Hearing Impairment among Children and Adolescents of Consanguineous Parents: A Study with Practical Challenges Encountered in Malakand, Northern Pakistan

Aim: The aim of the present study is to determine the prevalence of HI and its association with parental consanguinity in urban and rural areas of Malakand District, Khyber Pakhtunkhwa Province, Pakistan.

Methods: In this community-based study, data was collected by random sampling method. Families with children were recruited in the study sample. Families without children were excluded from the study sample. Information was collected by questionnaire from 1,506 families in their homes from January 2011 to February 2013 and from September 2013 to April 2014. Data collection was interrupted several times due to security concerns in the study area. In the first phase, data collection was not enough. After a while, sampling was resumed to achieve a reasonable sample size. Otoscope, Tympanometry, Tuning fork testing (Rinne Test) and Audiometry were used in this study. Audiometry was for air conduction (AC) and bone conduction (BC). Subjective testing was performed including pure tone audiometry, free field speech tests, evoked response audiometry, visual reinforcement audiometry (VRA), play audiometry (PA), speech testing and tuning fork tests. Objective testing was performed including tympanometry. Pure Tone Audiometry (PTA) was used to record the degree and types of HI in children and adolescents.

Results: A total of 7,888 out of 8,227 children born to consanguineous parents were recruited in this study. 339 children were excluded from the study sample due to incomplete data. Couples were recorded as first (F ≥ 0.125), second (F ≥ 0.0156), or third degree cousins (F ≥ 0.0039), and unrelated (F = 0.00). The HI testing, principally by free field speech testing, otoscopy, tuning fork tests, evoke response, visual reinforcement audiometry (VRA), play audiometry (PA) were initially performed at homes with pure tone audiometry (0.5-2kHs2) and tympanometry used to confirm and record the severity of HI in the HI examination centre at Seena Medical Centre at Dargai.

Conclusion: We found a strong positive association between parental consanguinity and HI. There is a need of several efforts, including awareness and genetic counselling programs for Hearing Impairment. Prevention is becoming highly essential to reduce the risk incidence of genetic hearing loss. Meanwhile, consanguinity should be discouraged through health education of the public concerning the adverse effect of interrelated marriage. Genetic counselling, Pre-marital and antenatal screening are to be applied whenever possible, at least for those at risk of developing genetic diseases including hearing impairment.