"Gait responder" to fampridine, a too restrictive concept?

OBJECTIVE: Fampridine is used as a symptomatic treatment in patients with multiple sclerosis (PwMS) gait disorders. Some clinical trials reported a positive effect on cognitive function especially on information-processing speed (IPS) or on fatigue. The aim of our clinical trial was to evaluate the effect of fampridine on IPS.

MATERIAL/PATIENTS AND METHODS: 60 PwMS with an EDSS score between 4 and 7 were included in a prospective monocentric open label trial. Two identical measures were conducted a week apart before initiating treatment in order to take into account the test-retest effect. Then, patients were treated for at least 14 days and were evaluated twice (again a week apart). Two tests were used to measure IPS: symbol digit modalities test (SDMT) and verbal fluencies test (VFT). The gait was measured at fast condition and the fatigue was evaluate using the modified fatigue impact scale (EMIF-SEP). Patients were divided into two groups regarding to the increase of gait speed after treatment: gait responders (GR) (more than 17.2%) and non-gait responders-NGR (less than 17.2%). The second group was also divided into two groups: those continuating treatment (on clinician appreciation) called others responders (OR) and those who stopped treatment called no responders (NR). For statistical analysis, a one-way analysis of variance for repeated measurement was used. When significant effects existed, Turkey post-hoc tests were performed.

RESULTS: Mean EDSS was 5.25±1.07. 24% of PwMS were qualified as gait responder (mean speed improvement of 49.4%). Those who improved their gait velocity were the most affected by the disease (regarding to EDSS). Fatigue and IPS improvement was found in GR, NGR and OR after treatment. It could be observed beyond 14 days of treatment (SDMT in GR, GNR and OR and EMIF-SEP in GNR). No improvement was shown in NR.

DISCUSSION/CONCLUSION: Our results suggest that fampridine could have an effect on cognition disorders and fatigue even on those who are not gait responder.