Validity and Test-Retest Reliability of the translated Stapesplasty Outcome Test 25 for Measurement of Disease-Specific Quality of Life in Patients with Otosclerosis

OBJECTIVES: To assess the validity and test-retest reliability of the Danish Stapesplasty Outcome Test 25 (SPOT-25) version.

MATERIALS AND METHODS: The German SPOT-25 questionnaire-consisting of 25 questions within the subscores "hearing function," "tinnitus," "mental condition," "social restrictions," and "general quality of life," found to be significant in terms of health-related quality of life in patients with otosclerosis-was translated into Danish in a three-step process according to the guidelines provided by the International Collegium of Rehabilitative Audiology. In total, 35 patients with otosclerosis were included as cases and 35 individuals without ear-problems as controls. The SPOT-25 questionnaire was filled out once by the patients and twice by the controls. Pure tone average (0.5, 1, 2, and 3 kHz) (PTA4) was obtained for cases.

RESULTS: The SPOT-25 clearly discriminated the individuals with otosclerosis from con-trols within all subscores (p<0.001). The internal consistency within the subscores was good to excellent with Cronbach alpha values of 0.85-0.95. The reproducibility (estimated by the control group) was moderate to high, with an intraclass correlation of 0.58-0.94 within the subscores. Although the SPOT-25 subscores within "hearing" and "social restrictions" showed a moderate correlation with PTA4 (Pearson correlation coefficient 0.51 and 0.42, respectively), this was not the case for the subscores regarding "tinnitus," "mental condition," and the "general."

CONCLUSION: The SPOT-25 questionnaire can be used as a valuable complement to audiometric data in patients with otosclerosis, especially for estimating factors such as tinnitus and "mental condition," which do not correlate with the audiometric data.