Assessing Short and Graphically the Mobility in MS and Other Neurological Disease with the Iphone App Sagas 10

Background: SaGAS 10 is an iPhone app developed as an alternative to the MS Functional Composite (MSFC) and as a complement to the EDSS for the moderately disabled MS patients between EDSS 3.0 and 7.0.

Objectives: Assuming that this tool could also be used for other neurological diseases where walking and hand function is impaired, we set out to examine the validity and the responsiveness of SaGAS 10 in neurological patients attending a rehabilitation facility. Furthermore, we evaluated whether the 25 feet walking has a high correlation with the 2-minutes walking test in patients with slow walking speed.

Methods: 646 consecutive patients with different neurological diseases (MS 296, stroke 152, Parkinson 21, neuromuscular disorders 42, trauma 42, others 93) were assessed at the beginning and at the end of their rehabilitation stay using the FIM (Functional Independence Measure), the RMI (Rivermead Mobility Index, the 2-minute timed walking distance at maximum speed (2MWD) and the 3 measures composing SaGAS 10 (the 25 feet timed walk at fast speed with a flying start (T25FW) and the nine-hole peg test (9-HPT) for each hand separately). Construct validity was assessed with correlations between FIM, RMI and the SaGAS 10, where correlations above 0.7 were hypothesized. Responsiveness was assessed by a receiver operating characteristic curves (ROCs) analyses comparing changes in SaGAS 10 with minimal clinically important changes in the RMI. An area under the curve value (AUC) of at least 0.7 was considered as appropriate. Analyses were performed for each patient-group separately.

Results: The correlation of the SaGAS 10 with the Rivermead Mobility Index is above 0.7 in all of the neurological diagnostic groups; the highest correlation coefficient was found in patients with stroke: 0.76 (95% CI 0.65 to 0.84). The correlation of the SaGAS 10 with the FIM was over 0.7 for stroke and MS. The responsiveness was acceptable with AUCs of 0.72 (95% CI 0.63 to 0.81) for stroke and values over 0.7 for all groups, with the exception of MS (AUC 0.58, 95% CI 0.47 to 0.69). The effect-sizes were moderate to high, especially for stroke with Cohen’s d values of 0.48 for the whole group and higher values for those walking slower (ES 0.61 for under 1.04 m/s and ES 0.72 for speed under 0.96 m/s). The correlation between the 25 feet test and the 2 minutes walking test was 0.63 (95% CI 0.56 to 0.69) for those walking slower than 0.96 m/s; and 0.64 (95% CI 0.54 to 0.73) for those walking faster than 0.96 m/s.

Conclusions: These results indicate that SaGAS 10 is valid and sensitive to changes over time and that it could be a useful measure not only for patients with MS, but also for patients with other neurological diseases. Our results indicate that particularly or slow walkers the 25 feet walking test might be a good alternative for the 2-minutes walking test.