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Magnetic Resonance Imaging of Multiple Sclerosis at 7.0 Tesla
Published on: February 19, 2021
Isolated cognitive impairment in people with multiple sclerosis: frequency, MRI patterns and its development over
Piet M Bouman1,2, Maureen A van Dam3,4,5, Laura E Jonkman4,6
1Department of Anatomy and Neurosciences, MS Center Amsterdam, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam UMC VUmc, De Boelelaan 1117, Amsterdam, The Netherlands. p.bouman@amsterdamumc.nl.
Objectives:
To study the frequency of isolated (i.e., single-domain) cognitive impairments, domain specific MRI correlates, and its longitudinal development in people with multiple sclerosis (PwMS).
Methods:
348 PwMS (mean age 48 ± 11 years, 67% female, 244RR/52SP/38PP) underwent neuropsychological testing (extended BRB-N) at baseline and at five-year follow-up. At baseline, structural MRI was acquired. Isolated cognitive impairment was defined as a Z-score of at least 1.5 SD below normative data in one domain only (processing speed, memory, executive functioning/working memory, and attention). Multi-domain cognitive impairment was defined as being affected in ≥ 2 domains, and cognitively preserved otherwise. For PwMS with isolated cognitive impairment, MRI correlates were explored using linear regression. Development of isolated cognitive impairment over time was evaluated based on reliable change index.
Results:
At baseline, 108 (31%) PwMS displayed isolated cognitive impairment, 148 (43%) PwMS displayed multi-domain cognitive impairment. Most PwMS with isolated cognitive impairment were impaired on executive functioning/working memory (EF/WM; N = 37), followed by processing speed (IPS; N = 25), memory (N = 23), and attention (N = 23). Isolated IPS impairment was explained by a model of cortical volume and fractional anisotropy (adj. R2 = 0.539, p < 0.001); memory by a model with cortical volume and hippocampal volume (adj. R2 = 0.493, p = 0.002); EF/WM and attention were not associated with any MRI measure. At follow-up, cognitive decline was present in 11/16 (69%) of PwMS with isolated IPS impairment at baseline. This percentage varied between 18 and 31% of PwMS with isolated cognitive impairment in domains other than IPS at baseline.
Conclusion:
Isolated cognitive impairment is frequently present in PwMS and can serve as a proxy for further decline, particularly when it concerns processing speed. Cortical and deep grey matter atrophy seem to play a pivotal role in isolated cognitive impairment. Timely detection and patient-tailored intervention, predominantly for IPS, may help to postpone further cognitive decline.
Insights
Isolated cognitive impairment is common in people with multiple sclerosis (PwMS) and can predict future decline, especially in processing speed. Early detection and intervention are key to managing cognitive changes in MS.
Area of Science:
- Neuroscience
- Neurology
- Radiology
Background:
- Cognitive impairments are prevalent in people with multiple sclerosis (PwMS).
- Understanding the frequency, MRI correlates, and longitudinal development of isolated cognitive impairments is crucial for effective management.
Purpose of the Study:
- To determine the frequency of isolated cognitive impairments in PwMS.
- To identify specific MRI correlates associated with single-domain cognitive deficits.
- To examine the longitudinal progression of isolated cognitive impairments over five years.
Main Methods:
- 348 PwMS underwent neuropsychological testing at baseline and five-year follow-up.
- Isolated cognitive impairment was defined as a Z-score of at least 1.5 SD below normative data in a single cognitive domain.
- Structural MRI was used to explore correlations with cognitive function.
Main Results:
- At baseline, 31% of PwMS had isolated cognitive impairment, with executive functioning/working memory being the most affected domain.
- Isolated impairment in information processing speed (IPS) was associated with cortical volume and fractional anisotropy.
- Memory impairment correlated with cortical and hippocampal volume.
- Cognitive decline was observed in 69% of PwMS with isolated IPS impairment at baseline after five years.
Conclusions:
- Isolated cognitive impairment is frequent in PwMS and can indicate future cognitive decline, particularly when affecting processing speed.
- Cortical and deep grey matter atrophy are significant factors in isolated cognitive impairment.
- Early detection and tailored interventions, especially for processing speed deficits, may help mitigate further cognitive decline in PwMS.
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