Differential patterns of cortical reorganization following constraint-induced movement therapy during early and late period after stroke: A preliminary study

Article type: Research Article

Authors: Sawaki, Lumy^{a; b; *} | Butler, Andrew J.^{c; d} | Leng, Xiaoyan^a | Wassenaar, Peter A.^e | Mohammad, Yousef M.^f | Blanton, Sarah^c | Sathian, K.^{c; d; g} | Nichols-Larsen, Deborah S.^h | Wolf, Steven L.^{c; d} | Good, David C.^{a; i} | Wittenberg, George F.^{a; j}

Affiliations: [a] Department of Neurology, Program in Rehabilitation, Wake Forest University, Winston Salem, NC, USA | [b] Department of Physical Medicine and Rehabilitation, University of Kentucky, Lexington, KY, USA | [c] Emory University, School of Medicine, Department of Rehabilitation Medicine, Atlanta, GA, USA | [d] Atlanta VAMC Rehabilitation R&D Center of Excellence in Rehabilitation of Aging Veterans with Vision Loss, Decatur, GA, USA | [e] Department of Radiology, The Ohio State University, Columbus, OH, USA | [f] Department of Neurology, The Ohio State University, Columbus, OH, USA | [g] Emory University, School of Medicine, Department of Neurology, Atlanta, GA, USA | [h] The Ohio State University, School of Allied Medical Professions, Columbus, OH, USA | [i] Penn State Milton S. Hershey Medical Center, Department of Neurology, Hershey, PA, USA | [j] VAMHCS, Geriatrics Research, Education, and Clinical Center, and University of Maryland, Department of Neurology, Baltimore, MD, USA

Correspondence: [*] Address for correspondence: Lumy Sawaki, MD, PhD, Associate Professor, Cardinal Hill Endowed Scholar in Stroke and Spinal Cord Injury Research, Department of Physical Medicine and Rehabilitation, University of Kentucky, Cardinal Hill Rehabilitation Hospital, 2050 Versailles Road, Lexington, KY 40504, USA. Tel.: +1 859 323 6226; Fax: +1 859 323 1123; E-mail: lumy.sawaki@uky.edu

Abstract: Objective:Constraint-induced movement therapy (CIMT) has been shown to improve upper extremity voluntary movement and change cortical movement representation after stroke. Direct comparison of the differential degree of cortical reorganization according to chronicity in stroke subjects receiving CIMT has not been performed and was the purpose of this study. We hypothesized that a higher degree of cortical reorganization would occur in the early (less than 9 months post-stroke) compared to the late group (more than 12 months post-stroke). Methods:17 early and 9 late subjects were enrolled. Each subject was evaluated using transcranial magnetic stimulation (TMS) and the Wolf Motor Function Test (WMFT) and received CIMT for 2 weeks. Results:The early group showed greater improvement in WMFT compared with the late group. TMS motor maps showed persistent enlargement in both groups but the late group trended toward more enlargement. The map shifted posteriorly in the late stroke group. The main limitation was the small number of TMS measures that could be acquired due to high motor thresholds, particularly in the late group. Conclusion:CIMT appears to lead to greater improvement in motor function in the early phase after stroke. Greater cortical reorganization in map size and position occurred in the late group in comparison. Significance:The contrast between larger functional gains in the early group vs larger map changes in the late group may indicate that mechanisms of recovery change over the several months following stroke or that map changes are a time-dependent epiphenomenon.

Keywords: Plasticity, recovery, transcranial magnetic stimulation, upper extremity, motor

DOI: 10.3233/NRE-141132

Journal: NeuroRehabilitation, vol. 35, no. 3, pp. 415-426, 2014