Catch the ruler: concurrent validity and test–retest reliability of the ReacStick measures of reaction time and inhibitory executive function in older people

Background: Reduced cognitive function, particularly executive function (EF), is associated with an increased risk of falling in older people. We evaluated the utility of the ReacStick test, a clinical test of reaction time, and inhibitory EF developed, for young athletes, for fall-risk assessment in older people. Aims: To evaluate the psychometric properties of ReacStick measures of reaction time and executive functioning in healthy community-dwelling older people. Methods: 140 participants (aged 77 ± 5 years) underwent testing. Two test conditions—simple and inhibitory go/no-go—provided measures of reaction time, recognition load (difference in reaction time between conditions), and go/no-go accuracy. Concurrent validity was evaluated against the conventional tests of reaction time and EF (simple hand reaction time, trail-making test, and Stroop colour test). Discriminant ability was determined for fall-risk factors (age, gender, physiological profile assessment, and fall history). Test–retest reliability after 1 week was evaluated in 30 participants. Results: ReacStick reaction time correlated with tests of reaction time and EF, recognition load correlated with inhibitory EF, and go accuracy correlated with reaction time and inhibitory EF. No-go accuracy was not significantly correlated with any of the reaction time and EF tests. Test–retest reliability was good-to-excellent (ICC > 0.6) for all the outcomes. ReacStick reaction time discriminated between groups based on age, recognition load between genders, and no-go accuracy between retrospective fallers and non-fallers. Discussion: An unavoidable time pressure may result in complementary information to the traditional measures. Conclusions: The ReacStick is a reliable test of reaction time and inhibitory EF in older people and could have value for fall-risk assessment.