Use of assistive technology to assess distal motor function in subjects with neuromuscular disease

Abstract

Among the 32 items of the Motor Function Measure scale, 3 concern the assessment of hand function on a paper-based support. Their characteristics make it possible to envisage the use of a tablet instead of the original paper-based support for their completion. This would then make it possible to automate the score to reduce intra- and inter-individual variability. The main objective of the present study was to validate the digital completion of items 18, 19, and 22 by measuring the agreement of the scores obtained using a digital tablet with those obtained using the original paper-based support in children and adults with various neuromuscular diseases (NMD). The secondary objective is to calibrate an algorithm for the automatic items scoring.

Design: Prospective, multicentre, non-interventional study.

Methods: Ninety-eight subjects aged 5 to 60 years with a confirmed NMD completed MFM items 18, 19, and 22 both on a paper support and a digital tablet.

Results: The median age of included subjects was 16.2 years. Agreement between scores as assessed using the weighted Kappa coefficient was almost perfect for the scores of items 18 and 22 (K = 0.93, and 0.95, respectively) and substantial for item 19 (K = 0.70). In all cases of disagreement, the difference was of 1 point. The most frequent disagreement concerned item 19; mainly in the direction of a scoring of 1 point less on the tablet. An automatic analysis algorithm was tested on 82 recordings to suggest improvements.

Conclusion: The switch from original paper-based support to the tablet results in minimal and acceptable differences, and maintains a valid and reproducible measure of the 3 items. The developed algorithm for automatic scoring appears feasible with the perspective to include them in a digital application that will make it easier to monitor patients.

Fig 1. Original paper-based support for item 18 (A), 19 (B) and 22 (C) and screenshots of the digital interfaces of the item 18 (D), 19 (E) and 22 (F).

Fig 2. Bangdiwala’s agreement charts for item 18 (A), 19 (B) and 22 (C) comparing item scores between the Paper-based support and the Tablet.

Each item is represented by a distinct panel in which the four levels are represented by rectangles with one to two shades of grey. A deep grey area represents an exact agreement and a light grey area a partial agreement with a ‘one level away’ discrepancy. The bias between these two modes is shown by the deviation of the “rectangles” from the 45° diagonal line within the larger square.

Fig 3. Assessment of the level of difficulty of the task from subjects (A) and therapists (B) when using the tablet compared to the paper-based support during the item 18, 19 and 22 completions.

For each item, assessments are grouped according to each pair of scoring P-score and T-score results. Black bars indicate that the subjects or therapists considered that difficulty for completion of the task was the same level for the tablet and paper-based support, hatched bars indicate that they considered that it was less easy using the tablet, and white bars that it was easier using the tablet.