Speed and Rhythm Affect Temporal Structure of Variability in Reaching Poststroke: A Pilot Study

ABSTRACT

Temporal structure reveals the potential adaptive strategies employed during upper extremity movements. The authors compared the temporal structure of upper extremity joints under 3 different reaching conditions: preferred speed, fast speed, and reaching with rhythmic auditory cues in 10 individuals poststroke. They also investigated the temporal structure of these 3 reaching conditions in 8 healthy controls to aid in the interpretation of the observed patterns in the poststroke cohort. Approximate entropy (ApEn) was used to measure the temporal structure of the upper extremity joints. ApEn was similar between conditions in controls. After stroke, ApEn was significantly higher for shoulder, elbow, and wrist both at fast speed and with rhythmic cues compared with preferred speed. ApEn at index finger was significantly higher only with rhythmic cues compared with preferred speed. The authors propose that practice reaching at faster speed and with rhythmic cues as a component of rehabilitation interventions may enhance adaptability after stroke.

Keywords:

• nonlinear
• rhythm
• stroke
• temporal structure
• upper extremity

Funding

Dr. Nick Stergiou was supported by the Center for Research in Human Movement Variability of the University of Nebraska Omaha and the NIH (P20GM109090). Dr. Lorie Richards and Dr. Carolynn Patten were supported by the Department of Veterans Affairs Rehabilitation Research and Development Service, Rehabilitation Research and Development Center, grant F2182C (Leslie J. Gonzalez Rothi), Career Development Award II B4789W (Lorie Richards), Pilot Grant B5016R and Research Career Scientist grant F7823S (Carolynn Patten), and NIH grant 1 R03 HD051624 (Lorie Richards).