ABSTRACT
BACKGROUND AND OBJECTIVES: 'Partial deafness' characterized by normal or slightly impaired hearing in the low frequency band and nearly total deafness in the high frequency range, is difficult to assess with conventional behavioral tests in infants and young children. Therefore, this study aimed to assess the usefulness of objective hearing tests, such as auditory brainstem response (ABR) and auditory steady state response (ASSR) in evaluating patients with partial deafness. SUBJECTS AND METHOD: One hundred thirty three patients who underwent ASSR in Ajou University Hospital from January 2008 to January 2013 were enrolled to this study. Correlations between ASSR, ABR and pure tone audiometry (PTA) thresholds were analyzed. RESULTS: ASSR thresholds of 133 patients were highly correlated with both ABR and PTA thresholds in majority of the tested frequencies. Partial deafness was detected in 9 out of 133 patients, based on the results of PTA and ASSR. ASSR thresholds of patients with partial deafness were significantly correlated with PTA thresholds in all frequencies, with especially high correlation found at 1 and 4 kHz. However, there was no significant correlation between ASSR and ABR thresholds. ABR thresholds of partial deafness patients were measured at 65 dB in one patient, 70-90 dB in 3 patients, and no response at 90 dB in 5 patients, respectively. In 8 (6%) out of 124 patients, ABR thresholds were measurable with profound hearing loss and residual hearing was observed at low frequencies. CONCLUSION: ASSR is useful for predicting residual hearing at low frequencies of infants and young children for whom assessment of hearing is difficult using conventional behavioral tests.
