Seventy male air grinder operators and 72 age-matched control
workers were examined Both groups of workers worked in the warm climate ( 20 �-33 �C) of southern Taiwan None of the workers had symptoms
of white fingers The investigation program comprised: ( 1) case history, ( 2) physical examination, ( 3) determination of maximal motor conduction velocity, proximal and distal sensory conduction velocity (NCV) of the median and ulnar nerves of the right upper extremity, ( 4) measurement of skin temperature, nail press test, pain threshold and vibratory sense threshold of
the upper extremities, and ( 5) testing of the motor function The dose-effect correlation between the NCV, various function tests and total operating time (TOT) was performed by multiple stepwise regression analyses The regression
analyses revealed a statistically significant correlation (dose/effect) between "the six NCV, vibratory sense threshold, pain threshold" and
"age", as well as "TOT".