Cognitive impairment differs between neuromyelitis optica spectrum disorder and multiple sclerosis

Area of Science:

• Neuroimmunology
• Neuropsychology

Background:

• Neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS) are inflammatory demyelinating diseases of the central nervous system.
• Cognitive impairment (CI) is a known complication in MS, but its prevalence and pattern in NMOSD are less understood.

Purpose of the Study:

• To compare the frequency and pattern of cognitive impairment (CI) between patients with NMOSD and MS.
• To investigate potential differences in the underlying mechanisms of brain injury.

Main Methods:

• A neuropsychological assessment was conducted on 82 NMOSD patients, 58 MS patients, and 45 healthy controls.
• Cognitive impairment was defined as scoring below the fifth percentile compared to healthy controls in at least three domains.

Main Results:

• CI was observed in 29% of NMOSD patients and 50% of MS patients (p < 0.001).
• MS patients performed significantly worse than NMOSD patients on verbal learning, verbal memory, and visual memory tests.
• In NMOSD, lower education, depression, and longer disease onset-to-treatment intervals were associated with poorer cognition.

Conclusions:

• CI is less frequent in NMOSD compared to MS.
• MS patients exhibit more severe cognitive deficits, particularly in learning and memory.
• The distinct prevalence and patterns of CI suggest different neuropathological mechanisms in NMOSD and MS.