Grip Force Coordination as a Determinant of Independence in Activities of Daily Living and Instrumental Activities of Daily Living in Incomplete Cervical Spinal Cord Injury: A Case Report.

Upper limb rehabilitation for individuals with cervical spinal cord injury (CSCI) primarily emphasizes strengthening residual muscles to enable grasping through the tenodesis action. While this approach is essential for achieving basic activities of daily living (ADLs), smooth object manipulation and fine motor performance require not only muscle strength but also the ability to regulate grip force. However, grip force modulation during tenodesis-based grasping has rarely been evaluated or specifically targeted in rehabilitation for cervical SCI. We report the case of a right-handed man in his late 50s with a C4-level cervical SCI who aimed to regain independence in daily activities and return to work as a school teacher. Although conventional occupational therapy led to improvements in upper limb strength and basic ADL, he continued to experience difficulty performing fine motor tasks, particularly handwriting, which required precise grip force control. Grip force regulation was quantitatively evaluated using a visual feedback-based force adjustment task, revealing greater errors during force-increasing phases than during force-decreasing phases. Based on these findings, occupational therapy was modified to incorporate training focused on grip force modulation using wrist extension, combined with explicit feedback and task-oriented practice in daily activities. At discharge, upper limb motor scores showed no further improvement; however, ADL performance improved, as reflected by higher Spinal Cord Independence Measure III scores, and the patient successfully returned to work, including performing handwriting tasks. This case suggests that assessing and training grip force regulation, in addition to muscle strengthening, may enhance functional upper limb use.