Validity and reliability of a 10-second foot-tap test in older adults

Abstract

The purposes of this study were to: (1) compare differences in foot-tap speed between younger and older adults; (2) examine the relationship between foot-tap time and foot-activated reaction time (RT); and (3) assess test-retest reliability of the foot-tap test. Number of Subjects: 115 adults (F=70, M4=5) were recruited from local schools and churches; the sample included 72 young adults (18-64 yo) and 43 older adults (65-92 yo). Subjects with known cognitive, visual, or lower extremity motor deficits were excluded. Methods: After signing an informed consent, subjects were seated at a table where they performed a computerized reaction time test by depressing a foot pedal when a stoplight changed colour. SRTs for 5 trials were averaged for each foot. Subjects then performed the foot-tap test using an electronic tapping device (Western Psychological Services, Los Angeles, CA) which recorded the number of foot taps performed during a 10-sec interval. The subjects’ dominant foot was tested first, followed by a test of the non-dominant foot, and a repeat test of the dominant foot (to assess reliability). A 1-min rest was provided between tests. An independent t-test compared the mean number of foot-taps (on each foot) between age groups, and a paired t-test compared the number of foot-taps between subjects’ dominant and non-dominant feet. A Pearson correlation coefficient was used to analyze the relationship between SRT and number of foot-taps, and an intraclass correlation coefficient (ICC3,1) and Limits of Agreement (LOA) graph were used to assess test-retest reliability. All data were analyzed at the .05 alpha level using SPSS 23 statistical software. Results: The mean number of foot taps differed significantly (p≤.001) between age groups with younger subjects averaging 41.45 (±10.91) taps with the dominant foot and 40.65 (±11.44) taps with the non-dominant foot. Older subjects averaged 28.29 (±10.21) taps with the dominant foot and 26.81 (±11.20) with the non-dominant foot. A mean difference of ≈ 3 taps was found between the dominant and non-dominant feet across all subjects (t=4.616, p≤.001). A moderate, inverse correlation (r=-.451,p=.001) was found between SRT and number of foot taps on the dominant foot. A significant correlation was found between the 2 foot-tap tests performed with the dominant foot (ICC=.793, p≤.001). Conclusions: Younger adults averaged 13 to 14 more foot-taps during the 10-sec test than older adults. Additionally, all subjects demonstrated slightly more foot taps using their dominant foot. Faster reaction times were moderately associated with a higher number of foot taps, and test-retest reliability of the foot-tap test was acceptable. Clinical Relevance: This study demonstrates the moderate effect that normal aging has on foot-tap speed and provides normal values that clinicians may use as a reference when testing individuals with various neurological pathologies. However, the moderate correlation found between reaction time and foot taps suggests that these tests do not necessarily measure the same psychomotor attribute.