Measurement of Loudness Discomfort Levels as a Test for Hyperacusis: Test-Retest Reliability and Its Clinical Value

Objectives. The aims of this study were to investigate the test-retest reliability of measurements of loudness discomfort levels (LDLs), to suggest cut-off values for diagnosing patients with hyperacusis, and to evaluate the clinical value of LDL measurements as a test for monitoring hyperacusis. Methods. For the test-retest reliability of LDL measurements (study 1), a total of 68 patients who sought consultations at our clinic were subcategorized into four groups: patients with tinnitus (group 1), tinnitus and hearing loss (group 2), hyperacusis (group 3), and normal controls (group 4). Inter-hour and inter-day test-retest reliability values using dif-ferent stimuli were investigated. For study 2, the clinical value of LDL measurements using pure tone stimuli was an-alyzed by comparing changes after sound generator use in patients with hyperacusis. Results. In study 1, the group 3 patients showed significantly lower LDLs than the other groups. High test-retest reliability of LDL tests was demonstrated, regardless of the type of stimulus used. The cut-off values for screening patients with hyperacusis were 90 dB HL using pure tone stimuli and 62 dB HL using white-band noise stimuli. In study 2, significantly increased LDLs were correlated with improved symptoms and improved scores on tinnitus questionnaires after sound generator use, indicating that LDL measurement is a reliable test for monitoring hyperacusis during an in-tervention. Conclusion. LDL measurement is a reliable diagnostic tool to reflect the condition of hyperacusis, especially during the course of treatment.