Radiological Anatomy of Inner Ear Malformation in Hearing Impaired Children and it's Correlation with Hearing Loss: A Hospital Based Observational Study.

Abstract

To see the radiological anatomy of inner ear malformations in hearing impaired children. This study was a prospective observational study done at a tertiary care teaching hospital in north India. The included were children of 1-7years with first time detected severe to profound SNHL. The evaluation of hearing was done by brainstem evoked response audiometry. Those with history of chronic suppurative otitis media and conductive hearing loss were excluded. The all included were undergone high resolution computed tomography of the tympano-mastoid region. A written informed consent was taken. The institutional ethics committee approved the study protocol. We screened 130 children of 1-7years of age with complaints of severe to profound hearing impairment (SNHL) by BERA. We excluded 38 and 14 children who had conductive hearing loss with or without CSOM and did not give consent, respectively. Among recruited 78 children, 47 (60.3%) had severe (71-90dB) and 31 (39.7%) had profound (>90dB) SNHL. The majority of children (60/78, 76.9%) had a bilateral hearing impairment, only 18 (23.1%) had unilateral hearing impairment. The mean±SD of age was 3.9±1.3years (95% CI=3.6-4.2). The incidence of severe to profound SNHL was higher, though not statistically significant among the girls. Only 7.7% children with severe to profound SNHL were detected within first 2years of life. Most of the children (92.3%) with severe to profound SNHL were detected after 2years of age. Among 78 with severe to profound SNHL, 16 (20.5%) children had structural anomalies in their internal ears. Only 2 (6.9%) ears had single anomaly, others (27, 93.1%) had multiple anomalies. A maximum number of anomalies found in one ear were 5. The most common anomalies were found in the vestibule. The total number of anomalies were 115. Five children (6.4%) with severe to profound SNHL had craniofacial dysmorphism. Approximately 20% of children with severe to profound SNHL have congenital anomalies in their internal ears. It is crucial to know these anomalies before planning of CI. HRCT of tympano-mastoid is the first modality to know these anomalies. MRI should also be included to know the details of vestibulocochlear nerve. Since, the neurocognitive outcome would be the best if CI will be done as early as possible preferably around 1year of age. Therefore, children must be screened at the appropriate age, firstly by OAE followed by BERA.