Objective
To longitudinally evaluate the role of depression in the development of impulse control disorders (ICDs) in Parkinson disease (PD) patients.
Methods
Using data from the Parkinson's ...Progression Markers Initiative, we included PD patients without ICDs at baseline according to the Questionnaire for Impulsive‐Compulsive Disorders in Parkinson's Disease (QUIP). Patients were prospectively evaluated first quarterly and then biannually. Development of an ICD was defined as an increase in QUIP scores during follow‐up. Using survival proportional hazard models, we studied the effect of baseline depression on ICD risk. We also evaluated this effect controlling for dopamine agonist use as a time‐dependent variable and for other potential confounders.
Results
Among 354 patients, 68 were depressed at baseline. The median follow‐up was 4.08 years. Depression at baseline was associated with higher ICD risk (hazard ratio HR = 1.96, 95% confidence interval CI = 1.32–2.9, p < 0.001). This risk remained significant after controlling for dopamine agonist use (HR = 1.97, 95% CI = 1.33–2.9, p < 0.001), which was also independently linked to ICD development (HR = 1.87, 95% CI = 1.3–2.7, p < 0.001). Therefore, depressed patients faced an even higher ICD risk when receiving dopamine agonists. Controlling for multiple potential confounders did not alter these results.
Interpretation
Depression predisposes to the development of ICDs in PD. This risk is magnified by dopamine agonists. Dopamine agonists should thus be used cautiously in depressed PD patients. ANN NEUROL 2019;86:762–769
Objective
This study was undertaken to evaluate whether the feedback‐related negativity (FRN)—a neurophysiological marker of incentive processing—can be used to predict the development of impulse ...control disorders (ICDs) in Parkinson disease (PD).
Methods
The longitudinal cohort consisted of consecutive nondemented PD patients with no ICD history. We recorded FRN signals while they performed a gambling task. We calculated the mean amplitude difference between losses and gains (FRNdiff) to be used as a predictor of future ICD development. We performed prospective biannual follow‐up assessments for 30 months to detect incident ICDs. Finally, we evaluated how basal FRNdiff was associated with posterior development of ICDs using survival models.
Results
Between October 7, 2015 and December 16, 2016, we screened 120 patients. Among them, 94 patients performed the gambling and 92 completed the follow‐up. Eighteen patients developed ICDs during follow‐up, whereas 74 remained free of ICDs. Baseline FRNdiff was greater in patients who developed ICDs than in those who did not (−2.33μV vs −0.84μV, p = 0.001). No other significant baseline differences were found. The FRNdiff was significantly associated with ICD development in the survival models both when not adjusted (hazard ratio HR = 0.73, 95% confidence interval CI = 0.58–0.91, p = 0.006) and when controlling for dopamine replacement therapy, sex, and age (HR = 0.74, 95% CI = 0.55–0.97, p = 0.035). None of the impulsivity measures evaluated was related to ICD development.
Interpretation
Reward‐processing differences measured by FRN signals precede ICD development in PD. This neurophysiological marker permits identification of patients with high risk of ICD development. ANN NEUROL 2022;92:974–984
Cognitive decline is a major disabling feature in Parkinson's disease (PD). Multimodal imaging studies have shown functional disruption in neurocognitive networks related to cognitive impairment. ...However, it remains unknown whether these changes are related to gray matter loss, or whether they outline network vulnerability in the early stages of cognitive impairment. In this work, we intended to assess functional connectivity and graph theoretical measures and their relation to gray matter loss in Parkinson's disease with mild cognitive impairment (PD‐MCI). We recruited 53 Parkinson's disease patients and classified them for cognitive impairment using Level‐1 Movement Disorders Society‐Task Force Criteria. Voxel‐based morphometry, functional connectivity and graph theoretical measures were obtained on a 3‐Tesla MRI scanner. Loss of gray matter was observed in the default mode network (bilateral precuneus), without a corresponding disruption of functional or graph theoretical properties. However, functional and graph theoretical changes appeared in salience network nodes, without evidence of gray matter loss. Global cognition and executive scores showed a correlation with node degree in the right anterior insula. We also found a correlation between visuospatial scores and right supramarginal gyrus node degree. Our findings highlight the loss of functional connectivity and topological features without structural damage in salience network regions in PD‐MCI. They also underline the importance of multimodal hubs in the transition to mild cognitive impairment. This functional disruption in the absence of gray matter atrophy suggests that the salience network is a key vulnerable system at the onset of mild cognitive impairment in PD.
Cognitive decline in Parkinson's disease (PD) is a highly prevalent condition with no effective treatment. Cortical atrophy is thought to promote its development but to design optimal therapeutic ...approaches in this clinical setting we need to understand the physiopathological mechanisms leading to this disorder.
