Use of Electrophysiological Markers to Predict Post-operative Cognitive Dysfunction

December 7, 2023 updated by: Rambam Health Care Campus

Assessing Brain Frailty; The Association Between Pre, Intra and Post-operative Electrophysiological Markers and Postoperative Cognitive Dysfunction

As the population ages and medical progress is made, many elderly patients that previously would not have been candidates for surgery are now undergoing operations. In this group of older patients, brain dysfunction after anesthesia and surgery, naming post-operative cognitive dysfunction, is well known.

Post-operative cognitive dysfunction (POCD) is a term used to describe subtle changes in cognition, such as memory and executive function. The most commonly seen problems are memory impairment and impaired performance on intellectual tasks. In severe cases, it can lead to inability to perform daily living functions. It was previously found that the presence of cognitive dysfunction 3 months after non-cardiac surgery was associated with increased mortality. The mechanisms leading to cognitive impairment after anesthesia and surgery are not yet fully clear. The risk factors are related to patient characteristics, type of operation and anesthetic management.

The investigators have recently shown that using different electrophysiological markers, they can monitor attention and perception which might be associated with brain frailty and brain injury.

The aims of this proof of concept study are: (i) to find-out whether attention processes might be in association with brain frailty. (ii) to find our whether brain injury which is expressed by interhemispheric synchronization is is associated with POCD; (iii) to find out whether the level of anesthesia, as measured electrophysiological by perception might be linked primary to POCD.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

As the population ages and medical progress is made, many elderly patients that previously would not have been candidates for surgery are now undergoing operations. In this group of older patients, brain dysfunction after anesthesia and surgery is well recognized, naming post-operative cognitive dysfunction.

Post-operative cognitive dysfunction (POCD) is a term used to describe subtle changes in cognition, such as memory and executive function. The most commonly seen problems are memory impairment and impaired performance on intellectual tasks. In severe cases, it can lead to inability to perform daily living functions. The reported incidence figures for postoperative cognitive dysfunction vary depending on the group of patients studied, the definition of POCD used, the tests used to establish the diagnosis and their statistical evaluation, the timing of testing, and the choice of control group. The diagnosis of POCD relies on the availability of the neuropsychological tests. In a large prospective multicenter cohort study, it was found that the presence of cognitive dysfunction 3 months after noncardiac surgery was associated with an increased mortality. Furthermore, patients with cognitive decline at 1 week had an increased risk of leaving the labor market prematurely and a higher prevalence of time receiving social transfer payments. The mechanisms leading to cognitive impairment after anesthesia and surgery are not yet fully clear. The risk factors for developing POCD are related to patient characteristics, type of operation and anesthetic management.

Cardiovascular, respiratory, hepatic, and renal insufficiency are all associated with impaired brain performance. It is theoretically obvious that an adequate intraoperative oxygen supply for all vital organs is essential if postoperative cerebral dysfunction is to be avoided. Casai et al found that brain desaturation (rSO2 decrease <75% of baseline) occurred in 40% of elderly patients after noncardiac surgery, and the cerebral desaturation was linked with a high incidence of POCD. A recent systematic review shows that reductions in cerebral oxygen saturation (rSO2) during cardiac surgery may indicate CPB cannula malposition, particularly during aortic surgery. However, only weak evidence links low rSO2 during cardiac surgery to POCD.

POCD is a well-recognized clinical phenomenon of multifactorial origin; emboli, hypoperfusion, inflammation, and patient's preoperative cerebral dysfunction. Meticulous surgical and anesthesiological techniques are important for preventing complications and keeping the risk of POCD to a minimum.

The EEG is an electrophysiological monitoring method used to record electrical activity of the brain, including normal and abnormal activity. In recent years, numerous clinical studies were performed to evaluate whether the use in intraoperative electroencephalography (EEG) to control the depth of anesthesia has any effect on POCD.

Recently it was confirmed that intraoperative neuro-monitoring for depth of anesthesia is associated with a lower incidence of delirium. However it is unrelated to the incidence of POCD. The most common available monitor for depth of anesthesia is the Bispectral index, developed more than 20 years ago. The device's output is based on electroencephalographic (EEG) signals from the frontal lobe (monitors brain activity) in combination with electromyographic (EMG) waves (monitors muscle activity). The BIS produces a number ranging from 0 -100, which matches the patient's level of consciousness (awake, sedated or unconscious) under GA.

