Affiliations: Department of Physical Medicine and Rehabilitation
Program in Physical Therapy/Rehabilitation Science, University of Minnesota,
Minneapolis, MN, USA
Note: [] Corresponding author: Teresa Jacobson Kimberley, PhD, PT,
Program in Physical Therapy, University of Minnesota, MMC 388, 426 Church St
SE, Minneapolis, MN 55455, USA. E-mail: tjk@umn.edu
Abstract: Purpose: Focal hand dystonia (FHD) is a rare but potentially
devastating disorder involving involuntary muscle spasms and abnormal posturing
that impairs functional hand use. Increased cortical excitability and lack of
inhibitory mechanisms have been associated with these symptoms. This study
investigated the short- and long-term effects of repeated administrations of
repetitive-transcranial magnetic stimulation (rTMS) on cortical excitability
and handwriting performance. Methods: Six subjects with FHD and nine healthy controls were
studied. All subjects with FHD received rTMS (1Hz) to the premotor cortex (PMC)
for five consecutive days; of those, three subjects received five days of sham
rTMS completed ten days prior to real treatment. Healthy subjects received one
real rTMS session. Cortical silent period (CSP) and measures of handwriting
performance were compared before and after treatment and at ten-day
post-treatment follow-up. Results: At baseline, significant differences in CSP and pen
pressure were observed between subjects with FHD and healthy controls.
Differences in CSP and pen velocity between subjects in real and sham rTMS
groups were observed across treatment sessions and maintained at follow-up.
Conclusions: After five days of rTMS to PMC, reduced cortical
excitability and improved handwriting performance were observed and maintained
at least ten days following treatment in subjects with FHD. These preliminary
results support further investigation of the therapeutic potential of rTMS in
FHD.
