by Stefan Zorn, Medizinische Hochschule Hannover

Mean z-scores of neuropsychological tests at baseline (patients <60 years). PASAT, Paced Auditory Serial Addition Task; SDMT, Symbol Digit Modalities Test. Credit: Journal of Neurology, Neurosurgery & Psychiatry (2024). DOI: 10.1136/jnnp-2024-333994

Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is a rare autoimmune disease of the central nervous system. According to estimates, 1 to 3 in 100,000 people are affected. They may suffer from visual disturbances, paralysis, incontinence and pain. But do they also have cognitive impairments?

Smaller scientific studies have so far provided contradictory findings. A team of researchers led by the Department of Neurology with Clinical Neurophysiology at the Hannover Medical School (MHH) therefore decided to address the question in a large multicenter study for the first time.

The result: Some patients with MOGAD show deficits, particularly in visual information processing speed and word fluency. The study is published in the Journal of Neurology, Neurosurgery & Psychiatry.

Participants from 14 NEMOS centers

"Our goal was to examine the extent and characteristics of possible cognitive deficits over a longer period of time," explains Dr. Martin Hümmert from the Department of Neurology. Together with his colleagues Professor Dr. Corinna Trebst, Sarah Passoke, Carlotta Stern and the neuropsychologist Professor Dr. Bruno Kopp, he launched the CogniMOG observational study with 122 adult MOGAD patients.

The participants had been recruited from 14 centers of the German Neuromyelitis Optica Study Group (NEMOS) network. These centers specialize in the treatment and research of MOGAD and similar disorders and collect extensive data from those affected in a standardized manner.

The study team determined the individual cognitive performance of the study participants using three neuropsychological tests: the Paced Auditory Serial Addition Task, the Symbol Digit Modalities Test, and the Multiple Sclerosis Inventarium Cognition. In addition, it analyzed possible correlations between cognitive performance and sociodemographic and clinical factors.

The results were compared with relevant data from healthy control groups. "To monitor the long-term development of cognitive performance, we repeated the neuropsychological tests after one and two years," explains Sarah Passoke, a doctoral student and first author of the study.

With the CogniMOG study, the team was able to show that 11% of MOGAD patients have cognitive deficits. These mainly affect the processing speed of visual information and semantic fluency, i.e., word fluency. The team found that pathological changes in the cerebrum are an important predictor of cognitive impairment. No deterioration in cognitive abilities was observed in the retakes of the tests after one and two years.

The CogniMOG study is the first to create a detailed cognitive profile of MOGAD patients. "The strength of our study lies in the large, clinically well-characterized patient sample from the NEMOS network centers," says PD Dr. Hümmert. "The study results help us to better understand the burden of disease in MOGAD, to better consider rehabilitation needs and to optimize treatment."

More information: Sarah Passoke et al, Cognition in patients with myelin oligodendrocyte glycoprotein antibody-associated disease: a prospective, longitudinal, multicentre study of 113 patients (CogniMOG-Study), Journal of Neurology, Neurosurgery & Psychiatry (2024). DOI: 10.1136/jnnp-2024-333994

Provided by Medizinische Hochschule Hannover