To characterize the impact of dopaminergic degeneration on cortical integrity in early PD.
We studied 87 recently-diagnosed PD patients and 38 healthy controls from the Parkinson's Progression Marker Initiative who underwent I123-ioflupane SPECT (DATSCAN) and T1-MRI imaging. Using Freesurfer 6.0, we characterized baseline and longitudinal (one-year) correlations between striatal DAT uptake and cortical thickness. We also addressed the association between these imaging biomarkers and cognitive measures.
Reduced DAT uptake in PD patients was associated with cross-sectional and longitudinal cortical thinning in frontal and posterior-cortical brain regions. Imaging parameters correlated with cognitive indicators in multiple domains that extend beyond frontal-executive tasks. Dopaminergic medication attenuated the longitudinal loss of cortical integrity in frontal and a subset of parietal regions, but not in other key regions such as the precuneus.
To date, posterior cortical alterations in PD, known to play a major role in the development of PD-dementia, have mainly been attributed to a cholinergic degeneration occurring in later stages of the disease. Our results suggest that dopamine loss also promotes posterior-cortical atrophy from the very early stages of Parkinson's disease, which may have potential clinical and therapeutic implications.
•Dementia in Parkinson's disease is a prevalent condition with no effective treatment.•We need to understand the processes leading to cortical damage in this disease.•We characterize the relationship between dopamine loss and cortical deterioration.•Dopamine loss induces frontal and posterior-cortical thinning in early disease stages.
Cognitive impairment and dementia are highly prevalent non-motor complications in Parkinson's disease (PD) with deleterious consequences for patients and caregivers. With no treatment currently ...available, finding and validating minimally-invasive biomarkers of neurodegeneration in this population represents an urgent need for clinical trials targeting its prevention or delay. Recently, serum neurofilament light chain (NfL) levels have been identified as a promising biomarker of neural loss, but whether they reflect cortical neurodegeneration in early PD stages has not been addressed.
From the Parkinson's Progression Markers Initiative (PPMI), we selected 133 de novo PD patients and 56 healthy controls (HC) with available structural neuroimaging and serum NfL data. We then studied whether NfL levels were abnormal in the PD group with respect to HC, and whether they correlated with cognitive indicators and cortical macro (cortical thinning) and microstructural (increased intracortical mean diffusivity) degeneration.
Serum NfL levels were significantly increased in the PD group (p = 0.010), and were also related to worse cognitive performance and a cortical macro and microstructural compromise (p < 0.05 corrected). These associations were observed both cross-sectionally and longitudinally within a one-year follow-up period. Topographically, NfL levels reflected posterior-cortical deterioration rather than frontal damage. Importantly, NfL levels were not associated with striatal SPECT-DAT uptake or β-amyloid burden.
Our results show that serum NfL levels reflect cortical neurodegeneration from the very early stages of PD. Moreover, its brain structural correlates and its lack of relationship with dopaminergic depletion or amyloidosis suggests that NfL could track the underlying pathological process leading to PD dementia.
•Cognitive decline is a frequent non-motor complication in Parkinson's disease (PD).•Finding and validating biomarkers of early neurodegeneration is needed in PD.•Serum NfL levels reflect cortical neurodegeneration from the very early stages of PD.•Serum NfL could track the underlying pathological process leading to PD dementia.
Cognitive impairment and dementia in Parkinson's disease (PD) are highly disabling non-motor symptoms with no effective treatment currently available. As cortical degeneration is thought to be ...involved in the development of these comorbidities, novel imaging biomarkers capable of detecting early cortical deterioration are needed. Recently, an increase in mean diffusivity (MD) within the cerebral cortex has been proposed as a highly sensitive imaging indicator of early microstructural cortical damage in neurodegenerative diseases. Using the Parkinson's Progression Markers Initiative (PPMI), we studied longitudinal changes in intracortical MD in recently-diagnosed and drug-naïve PD patients (n = 64). Compared to healthy controls (n = 20), de novo PD patients showed a higher one-year MD increase in frontal and occipital cortices (p < 0.05, corrected). These PD-specific MD changes correlated with changes in cognitive measures. Importantly, cortical MD increases were widespread in the PD group and loss of cortical thickness was only increased in a small parietal cluster. These results suggest that intracortical MD changes could be promising imaging biomarker in clinical trials targeting the prevention and treatment of early cortical degeneration in PD, but further research confirmation is needed.
•Cortical degeneration is involved in Parkinson's disease (PD) dementia.•Imaging biomarkers capable of detecting early cortical deterioration are needed.•Intracortical mean diffusivity is already altered in recently-diagnosed PD.•Intracortical diffusivity may be a promising imaging biomarker in early PD stages.
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