Multiple Sclerosis (MS)
American Neurological Association
Noninvasive Stimulation May Reduce Fatigue and Improve Memory in MS
Neurology Reviews. 2015 23(11):52.
Related Content
CHICAGO—Transcranial direct-current
stimulation (tDCS) reduces fatigue and improves aspects of verbal memory
in patients with multiple sclerosis (MS), according to data from a
pilot study presented at the 140th Annual Meeting of the American
Neurological Association. The stimulation may not consistently improve
working memory, however, contrary to the researchers’ expectations.
Cognitive dysfunction, including working memory
deficits, and fatigue are common and debilitating symptoms of MS, said
Tracy D. Vannorsdall, PhD, Assistant Professor of Neurology and
Psychiatry and Behavioral Sciences at Johns Hopkins University School of
Medicine in Baltimore. Prior studies have shown that tDCS enhances
working memory in healthy adults. To see if tDCS might improve working
memory in patients with MS, Dr. Vannorsdall and her research colleagues
conducted a sham-controlled, single-blind crossover study.
A Sham Stimulation Control
The investigators recruited five patients with
secondary progressive MS from the Johns Hopkins MS Center. All
participants were right-handed native English speakers, and three of the
participants were women. Participants were between the ages of 42 and
57, with an average age of 50. They had a mean estimated IQ of 119 and a
mean 18.4 years of schooling.
Participants completed cognitive testing before and
after receiving 2 mA of anodal or sham stimulation to the left
dorsolateral prefrontal cortex for 30 minutes once per day for five
consecutive days. Investigators administered the current using a
NeuroConn Stimulator Plus. For the sham stimulation, researchers
increased the anodal current to 2 mA and decreased it to 0 mA over 30
seconds. After a four-week washout period, participants repeated the
study procedures under the stimulation condition to which they had not
been assigned originally.
Evaluating Cognition
Participants completed the Minimal Assessment of
Cognitive Functioning in MS, a seven-subtest battery that assesses
verbal learning and memory, visuospatial learning and memory, working
memory, processing speed, verbal fluency, executive functioning, and
perceptual accuracy. Participants also completed self-report measures of
mood and fatigue and responded to a mental and physical side effects
questionnaire. The researchers performed two-tailed paired-samples
t-tests to compare changes in scores across anodal and sham conditions.
No adverse events occurred. Depression scale ratings did not significantly change during tDCS, compared with sham stimulation.
Fatigue Severity Scale
Participants’ scores on the Fatigue Severity Scale
increased by 7 points over the course of five days of sham stimulation,
compared with a decrease of 4.6 points over the course of anodal
stimulation.
In addition, researchers observed a trend toward
improved verbal immediate recall under the anodal condition, compared
with sham stimulation. Anodal stimulation also was associated with
better performance across most cognitive tests, but the differences were
not significant. The study was underpowered to detect whether reduced
fatigue contributed to the improvements in cognition. “These preliminary
findings suggest that tDCS may ameliorate fatigue and cognitive
dysfunction in secondary progressive MS,” concluded the researchers.
Future studies will investigate the mechanism of these effects.
—Jake Remaly
Suggested Reading
Chiaravalloti N, Hillary F, Ricker J, et al. Cerebral activation patterns during working memory performance in multiple sclerosis using FMRI. J Clin Exp Neuropsychol. 2005;27(1):33-54.
Tecchio F, Cancelli A, Cottone C, et al. Multiple sclerosis fatigue relief by bilateral somatosensory cortex neuromodulation. J Neurol. 2014;261(8):1552-1558.
Link: http://www.neurologyreviews.com/specialty-focus/multiple-sclerosis-ms/article/noninvasive-stimulation-may-reduce-fatigue-and-improve-memory-in-ms/776ce027722e6aa46e3f87dc3fa5e68e.html
Chiaravalloti N, Hillary F, Ricker J, et al. Cerebral activation patterns during working memory performance in multiple sclerosis using FMRI. J Clin Exp Neuropsychol. 2005;27(1):33-54.
Tecchio F, Cancelli A, Cottone C, et al. Multiple sclerosis fatigue relief by bilateral somatosensory cortex neuromodulation. J Neurol. 2014;261(8):1552-1558.
Link: http://www.neurologyreviews.com/specialty-focus/multiple-sclerosis-ms/article/noninvasive-stimulation-may-reduce-fatigue-and-improve-memory-in-ms/776ce027722e6aa46e3f87dc3fa5e68e.html
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