Effects of Auditory Training on Electrophysiological Measures in Individuals with Autism Spectrum Disorder

Background: Identifying objective changes following an auditory training program is central to the assessment of the program's efficacy. Purpose: This study aimed (1) to objectively determine the efficacy of a 12-week auditory processing training (APT) program in individuals with autism spectrumdisorder using auditory evoked potentials (AEPs) and (2) to identify the top central AEP predictors of the overall score on the Test of AuditoryProcessing Skills-3 (TAPS-3), the primary behavioral outcome measure of the APT program published in our earlier article. Research Design: A one-group pretraining, posttraining design was used. Study Sample: The sample included 15 children and young adults diagnosed with autism spectrum disorder. Participants underwent the APT program consisting of computerized dichotic training, one-on-one therapist-directed auditory training, and the use of remote microphone technology at home and in the classroom. Data Collection and Analysis: All participants underwent pre- A nd posttraining auditory brain stem responses (ABRs), complex auditory brain stem responses (cABRs), and auditory late responses (ALRs). Test results from ABRs and ALRs were grouped based on scores obtained in their dominant and nondominant ears. Paired t-tests were used to assess the efficacy of the training program, and least absolute shrinkage and selection operator regression was used to assess the relationship between ALRs and the TAPS-3 overall summed raw score reported in our earlier article. Results and Conclusions: When compared with pretraining results, posttraining results showed shorter ABR latencies and larger amplitudes. The cABRs showed decreased latencies of the frequency following waves, a reduction in pitch error, and enhancement of pitch strength and phase shift. ALR results indicated shorter latencies and larger amplitudes. Our earlier article showed that the TAPS-3 overall score was significantly higher after training. This study showed that the top three ALR predictors of TAPS-3 outcomes were P1 amplitude in the dominant ear, and N1 amplitude in the dominant and nondominant ears.