Figure 1.

Audiological assessment in a 5-year-old child with auditory neuropathy spectrum disorder (ANSD) caused by neonatal hypoxia. Poor unaided pure-tone perception (a, gray line) was restored with hearing aids ((a), black line). Panel (b) displays auditory brainstem responses (ABRs) evoked by clicks presented in rarefaction (R) and condensation (C) polarities and the subtraction and summation of R and C (R − C and R + C, respectively), showing detectable cochlear microphonic (CM) and absence of waves V. Electrocochleography (ECochG) recorded through a transtympanic electrode on the promontory wall using 1000 Hz tone burst presented in alternated R and C polarities at a rate of 14.3 s (c) shows a large summating potential (SP). Auditory steady-state responses (ASSRs) thresholds (d) are present in the left (X) more than in the right (O) ear.