The HV3 Score: A New Simple Tool to Suspect Cognitive Impairment in Multiple Sclerosis in Clinical Practice

INTRODUCTION Cognitive impairment in multiple sclerosis (MS) is common even in the early stages of the disease. Our objective was to improve early detection of cognitive impairment in MS. METHODS Seventy-five patients with relapsing remitting (RR) MS and 20 controls were enrolled. Two RRMS groups were defined according to their results at the Paced Auditory Serial Addition Test (PASAT). Patients with a z score below two standard deviations were considered impaired. We quantified T2 and T1 lesion volumes, and cerebral white and grey matter volumes on a conventional brain magnetic resonance imaging (MRI) scan. Global brain atrophy was evaluated using the third ventricle (V3) width (in mm). An average brain model was built based on controls and compared with the patient's MRI to quantify regional volumetric changes. RESULTS Sixteen (21.3%) patients with RRMS had low PASAT performance. They had a higher Expanded Disability Status Scale (EDSS) score (P = 0.019). T2 and T1 lesion volumes, and grey and white matter volumes were the same in both groups. An enlargement of the V3 width was observed in the low performer group (P = 0.044) and V3 width was correlated with the PASAT score (r = -0.271; P = 0.021). A composite score, named HV3, was obtained by adding the EDSS and V3 width (in mm) and correlated with the PASAT (r = -0.325; P = 0.006). A cutoff HV3 score of over 5.5 identified patients with low PASAT performance, with a positive predictive value of 92.5% and an accuracy of 70.1%. Focal atrophy was detected in the supplementary motor area, the cingulate gyrus, the right thalamus, and the inferior parietal lobules of patients with lower PASAT performance. CONCLUSION Specific brain morphological changes, including an enlargement of the V3 width, are associated with low PASAT performance in patients with RRMS. The HV3 score is an additional and complementary tool, accessible in clinical practice, to suspect easily cognitive impairment in patients with RRMS and to better identify patients requiring a complete cognitive assessment.