered to drive me back to my hotel. Everything was mesmerizing:
a dumpster in the rear-view camera, the wide roads, the Route 66 signs,
the Land of Enchantment license plates.
After some effort, I managed to ask about a paper I’d read regarding
the use of tDCS to treat tinnitus. My father has tinnitus; the ringing
in his ears is so loud it wakes him up at night. I had heard that some
people with tinnitus were helped by earplugs, but my father wasn’t, so
where in the head was tinnitus, and were there different kinds?
“There are different kinds,” Clark said. “Sometimes, there’s a real
noise. It’s rare, but it happens with dogs.” He told me a story about a
dog with this rare affliction. When a microphone was placed in its ear,
everyone could hear a ringing tone—the result, it turned out, of an
oversensitive tympanic membrane. “The poor dog,” he said.
We drove the rest of the way in silence.
