Commentary and response were provided on an article by Nathan et al (Journal of Hand Surgery; 13B(2):167-170, 1988) concerning occupational hand use and median nerve conduction slowing. In a letter to the editor, Hales contested that the research actually supported an association between occupational hand activity and slowing of nerve conduction at the carpal tunnel. Comparison of the exposure variables of repetition and force to nerve conduction results was not employed; rather, Nathan et al compared occupational grouping to nerve conduction results. Impairment of sensory conduction as influenced by length of employment, and severity of slowing with regard to occupational hand activity and previous carpal tunnel surgery were also contested. In rebuttal, Nathan states that the commentary ignores or minimizes certain important findings related to intergroup differences and follow up data which confirms a lack of association between hand use group and the prevalence of slowing. Nathan concludes that there is little objective evidence that the hand activities studied cause the conduction defect underlying carpal tunnel syndrome, but indicates that such hand use exacerbates the symptoms of carpal tunnel syndrome.