Persistence of otoacoustic emissions in children with auditory neuropathy spectrum disorders.

Objectives: Many studies confirmed the disappearance of otoacoustic emissions in some of the patients with auditory neuropathy spectrum disorder, yet the data about the incidence rate of such disappearance is scanty or even absent. This study aims to test the persistence of transient evoked otoacoustic emissions in patients with auditory neuropathy spectrum disorder over few years.

Methods: The study group consisted of 77 subjects (31 females and 46 males). Their ages ranged from 4 to 9 years (5.5 ± 1.5). All the subjects were previously diagnosed to have auditory neuropathy spectrum disorder affecting both ears. Transient evoked otoacoustic emissions test results of the recent follow up sessions were compared with their initial diagnostic evaluation sessions done 3-6 years ago (3.7 ± 0.8), in order to test the persistence of the emissions and the reduction of emissions level.

Results: The transient evoked otoacoustic emissions level was reduced in the follow up visit compared to the initial study group. The transient evoked otoacoustic emissions level showed insignificant reduction (less than 3dB) in 77.3% of the ears in the study group, and significant reduction (i.e. 3dB or more) in 20.8%, and was absent in 1.9%. The transient evoked otoacoustic emissions level reduction in the different study subgroups was homogenous; gender (males versus females) laterality (right versus left ears) incubated to neonatal intensive care unit versus those non incubated all showed no significant differences in transient evoked otoacoustic emissions level reduction. Moreover, the duration of auditory neuropathy spectrum disorder was not correlated to the degree of transient evoked otoacoustic emissions reduction. Those fitted with hearing aids had more reduction in their transient evoked otoacoustic emissions level compared with those not fitted with hearing aids.

Conclusions: (1) Transient evoked otoacoustic emissions was still detected in 98.1% of patients with auditoryneuropathy spectrum disorder few years after the diagnosis.(2) Those fitted with hearing aids showed the most pronounced reduction in transient evokedotoacoustic emissions level.