Investigation of Head Shake Sensory Organization Test (HS-SOT) in three planes: Test-retest reliability and age-related differences.

Background: In recent years, it has been determined that SOT sensitivity is insufficient in patients who develop vestibular compensation and therefore the Head Shake Sensory Organization Test (HS-SOT) has been developed.

Research Question: How differs the balance performance of healthy adults that is tested with HS-SOT according to age and test planes? What is the test-retest reliability level of the HS-SOT in three planes?

Methods: Our prospective study, which has a methodological research design, included 80 participants divided into three groups by age range (Group 1: 20-39 years (n = 30); Group 2: 40-49 years (n = 30) and Group 3: 50-64 years (n = 20)). SOT and HSSOT ( yaw, pitch, roll) were performed to all participants. To investigate the testretest reliability of the HS-SOT, a total of 27 participants were re-evaluated one week later. The HS-SOT performance of the participants was compared between age groups and test planes. Intra-class correlation coefficient and minimum detectable change values (MDC) was calculated to test-retest reliability of HS-SOT.

Results: HS-SOT scores (HS-2 and HS-5) did not differ significantly between age groups. The balance performance of individuals for the pitch plane was lower than other planes. Only the HS-5 score showed a significant difference between the sessions. HS-5 scores were higher in the re-test; for the first group in the pitch plane and for the third group in the yaw plane. The test-retest reliability level of these conditions was "moderate-good" for both groups. The corresponding MDC value was highest (14.01) for the HS-5 (yaw) score of the elderly group.

Significance: The findings from this study demonstrated that the test plane influences the HS-SOT, a learning/practice effect may occur because of repeated HS-SOT evaluation, and this effect is more explicit in the elderly. This study provides a perspective for the evaluation and follow-up processes of patients with balance problems.