Effects of computer keyboarding on ultrasonographic measures of the median nerve

Background Keyboarding is a highly repetitive daily task and has been linked to musculoskeletal disorders of the upper extremity. However, the effect of keyboarding on median nerve injuries is not well understood. The purpose of this study was to use ultrasonographic measurements to determine whether continuous keyboarding can cause acute changes in the median nerve. Methods Ultrasound images of the median nerve from 21 volunteers were captured at the levels of the pisiform and distal radius prior to and following a prolonged keyboarding task (i.e., 1 hr of continuous keyboarding). Images were analyzed by a blinded investigator to quantify the median nerve characteristics. Changes in the median nerve ultrasonographic measures as a result of continuous keyboarding task were evaluated. Results Cross‐sectional areas at the pisiform level were significantly larger in both dominant (P = 0.004) and non‐dominant (P = 0.001) hands following the keyboarding task. Swelling ratio was significantly greater in the dominant hand (P = 0.020) after 60 min of keyboarding when compared to the baseline measures. Flattening ratios were not significantly different in either hand as a result of keyboarding. Conclusion We were able to detect an acute increase in the area of the median nerve following 1 hr of keyboarding with a computer keyboard. This suggests that keyboarding has an impact on the median nerve. Further studies are required to understand this relationship, which would provide insight into the pathophysiology of median neuropathies such as carpal tunnel syndrome. Am. J. Ind. Med. 54:826–833, 2011. © 2011 Wiley Periodicals, Inc.