Annals of Clinical and Translational Neurology (Jul 2020)

Impaired cognition is related to microstructural integrity in relapsing remitting multiple sclerosis

  • Lin Zhao,
  • Angel Ng,
  • Qianyun Chen,
  • Bonnie Lam,
  • Jill Abrigo,
  • Cheryl Au,
  • Vincent C. T. Mok,
  • Adrian Wong,
  • Alexander Y. Lau

DOI
https://doi.org/10.1002/acn3.51100
Journal volume & issue
Vol. 7, no. 7
pp. 1193 – 1203

Abstract

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Abstract Background Cognitive impairment is common in multiple sclerosis (MS). However, the relationship between cognitive deficits and microstructural abnormalities in Chinese MS patients remains unclear. We aimed to investigate the importance of microstructural abnormalities and the associations with cognitive impairment in Chinese MS patients. Methods Three‐dimensional T1‐weighted magnetic resonance imaging (MRI) scans were obtained from 36 relapsing remitting MS patients. Diffusion tensor imaging (DTI) scans were acquired for 29 (81%) patients. Cognitive impairment was assessed using a comprehensive neuropsychological battery. Patients were classified into cognitively impaired (CI) group and cognitively preserved (CP) group. Using volBrain and FSL software, we assessed white matter lesion burden, white matter (WM) and gray matter (GM) volumetric as well as microstructural diffusivity. MRI variables explaining cognitive impairment were analyzed. Results Fifteen (42%) patients were classified as CI. Verbal learning and memory was the most commonly impaired domain (n = 16, 44%). CI patients had lower mean skeleton fractional anisotropy (FA) value than CP patients (275.45 vs. 283.61 × 10−3, P = 0.023). The final predicting model including demographic variables and global skeleton mean diffusivity (MD) explained 43.6% of variance of the presence of cognitive impairment (β = 0.131, P = 0.041). CI patients showed a widespread change of microstructural integrity comparing to CP patients, which was rarely overlapping with lesion probability map. Microstructural abnormalities in corpus callosum were associated with performance in verbal learning and memory, processing speed and selective attention (P < 0.05). Conclusion Loss of microstructural integrity demonstrated by DTI helps explain cognitive dysfunction in Chinese MS patients.

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