Browsing by Author "Browndyke, Jeffrey"
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Item Open Access Prefrontal contributions to relational encoding in amnestic mild cognitive impairment.(Neuroimage Clin, 2016) Foster, Chris; Addis, Donna; Ford, Jaclyn; Kaufer, Daniel; Browndyke, Jeffrey; Welsh-Bohmer, Kathleen; Giovanello, KellyRelational memory declines are well documented as an early marker for amnestic mild cognitive impairment (aMCI). Episodic memory formation relies on relational processing supported by two mnemonic mechanisms, generation and binding. Neuroimaging studies using functional magnetic resonance imaging (fMRI) have primarily focused on binding deficits which are thought to be mediated by medial temporal lobe dysfunction. In this study, prefrontal contributions to relational encoding were also investigated using fMRI by parametrically manipulating generation demands during the encoding of word triads. Participants diagnosed with aMCI and healthy control subjects encoded word triads consisting of a category word with either, zero, one, or two semantically related exemplars. As the need to generate increased (i.e., two- to one- to zero-link triads), both groups recruited a core set of regions associated with the encoding of word triads including the parahippocampal gyrus, superior temporal gyrus, and superior parietal lobule. Participants diagnosed with aMCI also parametrically recruited several frontal regions including the inferior frontal gyrus and middle frontal gyrus as the need to generate increased, whereas the control participants did not show this modulation. While there is some functional overlap in regions recruited by generation demands between the groups, the recruitment of frontal regions in the aMCI participants coincides with worse memory performance, likely representing a form of neural inefficiency associated with Alzheimer's disease.Item Open Access Preoperative Cognitive Impairment As a Predictor of Postoperative Outcomes in a Collaborative Care Model.(J Am Geriatr Soc, 2018-01-13) Zietlow, Kahli; McDonald, Shelley R; Sloane, Richard; Browndyke, Jeffrey; Lagoo-Deenadayalan, Sandhya; Heflin, Mitchell TOBJECTIVES: To compare postoperative outcomes of individuals with and without cognitive impairment enrolled in the Perioperative Optimization of Senior Health (POSH) program at Duke University, a comanagement model involving surgery, anesthesia, and geriatrics. DESIGN: Retrospective analysis of individuals enrolled in a quality improvement program. SETTING: Tertiary academic center. PARTICIPANTS: Older adults undergoing surgery and referred to POSH (N = 157). MEASUREMENTS: Cognitive impairment was defined as a score less than 25 out of 30 (adjusted for education) on the St. Louis University Mental Status (SLUMS) Examination. Median length of stay (LOS), mean number of postoperative complications, rates of postoperative delirium (POD, %), 30-day readmissions (%), and discharge to home (%) were compared using bivariate analysis. RESULTS: Seventy percent of participants met criteria for cognitive impairment (mean SLUMS score 20.3 for those with cognitive impairment and 27.7 for those without). Participants with and without cognitive impairment did not significantly differ in demographic characteristics, number of medications (including anticholinergics and benzodiazepines), or burden of comorbidities. Participants with and without cognitive impairment had similar LOS (P = .99), cumulative number of complications (P = .70), and 30-day readmission (P = .20). POD was more common in those with cognitive impairment (31% vs 24%), but the difference was not significant (P = .34). Participants without cognitive impairment had higher rates of discharge to home (80.4% vs 65.1%, P = .05). CONCLUSION: Older adults with and without cognitive impairment referred to the POSH program fared similarly on most postoperative outcomes. Individuals with cognitive impairment may benefit from perioperative geriatric comanagement. Questions remain regarding the validity of available measures of cognition in the preoperative period.