Auditory brainstem response and otoacoustic emissions in Duane retraction syndrome

Auditory brainstem response

The auditory brainstem response (ABR), consisting of five to six vertex-positive peaks with separation of about 0.8ms, is very sensitive to factors that affect conduction velocity and hence ABR wave latencies in the brainstem auditory pathways. In addition, disorders causing dissynchronization of neural activity result in an amplitude decrease or disappearance of ABR peaks. The opposite effects occur in the maturation process, which takes about 2 years postterm; here conduction velocity increases quickly to its adult value, but synaptic delays being sensitive to synchronous release of transmitter substance take considerably longer. In neurological disorders, those that cause dissynchrony, such as auditory neuropathy and vestibular schwannoma, Gaucher disease, and Krabbe disease, the (longer latency) ABR peaks are reduced or absent. Effects on neural conduction, resulting in increased ABR interwave latencies, are found in vestibular schwannomas, Bell's palsy, Duane retraction syndrome, Marcus Gunn ptosis, and various encephalomyopathies. These measures allow an assessment of the parts of the brainstem that are involved.

Audiologic and otologic phenotype in children with Duane's Retraction Syndrome: A rare ophthalmologic disorder

OBJECTIVE

The focus of this study was to evaluate the prevalence, type, and severity of hearing impairment in patients with Duane's Retraction Syndrome and to relate these measures to patient demographics and other otologic and audiologic factors.

STUDY DESIGN

Retrospective AudGen Database analysis

SETTING

Tertiary academic referral center

PATIENTS

Pediatric patients in AudGenDB with a diagnosis of Duane's Retraction Syndrome (DRS).

INTERVENTIONS

Appropriate audiologic, otologic, and demographic data were recorded.

MAIN OUTCOME MEASURE

Seventy-nine patients (n = 79) met inclusion criteria. The first encounter with available audiometric data or the first encounter with hearing loss were documented. Audiograms were stratified by type and severity of hearing loss, and common associated medical issues were documented.

RESULTS

57 children had normal hearing; 22 had hearing loss. 9 ears had pure conductive hearing loss, 1 had pure sensorineural, 14 ears had components of both, and 79 had hearing loss that could not be specified. Multivariate regression revealed episodes of chronic otitis and craniofacial anomalies are associated with worse hearing loss.

CONCLUSION

This study presents a detailed characterization of hearing loss in patients with Duane's retraction syndrome. Conductive and sensorineural hearing loss are both prevalent among these children. Careful and early audiologic evaluation of all patients with DRS is important.