The white matter hyperintensities within the cholinergic pathways and cognitive performance in patients with Parkinson's disease after bilateral STN DBS

Changes in Anticholinergic Burden in Parkinson's Disease After Deep Brain Stimulation

OBJECTIVE

This study aimed to evaluate the effect of deep brain stimulation (DBS) on anticholinergic burden in Parkinson's disease (PD) and the association of anticholinergic burden with cognition.

MATERIALS AND METHODS

A retrospective chart review in patients with PD who underwent bilateral subthalamic nucleus (STN) or globus pallidus internus (GPi) DBS from 2010 to 2020 reviewed medications with anticholinergic burden at baseline, six months, and one year (N = 216) after surgery. The cumulative anticholinergic burden at each visit was calculated using the Anticholinergic Risk Scale (ARS).

RESULTS

ARS scores were significantly lower for patients six months and one year after surgery than at baseline (z = 6.58, p < 0.0001; z = 6.99, p < 0.0001). Change in ARS scores at both six months and one year were driven by down-titration of PD medications (z = 9.35, p < 0.0001; z = 8.61, p < 0.0001), rather than changes in pain, psychiatric, or urinary medications with anticholinergic effects. There was no significant difference in change in ARS scores at one year between targets (t = 0.41, p = 0.68). In addition, there was no significant association between anticholinergic burden and cognitive performance.

CONCLUSION

GPi and STN DBS are associated with decreased anticholinergic burden due to PD medications in the first year after surgery.

Nomogram to Predict Cognitive State Improvement after Deep Brain Stimulation for Parkinson's Disease

Purpose: Parkinson’s disease (PD) is a common neurodegenerative disease, for which cognitive impairment is a non-motor symptom (NMS). Bilateral subthalamic nucleus deep brain stimulation (STN-DBS) is an effective treatment for PD. This study established a nomogram to predict cognitive improvement rate after STN-DBS in PD patients. Methods: We retrospectively analyzed 103 PD patients who underwent STN-DBS. Patients were followed up to measure improvement in MoCA scores one year after surgery. Univariate and multivariate logistic regression analyses were used to identify factors affecting improvement in cognitive status. A nomogram was developed to predict this factor. The discrimination and fitting performance were evaluated by receiver operating characteristics (ROC) analysis, calibration diagram, and decision curve analysis (DCA). Results: Among 103 patients, the mean improvement rate of the MoCA score was 37.3% and the median improvement rate was 27.3%, of which 64% improved cognition, 27% worsened cognition, and 8.7% remained unchanged. Logistic multivariate regression analysis showed that years of education, UPDRSIII drug use, MoCA Preop, and MMSE Preop scores were independent factors affecting the cognitive improvement rate. A nomogram model was subsequently developed. The C-index of the nomogram was 0.98 (95%CI, 0.97–1.00), and the area under the ROC was 0.98 (95%CI 0.97–1.00). The calibration plot and DCA demonstrated the goodness-of-fit between nomogram predictions and actual observations. Conclusion: Our nomogram could effectively predict the possibility of achieving good cognitive improvement one year after STN-DBS in patients with PD. This model has value in judging the expected cognitive improvement of patients with PD undergoing STN-DBS.

Clinical study of central cholinergic pathway damage in two mild cognitive impairment patients

Objectives

To explore the role of the central cholinergic system in amnestic mild cognitive impairment (aMCI) and mild vascular cognitive impairment (vMCI).

Methods

Twenty-five aMCI patients and 25 vMCI patients were enrolled in this study, and 25 healthy people were chosen as a control group. All participants performed a set of cognitive function scales and were subjected to a brain MRI. We analyzed differences in neuropsychological damage between groups, as well as the degree of brain atrophy and changes in the microstructure of central cholinergic pathways (CCP) in relation to effects on neuropsychological scores.

Results

(1) Regarding neuropsychological characteristics of the three groups, scores on the MoCA scale, immediate memory, delayed recall, cued recall, long time prolonged recognition, and CDR-SB of the control group were significantly better than those of the aMCI and vMCI groups. Scores on immediate memory, delayed memory, cued recall, long time delayed recognition, and Forward of Digital Span Test (FDST) in the aMCI group were lower than those in the vMCI group. Compared with the aMCI group, the vMCI group was significantly delayed in Trail Making Test (TMA)-A, TMT-B, and TMT B-A. There were no significant differences in HAMA, HAMD, MMSE, MoCA, the Boston Naming Test (BNT), language fluency or visual scale of posterior atrophy (Koedam score) between the vMCI and aMCI groups. (2) As for microstructure changes in the central cholinergic pathway, vMCI group had a decreased FA value in the cingulum (Cing) of the medial pathway, but an increased MD value in the external capsule (Excap) of the lateral pathway when compared to other two groups. Furthermore, the CingMD value of the vMCI group was higher than that of the control group, but the difference was not obvious when compared to the aMCI group. (3) Last, we researched microstructural changes to CCP, degree of brain atrophy, and neuropsychological scores by using partial correlation analysis for all participants. CingFA was negatively correlated with TMT-B, B-A, and FDST. CingMD was negatively correlated with FDST. ExcapFA was positively correlated with MMSE and Backward of BDST, while ExcapMD was negatively correlated with MMSE and MoCA. Claustrum (Claus)FA was positively related to MoCA and FDST, but was negatively related to TMT-A. ClausMD was negatively correlated with MoCA and language fluency. Koedam score was positively correlated with CDR-SB, ExcapMD, and ClausMD, but negatively correlated with MMSE score and inverse BDST.

Conclusion

The central cholinergic system is involved in the cognitive impairment of both aMCI and vMCI, and their mechanisms may be distinct. aMCI patients may present with primary CCP impairment while vMCI patients probably exhibit impairment secondary to vasogenic damage to the cholinergic system projection network. The lateral cholinergic pathway was more severely impaired than the medial pathway in vMCI patients, in addition to being associated with decreased executive and general cognitive functions. The damage to CCP was related to the degree of brain atrophy, and both may be involved in the development and progression of cognitive dysfunction.