Despite its limitations, over-anesthesia as monitored by BIS, was at-least correlative with POD (but not with POCD). Therefore, it is hopeful that an even more precise evaluation of the level of anesthesia will improve POD prediction (and thereby prevention) even further. On the other hand the measure of depth of anesthesia by itself does not provide sufficient prediction for POCD.

The investigators have recently that brain injury is demonstrated by interhemispheric desynchronization, which is recognized by our new algorithm, which monitors electrophysiological markers of attention and of perception. This algorithm was based on a previous set of studies, which showed the ability to decompose the entire multi-electrode EEG/ ERP sample to a superposition of attention and perception processes, spread in space (over the scalp) and time (hundreds of milliseconds). Our algorithm is unique in the ability to extract the needed perceptual and attentional information indicating depth of anesthesia and hemispheric damage (manifested by interhemispheric desynchronization) in real time every 30 seconds and with a minimal electrodes' setup.

The aims of this proof of concept study are: (i) to find-out whether attention processes might be in association with brain frailty. (ii) to find our whether brain injury which is expressed by interhemispheric synchronization is is associated with POCD; (iii) to find out whether the level of anesthesia, as measured electrophysiological by perception might be linked primary to POCD.

Study Type

Observational

Enrollment (Estimated)

100

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Israel
      • Haifa, Israel
        • Recruiting
        • Rambam Health Care Campus

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Patients 18 years or older, ASA 1-4, undergoing elective cardiac surgery (CABG or valve replacement).

Description

Inclusion Criteria:

  • Patients 18 years and older undergoing elective cardiac surgery (CABG or valve replacement).

Exclusion Criteria:

  1. inability or refusal to provide informed consent,
  2. significant visual impairment so that the pictures of the cognitive tests could not be interpreted accurately.
  3. profound dementia or aphasia that interfered with the cognitive assessment.
  4. inability to speak Hebrew/ Russian or Arabic so that a language barrier was not confused with postoperative cognitive dysfunction.
  5. . Any previously documented major neurologic or psychiatric dysfunction

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Cohort
  • Time Perspectives: Prospective

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Patients undergoing cardiac surgery
Diagnostic test: Cognitive assesment using MOCA test
Cognitive assesment using MOCA test

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Correlation of Post Operative cognitive dysfunction (POCD) to intra operative EEG changes
Time Frame: The diagnosis of cognitive dysfunction is assessed post operative on day 7 and compared to baseline pre surgery cognitive function
Correlation of post operative cognitive dysfunction as measured by cognitive tests (such as MOCA test) to changes in EEG pattern
The diagnosis of cognitive dysfunction is assessed post operative on day 7 and compared to baseline pre surgery cognitive function
Correlation of 45 days POCD to intra operative EEG changes
Time Frame: The diagnosis of cognitive dysfunction is assessed post operative on day 45 and is compared to baseline pre surgery cognitive function
Correlation of 45 days POCD, as measured with MOCA test, to intra operative changes in EEG pattern
The diagnosis of cognitive dysfunction is assessed post operative on day 45 and is compared to baseline pre surgery cognitive function
Assesing btain frailty
Time Frame: The diagnosis of cognitive dysfunction is assessed post operative on day 7 and day 45 and is compared to baseline pre surgery cognitive function
Correlation of success in pre operative cognitive tests, as measured by MOCA test, to post operative cognitive dysfunction (as measured again by MOCA test)
The diagnosis of cognitive dysfunction is assessed post operative on day 7 and day 45 and is compared to baseline pre surgery cognitive function

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Rambam Health Care Campus

Investigators

  • Principal Investigator: Dana Baron Shahaf, Rambam Health Care Campus

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

October 1, 2020

Primary Completion (Estimated)

December 31, 2023

Study Completion (Estimated)

December 31, 2024

Study Registration Dates

First Submitted

August 5, 2020

First Submitted That Met QC Criteria

August 11, 2020

First Posted (Actual)

August 14, 2020

Study Record Updates

Last Update Posted (Estimated)

December 8, 2023

Last Update Submitted That Met QC Criteria

December 7, 2023

Last Verified

December 1, 2023

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 542-20

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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