Eight subjects with carpal tunnel syndrome (CTS) (47.13 ± 7.83 years) and 8 matched controls (46.29 ± 7.27 years) manipulated a test object fitted with an accelerometer and force sensor, both before and after hand muscle fatigue. Grip force and object acceleration were recorded and used to calculate grip force control variables that included Grip Force Peak, Safety Margin, and Time to Grip Force Peak. Individuals with CTS exhibited a higher Safety Margin (p = .010) and longer Time to Peak of Grip Force (p = .012) than healthy controls during object manipulation. Once fatigued, both groups significantly decreased their grip force to perform the task (Grip Force Peak; p = .017 and Safety Margin; p < .001). Nevertheless, individuals with CTS maintained an unnecessarily high safety margin. Our results suggest that CTS can adversely affect how the central nervous system regulates grip force, which might aggravate the inflammatory process and exacerbate the symptoms of this disease.
The authors are with the Master in Human Movement Sciences Program, Sports and Health Sciences Center, Santa Catarina State University, Santa Catarina, Brazil. Domenech and Borges Junior are also with the Health Sciences Department, Sports and Health Sciences Center, Santa Catarina State University. Santos is also with the Physical Therapy Department, Sports and Health Sciences Center, Santa Catarina State University.