Ignite Creation Date:
2024-05-06 @ 7:54 PM
Last Modification Date:
2024-10-26 @ 3:16 PM
Study NCT ID:
NCT06179719
Status:
RECRUITING
Last Update Posted:
2023-12-22
First Post:
2023-11-23
Brief Title:
EEG-fMRI Experiments During Anesthesia Induction With Propofol
Sponsor:
Technical University of Munich
Organization:
Technical University of Munich
Study Overview
Official Title:
Simultaneous EEG-fMRI Study in Healthy Humans During Induction of Propofol Anesthesia to Investigate the Dynamics of Thalamocortical Functional Connectivity in the Alpha Frequency
Status:
RECRUITING
Status Verified Date:
2023-09
Last Known Status:
None
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
None
Brief Summary:
This observational study aims to investigate healthy cortical and subcortical neural processes involved in generating intrinsic alpha oscillations during induction of general anesthesia with propofol To do this the investigators have designed a simultaneous electroencephalogram EEG- MRI functional MRI and Spectroscopy experiment with a visual stimulation paradigm that addresses the subjects specific intrinsic alpha rhythm during anesthesia and wakefulness The main question it aims to answer is could the investigators address the alpha oscillation system of the healthy brain with external stimulation during anesthesia This experiment could lead to a better understanding of the mechanisms underlying the generation of alpha oscillations It could open new doors to diagnostic and treatment options for diseases where alpha oscillations such as post-operative delirium seem to be affected
Detailed Description:
This study aims to investigate healthy cortical and subcortical neural processes during induction of general anesthesia with propofol which is clinically relevant for postoperative delirium a common cognitive disorder after surgical intervention in the elderly
Intrinsic neural oscillations within the alpha frequency band 8-13Hz can be measured with the EEG showing the highest power ie amplitude in occipital electrodes during eyes-closed wakefulness resting state Under general anesthesia especially with propofol the power of these oscillations decreases in the occipital cortex but increases in the frontal cortex Although neither the exact mechanisms underlying the generation of alpha oscillations nor their dynamics under anesthesia are entirely understood it has been suggested that the thalamus might be a key player modulating the shift of alpha-band power throughout the brain
Post-operative delirium POD is a complication after a surgical intervention characterized by an acute impairment of consciousness attention and arousal with a fluctuating evolution This is prevalent mainly in elderly patients especially in those with pre-existing neurocognitive disorders neurodegenerative disease and those undergoing complex or emergency procedures Despite the functional and economic burden this disorder places on the patient and the health system eg it increases hospital stay and risk of mortality treatment options and risk management strategies are still limited Several of our previous studies and those from other groups have highlighted the link between alpha oscillations and clinical outcomes related to POD For instance low frontal alpha power - both during maintenance and emergence from general anesthesia - is associated with a higher risk of POD Low frontal alpha power is also associated with pre-operative neurocognitive impairment a well-described risk factor for POD The biochemical nature of this association is still unknown the role of the cholinergic system as a mediator has been suggested
Therefore a better understanding of the mechanisms underlying the generation of alpha oscillations and their dynamics under general anesthesia could open new doors to diagnostic and treatment options for POD
Based on our past EEG-fMRI experiments in healthy subjects applying visual stimulation at the alpha frequency the investigators have shown that i visual stimulation using a rhythmic flickering light at a specific frequency evokes a reliable response in the occipital brain which can be measured with EEG and functional resonance magnetic imaging fMRI ii the response to this stimulation can be evaluated via evoked potentialpowercoherence analyses EEG or functional connectivity analyses fMRI and iii visual flicker stimulation atnear to a subjects intrinsic alpha frequency known as the individual alpha frequency IAF generates a response within brain areas beyond the occipital cortex such as frontal and parietal regions and most importantly the thalamus suggesting an interaction with - and a method to assess - intrinsic alpha oscillations
The investigators propose a simultaneous EEG-fMRI study in which young healthy participants anesthetized with propofol are presented with a visual flicker stimulation paradigm ataround the participants IAF Our experimental design includes recordings before the participant is anesthetized wakefulness pre-anesthesia and during three different anesthesia concentrations low mid and deep Functional magnetic resonance spectroscopy will be acquired during resting state throughout all states A wakefulness post-anesthesia recording in resting state without stimulation is also planned This approach has several advantages For instance the simultaneous acquisition makes it possible to correlate the dynamics of alpha oscillations measured by EEG while having access to a whole-brain resolution via fMRI including subcortical areas like the thalamus This is relevant to understanding the interaction between cortical and subcortical neural processes generating alpha oscillations
