Linear and nonlinear changes in the auditory brainstem response of aging humans.
OBJECTIVE
This experiment was designed to characterize the changes in linear and nonlinear temporal interactions in the aging auditory brainstem of humans using maximum length sequence (MLS) stimulation.


METHODS
The MLS technique uses a quasi-random sequence of clicks and silences to determine the linear (linear averaging of single responses) and nonlinear (interactions between pairs or triplets of responses) temporal interactions in the auditory brainstem response (ABR). A group of 30 normal hearing females aged between 11 and 61years were tested. They were divided in three groups: young (<24years); middle (24-41years) and old (>41years).


RESULTS
The linear component showed a decrease in wave 5 amplitude with age which could also be related to increased thresholds for higher frequencies. The nonlinear component of the MLS-ABR showed significant differences between middle and old groups for wave 1 and 5 latencies and inter-wave interval (1-5).


CONCLUSIONS
The results suggest that the linear and nonlinear components of the MLS-ABR could be more sensitive to changes occurring in the auditory system before any functionally significant changes in hearing status.


CONCLUSIONS
The nonlinear components of the auditory brainstem could be used as an investigative tool to assess early changes in the aging auditory brainstem in young middle-aged women.
Lavoie
Brigitte A
BA
MRC Institute of Hearing Research, Royal South Hants Hospital, Brintons Terrace, Off St Mary's Road, Southampton, Hants SO14 OYG, United Kingdom. balavoie@soton.ac.uk
Mehta
R
R
Thornton
A R D
AR
D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D000375:Aging / Q000502:physiology*; D001300:Audiometry, Evoked Response; D001309:Auditory Threshold / Q000502:physiology; D001933:Brain Stem / Q000502:physiology*; D002648:Child; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005260:Female; D006801:Humans; D008875:Middle Aged