Whether A Positive Response at approximately 4.5 ms in Auditory Brainstem Response Signifies Cochlear Nerve Deficiency in Infants?

ObjectivesA positive response around 4.6 ms latency (IV wave) was observed at high intensity level in the ears which were always diagnosed with cochlear nerve deficiency (CND). This study is aimed to investigate the relationship between the IV wave and CND. Study DesignRetrospective study. SettingTertiary hospital MethodsThe raw Auditory Brainstem Response data and inner ear images of the infants were reviewed. Data were analyzed by ear and the CND ears were further divided into the IV wave present and IV wave absent group. The distortion product otoacoustic emissions (DPOAE) and auditory steady-state response (ASSR) results were compared between the two groups. ResultsIn total, 570 ears were included. There were 129 ears diagnosed with CND and the IV wave was observed in 52 ears. The latency of the IV wave averaged 4.60 ms at 95 dB. The positive predictive value of the IV wave for CND was 98.1%. The incidence of the IV wave in the CND is highly unlikely to occur by chance. The differences of the DPOAE amplitude between the two groups were not significant. The ASSR results of the IV wave present group was significantly better. ConclusionsOur study demonstrated a 4.6 ms positive response at high intensity level in the infants. The IV wave showed an excellent positive predictive value for CND. The extrapolated thresholds of the IV wave present group were better. The IV wave is expected to be a new indicator for the CND infants.