Background: Depression symptoms are common in Rheumatoid Arthritis (RA) patients. This could be caused by the limited activities of daily life experienced by RA patients as well as by the...Show moreBackground: Depression symptoms are common in Rheumatoid Arthritis (RA) patients. This could be caused by the limited activities of daily life experienced by RA patients as well as by the inflammation pathways altered by RA which are known to influence depression. Bright light therapy (BLT) has previously shown to be effective to tackle depression caused by an altered circadian rhythm. As a disrupted circadian rhythm is also common in RA patients, BLT might be effective as therapy to treat depression in RA. Objective: The goal of the present study is to examine the effects of BLT on depression and mental health, as well as to explorative examine whether this effect is mediated by changes in circadian rhythmicity in RA patients. Method: This study is a randomized, double-blind, parallel-arm, placebo controlled single center pilot trial study. It consists of 48 RA patients, divided into intervention group with active BLT, and control group with sham BLT. Measurements were taken at three periods: baseline (T0), at the end of the 4-week with BLT (T1), and at follow-up four weeks after BLT (T2). Measurement tools used consisted of a depression scale (HADS) and a mental health scale (RAND 36), as well as the time point of melatonin onset measured by the Dim Light Melatonin Onset test (DLMO). BLT was administered with Luminette glasses which emitted a different color for the intervention group (blue light, to induce circadian phase shift) compared to control group. Results: The results suggest that there is no significant difference with regards to depression, mental health and DLMO between the two groups in the changes between the measurement points from T0 to T1 and from T0 to T2. No significant results were found with regards to the mediating role of DLMO in the relationship between group and depression and mental health. Conclusion: No significant effects of group were found in the present study, with regards to changes in depression, mental health and DLMO, and no mediation effect of the DLMO in the relation between group, depression, and mental health was found. A possible explanation is the low levels of depression reported by the participants at baseline. Further studies are required before disregarding BLT as a potential therapeutic tool to treat depression in RA patients.Show less
In the search for a more affordable, less invasive biomarker to accurately diagnose and prognose Alzheimer’s disease (AD), measuring cortical thickness via magnetic resonance imaging is a promising...Show moreIn the search for a more affordable, less invasive biomarker to accurately diagnose and prognose Alzheimer’s disease (AD), measuring cortical thickness via magnetic resonance imaging is a promising method. Specific regions on the cortex are found to be related to AD, referred to as AD signature regions, but evidence for the persistence of the relationship between cortical thickness and cognitive decline in the preclinical phase of the disease is lacking. The aim of this study is to investigate whether a lower cortical thickness is related to worse cognitive performance and can predict cognitive decline over time. Furthermore, it is hypothesized that this trend is influenced by the presence of other AD biomarkers, e.g. amyloid status. In a cross-sectional and longitudinal study, we investigated 189 cognitively normal older adults (91 twin pairs and 7 single twins) and measured cortical thickness via magnetic resonance imaging, cognitive performance during neuropsychological assessment and amyloid pathology in positron emission tomography and cerebrospinal fluid. Neuropsychological assessment was repeated after approximately two years. Cognitive performance was divided into four domains: memory, attention, executive functions and language. Participants were on average 70.23 (SD = 7.46) years and 107 (57%) were female. Cross-sectionally, we found that lower cortical thickness was related to worse memory performance (b = 0.133 [SE = 0.046], p = 0.004). When cortical thickness on separate AD signature regions was examined, we found that certain regions were related to performance on memory and executive functioning. Longitudinally, we found that cortical thickness at baseline could not predict cognitive performance over time. When examining the role of amyloid status in these relationships cross-sectionally, we found that both lower cortical thickness and positive amyloid status were related to worse memory performance (respectively, b = 0.237 [SE = 0.053], p = <.001 and b = -0.240 [SE = 0.108], p = 0.026), yet the interaction effect was not significant. These results provide evidence for the cross-sectional relationship between lower cortical thickness and worse cognitive performance, more specifically worse memory and executive functions performance. Future research must determine whether cortical thinning in contrast to cortical thickness, can predict cognitive performance over time. In that case, individuals at risk of AD can be easier identified in a more affordable and less invasive way.Show less
