DEVELOPMENT OF AN OPTIMIZED METHOD FOR THE CLINICAL ASSESSMENT OF BINAURAL FUNCTION

Abstract

Obscure auditory dysfunction describes auditory deficits despite normal audiometric results. The causes are difficult to elucidate and not adequately assessed by currently available clinical assessments. Interaural phase difference (IPD) detection may be behavioural indicator of peripheral synaptic function because it reflects phase locking to temporal fine structure, sensitivity declines with age without reduced hearing, and it reflects temporal synchronization in the nerve. The objective was to develop three assessments to establish frequency thresholds for IPD detection, and to evaluate their efficiency and reliability; three alternative forced choice (3AFC), continuous adaptive tracking (CAT), and continuous non-adaptive tracking (CNT). Piloting revealed the 3AFC and CAT warranted investigation, and CNT was removed. Thresholds were correlated and demonstrated reliability. The CAT test was the most efficient and reliable. Age was a predictor of IPD thresholds for both tests. Findings indicate the CAT test is a promising approach to assess IPD detection in the clinic.