Evaluation of auditory pathways and comorbid inner ear malformations in pediatric patients with Duane retraction syndrome

Aims and objectives

This study aimed to investigate the presence, type, and severity of hearing losses in individuals with Duane Retraction Syndrome (DRS), and to ascertain if there are anomalies in the auditory pathways at the brainstem level in DRS, believed to arise from aberrant interaction between cranial nerves and brainstem nuclei.

Study design

Cross-sectional observational study.

Setting

Tertiary referral centre.

Patients

The study group comprised 20 patients diagnosed with DRS, aged between 5 and 18 years, who underwent ophthalmological, otological and audiological follow-up at our clinic. The control group was established using data obtained from the previous work of Sanfins M.D., et al., 2022.

Interventions

Participants underwent tympanometry and pure tone audiometry after ophthalmological and otological examination. Patients with hearing loss underwent auditory brainstem response (ABR) testing, while patients with normal hearing underwent temporal CT and MRI to detect possible aetiology.

Main outcome measures

Tympanograms, air and bone conduction pure tone averages, latencies of wave I, III and V and interwave latencies as well as radiological findings on CT and MRI were noted.

Results

Profound sensorineural hearing loss was detected in two of the 20 patients. One of the patients with hearing loss had left-sided exo-Duane, cochlear aplasia with dilated vestibule (CADV) anomaly in the right ear and profound sensorineural hearing loss in the right ear. The other patient had bilateral exo-Duane, incomplete partition type I (IP-I) malformation in the right ear and profound sensorineural hearing loss in the right ear. There was no significant difference observed in the ABR latencies of wave I, III, and V, as well as the inter-wave latencies, between the control group and the individuals diagnosed with DRS who had normal hearing.

Conclusions

No statistically significant difference was found in auditory brainstem responses between the control group and patients with DRS without hearing loss. It can be speculated that Duane retraction syndrome and hearing loss do not share a common pathogenesis at the level of the brainstem. However, it should be noted that hearing loss may be associated with inner ear malformations in DRS patients.