STEADY-STATE AUDITORY-EVOKED RESPONSES TO PULSED FREQUENCY MODULATIONS IN CHILDREN

This study investigated steady-state auditory evoked responses to puls ed frequency modulations (FM) of a continuous tone in normal children ranging in age from 6 to 12 years. We examined variations in response amplitude and phase as a function of age, recording site, and FM pulse duration. The surface topography of these evoked potentials suggested a relatively broad distribution with maximal responses observed at fr ontal electrode sites, smaller responses from parietal leads and the s mallest responses were evident at the temporal lobe placements. Respon se parameters varied significantly as a function of pulse duration. Fi fty milliseconds pulses elicited responses that were on average 20% la rger than 100 ms FM pulses. Mean phase differences suggested that resp onses to the 100 ms pulses also lagged behind responses to the 50 ms p ulses by the equivalent of 20 ms. There were no significant age-relate d variations in response amplitude. Phase varied with age only in resp onse to the 50 ms FM pulses. The findings indicated that steady-state responses are sensitive to temporal parameters of frequency change pre sent in pulsed modulations. The possibility is raised that this paradi gm may be clinically useful in detecting dysfunction of specialized au ditory mechanisms involved in frequency modulation analysis. (C) 1997 Elsevier Science Ireland Ltd.