This study demonstrates that muscle volume may be estimated accurately in typically developing individuals and individuals with cerebral palsy by a combination of anatomical cross-sectional area and muscle length. 2D ultrasound may be a convenient method of making these measurements routinely in the clinic.

Aim To assess test–retest reliability of the Dyskinesia Impairment Scale (DIS) in children and young adults with dyskinetic cerebral palsy (CP). Method Dystonia and choreoathetosis were assessed in 15 participants with dyskinetic CP (13 males, 2 females; age range 5–22y, mean 14y, SD 4y) using the DIS in two separate sessions over 7 days. Exclusion criteria were changes in muscle relaxant medication within the previous 3 months, orthopaedic or neurosurgical interventions within the previous year, and spinal fusion. Intraclass correlation coefficient, confidence intervals (CI), standard error of measurement, and the minimal detectable difference (MDD) were determined for test–retest reliability. Result Intraclass correlation coefficients of the DIS, the dystonia subscale of the DIS, and the choreoathetosis subscale of the DIS were 0.98 (95% CI 0.94–0.99), 0.97 (95% CI 0.92–0.99), and 0.96 (95% CI 0.90–0.99). The standard error of measurement and MDD were 2.6% and 7.2%. Interpretation The DIS is a reliable tool to assess dystonia and choreoathetosis; it remains stable over time in children and young adults with dyskinetic CP. These results add to the current evidence for good clinimetric properties of the DIS. What this paper adds The Dyskinesia Impairment Scale (DIS) shows stability in scoring dystonia and choreoathetosis. The total DIS score and dystonia and choreoathetosis subscales are clinically useful.

Background: This cross-sectional study aims to investigate the presence and severity of overflow movements of dystonia and horeoathetosis in dyskinetic cerebral palsy (CP) and to assess the relationship of overflow movements with functional classification scales. Methods: Fifty-two subjects with dyskinetic CP were included. Presence and severity of dystonia and choreoathetosis overflow movements were assessed with the Dyskinesia Impairment Scale. Functional abilities were classified with the Gross Motor Function Classification System, Manual Ability Classification System, Viking Speech Scale, Communication Function Classification System, and Eating and Drinking Ability Classification System. Results: Dystonia and choreoathetosis overflow movements were simultaneously present. Median scores of dystonia overflow movements were significantly higher than choreoathetosis overflow movements. Dystonia and choreoathetosis overflow movements were significantly higher in extremities than in the central body. Correlations between dystonia and choreoathetosis overflow movements were fair. Moderate to good correlations were found between dystonia overflow score and Gross Motor Function Classification System, Manual Ability Classification System, and Eating and Drinking Ability Classification System. Conclusions: This is the first study to assess overflow movements in dyskinetic CP. All participants presented with dystonia and choreoathetosis overflow movements, with higher values for dystonia overflow movements. Dystonia overflow movements seem to have a larger impact on functional abilities. Implications for rehabilitation • Dystonia and choreoathetosis overflow movements are both present in children with dyskinetic cerebral palsy, with dystonia overflow movements being more severe than choreoathetosis overflow movements. • Overflow movements impact heavily on daily functional ability and the execution of voluntary activities. • Dystonia overflow movements show good correlations with functional classification scales. • The measurable characteristics of overflow movements can be used as a guideline for targeted treatment with, e.g., botulinum-toxin-A injections.