The evaluation of children with sensorineural hearing loss.

Hearing impairment is the most common 1sensory deficit in children, and SNHL is the most common form of congenital hearing impairment. It is also a significant health care problem. More than 40 000 children are born in the United States with significant hearing impairment, including about 4000 who are profoundly deaf. The incidence is estimated at about 1 in every 1000 live births. Therefore, the otolaryngologist will frequently be challenged to determine the appropriate diagnostic regimen for this subset of children, a difficult and controversial procedure. It is well accepted that a careful history, physical examination, and audiological evaluation are the first and most crucial tools used to diagnose the cause of hearing loss. Many syndromes associated with SNHL can be diagnosed with these 3 methods. Subsequent testing remains controversial. The debate hinges on the yield and costeffectiveness of specific tests vs the risks of failing to identify a potentially significant disorder. Possible diagnostic tests include various urine and blood tests, electrocardiograms, and imaging studies. Recent articles have suggested that highresolution computed tomography (CT) has the best record of identifying underlying disorders contributing to SNHL. After performing a complete history, physical examination, and audiological evaluation, the physician must decide between 2 distinct diagnostic paradigms. The first includes performing extensive laboratory and radiographic evaluation and soliciting opinions from other consultants in fields such as ophthalmology and genetics. The Table lists the laboratory tests traditionally considered and the diagnoses they will help determine. Radiographic studies, in conjunction with laboratory tests, have also been recommended as important components of evaluation. Specifically, finecut CT of the temporal bone can demonstrate abnormalities of bony labyrinthine formation such as an enlarged vestibular aqueduct or an incomplete partition (ie, Mondini dysplasia). The second paradigm involves a more modest evaluation dictated only by abnormal findings on the history and/or physical and audiological evaluations. Proponents of this strategy take a more conservative approach to ordering special studies. Full laboratory and radiographic evaluations are expensive (nearly $2000 per patient) and produce a relatively small likelihood of determining the precise cause of the hearing loss. No matter how many tests are ordered, the diagnosis rate may still be less than 40%, although some studies have reported a higher rate of diagnoses (68%) with a more comprehensive diagnostic evaluation. Molecular genetic testing, a relatively new diagnostic technique, promises to improve the diagnosis of SNHL in children. The ability to unlock genetic information associated with hearing impairment is truly a revolutionary development. Any means to diminish the number of affected children who remain undiagnosed would seem to offer a distinct improvement in current medical care. In addition, the demands on our diagnostic acumen will increase as universal infant hearing screening programs become a reality. Otolaryngologists will begin to diagnose hearing impairment in children in the first several months of life, and parents will want to understand the cause of the problem. In light of the hundreds of mutations in dozens of genes found to be associated with hearing impairment, the identification of the high From the Department of Otolaryngology–Maxillofacial Surgery, Center for Hearing and Deafness Research, Children’s Hospital Medical Center, Cincinnati, Ohio. John H. Greinwald, Jr, MD Christopher J. Hartnick, MD CLINICAL CHALLENGES IN OTOLARYNGOLOGY