B. Conewesson et al., EFFECT OF STIMULUS LEVEL AND FREQUENCY ON ABR AND MLR BINAURAL INTERACTION IN HUMAN NEONATES, Hearing research, 106(1-2), 1997, pp. 163-178
Auditory brainstem (ABR) and middle latency (MLR) responses were evoke
d by click and tone-burst stimuli from human neonates. Electrophysiolo
gic evidence of binaural interaction was measured by subtracting wavef
orms obtained for binaural stimulus conditions from waveforms obtained
for the sum of right ear monaural and left ear monaural stimulus cond
itions. The effects of stimulus level and stimulus frequency on binaur
al interaction were evaluated by measuring the number, latency and amp
litude of components found in the derived binaural interaction wavefor
m, that is, binaural interaction components (BIG). BICs were more prev
alent in the latency range of ABRs than for MLRs. Click and tonal stim
uli were equally effective for deriving ABR-BICs, while tone-bursts we
re somewhat less effective than clicks for deriving MLR-BICs. Stimulus
-response dependencies for ABR and MLR component latencies were appare
nt in monaural, binaural and binaural interaction waveforms. Normalize
d amplitudes for BICs showed that low-frequency tone-burst stimuli res
ulted in the largest values compared to click and high-frequency tonal
stimuli. Comparison of these results with published results from adul
ts demonstrated immaturity of binaural interaction in neonates.