Diagnostic Accuracy of ABR Wave I Amplitude and SPIN Test in Identifying Cochlear Synaptopathy: A Case-Control Study

Abstract

Cochlear synaptopathy represents auditory dysfunction where patients present with normal pure tone audiometry but experience tinnitus and speech-in-noise difficulties. This case-control study at King Edward Medical University evaluated the diagnostic capability of auditory brainstem response (ABR) Wave I amplitude and Speech Intelligibility in Noise (SPIN) test in identifying cochlear synaptopathy among 60 participants (30 cases, 30 controls) with normal hearing thresholds. ABR Wave I amplitude was significantly reduced in cases (0.14±0.04 μV) compared to controls (0.24±0.02 μV), p<0.001. SPIN scores were lower in cases (72.8±9.1%) versus controls (95.1±2.8%), p<0.001. Using <0.20 μV for Wave I and <90% for SPIN as thresholds, sensitivity and specificity exceeded 93% for both measures. These findings support ABR Wave I amplitude and SPIN testing as reliable diagnostic tools for hidden hearing loss in Pakistani populations with noise exposure.