Summary

Skilled manipulatory behaviors require complex spatial and temporal coordination of the digits. In healthy individuals, visual and somatosensory feedback is processed and integrated with motor commands thus ensuring successful interactions with objects. This process can be disrupted by a number of neuromuscular diseases. One of the most severely debilitating diseases of hand function is carpal tunnel syndrome (CTS), a compression neuropathy of the median nerve resulting in (1) somatosensory deficits in the thumb, index, middle and ring fingers (lateral half) and, in severe cases, (2) motor deficits in the thumb. Most studies that have investigated the effect of CTS on grasp control have focused on force coordination between the affected digits only. For patients with CTS, control of whole-hand grasping poses the additional challenge of coordinating all digits, a subset of which is characterized by deficits in sensorimotor capabilities. Our research on five-digit grasping shows that CTS affects patients' ability to create accurate sensorimotor memories of multi-digit forces for dexterous manipulation. This knowledge significantly extends and complements the information provided by existing clinical tools to diagnose and monitor CTS, with potential to improve the efficacy of clinical interventions such as physical rehabilitation and hand surgery.

Introduction

The coordination of digit forces during manipulatory behaviors relies on the ability to effectively integrate somatosensory and visual feedback with motor commands responsible for modulating forces at individual digits.