Auditory evoked potentials : ABR, MLR, and the late auditory responses for children with and without histories of otitis media

A consequence of chronic otitis media in early childhood is a reduction of sensory stimulation of the peripheral and central auditory system. This reduction in sensory stimulation may be viewed as a form of auditory deprivation. Three groups included for this study were children with minimal history of otitis media (NL), children with history of otitis media (OMR), and children with active otitis media (AOM). The purpose was to compare the measurements of the auditory brainstem response (ABR), middle latency response (MLR), and the late auditory response (LAR) across the groups to determine if there were effects of sensory deprivation on these responses. Shorter latency for the waves I and III were identified for the NL and OMR groups when compared to the AOM group. The interwave interval latency for III-V was shorter for the AOM group when compared to the NL and OMR groups. No differences were identified between the NL and OMR groups. Waveform replication and identification were 100% for the NL group for the MLR. The numbers of waves present for the OMR group were 81.25% for the right ear and 62.5% for the left ear. The wave identification was 77.78% for the AOM group. The results show that otitis media influences the morphology and replication of the waves of the MLR. The wave N1 latency of the LAR was longer for the AOM group compared to the NL group. The P2 latency was longer for the left ear for the AOM group compared to the NL group. Consequences of otitis media were reflected in delayed wave latencies. ABR latencies on the whole were not affected by history or presence of otitis media. The percentage of subjects with MLRs was smaller for the OMR or those with AOM. LARS were delayed in latency for subjects with history of otitis media and even more delayed for subjects with active otitis media. It was hypothesized that these changes for the LAR represent alterations in the maturation pattern. The rank order pattern identified with the AOM group exhibiting the longest latencies and the OMH group second with longer latencies than the NL group suggest a slowly recovering system. Re-testing of the subjects in one year may provide additional information about recovery of the LAR latency.