Personal Amplification for School-Age Children with Auditory Processing Disorders

Background: Children with auditory processing disorders (APD) are described to have a signal-to-noise ratio (SNR) difficulty. Frequency-modulated (FM) systems have been reported to improve this situation. Yet the use of personal amplification that may be more portable has not been attempted. Purpose: To determine whether personal amplification would result in improvement in speech-in-noise performances (attentiveness and speech recognition) and daily functioning in children with diagnosed APD. In addition, the desired hearing aid features (such as required gain, directional microphone and noise reduction, and open-ear fitting) are examined. Research Design: A single-blind, longitudinal descriptive study in which subjects served as their own control in various hearing aid conditions. Study Sample: Fourteen normal hearing children who had a diagnosis of APD and who were between the ages of 7 and 11 participated. Intervention: All subjects wore bilateral, mild-gain, behind-the-ear, wide dynamic range compression hearing aids fitted in an open-ear mode. Gain on the hearing aids was adjusted to provide approximately 10 dB of insertion gain for conversational input. Directional microphone and noise reduction were used on the hearing aids. Subjects wore the hearing aids home and were encouraged to use them as much as possible in their daily environments (school, home, and social activities). Subjects were seen four times: an initial visit where hearing aids were fitted, then visits at 2 weeks, 3 months, and 6 months after the initial fitting. The majority of the testing was completed during these final three visits. Data Collection and Analysis: The children were evaluated on the Northwestern University word-list (NU-6) and the Auditory Continuous Performance Test (ACPT) in noise at most visits. The hearing aids were evaluated in the omnidirectional microphone mode only, omnidirectional microphone with noise reduction (NR) mode, and directional microphone with NR mode. The children's parents and teachers were asked to complete the Children's Auditory Processing Performance Scale (CHAPS) questionnaire both before and at the end of the study. Results: The results showed that the use of hearing aids in the omnidirectional microphone mode alone did not improve speech identification in noise over the unaided condition. However, the inclusion of the NR algorithm and directional microphones improved speech understanding in noise. Amplification reduced the number of errors on the ACPT and improved several areas on the CHAPS; however, the results were not statistically significant. Conclusions: The use of mild-gain, open-ear fitting hearing aids with a directional microphone and noise reduction algorithm may be attempted on some children with APD on a trial basis.