Dalfampridine benefits ambulation but not cognition in multiple sclerosis.

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).