A Digital Filter-Based Method for Diagnosing Speech Comprehension Deficits

OBJECTIVE: To improve the diagnostic efficiency of current tests for auditory processing disorders (APDs) by creating new test signals using digital filtering methods. METHODS: We conducted a prospective study from August 1, 2014, to August 31, 2019, using 3 low speech redundancy tests with novel test signals that we created with specially designed digital filters: the binaural resynthesis test and the low pass and high pass filtered speech tests. We validated and optimized these new tests, then applied them to healthy individuals across different age groups to examine how age affected performance and to children with APD before and after acoustically controlled auditory training (ACAT) to assess clinical improvement after treatment. RESULTS: We found a progressive increase in performance accuracy with less restrictive filters (P<.001) and with increasing age for all tests (P<.001). Our results suggest that binaural resynthesis and auditory closure mature at similar rates. We also demonstrate that the new tests can be used for the diagnosis of APD and for the monitoring of ACAT effects. Interestingly, we found that patients having the most severe deficits also benefited the most from ACAT (P<.001). CONCLUSION: We introduce a method that substantially improves current diagnostic tools for APD. In addition, we provide information on auditory processing maturation in normal development and validate that our method can detect APD-related deficits and ACAT-induced improvements in auditory processing.