Session Time: 1:15pm-2:45pm
Location: Les Muses Terrace, Level 3
Objective: We aimed to elucidate neural responses associated with working memory (WM) tasks in Parkinson’s disease (PD) patients during disease progression.
Background: PD patients often have impaired working memory, which worsens with disease progression.
Method: Eighteen PD patients with normal cognition (PD-CogNL); 17 with PD with mild cognitive impairment (PD-MCI); 11 with PD with dementia (PDD); and 17 healthy subjects were enrolled. In a 3-Tesla MRI scanner, subjects performed an n-back task, including 0, 1, 2 and 3-back loads. Event-related functional MRI analysis was performed for correct responses. Region of interest (ROI) masks for WM-related areas were created by comparing 1-, 2-, 3-back task and 0-back task for all subjects. Beta-weight in each WM-related ROI for performing 0-back, 1-back, 2-back or 3-back task in contrast to baseline (staring at fixation cross) was compared among patient subgroups and HV group using Bayesian Multilevel Modeling.
Results: WM-related ROIs were created for the bilateral dorsolateral prefrontal cortex (DLPFC), rostral prefrontal cortex (RPFC), inferior parietal lobule (IPL), superior parietal lobule (SPL), frontal eye field (FEF) and anterior cingulate cortex (ACC). In the 0-back task, all PD subgroups had more activation than HVs in some of the ROIs. PDD had more activation than PD-CogNL or PD-MCI in all ROIs. In the 1-back task, PDD had more activation than HV in all ROIs. In the 2-back task, PD-CogNL had more activation than HV or PD-MCI in some ROIs. In the 3-back task, PD-CogNL had more activation than HV, PD-MCI or PDD in some ROIs.
Conclusion: Our results suggest that PD patients have hyperactivation in WM-related areas during performing a working memory task, which may be a compensatory process allowing PD-CogNL patients to successfully maintain normal cognitive function. While PD-MCI and PDD use this compensatory process for lower cognitive loads (0-back and 1-back task), no additional resource might be left to hyperactivate for higher cognitive loads (2-back and 3-back task), resulting in impaired cognitive function.
To cite this abstract in AMA style:T. Hattori, R. Reynolds, S. Horovitz, G. Chen, C. Lungu, E. Wassermann, M. Hallett. Neural correlates of compensatory process and impaired working memory in Parkinson’s disease during disease progression [abstract]. Mov Disord. 2019; 34 (suppl 2). https://www.mdsabstracts.org/abstract/neural-correlates-of-compensatory-process-and-impaired-working-memory-in-parkinsons-disease-during-disease-progression/. Accessed December 10, 2023.
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MDS Abstracts - https://www.mdsabstracts.org/abstract/neural-correlates-of-compensatory-process-and-impaired-working-memory-in-parkinsons-disease-during-disease-progression/