Nerve Stimulation May Restore Hand Function After Spinal Injury11/29/12
THURSDAY, Nov. 29 (HealthDay News) -- Noninvasive stimulation of
nerves in the brain and wrist may temporarily improve hand movement
in people with partial spinal cord injuries, an early study
The study, published Nov. 29 in the journal
Current Biology, involved just 19 people with spinal cord
injuries that had partially damaged their ability to move and feel
their arms and hands. And it looked only at the short-term effects
of the nerve stimulation technique.
But researchers say the findings are a step toward helping
people regain better use of their hands after such injuries.
If further work pans out, they envision developing portable
devices that people could use at home to stimulate nerves and
promote longer-lasting improvements in their muscle function.
"But we're still far from that goal," cautioned Monica Perez, study co-author and an assistant professor of physical medicine and rehabilitation at the University of Pittsburgh School of Medicine.
Before the technique is used as an actual therapy, the
researchers need to know if it can lead to lasting changes in hand
"We're trying to understand the mechanisms of this plasticity, and how we can make these changes more permanent," Perez said.
More than half of people who survive spinal cord injuries are
left with damage to the cervical spine, the upper portion of the
spinal cord. And that often causes impairments in the hands and
arms, Perez noted.
For the current study, she and University of Pittsburgh
colleague Karen Bunday paired two forms of noninvasive nerve
stimulation. The first was electrical stimulation of the ulnar
nerve in the wrist. The other was transcranial magnetic
stimulation, where an electromagnetic coil is placed near the scalp
to create electric currents that stimulate targeted nerve cells --
in this case, in the part of the brain connected to hand
The researchers tested the combination's effects on 19 people
with cervical spinal cord injuries and 14 healthy people. Each
participant received 100 paired electrical pulses over about 20
Perez and Bunday found that when they precisely timed the
stimulation of the brain and wrist nerves, temporary improvements
occurred in the injured participants' hand muscle strength and
their ability to grasp and move small pegs.
The effects lasted up to 80 minutes.
Other stimulation techniques are currently under study to help
people recover from spinal cord injuries. Some are invasive: Last
year, researchers at the University of Louisville in Kentucky
The Lancetthat electrodes implanted along the spine had
helped a paralyzed 25-year-old man learn to walk again.
The tactic used in the new study combines noninvasive nerve
stimulation approaches and focuses on timing.
The researchers found that electrical pulses from the brain
needed to be precisely timed to arrive at the spinal cord one to
two milliseconds before pulses from the wrist nerve did. And to do
that, the stimulation needed to be individualized for each study
In the future, it might be possible to use the approach in
formal rehab programs for people with partial spinal cord injuries
-- or even create at-home devices that would do the job, according
Dr. Robert Grossman, chairman of neurosurgery at the Methodist
Neurological Institute in Houston, agreed that there is potential
for this technique to "enhance the rehabilitation" of some
patients. He was not associated with the study.
He said the findings confirm previous research suggesting
benefits from "raising the excitability of motor neurons" -- spinal
nerve cells that send impulses to muscle.
Like Perez, Grossman urged caution in interpreting the findings
of an early study. But he said the work is encouraging.
"Scientists are making slow but steady progress toward helping [spinal cord injury] patients recover some of their function," Grossman said.
Learn more about spinal cord injuries from the
U.S. National Institute of Neurological Disorders and
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