Perioperative neurocognitive and functional neuroimaging trajectories in older APOE4 carriers compared with non-carriers: secondary analysis of a prospective cohort study

Research on Voxel-Based Features Detection and Analysis of Alzheimer’s Disease Using Random Survey Support Vector Machine

“…Gray matter atrophy gradually spread from the basal ganglia to the angular gyrus, temporal regions, and eventually to the subcortical-cortical network as neurological disease progresses. The angular gyrus was key AD-risk region ( Browndyke et al, 2021 ; Zenke et al, 2021 ). The calcarine sulcus was located posterior to the medial surface of the hemisphere.…”

Realising the potential of functional imaging to reveal brain changes after anaesthesia and surgery

“…APOE4 status did not affect global cognitive change, and the trajectory of postoperative cognitive changes was similar for both groups. However, many studies presented as supporting literature by Browndyke and colleagues 1 show evidence that surgery/anaesthesia can lead to neurocognitive issues across the same older population, with changes seen in verbal memory, spatial memory, and executive function. Thus, discussing this possibility with older patients as part of the informed consent process should be done, as well as highlighting that it is unclear if it is the anaesthesia, the surgery, or a combination of both that may be the cause.…”

“…12,13 Therefore, when investigating postoperative connectivity changes, it is possible that these patterns also differ for patients at different disease stages, thus the mixing of participants at different disease stages in a study may lead to mixed and conflicting findings. Browndyke and colleagues 1 did not report individual scores on all cognitive tests; doing so would allow consideration of baseline values in each test (as undiagnosed cognitive impairment is common in surgical patients) and would be helpful for meta-analysis (see next section). However, taken at face value, their study almost exclusively used cognitively normal older adults (only one had MCI); therefore, the observed functional changes mostly reflect the effects of APOE4 and surgery/anaesthesia in cognitively normal older adults, which are likely different from patients with MCI or AD.…”

“…As the most prevalent genetic risk factor for Alzheimer's disease (AD), the apolipoprotein E4 allele (APOE4) is a popular target for research on dementia. Browndyke and colleagues 1 sought to determine the effect of APOE4 status on perioperative neurocognitive function in a group of patients aged 60 yr or older and scheduled for non-neurologic and noncardiac surgery under general anaesthesia. CSF samples were collected at three time points (preoperative baseline, 24 h postoperative, and 6 weeks postoperative) to measure changes in CSF beta-amyloid (Ab), tau, and phospho-tau (p-tau) levels.…”

The inter-relationship between delirium and dementia: the importance of delirium prevention

“…To date, most of the fluid biomarker studies in delirium and dementia have used cerebrospinal fluid (CSF) or blood (plasma or serum). Although CSF is thought to more accurately represent processes occurring in the brain, the collection of CSF, particularly in people with delirium, over multiple time points or in large-scale studies holds particular challenges [58][59][60][61][62] . Blood-based biomarkers are more accessible during acute illness, but plasma concentrations of biomarkers are often very low.…”