Reliability of the Therapy Behavior Scale version 2.2 in infants with congenital muscular torticollis: A pilot study

Background The Therapy Behavior Scale (TBS) is a standardized instrument that is used to evaluate behavior of infants and toddlers during physical, occupational, and developmental therapy sessions. The TBS can be applied in intervention comparison research to assess therapy-related behaviors exhibited by study participants. Purpose The purpose of this pilot study was to establish the reliability of the TBS Version 2.2 prior to its use in a randomized clinical trial comparing two physical therapy (PT) interventions in infants with congenital muscular torticollis (CMT). Methods Three infants with right and 7 with left CMT, severity grades 1-3, 3 girls and 7 boys, age range 3-6 months, participated in this research. Examiners were 2 experienced pediatric physical therapists. To obtain the intrarater reliability estimates, each examiner conducted 2 PT sessions with 5 infants and scored their behavior "live," and then scored the video recordings of these 10 sessions at least 1 month later. To obtain the interrater reliability estimates, both examiners scored a total of 20 video recordings. Results Results indicated good intrarater reliability, with ICC((3,1))of 0.92, 95% CI = 0.81-0.99, and 0.95, 95% CI = 73-0.98, and moderate to good interrater reliability, with ICC((2,1))of 0.84, 95% CI = 0.48-0.96, and 0.91, 95% CI = 0.67-0.98. Conclusion This study established the reliability of the TBS Version 2.2 for 2 examiners who subsequently used it in a RCT of 2 PT interventions. Further research is necessary to demonstrate the reliability of this instrument in a larger population of infants with CMT, and in infants and toddlers with other conditions.