ORIGINAL ARTICLE Validation of the Physical Activity Scale for Individuals With Physical Disabilities Rita J. van den Berg-Emons, PhD, Annemiek A. L’Ortye, MD, Laurien M. Buffart, PhD, Channah Nieuwenhuijsen, MSc, Carla F. Nooijen, MSc, Michael P. Bergen, PhD, Henk J. Stam, PhD, Johannes B. Bussmann, PhD ABSTRACT. van den Berg-Emons RJ, L’Ortye AA, Buffart LM, Nieuwenhuijsen C, Nooijen CF, Bergen MP, Stam HJ, Bussmann JB. Validation of the Physical Activity Scale for Individuals With Physical Disabilities. Arch Phys Med Rehabil 2011;92:923-8. Objective: To determine the criterion validity of the Phys- ical Activity Scale for Individuals With Physical Disabilities (PASIPD) by means of daily physical activity levels measured by using a validated accelerometry-based activity monitor in a large group of persons with a physical disability. Design: Cross-sectional. Setting: Participants’ home environment. Participants: Ambulatory and nonambulatory persons with ce- rebral palsy, meningomyelocele, or spinal cord injury (N=124). Interventions: Not applicable. Main Outcome Measures: Self-reported physical activity level measured by using the PASIPD, a 2-day recall questionnaire, was correlated to objectively measured physical activity level measured by using a validated accelerometry-based activity monitor. Results: Significant Spearman correlation coefficients be- tween the PASIPD and activity monitor outcome measures ranged from .22 to .37. The PASIPD overestimated the dura- tion of physical activity measured by using the activity monitor (mean  SD, 3.92.9 vs 1.50.9h/d; P.01). Significant correlation (=-.74; P.01) was found between average number of hours of physical activity per day measured by using the 2 methods and difference in hours between methods. This indicates larger overestimation for persons with higher activity levels. Conclusions: The PASIPD correlated poorly with objective measurements using an accelerometry-based activity monitor in people with a physical disability. However, similar low correlations between objective and subjective activity measure- ments have been found in the general population. Users of the PASIPD should be cautious about overestimating physical activity levels. Key Words: Activities of daily living; Cerebral palsy; Me- ningomyelocele; Rehabilitation; Spinal cord injuries. © 2011 by the American Congress of Rehabilitation Medicine T HERE IS INCREASING interest in the effects of an inactive lifestyle on health. Previous studies in the general population showed an inverse relationship between daily phys- ical activity level and risk for such secondary health problems as coronary heart disease, diabetes, and overweight or obesity. 1 Persons with a physical disability often are restricted in their performance of daily physical activities and are more at risk for developing inactive lifestyles compared with the general pop- ulation. Over time, inactivity may lead to decreased physical capacity and increased body fat, which in turn may lead to further inactivity. 2-4 Furthermore, inactive lifestyles may lead to impaired everyday functioning, decreased social participa- tion, and decreased quality of life. 1,4 Previous research has focused on instruments to assess daily physical activity in persons with a physical disability. For example, an activity monitor with body-fixed accelerometers has been used to assess body postures and physical activities in persons with bilateral spastic cerebral palsy (CP), meningomy- elocele (MMC), and spinal cord injuries (SCIs). These studies showed subnormal daily physical activity levels. 3,5-8 Although the activity monitor provides objective, detailed, and valid data for daily physical activity for ambulatory and wheelchair- dependent persons 9-14 and is able to detect differences in daily physical activity levels between groups, 2,7 measurements are time consuming and relatively expensive. Therefore, the activ- ity monitor is less useful in large population studies and alter- natives are needed. The Physical Activity Scale for Individuals With Physical Disabilities (PASIPD) is a 7-day physical activity recall ques- tionnaire designed to evaluate physical activity levels in per- sons with physical disabilities. 15 The PASIPD is based on the Physical Activity Scale for the Elderly, which has shown validity in classifying healthy elderly people by level of daily physical activity. 16-19 To our knowledge, 3 studies assessed the criterion validity of the PASIPD. van der Ploeg et al 20 found weak nonsignificant correlations between the PASIPD and accelerometry-based systems (RT2 and Actigraph, respectively) in ambulatory per- From the Department of Rehabilitation Medicine and Physical Therapy, Erasmus Medical Center, Rotterdam (van den Berg-Emons, L’Ortye, Buffart, Nieuwenhuijsen, Nooijen, Stam, Bussmann); and Rijndam Rehabilitation Center, Rotterdam (L’Ortye, Bergen), The Netherlands. Supported by Kinder Fonds Adriaanstichting (grant no. 2003/0047-063), Johanna Kinder Fonds (grant nos. 2003/0047-063, 20000005/20000158, 2002/0067), and ZONmw Rehabilitation program (grant no. 1435.0003). No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the authors or on any organi- zation with which the authors are associated. Correspondence to Rita J. van den Berg-Emons, PhD, Erasmus Medical Center Rotterdam, Dept of Rehabilitation Medicine and Physical Therapy, PO Box 2040, 3000 CA Rotterdam, The Netherlands, e-mail: h.j.g.vandenberg@erasmusmc.nl. Reprints are not available from the author. Published online April 19, 2011 at www.archives-pmr.org. 0003-9993/11/9206-00816$36.00/0 doi:10.1016/j.apmr.2010.12.006 List of Abbreviations CP cerebral palsy MET metabolic equivalent MMC meningomyelocele PASIPD Physical Activity Scale for Individuals With Physical Disabilities SCI spinal cord injury 923 Arch Phys Med Rehabil Vol 92, June 2011