Assessing the effect of repetitive TMS on people with multiple sclerosis — The Association Specialists
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Assessing the effect of repetitive TMS on people with multiple sclerosis (21443)

Madison R Boda 1 , Eva Moore 1 , Ashleigh Smith 2 , Mitchell Goldsworthy 3 , Simranjit K Sidhu 1
  1. School of Biomedicine, The University of Adelaide, Adelaide, SA, Australia
  2. Alliance for Research in Exercise, Nutrition and Activity, University of South Australia, Adelaide, SA, Australia
  3. Behaviour-Brain-Body Research Centre, Justice and Society, University of South Australia, Adelaide, SA, Australia

80% of people with multiple sclerosis (PwMS) experience motor impairment
associated with decreased corticospinal excitability from demyelination of the
corticospinal tract. Restoration of corticospinal excitability by repetitive transcranial
magnetic stimulation (TMS) techniques can enhance the performance of voluntary
muscle contractions for motor rehabilitation. There is some evidence suggesting that
repetitive i-wave periodicity TMS (iTMS) enhances corticospinal excitability in healthy
individuals, but it is not known whether the same neuroplastic effects can be induced
by iTMS in PwMS. Therefore, this study aimed to investigate if differences exist in
iTMS-induced corticospinal excitability between PwMS and healthy individuals. Ten
PwMS (47 ± 11 years) and ten healthy age-matched controls (51 ± 21
years) participated in the study. Corticospinal excitability was induced with a 15-minute
iTMS intervention on the primary motor cortex (M1), and quantified with motor evoked
potential (MEP) by applying single pulse TMS on M1. MEP was recorded before
intervention at baseline, and after intervention at 5-minute and 30-minute post-iTMS
timepoints. MEP was compared across time and groups to assess change in
corticospinal excitability. There was no change in MEP from baseline to post-iTMS
timepoints in either group (all P values ≥ 0.30). These preliminary findings do not support clinical
application of iTMS for motor rehabilitation in PwMS. Additionally, MEP did not change
in controls, which is inconsistent with existing literature. This inconsistency highlights
the need for further research into factors affecting iTMS-induced plasticity.