Trajectory of Recovery in the Elderly (TORIE)

The purpose of this study is to understand how elderly individuals regain their cognitive skills following general anesthesia. The investigators will compare an age stratified group of volunteers who will be evaluated with a series of cognitive tests and a functional MRI. The participants will then be administered general anesthesia for two hours. The investigators will then assess the participants using state of the art tools to determine when participants return to their cognitive baseline.

Elderly patients undergoing anesthesia and surgery frequently suffer from postoperative cognitive dysfunction (POCD) and postoperative delirium (PD). The cause of these entities is unknown. It is unclear what part anesthetics play in the development of POCD and PD. The investigators hypothesize that elderly patient's cognitive capacities recover more slowly after receiving general anesthesia, perhaps because they have more limited cognitive reserve. A more prolonged recovery would confound diagnoses of POCD and PD and potentially puts patients who are discharged on the day of surgery at risk of not understanding postoperative instructions. The trajectory of postoperative cognitive recovery has never been explored and elderly participants have been explicitly not included in any type of emergence research. To explore this vital area the investigators propose to study young and elderly volunteers with a combination of two state of the art neuropsychological tests (Postoperative Quality of Recovery Scale and the NIH Toolbox) and functional magnetic resonance imaging. Starting from baseline, the investigators will determine multiple cognitive domains and resting state networks, treat the participants with general anesthesia for two hours while continuing to examine network activity, and then explore the recovery of the cognitive domains and alterations in functional networks using both the PQRS and the NIH Toolbox Cognitive Measures. Participants will be evaluated at 1 month, 6 months, and 12 months.

Magnetic resonance images will be acquired on a 3 Tesla scanner (Skyra, Siemens, Erlangen, Germany) with a 20 channel receiver coil.

Cognitive Function using scales of the PQRS to test whether age is associated with the time of return to baseline cognitive function. The PQRS is a brief measurement tool to assess multiple domains of recovery, including cognition, over time. It is scored as recovered / not recovered based on level of performance, within a certain tolerance range, relative to preoperative (baseline) performance - before the general anesthesia / MRI scanning session. Postoperative Quality of Recovery Cognitive Scale at each study timepoint by age decade. Postoperative Quality of Recovery Cognitive

NIH Toolbox Cognitive Battery is a multidimensional set of brief measures assessing cognitive (as well as emotional, motor and sensory) function. There is no score range, but mean score is 100 with standard deviation 15. A score at or near 100 indicates average ability compared with others. Scores around 115 suggest above-average ability. Scores around 130 suggest superior ability (in the top 2 percent nationally). A score around 85 suggests below-average ability. A score in the range of 70 or below suggests significant impairment.

Inclusion Criteria: 40-80 years old American Society of Anesthesiologists (ASA) Physical Status I or II (i.e. Individuals with minimal disease burden) Capable and willing to consent Exclusion Criteria: Airway assessment as potentially difficult (Mallampati III or greater) Allergies or hypersensitivity to drug or class Chronic Inflammatory conditions such a lupus or system rheumatoid arthritis (arthritis limited to 1 or 2 joints will be acceptable) Patients with diabetes mellitus Patients with a recent illness (within the last 2 weeks) Patients with severe visual or auditory disorder/handicaps English illiteracy Pregnancy Participants not expected to be able to complete the postoperative tests History of malignant hyperthermia Nursing mothers Body Mass Index > 30 Patients with significant metal implants in body Current use of cocaine or opiates Current smokers

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