Original Article Epidemiology of Severe Hearing Impairment in a Population- Based Cerebral Palsy Cohort David Dufresne MD, Lynn Dagenais BSc, Michael I. Shevell MD * REPACQ Consortium Division of Pediatric Neurology, Montreal Children’s Hospital, Department of Pediatrics, McGill University, Montreal, Quebec, Canada abstract BACKGROUND: Comorbidities including hearing impairment occur commonly in individuals with cerebral palsy (CP). METHODS: Hearing impairment was assessed in a registry-derived population-based sample of children with CP. RESULTS: Hearing impairment was documented in 12.7% (27 of 212) with less than a quarter of these (or 2.7% overall [6 of 212]) having a severe hearing loss of greater than 70 dB bi-aurally. Those with severe hearing impairment were more likely to be nonambulatory (Gross Motor Function Classification System IV/V; 100% versus 34.0% in the registry; P < 0.001) and have a spastic quadriplegic or dyskinetic CP variant (100% versus 42%, P ¼ 0.001). Severe neonatal hyperbilirubinemia necessitating exchange transfusion demonstrated a striking as- sociation with hearing impairment in the context of CP in spite of small observed numbers; three of three had severe hearing loss, accounting for 50% of cases of severe hearing loss. CONCLUSIONS: These results suggest a specific CP context and antecedent conditions that necessitate a heightened vigilance for the detection and remediation of hearing impairment. Keywords: hearing loss, CP, population-based registry, epidemiology Pediatr Neurol 2014; 51: 641-644 Ó 2014 Elsevier Inc. All rights reserved. Introduction Cerebral palsy (CP) is defined as a group of permanent disorders of movement and posture, causing activity limitation, attributed to nonprogressive disturbance that occurred in the developing fetal or infant brain, which is often accompanied by disturbance of sensation, perception, cognition, communication, and behavior, by epilepsy and by secondary musculoskeletal problems. 1 Its incidence aver- ages 2-2.5 children per 1000 live births, 2-5 making it the most common cause of physical disability in childhood. 6 Recent consensus definitions have highlighted the pres- ence of nonmotor features associated with CP such as dis- turbances of sensation, cognition, communication, perception, behavior, or a seizure disorder. 7 Although the motor features of CP are often the most visible, other comorbidities may have a profound effect on the child’s neurodevelopmental outcome, quality of life, and eventual capacity for independent living. Audition is a prerequisite in the acquisition of verbal lan- guage and eventual knowledge acquisition, so much, so that a hearing evaluation is part of the first-line evaluation in cases of language delay. Among the pediatric population, almost half the cases of sensorineural hearing loss have an inherited etiology, 8 with the etiologies generally being reported as 50% inherited, 25% acquired, and 25% unknown. Children with CP, however, have numerous potential acquired etiologies such as intrauterine and neonatal infection, hyperbilirubinemia, hypoxic-ischemic injury, prematurity, or very low birth weight that predispose them to hearing loss. Hearing loss has been reported to occur in approximately 12% of patients with CP, 9 with severe bilateral hearing loss being present in a subset. The definition of severe hearing loss, however, has been defined very differently from study to study. Review of the literature concerning hearing loss in children with CP assessed its prevalence in CP cohorts. Moderate-to-severe hearing loss was evident in 7% of their population and se- vere to profound (defined as bilateral loss of greater than Article History: Received April 24, 2014; Accepted in final form July 9, 2014 * Communications should be addressed to: Dr. Shevell; Montreal Children’s Hospital; McGill University; C-414, 2300; Montreal, Quebec H3H 1P3, Canada. E-mail address: michael.shevell@muhc.mcgill.ca Contents lists available at ScienceDirect Pediatric Neurology journal homepage: www.elsevier.com/locate/pnu 0887-8994/$ - see front matter Ó 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.pediatrneurol.2014.07.005 Pediatric Neurology 51 (2014) 641e644