Higher Working Memory Predicts Slower Functional Decline in Autopsy-Confirmed Alzheimer's Disease

Abstract

Background: There is heterogeneity in the pattern of early cognitive deficits in Alzheimer's disease (AD). However, whether the severity of initial cognitive deficits relates to different clinical trajectories of AD progression is unclear. Objective: To determine if deficits in specific cognitive domains at the initial visit relate to the rate of progression in clinical trajectories of AD dementia. Methods: 68 subjects from the National Alzheimer's Coordinating Center database who had autopsy-confirmed AD as the primary diagnosis and at least 3 serial assessments a year apart, with a Mini-Mental State Examination (MMSE) score >15 and a Clinical Dementia Rating Scale-Global (CDR-G) score ≤1 at the initial visit were included. A mixed regression model was used to examine the association between initial neuropsychological performance and rate of change on the MMSE and CDR Sum of Boxes. Results: Preservation of working memory, but not episodic memory, in the mild cognitive impairment and early dementia stages of AD relates to slower rate of functional decline. Discussion: These findings are relevant for estimating the rate of decline in AD clinical trials and in counseling patients and families. Improving working memory performance as a possible avenue to decrease the rate of functional decline in AD dementia warrants closer investigation.

Cognitive and physical factors affecting daily function in Alzheimer's disease: A cross‐sectional analysis

“…Compared to participants who had reduced or stable BPSD severity, those with increased BPSD severity experienced more rapid and greater decline in ADL (David et al, ). Our finding of a positive association between executive function and ADL is also consistent with the emerging evidence that supports the independent role that executive function plays on ADL in older adults (Freels et al, ; Pillai et al, ; Royall et al, ). In addition, our findings indicate that aerobic fitness is associated positively with physical performance, and this association is the strongest among all the relationships examined.…”

“…For example, executive function, the ability to organize, plan, and sequence complex goal-directed behaviors have demonstrated a salient effect on ADL and care needs in healthy older adults (Royall, Chiodo, & Polk, 2000;Yu et al, 2006). The preservation of executive function instead of memory has been linked to a slower rate of decline in ADL in AD (Pillai, Bonner-Jackson, Walker, Mourany, & Cummings, 2014). Individuals with both AD and executive dysfunction have a greater decline in ADL compared to those with AD but without executive dysfunction (Freels et al, 1992;Swanberg, Tractenberg, Mohs, Thal, & Cummings, 2004).…”

Effect and mechanism of oyster hydrolytic peptides on spatial learning and memory in mice

“…9 Some researchers have found that the higher memory capacity a person has, the slower the decline in his or her cognitive ability during the early stage of AD. 10 In recent years, researchers have focused on the impairment of learning and memory. Despite the research, the most effective approach and the precise underlying mechanism for memory-enhancing effects remained unknown.…”

Working memory test battery for young adults: Computerized working memory assessment

“…Therefore, if we develop a WM assessment for adults, researchers can estimate the severity of disease from a cognitive perspective. In neuropathological research on Alzheimer’s disease, the cognitive decline associated with dementia has provided subtle evidence of a decline in WM capacity [15]; the higher WM capacity a person has, the slower the decline in his or her cognitive ability during the early stage of the disease [16]. In addition, other cognitive diseases such as attention deficit hyperactivity disorder [17], schizophrenia [18], time estimation disorder [19], reading disorders [20], and emotional regulation disorder [21, 22] correlate highly with WM capacity.…”