Auditory Discrimination-A Missing Piece of Speech and Language Development: A Study on 6-9-Year-Old Children with Auditory Processing Disorder

Auditory discrimination, the hearing ability crucial for speech and language development, allowing one to perceive changes in volume, duration and frequency of sounds, was assessed for 366 participants with normal peripheral hearing: 220 participants with auditory processing disorders (APD) and 146 typically developing (TD) children, all aged 6-9 years. Discrimination of speech was tested with nonsense words using the phoneme discrimination test (PDT), while pure tones-with the frequency pattern test (FPT). The obtained results were statistically analyzed and correlated. The median of the FPT results obtained by participants with APD was more than twice lower than those of TD (20% vs. 50%; p < 0.05), similarly in the PDT (21 vs. 24; p < 0.05). The FPT results of 9-year-old APD participants were worse than the results of TD 6-year-olds (30% vs. 40%; p < 0.05), indicating that the significant FPT deficit strongly suggests APD. The process of auditory discrimination development does not complete with the acquisition of phonemes but continues during school age. Physiological phonemes discrimination is not yet equalized among 9-year-olds. Nonsense word tests allow for reliable testing of phoneme discrimination. APD children require testing with PDT and FPT because both test results allow for developing individual therapeutic programs.