ABSTRACT
The application of probe-microphone measurements to children is one of the most useful new developments in pediatric hearing aid selection. They offer a reliable method to verify hearing aid selection decisions. To assess the matching between real ear insertion gain [REIG] and prescribed target gain according to the desired sensation level [DSL] formula. This study included 40 ears of 30 children aged between 4 to 12 years with different degrees of hearing loss. They were fitted with linear hearing aids [10 binaural and 20 monaural]. Real ear unaided response [REUR], and real ear aided response [REAR] were measured. The real ear insertion gain was then calculated and compared to the prescribed target gain. There were 26 ears [of 19 children] failed to be within 10 dB of the DSL target gain at one or more frequencies from 500-3000Hz. Among these 26 ears who failed to achieve the DSL target gain, there were 16 ears [61.5%] found to have a flat audiogram and 13 ears [50%] had profound hearing loss. The difference in hearing threshold level was found to be of no clinical value in predicting the likelihood of failure. After appropriate modifications in hearing aid fitting, out of the 16 children [22 ears] who attended for hearing aid modifications, 18 ears [82 %] achieved a satisfactory gain within 10dB of the DSL target at all frequencies up to 3000Hz. No audiometric index was of clinical value in predicting those cases that required insertion gain measurements to ensure an adequate hearing aid prescription. The number of children who fail to achieve adequate gain with their initial hearing aid fitting is very high. These children have a wide range of degree and configuration of hearing loss. The routine measurement of real ear insertion gain in all first-time fittings would result in greatly improved amplification in many patients. More research in the field of pediatric hearing aid fitting is recommended to ensure delivery of adequate amplification to infants and young children