title: Ipsilesional motor-evoked potential absence in pediatric hemiparesis impacts tracking accuracy of the less affected hand.
abstract: 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.
authors.affiliation: Department of Physical Medicine and Rehabilitation, University of Minnesota, Minneapolis, MN, United States. Electronic address: krea0014@umn.edu.
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Cassidy
authors.affiliation: Department of Physical Medicine and Rehabilitation, University of Minnesota, Minneapolis, MN, United States.
authors.forename: James R
authors.initials: JR
authors.lastname: Carey
authors.affiliation: Department of Neurology, University of Minnesota, Minneapolis, MN, United States.
authors.forename: Chiahao
authors.initials: C
authors.lastname: Lu
authors.affiliation: Courage Kenny Rehabilitation Institute, Minneapolis, MN, United States.
authors.forename: Linda E
authors.initials: LE
authors.lastname: Krach
authors.affiliation: Pediatric Neurology, Gillette Children's Specialty Healthcare, Saint Paul, MN, United States.
authors.forename: Tim
authors.initials: T
authors.lastname: Feyma
authors.affiliation: Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, United States.
authors.forename: William K
authors.initials: WK
authors.lastname: Durfee
authors.affiliation: Department of Physical Medicine and Rehabilitation, University of Minnesota, Minneapolis, MN, United States.
authors.forename: Bernadette T
authors.initials: BT
authors.lastname: Gillick
mesh_terms: D000293:Adolescent; D001921:Brain / Q000473:pathology*; D002648:Child; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D005385:Fingers / Q000502:physiology / Q000503:physiopathology*; D007839:Functional Laterality; D006225:Hand / Q000502:physiology / Q000503:physiopathology; D006801:Humans; D020772:Internal Capsule / Q000473:pathology / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D009044:Motor Cortex / Q000473:pathology / Q000503:physiopathology*; D010291:Paresis / Q000151:congenital / Q000473:pathology / Q000503:physiopathology* / Q000534:rehabilitation; D050781:Transcranial Magnetic Stimulation
keywords: Corticospinal tract; Hemiparesis; Motor-evoked potential; Pediatrics; Stroke; Transcranial magnetic stimulation