Related Experiment Video
Updated: Jul 19, 2026
The Multiple Sclerosis Performance Test MSPT: An iPad-Based Disability Assessment Tool
Published on: June 30, 2014
The written symbol digit modalities test in multiple sclerosis is sensitive to cognitive and motor disability
Matthew A Greenwald1, Héctor G Cancel Asencio2, Kevin Hu1
1National Institute of Neurological Disorders and Stroke, Translational Neuroradiology Section, Bethesda, MD, USA.
Background:
The symbol digit modalities test is a commonly used cognitive assessment for which the written (wSDMT) version remains poorly studied in multiple sclerosis (MS).
Objective:
To establish performance benchmarks, assess learning effects, and explore the utility of the wSDMT as a joint indicator of cognitive and motor disability progression in MS.
Methods:
A retrospective analysis of wSDMT scores, collected over a decade in conjunction with common clinical measures, was carried out using reliable change indices and linear mixed-effects modeling.
Results:
In total, 866 participants (753 MS, 113 healthy) took 3618 wSDMTs. 544 (64 %) were females, who outperformed males (mean: 48.4 vs mean: 46.3, p < 0.01). wSDMT scores declined with age (-0.34 points/year, p < 0.01) and displayed evidence of learning effects (2.18 points per test). Changes in 9-Hole Peg Test times predicted wSDMT score changes (-0.27 points/second, p < 0.01), and the wSDMT was moderately sensitive to declines in both upper extremity motor (30 %) and cognitive function (44 %).
Conclusion:
The wSDMT is sensitive to both cognitive and motor disability progression but exhibits heterogeneous aging and learning effects, potentially skewing interpretations of reliable change.
