Behavioral and Questionnaire-Based Analysis of Auditory Processing Disorder in Korean Patients

Background and Objectives This study examined questionnaire and behavioral test results in Korean individuals with suspected auditory processing disorder (APD) to identify characteristics and estimate possible lesion sites of the disease.Subjects and Method Fifty participants with symptoms of APD and 36 age-matched controls with normal hearing and cognition were included. A 25-item APD questionnaire (total score: 100) was developed based on established guidelines and scales. Behavioral tests included a dichotic 3-digit test, a dichotic consonant-vowel test, a frequency pattern test, a temporal modulation detection (TMD) test, a time-compressed speech test, and a speech-in-noise test. APD was diagnosed when participants scored more than 2 standard deviations below the mean in at least two test domains.Results Of the 50 participants, 40 (mean age 38.18±10.82 years; M:F=14:26) were diagnosed with APD (APD+). Both APD+ and APD- groups scored significantly higher on the questionnaire than controls (<i>p</i><0.001), but there was no difference between the APD+ and APD- groups. All behavioral tests except the TMD test showed significantly poorer performance in the APD+ group than the controls (<i>p</i><0.001). Questionnaire scores correlated well with most behavioral test scores. Estimated lesion sites included the right auditory cortex (13), right auditory cortex or corpus callosum (6), left auditory cortex (4), left auditory cortex or corpus callosum (2), corpus callosum (3), and 12 indeterminate sites.Conclusion A substantial proportion of individuals reporting APD symptoms met the diagnostic criteria. The right auditory cortex may be a frequent lesion site, but further studies are needed to clarify the neural basis.