Reaction Time in Relation to Amplitude of the Achilles Tendon Reflex

The Achilles tendon reflex was elicited by mechanical percussion of the tendon at the rate of 1 blow/sec. in 32 healthy males, aged 28 to 56 yr. Amplitude of the reflex was recorded electromyographically while subjects performed a reaction task in which 75-db tones, presented at random and without a warning signal, were the stimuli. Conditions of the test were designed to provide a wide range of arousal states from drowsiness to alertness. Findings showed that there is little or no relationship—either linear or inverted-U shaped—between the reaction time and amplitude of the Achilles tendon reflex recorded immediately prior to the presentation of the auditory stimuli.