The concurrent validity of the physical activity vital sign and online physical activity logbook in adolescents with autism

Background and aims: There is an urgent need for valid assessment tools to assess physical activity (PA) levels in adolescents with autism. This study examines the concurrent validity of the Physical Activity Vital Sign (PAVS) and Online Physical Activity Logbook (OPAL) with accelerometry in adolescents with autism. A secondary aim was to explore the association and agreement between self-perceived and objectively measured PA intensity levels. Methods: Forty-five adolescents with autism (71% males, Mdn = 14.0 (IQR = 13.0-15.5) years) completed the PAVS and OPAL and wore a wGT3X-BT ActiGraph accelerometer twice for seven consecutive days. Concurrent validity was assessed with Spearman correlations (rho) and Wilcoxon Signed Rank/Paired Sample T-tests. Results: A poor association was found between the PAVS and accelerometry (rho = .37). The PAVS overestimated moderate-to-vigorous PA (MVPA) levels [Mdn = 152.1 min (IQR = 76.8-283.9), p < .001]. Poor associations (rho =-.06 up to-.45) were observed between the OPAL and accelerometry for time spent in sedentary behavior (SB), light PA (LPA), moderate PA (MPA), vigorous PA (VPA) and MVPA. No significant mean and median differences were found for SB and VPA between the two methods respectively. A moderate association was found between self-perceived (OPAL) and objectively measured (accelerometry) VPA (rho = .60) and MVPA (rho = .51), while those for LPA and MPA were poor (rho < .50). No significant median differences were found between self- perceived and objectively measured VPA. Conclusion: Clinicians and researchers should be very cautious in using the PAVS to assess MVPA levels in adolescents with autism, while the utility of the OPAL, in its current form, is questionable. Adolescents with autism may estimate PA at a vigorous intensity accurately. Future research should further focus on examining the psychometric properties of self-report PA instruments, as well as the ability of adolescents with autism to accurately estimate the intensity of performed PA's.