Journal of Alzheimer's disease : JAD
-
Review
Postoperative cognitive dysfunction: toward the Alzheimer's disease pathomechanism hypothesis.
Alzheimer's disease (AD), a chronic and progressive deterioration of memory and other cognitive domains, is the most common form of dementia. Because of related health and social impact, there is growing interest in assessing potential relationship between anesthesia and the onset and progression of chronic neurodegenerative disorders, including AD. ⋯ Preclinical studies are providing an increasing body of evidences on some of the mechanisms that link anesthetics to neuronal programmed cell death (apoptosis) and accumulation of misfolded proteins in the aging brain. Therefore, risk factors and pathomechanisms of chronic neurodegenerative disorders, including AD, and persistent postoperative-postanesthesia cognitive dysfunction may overlap.
-
Both short and long term cognitive changes occur after cardiac surgery but the pathophysiology of these neurobehavioral changes remain incompletely understood. The cause of cognitive decline is most likely multifactorial and probably represents a complex interaction between cerebral microemboli, global cerebral hypoperfusion, inflammation, and genetic susceptibility. The problem of cognitive decline after cardiac surgery continues to increase as the surgical population becomes older and has more prevalent comorbid diseases. A better understanding of the etiology is essential to finding new preventive strategies as no definitive therapy exists for cognitive dysfunction.
-
With a growing aging population, more patients suffering from dementia are expected to undergo surgery, thus being exposed to either general or regional anesthesia. This calls for specific attention ranging from the legal aspects of obtaining informed consent in demented patients to deciding on the use of premedication, choice of anesthetics, and management of postoperative pain. This review reflects on both general considerations concerning geriatric patients but also on the specific features of perioperatively used drugs and anesthetics that might have an impact on patients with Alzheimer's disease (AD).
-
Cross-sectional studies using diffusion tensor imaging (DTI) suggest decline of the integrity of intracortically projecting fiber tracts with aging and in neurodegenerative diseases, such as Alzheimer's disease (AD). Longitudinal studies on the change of fiber tract integrity in normal and pathological aging are still rare. Here, we prospectively studied 11 healthy elderly subjects and 14 subjects with amnestic mild cognitive impairment (MCI), a clinical risk group for AD, using high-resolution DTI and MRI at baseline and after 13 to 16 months follow-up. ⋯ Grey and white matter atrophy involved prefrontal, parietal, and temporal lobe areas in controls and prefrontal, cingulate, and parietal lobe areas in MCI subjects and agreed with the pattern of fiber tract changes. Our findings indicate that DTI allows detection of microstructural changes in subcortical fiber tracts over time that are related to aging as well as to early stages of AD type neurodegeneration. The underlying mechanisms for these changes are unknown.
-
Cognitive dysfunction in the elderly commonly observed following anesthesia has been attributed to age-related neuronal changes exacerbated by pharmacotoxic effects. However, the extent to which these changes may persist following recovery from surgery is still largely unknown. This study investigates the long-term effects of anesthesia on cognitive functioning after orthopedic surgery in 270 elderly patients over the age of 65 who completed a computerized cognitive battery before and 8 days, 4 and 13 months after surgery. ⋯ On the other hand, a clear dissociation effect was observed for several areas of visuospatial functioning which persisted up to the 13-month follow-up. This specific pattern of visuospatial deficit was found to be independent of apolipoprotein E genotype and closely resembles what has recently been termed vascular mild cognitive impairment, in turn associated with subtle sub-cortical vascular changes. The observation of only minor differences between persons operated by general and regional anesthesia makes it difficult to attribute these changes directly to the anesthetic agents themselves, suggesting that cognitive dysfunction may be attributable at least in part to peri-operative conditions, notably stress and glucocorticoid exposure.