Date of Degree


Document Type

Capstone Project

Degree Name



Physical Therapy


Wei Zhang

Subject Categories

Physical Therapy


We investigated the effect of anesthesia, causing absent tactile sensation feedback, on multi-digit coordination underlying hand control. The purpose of the study is to expand our understanding on the essential role of tactile sensation feedback in the sensorimotor integration process by examining the motor coordination patterns during multi-digit forces production tasks. We hypothesized that absent tactile sensation feedback would interrupt the force sharing pattern at local and non-local digits. Twelve participants were utilized for data collection and statistical analysis (25.6 ± 4.1 years old, 6 males and 6 females), right-handed (according to their preferred hand use for writing and eating) and had no significant hand injury within the last five years. All participants performed a maximal voluntary contraction (MVC), ramp, and step task, pre- and post-anesthesia. In general, participants presented lower maximal force production in all MVC conditions after anesthesia, total MVC force was not distributed evenly among individual digits, and when sensory function of the MVC involved digits are uniformly absent or intact, force sharing pattern across the individual digits would be maintained. When the instructed finger (master finger) was index, other fingers (enslaved fingers) barely produced force. However, other enslaved fingers showed relatively higher forces when the master finger was ring or little finger. When required force level increased, performance error was increased accordingly. The findings from the current study confirmed our hypothesis that absent tactile sensation feedback (somatosensory feedback) will not only affect force production at local digits, but also at non-local digits as well.