A clinical screening tool for objective and subjective cognitive disorders in multiple sclerosis

Cognitive dysfunction is common in multiple sclerosis (MS). Deficits can affect attention, concentration, planning, and memory. They can have severe functional consequences in many domains. Cognitive complaints are frequently associated with other confounding factors (fatigue, anxiety, depression, or treatment side effects). In most cases, cognitive assessment is proposed after a spontaneous complaint, but determining the extent of discomfort perceived by the patient, the influence of coexisting factors, or the optimal timing for a more complete neuropsychological assessment is difficult.

The objective of this work was to evaluate the feasibility and relevance of a fast global assessment of both objective and subjective cognitive dysfunction in MS.

MS patients underwent a brief cognitive assessment including 7 visual analogue scales (VASs) asking about the patient's subjective level of discomfort in various domains, a memory test (Barbizet's lion story), a commonly used test of information processing speed (Symbol Digit Modalities Test [SDMT]) and self-reporting questionnaires for fatigue and mood (Fatigue Severity Scale [FSS] and Hospital Anxiety and Depression Scale [HADS]). Spearman correlation coefficients among scores were estimated.

The mean age of the 73 patients included was 48.3 (SD 11.1) years; 78% were females and 52.8% had the remittent-recurrent MS form, 8.3% the primary progressive form, and 38.9% the secondary progressive form. In less than 20min, this brief cognitive assessment was able to identify symptoms and quantify discomfort level. Symptoms of fatigue and anxiety frequently coexisted with cognitive complaints. We found modest correlations between scores on the VAS fatigue and the FSS and between scores on the VAS mood and the HADS. Analytical evaluation revealed that most patients had similar SDMT and recall profiles; however, a small proportion showed a dissociation between these 2 tests, which validated the inclusion of both tests in the assessment. Accounting for coexisting factors (e.g., anxiety and fatigue) and their functional repercussions is essential for prioritizing these problems within the context of multidisciplinary patient treatment.

Considering the possible multifactorial character of cognitive dysfunction in MS, it is essential to ask patients about their experiences and to take into account cognitive complaints in the follow-up of patients. The assessment tool we propose is simple and easy to use in a clinical setting and provides the information necessary for requesting (or not) a more complete neuropsychological assessment.