A Retrospective Study of the Hearing Loss in Microcephaly Children

Abstract

BACKGROUND Microcephaly is defined as a head circumference more than two standard deviations below the mean for gender and age. Congenital microcephaly is present at birth, whereas postnatal microcephaly occurs later in life and associated with developmental delay in children. Genetic abnormalities, syndromes, metabolic disorders, teratogens, infections, prenatal, perinatal, and postnatal injuries can cause both congenital and postnatal microcephaly. In patients with microcephaly and global developmental delay, hearing loss may affect further development. We wanted to assess and analyse the audiological profile in children with microcephaly. METHODS A cross sectional retrospective and analytical study was conducted by studying the charts and medical records of 121 children with developmental delay for a period of six month with permission of ethical committee of the institution. The children included in this study were those who came to paediatric ENT OPD of Christian Medical College, Vellore. Out of 121 children studied, 44 children had microcephaly. Hospital records from medical records section were taken and history of consanguineous marriage, detailed paediatric birth history and developmental milestone records were noted. All children had undergone detailed ENT examination including microscopic examination of the ear. Audiological evaluation was done by Behavioural Observation Audiometry (BOA), Oto Acoustic Emission (OAE) and Brainstem Evoked Response Audiometry (BERA), Tympanometry (Tymps). They showed hearing loss which was analysed. Degree of hearing loss was classified using American Speech-Language Hearing Association ASHA classification. RESULTS Among 44 children with microcephaly, there were 27 (61.4%) males. The mean age of the study group was 3.1±1.05 years. The age group below 6 yrs. in this cohort was 36 (81.8%). The youngest child in the study was 6 months old and oldest child being 10 years old. Behavioural observation Audiometry (BOA) results showed that out of 44 children, 30 (68.2%) with normal hearing and 14 (31.2%) had hearing loss. Consanguinity of marriage was seen in 7(15.9%). On examination of birth history records, these microcephaly children were born full term babies; 39 (88.6%) and 28 (63.6%) were appropriate to age. 21 (47.7%) children cried immediately at birth. Chi square test was applied, and the results show that microcephaly was not associated with hearing loss. CONCLUSIONS Among the 44 microcephaly children included in the study, 14 (31.2%) had hearing loss. Our study detected a higher incidence of undetected hearing loss among 14 (31.2%) children with microcephaly. It was concluded that children with microcephaly should be routinely screened for potential hearing loss. On statistical analysis no association of hearing loss with microcephaly was observed.