Grip Force Regulation During Pinch Grip Lifts Under Somatosensory Guidance: Comparison Between People With Stroke and Healthy Controls  Jannette M. Blennerhassett, BAppSc(PT), Leeanne M. Carey, PhD, Thomas A. Matyas, PhD  Archives of Physical Medicine and Rehabilitation  Volume 87, Issue 3, Pages 418-429 (March 2006) DOI: 10.1016/j.apmr.2005.11.018 Copyright © 2006 American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation Terms and Conditions

Fig 1 Grip and load forces applied to pinch grip, lift, and hold object. Grip force applied perpendicularly to surface and load force tangential to surface are shown. Interchangeable surfaces and concealing screen also shown. Archives of Physical Medicine and Rehabilitation 2006 87, 418-429DOI: (10.1016/j.apmr.2005.11.018) Copyright © 2006 American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation Terms and Conditions

Fig 2 PGLH trial. (A) Grip and load force are shown relative to (B) velocity and vertical position for 1 PGLH trial performed by a matched control. Dashed vertical lines delineate the PGLH phases and the phases are labeled beneath. A horizontal line indicates the slip force. The safety margin is the difference between grip force and slip force as indicated by an arrow. Details of PGLH variables for each phase are outlined in table 2. Archives of Physical Medicine and Rehabilitation 2006 87, 418-429DOI: (10.1016/j.apmr.2005.11.018) Copyright © 2006 American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation Terms and Conditions

Fig 3 PGLH examples. (A) Typical performance of a matched control; (B) mildly impaired stroke performance; and (C) severely impaired stroke performance. (Two examples are shown for each person. Lifting conditions are Rubber 400 and Teflon 400.) (D) Unsuccessful lifting attempts by 2 stroke participants. Archives of Physical Medicine and Rehabilitation 2006 87, 418-429DOI: (10.1016/j.apmr.2005.11.018) Copyright © 2006 American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation Terms and Conditions

Fig 4 Stroke (ipsilesional and contralesional hands) and matched-control scores for selected PGLH variables: (A) preload time; (B) load time; (C) preload grip force maximum; (D) transition grip force maximum; (E) slip force; and (F) safety margin. The object condition is Rubber 400. Archives of Physical Medicine and Rehabilitation 2006 87, 418-429DOI: (10.1016/j.apmr.2005.11.018) Copyright © 2006 American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation Terms and Conditions

Fig 5 Influence of object condition on PGLH variables for matched controls (left side) and stroke contralesional (right side) for (A) preload time; (B) maximum grip force in transition phase; and (C) safety margin. Archives of Physical Medicine and Rehabilitation 2006 87, 418-429DOI: (10.1016/j.apmr.2005.11.018) Copyright © 2006 American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation Terms and Conditions

Fig 6 Mean safety margins for stroke and matched controls recorded for the differing object weight and grip surface. The object condition is arranged in order from that requiring least to most grip force to lift. Archives of Physical Medicine and Rehabilitation 2006 87, 418-429DOI: (10.1016/j.apmr.2005.11.018) Copyright © 2006 American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation Terms and Conditions

Fig 7 Relationship between standardized deficit scores for preload time and grip force for the contralesional hand of (A) stroke and (B) matched controls. Both scatterplots have similar axes to aid group comparison. For both variables, a dashed line shows the criterion of abnormality indicated by standard deficit score of 0 SDU. An SDU corresponds to 1 SD of matched-control performance. The lower left quadrant indicates normative performance for both variables as defined by matched-control data. Archives of Physical Medicine and Rehabilitation 2006 87, 418-429DOI: (10.1016/j.apmr.2005.11.018) Copyright © 2006 American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation Terms and Conditions