The Dyskinetic Cerebral Palsy Functional Impact Scale: development and validation of a new tool
Kirsty Stewart, Jennifer Lewis, Margaret Wallen, Natasha Bear, Adrienne Harvey
Abstract
AIM: To outline the development and examine the content and construct validity of a new tool, the Dyskinetic Cerebral Palsy Functional Impact Scale (D-FIS), which measures the impact of dyskinesia on everyday activities in children with cerebral palsy (CP). METHOD: D-FIS content was informed by a systematic review of dyskinesia outcome measures, in collaboration with children with dyskinetic CP, parents, caregivers, and expert clinicians. The D-FIS uses parent proxy to rate impact of dyskinesia on everyday activities. Construct validity was determined by examining internal consistency; known groups validity with the Gross Motor Function Classification System (GMFCS), Manual Ability Classification System (MACS), Communication Function Classification System (CFCS), and Eating and Drinking Ability Classification System (EDACS); and convergent validity with the Barry-Albright Dystonia Scale (BADS). RESULTS: Fifty-seven parents of children (29 males, 28 females, mean [SD] age 11y 8mo [4y 4mo], range 2y 6mo-18y) completed the D-FIS. Correlation between D-FIS and GMFCS was r=0.86 (95% confidence interval [CI]: 0.77-0.91, p<0.001); MACS r=0.84 (95% CI: 0.73-0.90, p<0.001); CFCS r=0.80 (95% CI: 0.67-0.88, p<0.001); and EDACS r=0.78 (95% CI: 0.66-0.87). Correlation between D-FIS and BADS was r=0.77 (95% CI: 0.64-0.86, p<0.001). Cronbach's alpha was 0.96. INTERPRETATION: The D-FIS demonstrates good construct validity and high internal consistency. The D-FIS will be useful for identifying priorities for intervention. It adds to the measurement tool kit for children with dyskinetic CP by addressing functional impact of dyskinetic movements and postures. What this paper adds The Dyskinetic Cerebral Palsy Functional Impact Scale (D-FIS) assesses the perceived impact of dyskinesia on daily activities in children with cerebral palsy (CP). The D-FIS demonstrates good construct validity and high internal consistency. The D-FIS is a clinically feasible, family-centred tool that fills a current gap in the dyskinetic CP assessment toolkit.