Background: Impaired cognition and ambulation are common in multiple sclerosis (MS). Dalfampridine is the first Food and Drug Administration (FDA)-approved medication to treat impaired ambulation in MS. Dalfampridine may benefit patients with cognitive impairment, given its effects on saltatory conduction and the association between cognitive and motor function.
Objective: To examine the effects of dalfampridine on cognition in MS. To determine if the anticipated improved cognition is grounded in dalfampridine's effects on ambulation.
Methods: Adults with MS were randomized to dalfampridine (n = 45) or placebo (n = 16) for 12 weeks. Cognition and motor function were assessed at baseline and end-point.
Results: T25FW and 6-minute walk (6MW) performance improved at end-point in the treatment group but not in the placebo group (p < 0.05). Our primary outcome, performance on the Symbol Digit Modalities Test, did not improve. About 30% (n = 12) of the dalfampridine group demonstrated ⩾20% improved ambulation and were categorized "responders." Among "responders", Symbol Digit Modalities test performance did not improve. However, performance on the Paced Auditory Serial Addition Test improved among "responders" (p < 0.05).
Conclusion: Dalfampridine benefits timed ambulation but not cognition. Some improvement among ambulation "responders" is consistent with prior reports of cognition-motor coupling in MS ( ClinicalTrials.gov #: NCT02006160).
Keywords: Multiple sclerosis; ambulation; aminopyradine; cognition; cognitive processing speed; dalfampridine.