Gray Matter Morphometry Correlates with Attentional Efficiency in Young-Adult Multiple Sclerosis

Sindhuja T Govindarajan,Ruiqi Pan,Lauren Krupp,Tim Q Duong,Leigh Charvet

doi:10.3390/brainsci11010080

Abstract

Slowed processing on the alerting, orienting and executive control components of attention measured using the Attention Network Test-Interactions (ANT-I) have been widely reported in multiple sclerosis (MS). Despite the assumption that these components correspond to specific neuroanatomical networks in the brain, little is known about gray matter changes that occur in MS and their association with ANT-I performance. We investigated vertex-wise cortical thickness changes and deep gray matter volumetric changes in young MS participants (N = 21, age range: 18–35) with pediatric or young-adult onset and mild disease severity. ANT-I scores and cortical thickness were not significantly different between MS participants and healthy volunteers (N = 19, age range: 18–35), but thalamic volumes were significantly lower in MS. Slowed reaction times on the alerting component in MS correlated significantly with reduced volume of the right pallidum in MS. Slowed reaction times on executive control component correlated significantly with reduced thickness in the frontal, parietal and visual cortical areas and with reduced volume of the left putamen in MS. These findings demonstrate associations between gray matter changes and attentional performance even in the absence of widespread atrophy or slowed attentional processes.

Highlights

Multiple sclerosis (MS) is a chronic and progressive disease of the central nervous system, marked by periods of acute neuro inflammation and demyelination
The mean disease duration of MS participants was 5.9 ± 3.5 at the time of the study. We included those participants with mild (EDSS 0–3.5) and moderate (EDSS 4.0–6.0) neurologic disability
We found: (i) MS participants showed no significant global or vertex-wise cortical thinning but showed reduced volume of subcortical gray matter (GM) structures, especially the thalamus, compared to healthy controls, (ii) slowed reaction times on the alerting component correlated with lower volume of the right pallidum in MS, (iii) slowed reaction times on the executive control component correlated with reduced thickness in the frontal, parietal and visual cortices, and lower volume of the left putamen in MS, and (iv) there were no significant associations between alerting function and cortical thickness, and between orienting function OR Symbol Digits Modality Test (SDMT) and either morphometric measures in MS

Summary

Introduction

Multiple sclerosis (MS) is a chronic and progressive disease of the central nervous system, marked by periods of acute neuro inflammation and demyelination. Slowed information processing speed and attention are among the most common cognitive changes observed in MS [4], which in turn can negatively and broadly influence additional cognitive processes including executive functions and memory [5,6,7]. Altered attention and processing speed in pediatric and young adult cohorts are concerning because they can interfere with educational and occupational attainment. By definition, those with earlier onset will have a longer disease course and may be more susceptible to accumulation of disability into adulthood [11,12,13]

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