Nonparetic Arm Force Does Not Overinhibit the Paretic Arm in Chronic Poststroke Hemiparesis  Michael A. Dimyan, MD, Monica A. Perez, PT, PhD, Sungyoung Auh, PhD, Erick Tarula, MD, Matthew Wilson, MD, Leonardo G. Cohen, MD  Archives of Physical Medicine and Rehabilitation  Volume 95, Issue 5, Pages 849-856 (May 2014) DOI: 10.1016/j.apmr.2013.12.023 Copyright © 2014 American Congress of Rehabilitation Medicine Terms and Conditions

Fig 1 Stroke lesion overlap map. The color map demonstrates the voxels in which stroke lesions overlapped across the enrolled patients overlaid on a template normalized brain. The figure demonstrates that stroke affected corticofugal white matter in all 9 patients. Archives of Physical Medicine and Rehabilitation 2014 95, 849-856DOI: (10.1016/j.apmr.2013.12.023) Copyright © 2014 American Congress of Rehabilitation Medicine Terms and Conditions

Fig 2 The nonparetic arm force does not overinhibit the paretic arm. (A) Diagrams provide a reference for the graphs in B, C, and D. On the left, all graphs represent the data obtained from the paretic arm while the nonparetic arm produced force. In the middle, all the graphs represent data obtained from the nonparetic arm while the paretic arm produced force. Finally, on the far right in all the graphs, the data from the healthy controls are seen. (B) In healthy controls and patients with stroke producing force with the paretic arm, IHI (%changeIHI) increases. In patients with stroke producing force with the nonparetic arm, IHI is significantly reduced, demonstrating that there is not an overinhibition but rather an underinhibition from nonparetic to paretic arms. (C) Local inhibition (%changeSICI) is reduced in healthy controls and in the nonparetic arms of patients producing force with the paretic arm. However, local inhibition does not change in the paretic arm when the nonparetic arm produces force. (D) Corticospinal excitability (%changeMEP) increases in healthy controls and in the nonparetic arms of patients with stroke producing paretic arm force. However, excitability does not change in the paretic arm when patients with stroke produce force with the nonparetic arm. *Statistically significant difference, P<.05. Archives of Physical Medicine and Rehabilitation 2014 95, 849-856DOI: (10.1016/j.apmr.2013.12.023) Copyright © 2014 American Congress of Rehabilitation Medicine Terms and Conditions

Fig 3 Inhibition and hand function. A robust regression revealed a positive relation between increasing IHI (%changeIHI) targeting the paretic arm during nonparetic force and paretic arm performance on the NHPT. The gray point is the outlier identified by the robust regression method. Archives of Physical Medicine and Rehabilitation 2014 95, 849-856DOI: (10.1016/j.apmr.2013.12.023) Copyright © 2014 American Congress of Rehabilitation Medicine Terms and Conditions