Fampridine and real-life walking in multiple sclerosis: Low predictive value of clinical test for habitual short-term changes

BACKGROUND: Fampridine improves walking speed in patients with multiple sclerosis (MS) in performance-based tests. The impact on habitual mobility and its correlation with clinical tests has not been analysed.

OBJECTIVE: To investigate the association between clinical response criteria and habitual mobility in MS patients starting a fampridine treatment.

METHODS: During a four-week baseline-to-treatment study, we assessed in 28 patients (median EDSS 4.75, range 4-6.5) walking tests as the Timed-25-Foot-Walk (T25FW) and mobility questionnaires at day 0, 14 (start of treatment) and 28. Habitual steps and distance per day, total activity and walking speed was measured by accelerometry over four weeks. Beside improvement in real-life mobility, we investigated if such measures differed between non-responders and responders defined by a 20% improvement in clinical tests.

RESULTS: All clinical test, patient reported outcomes and total activity improved significantly (p<0.05). 46% improved (any change >0) in three of four real-life measures. Change of the T25FW predicted only an increase of distance per day. Subjective rating of patients performed better by predicting distance and walking speed changes correctly.

CONCLUSION: Fampridine might improve walking in daily life of MS, but clinical tests are weak predictors. Accelerometry opens a new perspective on mobility measurment, but the current data do not show a consistent effect on non-performance based accelerometry outcomes.