Progressive loss of ambulation is one of the main disability causes in ALS. In Duchenne Muscular Dystrophy, the 95^th centile of stride velocity (SV95C) as measured by a magneto-inertial device specifically designed for continuous assessment of patients with neurological diseases (ActiMyo®) in uncontrolled environment has been qualified as a primary endpoint by European Medical Agency and is currently considered by FDA.

Longitudinal multisite natural history study in ALS. Participants were assessed with standard evaluations including the ALS functional rating scale, six-minute walk test, Medical Research Council scores (MRC-S), Ashworth score and hand dynamometer every 3 months for 1 year. After each visit, patients were asked to wear for one month one inertial sensor at the ankle and one at the wrist for continuous assessment of motor function in real-life. These data are compared with already acquired normative data in matched healthy controls

We included 19 patients with ALS (6 females and 13 males) aged from 20 to 70 years. Eighteen of them (94%) provided a recording period over 50 hours at baseline.

On the first 8 patients aged from 44 to 68 years, reliability was excellent with an inter-class correlation of 0.98. Correlation with MRC-S was 0.46 (p<0.05). ICC was 0.98. All patients declined rapidly with a standardized response mean of -2.78 at month 3 and -2.63 at months 6. We will present the entire set of data.

If confirmed on the entire cohort- these data demonstrate the excellent metric property of SV95C in ALS, which allows to consider short clinical trials with limited number of patients.