Effects of Brain Beta-Amyloid on Postoperative Cognition

Inclusion Criteria:

- Scheduled for total knee arthroplasty or total hip arthroplasty under general
anesthesia (primary arthroplasties and revisions)

- English speaking

- Anticipated stay in the hospital

- Not anticipated to stay intubated postoperatively

- Patients who live with or have regular visits from an individual ("study partner")
willing to provide information about the patient's cognitive status

- Willing and able to undergo all testing procedures including neuroimaging and agree to
longitudinal follow up

- Adequate visual and auditory acuity to allow neuropsychological testing

- Subjects with Clinical Dementia Rating Scale (CDR) of 0-0.5

- Patients who are not demented

- Subjects sho signed an IRB approved informed consent prior to any study procedures

Exclusion Criteria:

- Clinically significant hepatic, renal, pulmonary, metabolic, or endocrine disturbances
as indicated by history, which in the opinion of the investigator might pose a
potential safety risk to the subject

- Current clinically significant cardiovascular disease.

- History of drug or alcohol abuse within the last year, or prior prolonged history of
abuse

- Clinically significant infections disease, including Acquired Immune Deficiency
Syndrome (AIDS) or Human Immunodeficiency Virus (HIV) infection or previous positive
test for hepatitis

- History of relevant severe drug allergy or hypersensitivity

- Received an investigational medication under an FDA IND protocol within the last 30
days.

- Current clinically significant unstable medical comorbidities, as indicated by history
or physical exam, that pose a potential safety risk to the subject

- Received a radiopharmaceutical for imaging or therapy within the past 24 hours prior
to the imaging session for this study

- Severe psychiatric disorders including schizophrenia, bipolar disorders, and major
depression as described in DSM-IV within the past year (medical record, GDS score,
interview with the patient and study partner)

- Obvious causes for their cognitive impairment (e.g. onset coincides with recent head
trauma or stroke)

- Dementia of any cause

- CDR score > 0.5

- Expressed the preference to undergo the procedure under regional anesthesia in form of
spinal or epidural anesthesia

- Patients who, in the opinion of the investigator, are otherwise unsuitable for a study
of this type