Cognitive and Brain Reserve and the Risk of Postoperative Delirium in Older Patients
Department of Medicine; Meyers Primary Care Institute
Geriatrics | Mental and Social Health | Mental Disorders | Psychiatric and Mental Health | Psychiatry and Psychology
BACKGROUND: Cognitive and brain reserve theories suggest that aspects of neural architecture or cognitive processes modify the impact of neuropathological processes on cognitive outcomes. While frequently studied in the context of dementia, reserve in delirium is relatively understudied.
METHODS: We examined the association of three markers of brain reserve (head circumference, MRI-derived brain volume, and leisure time physical activity) and five markers of cognitive reserve (education, vocabulary, cognitive activities, cognitive demand of lifetime occupation, and interpersonal demand of lifetime occupation) and the risk of postoperative delirium in a prospective observational study of 566 older adults free of dementia undergoing scheduled surgery.
FINDINGS: Twenty four percent of patients (135/566) developed delirium during the postoperative hospitalization period. Of the reserve markers examined, only the Wechsler Test of Adult Reading (WTAR) was significantly associated with the risk of delirium. A one-half standard deviation better performance on the WTAR was associated with a 38% reduction in delirium risk (P = 0.01); adjusted relative risk of 0.62, 95% confidence interval 0.45-0.85.
INTERPRETATION: In this relatively large and well-designed study, most markers of reserve fail to predict delirium risk. The exception to this is the WTAR. Our findings suggest that the reserve markers that are important for delirium may be different from those considered to be important for dementia.
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Citation: Lancet Psychiatry. 2014 Nov;1(6):437-443. Link to article on publisher's site
Saczynski, Jane S.; Inouye, Sharon K.; Kosar, Cyrus; Tommet, Doug; Marcantonio, Edward R.; Fong, Tamara; Hshieh, Tammy; Vasunilashorn, Sarinnapha; Metzger, Eran D.; Schmitt, Eva; Alsop, David C.; and Jones, Richard N., "Cognitive and Brain Reserve and the Risk of Postoperative Delirium in Older Patients" (2014). Meyers Primary Care Institute Publications and Presentations. 717.