OBJECTIVE HEARING AID FITTINGS USING AUDITORY STEADY-STATE EVOKED RESPONSES
 
Shemesh R, Attias J, Hassan M, Doa G.
 
Department of Communication Disorders, University of Haifa, Haifa, Israel.

The ultimate goal of universal newborn hearing screening is to manage those born with hearing loss and if needed to rehabilitate them by fitting hearing aids immediately following auditory diagnosis and within the first few months of age. Unfortunately, infants and young children can not provide reliable behavioral responses to either aided or unaided sounds. In addition, real ear acoustic measurements are not always available in this age. Thus, the fitting of young children with hearing aids is therefore much uncertain than adults and may last months of repeated fitting sessions. Electrophysiological tests may provide an objective and reliable tool both in the diagnosis process and in the hearing aid procedure of infants and small children identified with significant hearing loss and need early auditory intervention. The present study, investigated the possible use of auditory steady state response (ASSR) in hearing aid fitting. Previous studies showed that ASSR predict accurately the behavioral auditory thresholds both at the high and low frequencies and were found to be reliable in infants and small children candidates for cochlear implants.
 
Fifteen subjects with mild to moderately severe sensorineural hearing loss with age range of  19 to 48 years, participated in this study.  The Free-filed ASSR threshold across most frequencies were highly correlated with the behavioral auditory responses. Real ear measurements revealed that the ASSR stimuli were not distorted. The intensity-amplitude ASSR growth function of the aided and unaided group differed significantly. The objective hearing aid procedure was relatively quick and could be done in a sleeping subject. The results of this study show great promise in hearing aid fitting for those who can not reliably respond on behavioral testing. This technique should reduce significantly the time between identification and auditory intervention in infants suffering from significant hearing loss.
 

E-mail: attiasj@netvision.net.il