Ipsilesional motor-evoked potential absence in pediatric hemiparesis impacts tracking accuracy of the less affected hand

Jessica M. Cassidy, James R. Carey, Chiahao Lu, Linda E. Krach, Tim Feyma, William K. Durfee, Bernadette T. Gillick

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


This study analyzed the relationship between electrophysiological responses to transcranial magnetic stimulation (TMS), finger tracking accuracy, and volume of neural substrate in children with congenital hemiparesis. Nineteen participants demonstrating an ipsilesional motor-evoked potential (MEP) were compared with eleven participants showing an absent ipsilesional MEP response. Comparisons of finger tracking accuracy from the affected and less affected hands and ipsilesional/contralesional (I/C) volume ratio for the primary motor cortex (M1) and posterior limb of internal capsule (PLIC) were done using two-sample t-tests. Participants showing an ipsilesional MEP response demonstrated superior tracking performance from the less affected hand (p=0.016) and significantly higher I/C volume ratios for M1 (p=0.028) and PLIC (p=0.005) compared to participants without an ipsilesional MEP response. Group differences in finger tracking accuracy from the affected hand were not significant. These results highlight differentiating factors amongst children with congenital hemiparesis showing contrasting MEP responses: less affected hand performance and preserved M1 and PLIC volume. Along with MEP status, these factors pose important clinical implications in pediatric stroke rehabilitation. These findings may also reflect competitive developmental processes associated with the preservation of affected hand function at the expense of some function in the less affected hand.

Original languageEnglish (US)
Pages (from-to)154-164
Number of pages11
JournalResearch in Developmental Disabilities
StatePublished - Dec 1 2015

Bibliographical note

Funding Information:
This project received support from the National Institute of Health (1RC1HD063838-01) and from the National Center for Research Resources to the University of Minnesota Clinical and Translational Science Institute (CTSI) (1UL1RR033183). Drs. Cassidy and Gillick received support from the Foundation for Physical Therapy. Dr. Gillick received additional support from the American Academy of Cerebral Palsy. We further extend our gratitude to William Thomas, PhD and doctoral physical therapy graduate students Brian Battista, Chris Brown, Jaime Calmes, and Jaime Cupit. We are especially grateful for the dedicated children and families involved in our research.

Publisher Copyright:
© 2015 Elsevier Ltd.


  • Corticospinal tract
  • Hemiparesis
  • Motor-evoked potential
  • Pediatrics
  • Stroke
  • Transcranial magnetic stimulation


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