Validity of ACTIVE for use across ambulatory abilities in Duchenne muscular dystrophy.

Research Report
Population: Pediatric

Lindsay N Alfano, PT, DPT, PCS, Research Physical Therapist, Nationwide Children’s Hospital

Katherine Berry, PT, Physical Therapist, Nationwide Children’s Hospital

Linda Lowes, PT, PhD, Principal Investigator, Nationwide Children’s Hospital

Keywords: Prediction, outcome measures, neuromuscular disease, function

Purpose: To develop a simple, motivating measure of functional reaching volume (FRV). FRV incorporates limb and trunk motion, allows compensatory movements, and measures the effective region of space that a person can interact.

Subjects: 53 boys and men (mean age: 10.3 years, range: 5-23 years; 35 ambulant) with Duchenne muscular dystrophy (DMD).

Methods: We designed a Kinect-based tool called ACTIVE (Ability Captured Through Interactive Video Evaluation) to measure FRV while playing a customized 1-minute video game encouraging maximal reach. Patient interviews were used to develop the game concepts voted most motivating to a pediatric population (i.e. spider-squishing or treasure-hunt). Subjects completed a minimum of two 1-minute ACTIVE trials encouraging them to reach as far as possible overhead, to each side, and forward. Leaning with the trunk and compensatory movements were permitted to maximize the relationship to function.   The total FRV was quantified and adjusted for height to accommodate growth, resulting in a percent predicted value. One hundred percent predicted would encompass the ‘box’ accessible in all directions (forward, side to side, and overhead) if the subject did not move their trunk. The Brooke Upper Extremity scale was also scored to categorize upper extremity function. Subjects also completed standard functional assessments such as the 6 minute walk test (6MWT), North Star Ambulatory Assessment (NSAA), timed stair climb and the Performance of Upper Limb as well as the Pediatric Evaluation of Disability Inventory (PEDI-CAT).

Results: The percent predicted reaching volume ranged from 3 to 169% (mean: 72%). ACTIVE performance was significantly correlated to Brooke score (r = -0.65, p<0.001), 6MWT (r = 0.49, p =0.01), NSAA (r = 0.71, p=0.00), 10 m run/walk (r=-0.8, p=0.0), Time to Rise (r=-0.70, p<0.001), ascending (r=-0.75, p=0.001) and descending stairs(r=-0.60, p=0.02) the PUL (r=0.67, p=0.005), and the PEDI-CAT (mobility r=0.76 p<0.01; self-care r=0.45 p=0.05). Test-retest reliability of ACTIVE between two consecutive days (N= 9) was also excellent (ICC=0.92, p=0.001).

Conclusions: ACTIVE is correlated to traditional upper limb measures in DMD as well as to measures of ambulation. The correlation with ambulation is likely due to the inclusion of the trunk as these muscles weaken early in the disease and contribute to ambulation. The high test-retest reliability of the system is likely due to increased motivation to perform maximally at each visit.

Clinical Relevance: Functional reaching volume is a composite of strength, range of motion, and other discrete variables. It is relevant to the patient, in that it directly measures whether a subject is gaining, or losing access to the world around him. ACTIVE could be used in a variety of chronic patient populations such as stroke, cerebral palsy or muscular dystrophy or injuries such brachial plexus, spinal cord or rotator cuff injury. The addition of a gaming component has the potential to increase motivation and consistency of performance over time, especially in a pediatric population.

Alfano, Lindsay N, PT, DPT, PCS; Berry, Katherine M, PT; Lowes, Linda P, PT, PhD. Validity of ACTIVE for use across ambulatory abilities in Duchenne muscular dystrophy.. Poster Presentation. IV STEP Conference, American Physical Therapy Association, Columbus, OH, July 17, 2016. Online.