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Genetic Hearing Loss | Overview

Topic: Hearing loss with patients that have Trisomy 21 (Down Syndrome)
Principal Investegator: Dr. Margaret Kenna
Summary: Although hearing loss, one of the most common disabilities in children with Down syndrome (DS), is estimated to affect 38-78% compared with 2.5% in the general population, the true incidence of both conductive and sensorineural hearing loss in this population has not been determined. Therefore, we are currently conducting a retrospective review of the medical records for children enrolled in the Down Syndrome Program at Boston Children’s and who have had audiometric evaluations. The hearing status of each patient was analyzed using behavioral audiograms, tympanometric measurement, Auditory Brainstem Response (ABR) and Otoacoustic Emissions (OAEs) tests. We have also collected information on gender, age, genetics, otitis media history, and imaging (CT and/or MRI) of the temporal bones. Statistical analysis of hearing loss in relationship to these factors is ongoing. We hypothesize that both conductive and sensorineural hearing loss are common in children with DS, and may be related to gender, older age, anatomic inner ear anomalies, otitis media, and genetic type of DS.

Topic: Hearing loss with patients that have Usher Syndrome
Principal Investegator: Dr. Margaret Kenna
Summary: Usher syndrome is a rare genetic condition that causes hearings loss, retinitis pigmentosa (RP), and balance dysfunction. The degree and onset of the impairments associated with the syndrome vary. There are three clinical types of Usher syndrome (types 1, 2, and 3) which are grouped according to particular hearing loss, balance dysfunction, and vision impairment profiles.  Our current research focuses on the various clinical assessments which measure these three aspects of Usher syndrome in pediatric patients. We are working closely with doctors in Ophthalmology and Boston Children’s Balance Lab to collect patient data from these assessments and analyze these results. Our primary aim is to describe the onset and degree of the symptoms associated with each type of Usher syndrome, and the associated genetic mutations, to ultimately improve the care and treatment of these patients. We also aim to determine which exams most accurately detect Usher syndrome, to possibly facilitate earlier diagnosis. 

Topic: Autistic Spectrum Disorder in Children with Hearing Loss
Principal Investegator: Dr. Greg Licameli
Summary: To explore the possible connections between pervasive developmental disorders (PDD)/autistic spectrum disorders (ASD) and hearing loss by reviewing medical and developmental histories of individuals with both diagnoses. The presentation of PDD/ASD in children with hearing loss is not yet well understood. What is the prevalence of such dual diagnosis? Data collected will include: medical and developmental histories; the presentation of PDD/ASD symptoms (age of onset, age at diagnosis); the etiology of the hearing loss; level of cognitive functioning; communication mode most commonly used (American Sign Language, Simultaneous Communication, Spoken English, etc.); use of hearing aids or cochlear implants; language outcomes (if available). This information is needed to determine the trends that might exist in individuals with hearing loss and an autism spectrum disorder diagnosis. Analysis of data will provide the investigators with needed information to set the direction for their prospective research in this area.