Children With Auditory Neuropathy Spectrum Disorder (ANSD)

In 1991, Arnold Starr and colleagues described an 11-year-old child with the paradoxic findings of absent auditory brainstem responses in the presence of normal cochlear microphonics (CMs) and otoacoustic emissions (OAEs). The child demonstrated severely impaired speech understanding despite a mild loss of hearing sensitivity. Further evaluation showed impaired temporal processing as exhibited by abnormal findings on a battery of psychophysical tests that included gap detection and binaural masking level differences. In 1996, Starr and colleagues reported on a group of 10 children and adults with similar findings (Starr, Picton, Sininger, Hood, & Berlin, 1996). Although the patients presented with no apparent neurologic involvement when their hearing impairments were first identified , eight of the ten showed later evidence of other peripheral neuropathies. Starr and colleagues coined the term " auditory neuropathy " (AN) to describe patients whose hearing impairment was attributed to " neurop-athy of the auditory nerve. " Since the initial report by Starr and colleagues it has become clear that individuals diagnosed with AN are a heterogeneous group even though they may exhibit common audiologic findings. Some individuals who exhibit the AN pattern may have a congenital form of the disorder resulting from a genetic mutation or pre/perinatal causes, whereas others may have a later onset form of the disorder associated with other peripheral neuropathies. Speculation regarding the underlying mechanisms of AN includes selective inner hair cell loss, a synaptic or myelinization disorder, or an auditory nerve disorder with other peripheral neu-ropathies