Cognitive Decline in Older People with Multiple Sclerosis—A Narrative Review of the Literature

Abstract

Several important questions regarding cognitive aging and dementia in older people with multiple sclerosis (PwMS) are the focus of this narrative review: Do older PwMS have worse cognitive decline compared to older people without MS? Can older PwMS develop dementia or other neurodegenerative diseases such as Alzheimer’s disease (AD) that may be accelerated due to MS? Are there any potential biomarkers that can help to determine the etiology of cognitive decline in older PwMS? What are the neural and cellular bases of cognitive aging and neurodegeneration in MS? Current evidence suggests that cognitive impairment in MS is distinguishable from that due to other neurodegenerative diseases, although older PwMS may present with accelerated cognitive decline. While dementia is prevalent in PwMS, there is currently no consensus on defining it. Cerebrospinal fluid and imaging biomarkers have the potential to identify disease processes linked to MS and other comorbidities—such as AD and vascular disease—in older PwMS, although more research is required. In conclusion, one should be aware that multiple underlying pathologies can coexist in older PwMS and cause cognitive decline. Future basic and clinical research will need to consider these complex factors to better understand the underlying pathophysiology, and to improve diagnostic accuracy.

Age and asymmetry of corticospinal excitability, but not cardiorespiratory fitness, predict cognitive impairments in multiple sclerosis

“…Whereas persons with PSI have disabling cognitive complaints as early as their 30s ( Staff et al, 2009 ), age-related MCI follows a more indolent course and usually affects individuals in their 50s or later ( Benedict et al, 2020 ). A recent review of the literature suggested that, compared to age-related MCI, MS-related impairments involve reduced processing speed but superior memory, executive, and language functions ( Chiang et al, 2022 ). In terms of neuroimaging findings, persons with age-related MCI in MS have a similar pattern of atherosclerotic cerebral small vessel disease to persons with MCI but without MS ( DeLuca et al, 2015 ).…”