INTRODUCTION: Understanding signs and symptoms that matter to patients is integral to ensuring content validity of clinical outcome assessments. FLOODLIGHT is a battery of digital performance assessments, conducted remotely on a smartphone that enables objective and frequent measurement of upper limb, lower limb and cognitive symptoms in people with multiple sclerosis (PwMS). Ensuring assessed abilities are relevant and important to PwMS and drawing associations between FLOODLIGHT tests and common activities supports content validity.
AIM: As no standard approach to establishing content validity for digital performance assessments exists, we obtained feedback on FLOODLIGHT from neurologists and PwMS to understand how MS symptoms impact test performance and related daily activities. Methods: Semi-structured, 60- or 90-minute interviews were conducted with neurologists and PwMS, respectively. Disease severity was gauged using the patient-reported Expanded Disability Status Scale (prEDSS) and Patient Determined Disease Steps (PDDS). Subjects performed FLOODLIGHT tests one at a time, responding to questions after each. Subjects were asked to describe their experience performing the test, any associated challenges and to what degree daily activities required similar skills as the test.
RESULTS: Sixteen PwMS (female 68.7%; n=9 RRMS, n=7 SPMS; prEDSS mean score 4.7 [range: 1.5-8]; PDDS mean score 3.6 [range 0-7]; mean age 49.4 years [range: 29-62]) and 5 neurologists (mean MS experience 19.2 years) were recruited. Feedback from neurologists and PwMS were aligned, with all subjects relating skills required for each test to actions needed to perform daily activities. Fine motor skills were reported as important for completing the upper limb tests, which were related to writing, drawing and picking up objects. Lower limb tests challenged balance and strength/coordination, which were related to walking, grocery shopping and changing direction. The cognitive test required thinking quickly, remembering detail and maintaining focus; these abilities were associated with skills required for working, driving and managing personal finances. Subjects reported that impairments in daily activities increase dependence and isolation, and diminish health-related quality of life.
CONCLUSIONS: PwMS and neurologists directly related skills required to perform each FLOODLIGHT test to common daily activities. These data provide evidence to support the content validity of FLOODLIGHT.
