TY - JOUR
T1 - Priming for improved hand strength in persons with chronic tetraplegia
T2 - A comparison of priming-augmented functional task practice, priming alone, and conventional exercise training
AU - Gomes-Osman, Joyce
AU - Tibbett, Jacqueline A.
AU - Poe, Brandon P.
AU - Field-Fote, Edelle C.
N1 - Funding Information:
The authors are indebted to the research participants who volunteered to be part of this study. They are grateful for the input of Dr. Kathryn Roach who provided input regarding the study design and contributed to the organization of the data, Dr. Mark Nash and Patricia Burns who carried out the CET protocol, Kathrine Brisson who contributed to the processing of the neuropnysiologic data, Deena Cilien who assisted with administration of the subject training, Dr. Kimberly Anderson-Erisman who assisted with subject recruitment, and Dr. Larisa Hoffman who created Figure 1. This study was supported by NIH R01HD053854 (EF-F) and by the Miami Project to Cure Paralysis.
Publisher Copyright:
© 2017 Gomes-Osman, Tibbett, Poe and Field-Fote.
PY - 2017/1/17
Y1 - 2017/1/17
N2 - Many everyday tasks cannot be accomplished without adequate grip strength, and corticomotor drive to the spinal motoneurons is a key determinant of grip strength. In persons with tetraplegia, damage to spinal pathways limits transmission of signals from motor cortex to spinal motoneurons. Corticomotor priming, which increases descending drive, should increase corticospinal transmission through the remaining spinal pathways resulting in increased grip strength. Since the motor and somatosensory cortices share reciprocal connections, corticomotor priming may also have potential to influence somatosensory function. The purpose of this study was to assess changes in grip (precision, power) force and tactile sensation associated with two different corticomotor priming approaches and a conventional training approach and to determine whether baseline values can predict responsiveness to training. Participants with chronic (=1 year) tetraplegia (n = 49) were randomized to one of two corticomotor priming approaches: functional task practice plus peripheral nerve somatosensory stimulation (FTP + PNSS) or PNSS alone, or to conventional exercise training (CET). To assess whether baseline corticospinal excitability (CSE) is predictive of responsiveness to training, in a subset of participants, we assessed pre-intervention CSE of the thenar muscles. Participants were trained 2 h daily, 5 days/week for 4 weeks. Thirty-seven participants completed the study. Following intervention, significant improvements in precision grip force were observed in both the stronger and weaker hand in the FTP + PNSS group (effect size: 0.51, p = 0.04 and 0.54, p = 0.03, respectively), and significant improvements in weak hand precision grip force were associated with both PNSS and CET (effect size: 0.54, p = 0.03 and 0.75, p = 0.02, respectively). No significant changes were observed in power grip force or somatosensory scores in any group. Across all groups, responsiveness to training as measured by change in weak hand power grip force was correlated with baseline force. Change in precision grip strength was correlated with measures of baseline CSE. These findings indicate that corticomotor priming with FTP + PNSS had the greatest influence on precision grip strength in both the stronger and weaker hand; however, both PNSS and CET were associated with improved precision grip strength in the weaker hand. Responsiveness to training may be associated with baseline CSE.
AB - Many everyday tasks cannot be accomplished without adequate grip strength, and corticomotor drive to the spinal motoneurons is a key determinant of grip strength. In persons with tetraplegia, damage to spinal pathways limits transmission of signals from motor cortex to spinal motoneurons. Corticomotor priming, which increases descending drive, should increase corticospinal transmission through the remaining spinal pathways resulting in increased grip strength. Since the motor and somatosensory cortices share reciprocal connections, corticomotor priming may also have potential to influence somatosensory function. The purpose of this study was to assess changes in grip (precision, power) force and tactile sensation associated with two different corticomotor priming approaches and a conventional training approach and to determine whether baseline values can predict responsiveness to training. Participants with chronic (=1 year) tetraplegia (n = 49) were randomized to one of two corticomotor priming approaches: functional task practice plus peripheral nerve somatosensory stimulation (FTP + PNSS) or PNSS alone, or to conventional exercise training (CET). To assess whether baseline corticospinal excitability (CSE) is predictive of responsiveness to training, in a subset of participants, we assessed pre-intervention CSE of the thenar muscles. Participants were trained 2 h daily, 5 days/week for 4 weeks. Thirty-seven participants completed the study. Following intervention, significant improvements in precision grip force were observed in both the stronger and weaker hand in the FTP + PNSS group (effect size: 0.51, p = 0.04 and 0.54, p = 0.03, respectively), and significant improvements in weak hand precision grip force were associated with both PNSS and CET (effect size: 0.54, p = 0.03 and 0.75, p = 0.02, respectively). No significant changes were observed in power grip force or somatosensory scores in any group. Across all groups, responsiveness to training as measured by change in weak hand power grip force was correlated with baseline force. Change in precision grip strength was correlated with measures of baseline CSE. These findings indicate that corticomotor priming with FTP + PNSS had the greatest influence on precision grip strength in both the stronger and weaker hand; however, both PNSS and CET were associated with improved precision grip strength in the weaker hand. Responsiveness to training may be associated with baseline CSE.
KW - Activities of daily living
KW - Hand function
KW - Human movement system
KW - Rehabilitation
KW - Spinal cord injury
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UR - http://www.scopus.com/inward/citedby.url?scp=85012049324&partnerID=8YFLogxK
U2 - 10.3389/fneur.2016.00242
DO - 10.3389/fneur.2016.00242
M3 - Article
AN - SCOPUS:85012049324
VL - 7
JO - Frontiers in Neurology
JF - Frontiers in Neurology
SN - 1664-2295
IS - JAN
M1 - 242
ER -