Challenges and advancements in measuring dyskinesia in cerebral palsy

Kinematic upper limb analysis outperforms electromyography at grading the severity of dystonia in children with cerebral palsy

BACKGROUND

Severity of dyskinesia in children with cerebral palsy is often assessed using observation-based clinical tools. Instrumented methods to objectively measure dyskinesia have been proposed to improve assessment accuracy and reliability. Here, we investigated the technique and movement features that were most suitable to objectively measure the severity of dystonia in children with cerebral palsy.

METHODS

A prospective observational study was conducted with 12 participants with cerebral palsy with a predominant motor type of dyskinesia, spasticity, or mixed dyskinesia/spasticity who had upper limb involvement (mean age: 12.6 years, range: 6.7-18.2 years). Kinematic and electromyography data were collected bilaterally during three upper limb tasks. Spearman rank correlations of kinematic or electromyography features were calculated against dystonia severity, quantified by the Dyskinesia Impairment Scale.

FINDINGS

Kinematic features were more influential compared to electromyography features at grading the severity of dystonia in children with cerebral palsy. Kinematic measures quantifying jerkiness of volitional movement during an upper limb task with a reaching component performed best (|rs| = 0.78-0.9, p < 0.001).

INTERPRETATION

This study provides guidance on the types of data, features of movement, and activity protocols that instrumented methods should focus on when objectively measuring the severity of dystonia in children with cerebral palsy.

The Dyskinetic Cerebral Palsy Functional Impact Scale: development and validation of a new tool

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.