Cognitive assessment and quantitative MRI in systemic lupus erythematosus
Year: 2012
Type: dissertation
Study design: Observational Study
Abstract: This thesis investigates the relationship between quantitative correlates of diffuse brain damage and neurological and psychiatric manifestations in Systemic Lupus Erythematosus (SLE). A group of 37 patients with a primary diagnosis of SLE (mean age 43.97±12.SS) were compared to 29 matched healthy controls. The SLE group were subdivided into those who had experienced neuropsychiatric (NP) manifestations (NPSLE - n=lS) and those who had never had NP manifestations (non-NPSLE). Participants completed a broad cognitive test battery, neuropsychological measures and quantitative MRI (magnetisation transfer (MTI) and diffusion tensor imaging (OTI)). From MTI the magnetisation transfer ratio (MTR) was measured, which can be a marker for demyelination. Using OTI the extent (apparent diffusion coefficient) and directionality (fractional anisotropy) of diffusion were assessed, which are sensitive measures of brain structural integrity. Results indicate that both SLE groups had significantly higher scores on depression and anxiety and lower quality of life compared to healthy controls. The only difference between the NPSLE and non-NPSLE groups was lower physical health related quality of life in the former group. On cognitive tasks the NPSLE group scored significantly worse than controls on multiple domains, and worse than the non-NPSLE group on memory and speed of processing. There were no differences between the non-NPSLE patients and controls. On OTI measures the NPSLE group showed increased white matter ADC and a non significant decrease in FA, changes which are consistent with subtle brain damage in this group. The non-NPSLE group had higher ADC than controls if measured in the whole brain. There were no differences on MTI and few differences on measures of brain volume, suggesting demyelination and atrophy were not noteworthy in this cohort. Correlations were assessed between cognition and the other factors. In the NPSLE group cognitive function correlated with white matter FA suggesting this was driven by changes in brain parenchyma. Cognitive function also correlated with pain, fatigue, physical health, disease activity and anxiety scores suggesting general health related factors also play a role in cognitive dysfunction. In the non-NPSLE group processing speed correlated with depression scores, but no other relationships were evident. The role of anti-phospholipid antibodies, anti- Ro antibodies, corticosteroid dose and confounds such as renal involvement in SLE, hypertension and motor speed differences were considered. None of these factors could explain cognitive dysfunction in the patient group. These findings are interpreted as indicating that cognitive performance in NPSLE is unlikely to be driven by emotional health. Instead performance related to white matter integrity and general illness, two factors which may be interlinked.
Author: Rebecca Ilana Haynes
Language: English
Subfield: Rheumatology
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W836589891