A Case of Auditory Neuropathy with Recovery of Normal Hearing
A six-year-old boy presented to the outpatient clinic with abnormalities of hearing and language development. The patient was born vaginally at 40 weeks. No congenital anomalies were evident at birth. However, he was not able to speak until 16 months of age and his response to external sound stimuli was slow. He showed no ABR-response to 65 dB nHL click stimuli at 16 months age. Since then he had worn a hearing aid in the right ear (). At 25 months of age, aided hearing threshold was about 30 dB HL in sound field pure tone audiometry (). He wore the hearing aid for another 2 years.\nAt 5 years, 10 months of age, he visited our hospital for a hearing evaluation. His parents related that his hearing function seemed to have improved with time, because he had no difficulty communicating with others without a hearing aid. Physical examination revealed that both tympanic membranes were normal. ABR test showed no click sound response in both ears at 90 dB nHL (). Transient evoked otoacoustic emission showed response reproducibility of 88% (right ear) and 95% (left ear), and normal distortion product otoacoustic emissions responses were reported (). These results were compatible with auditory neuropathy. However, normal pure tone threshold was evident at both ears; speech reception threshold was 22 dB (right ear) and 26 dB (left ear) and speech discrimination score was 96% (right ear) and 88% (left ear) (). He was recommended to stop wearing the hearing aid. A language development test conducted at 7 years, 4 months of age revealed an age equivalent of 6 years on expressive vocabulary test and 5 years on receptive vocabulary test. Language developmental delay and mild phonological disorder were diagnosed. He is still participating in language therapy