Reaction Time of Jaw Movement to Auditory and Tactile Stimulation in Children

It has been hypothesized that the development of speech is achieved through auditory and tactile or kinesthetic monitoring and that early in life the auditory channel is the more important while later it becomes secondary. It was assumed that a servosystem operates through its more efficient feedback channel and that one evidence of efficiency is reaction time to stimuli. Reaction times were obtained by a bite mechanism on 60 normal children 4 through 11 yr. of age. Stimuli were a 1000 Hz tone at 88 db re .0002 dy/cm 2 and a 10-gm. touch to the lower lip. Biting reaction time for children ages 6 through 11 is shorter for tactile than for auditory stimulus. For 4- and 5-yr.-old children the difference is not significant, bur there is a trend toward shorter auditory than tactile reaction times. This study supports the important function of tactile feedback in the monitoring of speech, especially beyond about 5 yr. of age.