Working Memory Deficits Related to Brain Atrophy in Early Stage Parkinson's Disease

Abstract

<h3>Research Objectives</h3> To explore the relationship between attention/working memory (WM) performance and grey matter volume in the dorsal attention network (DAN), a neural network in the brain that supports encoding and maintenance of external information. <h3>Design</h3> Observational. <h3>Setting</h3> Data obtained from the Parkinson's Progression Marker Initiative (PPMI; www.ppmi-info.org), an international longitudinal multisite study. <h3>Participants</h3> Participants with persistent WM impairment (n= 10) and persistent normal WM performance (n=10) were compared. WM was measured using the Letter Number Sequencing (LNS) test. Persistent impairment was defined by a standardized test score of 8 or less for 4 consecutive years since baseline imaging. Normal WM performance was defined by a standardized test score of 10 or more for 4 consecutive years since baseline imaging. Groups were matched on sex, age, years of education, and disease duration. <h3>Interventions</h3> Not Applicable. <h3>Main Outcome Measures</h3> Grey matter volume was measured using voxel-based morphometry (VBM) through SPM12 and CAT12. Region of interest analysis within the DAN (Schaeffer et al., 2018 100-parcel atlas), was conducted. Whole brain cluster analysis was conducted for confirmatory evidence. Significant clusters within a DAN mask (Schaeffer et al., 2018 100-parcel atlas) are reported with a FDR (p=0.05). <h3>Results</h3> For ROI analysis, grey matter atrophy in the bilateral visuomotor cortex (p=0.005), bilateral intraparietal sulcus (p=0.04), and right superior parietal lobule (p=0.021) was found in the impaired WM group compared to the normal WM group. Between groups, differences in several clusters within the DAN masks were observed. <h3>Conclusions</h3> These promising preliminary findings support the notion that changes in grey matter volume within cognitive neural networks, such as the DAN, can be a biomarker for decline in cognitive function, as well as treatment responsiveness in people living with PD. <h3>Author(s) Disclosures</h3> None.