Maíra C Lixandrão1, James W Stinear2, Tonya Rich3, Chao-Ying Chen3, Tim Feyma4, Gregg D Meekins5, Bernadette T Gillick6. 1. Division of Rehabilitation Science, Medical School, University of Minnesota, Minneapolis, MN, United States; Department of Physical Therapy, Universidade Federal de São Carlos (UFSCar), São Carlos, SP, Brazil. 2. New Zealand Movement Neuroscience Laboratory, Department of Exercise Sciences, Centre for Brain Research, The University of Auckland, Auckland, New Zealand. 3. Division of Rehabilitation Science, Medical School, University of Minnesota, Minneapolis, MN, United States. 4. Gillette Children's Specialty Healthcare, St. Paul, MN, United States. 5. Department of Neurology, Medical School, University of Minnesota, Minneapolis, MN, United States. 6. Division of Rehabilitation Science, Medical School, University of Minnesota, Minneapolis, MN, United States. Electronic address: gillick@umn.edu.
Abstract
BACKGROUND: The cortical silent period is a transient suppression of electromyographic activity after a transcranial magnetic stimulation pulse, attributed to spinal and supraspinal inhibitory mechanisms. Electromyographic breakthrough activity has been observed in healthy adults as a result of a spinal reflex response within the cortical silent period. OBJECTIVES: The objective of this case series is to report the ipsilesional and contralesional cortical silent period and the electromyographic breakthrough activity of 7 children with congenital hemiparesis. METHODS: TMS was delivered over the ipsilesional and contralesional primary motor cortices with resting motor threshold and cortical silent period measures recorded from first dorsal interosseous muscle. RESULTS: Seven children (13±2 years) were included. Ipsilesional and contralesional resting motor thresholds ranged from 49 to 80% and from 38 to 63% of maximum stimulator output, respectively. Ipsilesional (n=4) and contralesional (n=7) cortical silent period duration ranged from 49 to 206ms and 81 to 150ms, respectively. Electromyographic breakthrough activity was observed ipsilesionally in 3/4 (75%) and contralesionally in 3/7 (42.8%) participants. In the 3 children with ipsilesional breakthrough activity during the cortical silent period, all testing trials showed breakthrough. Contralesional breakthrough activity was observed in only one of the analyzable trials in each of those 3 participants. The mean peak amplitude of breakthrough activity ranged from 45 to 214μV (ipsilesional) and from 23 to 93μV (contralesional). CONCLUSION: Further research is warranted to understand the mechanisms and significance of electromyographic breakthrough activity within the cortical silent period in congenital hemiparesis. Understanding these mechanisms may lead to the design of tailored neuromodulation interventions for physical rehabilitation. TRIAL REGISTRATION: NCT02250092 (https://clinicaltrials.gov/ct2/show/NCT02250092).
BACKGROUND: The cortical silent period is a transient suppression of electromyographic activity after a transcranial magnetic stimulation pulse, attributed to spinal and supraspinal inhibitory mechanisms. Electromyographic breakthrough activity has been observed in healthy adults as a result of a spinal reflex response within the cortical silent period. OBJECTIVES: The objective of this case series is to report the ipsilesional and contralesional cortical silent period and the electromyographic breakthrough activity of 7 children with congenital hemiparesis. METHODS: TMS was delivered over the ipsilesional and contralesional primary motor cortices with resting motor threshold and cortical silent period measures recorded from first dorsal interosseous muscle. RESULTS: Seven children (13±2 years) were included. Ipsilesional and contralesional resting motor thresholds ranged from 49 to 80% and from 38 to 63% of maximum stimulator output, respectively. Ipsilesional (n=4) and contralesional (n=7) cortical silent period duration ranged from 49 to 206ms and 81 to 150ms, respectively. Electromyographic breakthrough activity was observed ipsilesionally in 3/4 (75%) and contralesionally in 3/7 (42.8%) participants. In the 3 children with ipsilesional breakthrough activity during the cortical silent period, all testing trials showed breakthrough. Contralesional breakthrough activity was observed in only one of the analyzable trials in each of those 3 participants. The mean peak amplitude of breakthrough activity ranged from 45 to 214μV (ipsilesional) and from 23 to 93μV (contralesional). CONCLUSION: Further research is warranted to understand the mechanisms and significance of electromyographic breakthrough activity within the cortical silent period in congenital hemiparesis. Understanding these mechanisms may lead to the design of tailored neuromodulation interventions for physical rehabilitation. TRIAL REGISTRATION: NCT02250092 (https://clinicaltrials.gov/ct2/show/NCT02250092).
Authors: Ann-Christin Eliasson; Lena Krumlinde-Sundholm; Birgit Rösblad; Eva Beckung; Marianne Arner; Ann-Marie Ohrvall; Peter Rosenbaum Journal: Dev Med Child Neurol Date: 2006-07 Impact factor: 5.449
Authors: Bernadette T Gillick; Linda E Krach; Tim Feyma; Tonya L Rich; Kelli Moberg; Jeremiah Menk; Jessica Cassidy; Teresa Kimberley; James R Carey Journal: Arch Phys Med Rehabil Date: 2014-10-02 Impact factor: 3.966