Slow Cortical Responses and the Diagnosis of Central Hearing Loss in Infants and Young Children

Abstract

To evaluate the usefulness of slow cortical responses (ERA [anditory-evoked vertex responses]) for threshold estimation in infants and young children, 83 children were investigated with combinations of pure-tone autiometry, electrocochleography (ECochG) and ERA. The deviations between ECochG and ERA thresholds were correlated to brain function in order to diagnose central hearing losses. By comparing corresponding values of 2 kHz pure-tone and ERA thresholds, 32% (10/31) errors were found, mainly < 35 dB HL [hearing level]. In a group of patients with no sign of brain disorder, an overall error rate of 37% (20/53) was found. Below 35 dB HL, 72% (11/15) errors were found. In a group of patients with brain dysfunction the overall error rate was 70% (21/30), < 35 dB HL it was 84% (21/25). In the range < 35 dB HL, no significant difference (P > 0.05) in errors was found between the groups with and without brain disorders. Apparently ERA is unreliable for the estimation of moderate hearing losses and cannot detect a central hearing dysfunction. Elevated ERA thresholds may indicate a central hearing loss, but to establish this topical diagnosis, ECochG and neuropsychological examinations are necessary.