Frequency and age-dependent auditory evoked potential thresholds in infants.
Auditory evoked-potential thresholds to 0.5, 4.0 and 10.0 kHz tone pips were measured in 40 normal infants 2-28 wks old and 14 normal hearing adults. Thresholds to 500 Hz tone pips were based upon the steady-state, 40 Hz evoked potential. Thresholds to 4.0 and 10.0 kHz tone pips were based upon the brainstem response. Stimulus intensity was varied in 5-dB steps for threshold search. The greatest difference between infant and adult thresholds occurred at 4.0 kHz. The magnitude of this difference decreased with age; however, differences were still significant up to 28 wks of age. No significant differences were seen at 500 Hz. To the 10.0 kHz stimulus only the youngest (2-4 wk) infants had thresholds that were significantly higher than adults. The reasons proposed to explain these results are complex interactions between immaturity of the conductive mechanism, brainstem pathways, and possibly the cochlea.
D000161:Acoustic Stimulation; D000328:Adult; D000367:Age Factors; D001309:Auditory Threshold / Q000502:physiology; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn