Introduction

Application of multidimensional assessment batteries is a well-established approach to detect cognitive impairment in multiple sclerosis (MS), the best known example being the Brief Repeatable Neuropsychological Battery. Although relatively easy to administer, these batteries require equipment, training and take 30–60 min.1 Current bedside screening techniques based on the Symbol Digit Modality Test, Paced Auditory Serial Additions Test (PASAT) and Faces Symbol Test are quick to administer (5–10 min), but they also require training and availability of relevant equipment.2 A rapid portable screening test that could be widely applied at the bedside or in the busy clinic is therefore highly desirable.

Given that deficits in both phonemic (letter) and semantic (category) fluency are common in progressive MS and have been described among the earliest detectable cognitive features, both are of interest as candidate screening tests.3 Testing requires the subject to generate words beginning with a given letter (eg, p) or semantic category (eg, animals) over a defined time period (usually 1 min). Crucially, minimal test equipment is …