A prospective, longitudinal, multicenter study of 217 patients with neuromyelitis optica spectrum disorder (NMOSD) found a lower prevalence of cognitive deficits than was previously reported. A subset of patients was cognitively impaired in visual processing speed and semantic fluency regardless of their serostatus.
To what extent NMOSD patients face cognitive deficits is unclear. Previous studies showed inconsistent results, with a prevalence ranging between 30–70%. A prospective, longitudinal, multicenter, observational study, initiated by Dr. Martin W Hümmert (Hannover Medical School, Germany) and colleagues, included data from 217 NMOSD patients from 17 specialized German centers. Of these participants, 174 (80%) were aquaporin-4-IgG-seropositive (AQP4-IgG+) and 43 (20%) were seronegative. To determine their cognitive status, they underwent Symbol Digit Modalities Test (SDMT, testing visual processing speed), Paced Auditory Serial-Addition Task (PASAT, a hearing test of processing speed), and/or Multiple Sclerosis Inventory Cognition (MUSIC, a multiple-domain cognitive screening test of the most frequently impaired cognitive domains in MS: immediate recall, semantic fluency, visual processing speed, inhibition score, and delayed recall). Test results were compared with normative data from healthy controls. To assess changes over time, intra-individual cognitive performances were analyzed after 1–2 years.
The median age was 52 years (range: 21–81), with a median disease duration of 6 years (0–47), and an Expanded Disability Status Scale (EDSS) score of 3.5 (0–8.5). Compared with healthy controls, NMOSD patients were impaired in SDMT (P=0.007), MUSIC verbal fluency (P<0.001), and MUSIC congruent naming speed (P<0.001). Every fifth patient (23/123; 19%) showed impaired performance in at least 2 test scores; 40% (62/157) in at least 1 test score. There was no significant decrease in individual performance after 1–2 years. EDSS scores were associated with lower test performance and SDMT scores were related to physical disability (r=-0.43; P<0.0010) and visual disability (r=-0.32; P<0.001). No differences were present between AQP4-IgG-seropositive and -seronegative NMOSD patients.
The authors concluded that the prevalence of cognitive deficits found was lower than previously reported, and did not noticeably deteriorate after 2 years. They argued that neuropsychological measurements should be adapted to physical and visual disabilities typically seen in NMOSD patients. In order to assess elderly (60+ years) NMOSD patients, normative data of healthy controls are needed.
- Hümmert MW. Cognition in patients with neuromyelitis optica spectrum disorders: A prospective longitudinal multicentre study of 217 patients (CogniNMO-Study). Poster P020, ECTRIMS 2022, 26–28 October, Amsterdam, the Netherlands.
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