Objectives: The relationship between cognitive symptoms and underlying neuropathology in primary SS (PSS) is poorly understood. We used high-resolution quantitative brain MRI to identify potential structural correlates of cognitive symptoms. Methods: Subjects completed a comprehensive neuropsychometric evaluation. Imaging was performed on a 3 T MRI scanner with T1 and proton density-weighted, fluid-attenuated inversion recovery (FLAIR) and diffusion tensor imaging (DTI) sequences. We compared MRI group metrics (impaired PSS, not-impaired PSS and controls) and tested for correlations between DTI results and neuropsychological measurements (significance threshold P = 0.05). Results: Nineteen PSS patients (who met American-European Consensus Group 2002 criteria) and 17 healthy controls completed the cognitive evaluation. MRI scans were performed in six impaired PSS, seven not-impaired PSS and seven controls. No differences were found in regional volumetrics, nor was there a difference in T2 lesion load between groups. Fractional anisotropy (FA) in the inferior frontal white matter (WM) was lower (P = 0.021) and mean diffusivity higher (P = 0.003) in the impaired PSS relative to the control group. Inferior frontal FA was correlated with cognitive symptoms (P = 0.0064) and with verbal memory (P = 0.0125). Conclusions: In this exploratory study, frontal region WM microstructure alterations accompanied cognitive symptoms and were associated with mild cognitive impairment in PSS. While additional study is warranted to assess the specificity and stability of these results, DTI could provide novel insight into the pathological processes accompanying the subtle cognitive dysfunction commonly experienced by PSS patients.
Bibliographical noteFunding Information:
We are grateful for the support from the Center for Magnetic Resonance Research, University of Minnesota. Assistance with neuropsychometric testing was provided by Abry Deshong and Kathleen Rieke. We also gratefully acknowledge the kind cooperation of the patients; without their cooperation this study would not have been possible.
Funding: This work was supported by the Arthritis Foundation, Minnesota Chapter and the Center for Magnetic Resonance Research, University of Minnesota.
- Brain magnetic resonance-diffusion tensor imaging
- Neurological involvement
- Sjögren's syndrome