The association between body mass index, demographic and clinical characteristics with cognitive performance in patients with neuromyelitis optica spectrum disorder

Cognitive dysfunction is one of the problems that patients with neuromyelitis optica spectrum disorder (NMOSD) suffer from. We aimed to assess the association between demographic and clinical features as well as body mass index (BMI) and cognitive function in patients with NMOSD.

A cross-sectional study was performed on 41 patients with definite diagnosis of NMOSD. Serum status of neuromyelitis optica immunoglobulin G (NMO-IgG) was determined using enzyme-linked immunosorbent assay (ELISA) method. Cognitive function was assessed by Minimal Assessment of Cognitive Function in Multiple Sclerosis (MACFIMS) battery which is validated for Persian people before and North American Adult Reading Test (NAART).

The mean score of NAART test was higher in participants with normal weight compared with overweight patients (40.47 ± 3.51 vs. 36.00 ± 5.74, P = 0.02). Current age was negatively correlated with Delis-Kaplan Executive Function System (D-KEFS)-Sorting (P = 0.05, r = -0.30). The correlation of duration of disease and cognitive performance was not significant (P > 0.05). Higher physical disability based on Expanded Disability Status Scale (EDSS) was correlated with lower results in Brief Visuospatial Memory Test-Revised (BVMT-R) (P < 0.01, r = -0.50), California Verbal Learning Test-second edition (CVLT-II)-Delayed Recall (P = 0.02, r = -0.35), and Symbol Digit Modalities Test (SDMT) (P = 0.03, r = -0.33) subtests of MACFIMS. Annual relapse rate was indirectly correlated with CVLT-II (P = 0.03, r = -0.34) and CVLT-II-Delayed Recall (P = 0.01, r = -0.38). Male participants obtained better scores in Paced Auditory Serial Addition Test (PASAT) subtest (P = 0.05). NMO-IgG seropositive patients had poorer performance in terms of CVLT-II-Delayed Recall, Controlled Oral Word Association Test (COWAT), and D-KEFS-Descriptive (P < 0.05). Participants with bachelor and master education degrees showed significantly better results compared to those with high school degree (P < 0.05).

Investigating the clinical and demographic factors affecting cognitive impairment can increase the awareness of health care providers for early diagnosis of cognitive impairment in patients with NMOSD and increase the quality of health services.