Response shift after a 4-week multimodal intervention for chronic ankle instability

Context: The accurate evaluation of self-reported changes in function throughout the rehabilitation process is important for determining patient progression. Currently, how a response shift (RS) may affect the accuracy of self-reported functional assessment in a population with chronic ankle instability (CAI) is unknown. Objective: To examine the RS in individuals with CAI after a 4-week multimodal rehabilitation program. Design: Controlled laboratory study. Setting: Laboratory. Patients or Other Participants: Twenty adults (5 men, 15 women; age ¼ 24.35 6 6.95 years, height ¼ 169.29 6 10.10 cm, mass ¼ 70.58 6 12.90 kg) with self-reported CAI participated. Inclusion criteria were at least 1 previous ankle sprain, at least 2 episodes of the ankle ‘‘giving way’’ in the 3 months before the study, and a score 24 on the Cumberland Ankle Instability Tool. Intervention(s): Individuals participated in 12 intervention sessions over 4 weeks and daily home ankle strengthening and stretching. Main Outcome Measure(s): Patient-reported outcomes (PROs) were assessed at 4 times (baseline, preintervention, postintervention, and 2-week follow-up). At the postintervention and 2-week follow-up, participants completed then-test assessments to measure RS. Then-test assessments are retrospective evaluations of perceived baseline function completed after an intervention. The PROs consisted of the Foot and Ankle Ability Measure-Activities of Daily Living and Sport subscales, the modified Disablement in the Physically Active scale physical and mental summary components, and the Fear-Avoidance Beliefs Questionnaire Physical Activity and Work subscales. We used repeated-measures analyses of variance to compare preintervention with then-test measurements. Individual-level RSs were examined by determining the number of participants who experienced preintervention to then-test differences that exceeded the calculated minimal detectable change. Results: We did not identify an RS for any PRO (F . 2.338, P . .12), indicating no group-level differences between the preintervention and retrospective then-test assessments. Individual-level RS was most prominent in the Foot and Ankle Ability Measure-Sport subscale (n ¼ 6, 30%) and the Fear-Avoidance Beliefs Questionnaire Physical Activity subscale (n ¼ 9, 45%). Conclusions: No group-level RS was identified for any PRO after a 4-week multimodal rehabilitation program in individuals with CAI. This finding indicates that traditional assessment of self-reported function was accurate for evaluating the short-term effects of rehabilitation in those with CAI. Low levels of individual-level RS were identified.