Acoustic change complex (ACC) as a new tool in assessment of hearing aid performance in children

Abstract

To evaluate the clinical use of acoustic change complex (ACC) as an objective tool in children who use hearing aids (H.As) and explore how far ACC threshold could be correlated to behavioral measures. Sixty Arabic-speaking children (34 boys & 26 girls) using binaural H.As participated in the present study. Their age ranged from 6 to 12 years. The short stimulus used in the present study to elicit ACC response was “gap in tone.” Evaluation of H.As of children was performed in the form of questionnaire, aided sound field thresholds, central auditory tests, and aided/unaided cortical ACC recordings. The replicated ACC waveforms were collected and analyzed, and the aided ACC responses were compared with unaided ACC in addition to correlation of ACC-GDT to behavioral thresholds/scores. The highest percent of ACC detectability achieved with gap in tone with 50-ms duration. Percent detectability reached 65% in aided condition and decreased to 25% in unaided test condition. The aided ACC wave morphology showed no significant difference when compared with unaided condition; however, a significant decrease in ACC latency was observed in the aided condition. The ACC response was elicited easily at 40-dB sensation levels or at MCL in both conditions. The ACC-GDT showed correlation to questionnaire scores rather than behavioral test (AFT). ACC to relatively short duration stimulus can be successfully recorded in hearing-impaired children in aided and unaided conditions. ACC response parameters (detectability and P1 latency) can reflect the benefit from H.As as an objective measure in evaluation of young children and difficult to test subjects with the usual subjective measures, and finally, ACC-GDT may add a predictive value to questionnaire scores which may help in case of inability of parents or caregivers to fulfill the entire questionnaire items.