EEG Spectrogram, Brain Vulnerability and POD

Study Overview
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Brief Summary
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An assessment of difference in prespecified processed electroencephalography variables between cognitively intact older surgical patients who develop postoperative delirium compared to those who do not develop postoperative delirium

Detailed Description
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Postoperative delirium in older people may be contributed to by intrinsic brain vulnerability such as pre-existing dementia. Some cognitively intact older people also experience postoperative delirium and in these patients some go on to develop later dementia. The investigators propose that postoperative delirium may be an unmasking of covert brain vulnerability by the dyshomeostasis of the anaesthesia/surgical intervention. In people with dementia or mild cognitive impairment, electroencephalography (EEG) studies have shown slowing of brain wave activity, especially in the back of the brain. Processed electroencephalography, using a limited number of channels, is routinely used during anaesthesia to aid assessment of anaesthetic depth of the patient. In this study the investigators will assess the feasibility of acquiring EEG data from the front and back of the brain. The investigators will also explore the data for early signals of brain vulnerability

Official Title
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EEG Spectrogram to Assess Brain Vulnerability as a Risk Factor for Postoperative Delirium in Older People - a Feasibility Study

Conditions
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Postoperative Delirium

Intervention / Treatment
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* Other: Processed electroencephalography
* Other: Postoperative delirium assessment


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ≥ 65 years old Elective, moderate/major, non-neuro, non-cardiac surgery Ability to give informed consent Exclusion Criteria: Preoperative cognitive impairment Current systemic infection Current use of medication that may modify EEG History of neurosurgery/significant head trauma Presence of neurological diseases including overt stroke, dementia, epilepsy, multiple sclerosis, Parkinson's disease, intracranial tumours and other significant neurologic disorders Current significant psychiatric conditions such as severe depression. Palliative surgery

Ages Eligible for Study
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Minimum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Other: Processed electroencephalography|Acquisition of raw EEG data from processed EEG monitor. Analysis of data acquired for prespecified bandwidth properties|
|Other: Postoperative delirium assessment|Twice daily assessment for the incidence of postoperative delirium using validated tool (questionnaire)|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Feasibility of acquiring frontal and posterior EEG data from the Narcotrend monitor during the preoperative and intraoperative period | Feasibility will be assessed by the ability to get preoperative and intraoperative epochs of EEG that clearly demonstrates the different brain wave bands (alpha, theta and delta) | Approximately 1 - 2 hours per participant | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Preoperative brain wave differences | Identify any differences in frontal and posterior narrowband (i.e. alpha, delta and theta) power preoperatively between older people who develop POD compared to those who do not. | Approximately 10 minutes per participant | 
| Change in brain wave power due to induction of anaesthesia | Identify if the change in narrowband power from the preoperative values to steady state intraoperative values are different between groups (i.e. people who develop POD vs people who do not develop POD) | Approximately 1 hour per particpant | 
| Intraoperative brain wave patterns | Identify any differences in mean and spectral edge frequencies preoperatively and intraoperatively between older people who develop POD and those who do not. | Duration of surgery or 2 hours (shortest option) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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processed EEG, Postoperative vulnerability, Older people, Brain vulnerability