[Long-term study of age-related changes in brain stem potentials in the guinea pig]

The purpose of this study was to investigate the time-related influence of aging on the lower parts of the auditory pathway. Furthermore it was intended to examine as to how far recently obtained results of studies of two different collectives correspond to individual changes correlated with age. For this purpose, auditory brain stem responses were periodically recorded in the same guinea-pigs between the age of six months and three years. Not only the thresholds, but also the latencies and amplitudes of the individual potentials were analyzed for suprathreshold stimuli. A distinct threshold elevation was found at an age of two years. The further loss of sensitivity occurring up to an age of three years was less marked. The amplitudes of all potentials showed a uniform reduction with advancing age, whereas the latencies did not differ. These age-related changes correspond to results obtained previously in two different groups.