Furthermore it exploits the fact that our modality of stimulation at the IAF enhances intrinsic alpha processes which can potentially become a treatment to reduce the risk of POD under anesthesia Furthermore by acquiring functional spectroscopy data the investigators can detect biochemical changes in the brain during each state Finally our experimental design enables first a chronologic follow-up of alpha dynamics during the induction of propofol anesthesia and second by acquiring data after the intervention investigators will have an immediate control to contrast before and after anesthesia
For our participants safety propofol anesthesia will be titrated until deep concentrations without eliciting a burst suppression state avoiding intubation and artificial respiration support
This study represents an essential step towards understanding alpha oscillatory processes in the awake and anesthetized brain relevant to the future development of potential preventativetreatment options for POD
Intrinsic neural oscillations within the alpha frequency band 8-13Hz can be measured with the EEG showing the highest power ie amplitude in occipital electrodes during eyes-closed wakefulness resting state Under general anesthesia especially with propofol the power of these oscillations decreases in the occipital cortex but increases in the frontal cortex Although neither the exact mechanisms underlying the generation of alpha oscillations nor their dynamics under anesthesia are entirely understood it has been suggested that the thalamus might be a key player modulating the shift of alpha-band power throughout the brain
Post-operative delirium POD is a complication after a surgical intervention characterized by an acute impairment of consciousness attention and arousal with a fluctuating evolution This is prevalent mainly in elderly patients especially in those with pre-existing neurocognitive disorders neurodegenerative disease and those undergoing complex or emergency procedures Despite the functional and economic burden this disorder places on the patient and the health system eg it increases hospital stay and risk of mortality treatment options and risk management strategies are still limited Several of our previous studies and those from other groups have highlighted the link between alpha oscillations and clinical outcomes related to POD For instance low frontal alpha power - both during maintenance and emergence from general anesthesia - is associated with a higher risk of POD Low frontal alpha power is also associated with pre-operative neurocognitive impairment a well-described risk factor for POD The biochemical nature of this association is still unknown the role of the cholinergic system as a mediator has been suggested
Therefore a better understanding of the mechanisms underlying the generation of alpha oscillations and their dynamics under general anesthesia could open new doors to diagnostic and treatment options for POD
Based on our past EEG-fMRI experiments in healthy subjects applying visual stimulation at the alpha frequency the investigators have shown that i visual stimulation using a rhythmic flickering light at a specific frequency evokes a reliable response in the occipital brain which can be measured with EEG and functional resonance magnetic imaging fMRI ii the response to this stimulation can be evaluated via evoked potentialpowercoherence analyses EEG or functional connectivity analyses fMRI and iii visual flicker stimulation atnear to a subjects intrinsic alpha frequency known as the individual alpha frequency IAF generates a response within brain areas beyond the occipital cortex such as frontal and parietal regions and most importantly the thalamus suggesting an interaction with - and a method to assess - intrinsic alpha oscillations
The investigators propose a simultaneous EEG-fMRI study in which young healthy participants anesthetized with propofol are presented with a visual flicker stimulation paradigm ataround the participants IAF Our experimental design includes recordings before the participant is anesthetized wakefulness pre-anesthesia and during three different anesthesia concentrations low mid and deep Functional magnetic resonance spectroscopy will be acquired during resting state throughout all states A wakefulness post-anesthesia recording in resting state without stimulation is also planned This approach has several advantages For instance the simultaneous acquisition makes it possible to correlate the dynamics of alpha oscillations measured by EEG while having access to a whole-brain resolution via fMRI including subcortical areas like the thalamus This is relevant to understanding the interaction between cortical and subcortical neural processes generating alpha oscillations
Furthermore it exploits the fact that our modality of stimulation at the IAF enhances intrinsic alpha processes which can potentially become a treatment to reduce the risk of POD under anesthesia Furthermore by acquiring functional spectroscopy data the investigators can detect biochemical changes in the brain during each state Finally our experimental design enables first a chronologic follow-up of alpha dynamics during the induction of propofol anesthesia and second by acquiring data after the intervention investigators will have an immediate control to contrast before and after anesthesia
For our participants safety propofol anesthesia will be titrated until deep concentrations without eliciting a burst suppression state avoiding intubation and artificial respiration support
This study represents an essential step towards understanding alpha oscillatory processes in the awake and anesthetized brain relevant to the future development of potential preventativetreatment options for POD
Study Oversight
Has Oversight DMC:
None
Is a FDA Regulated Drug?:
False
Is a FDA Regulated Device?:
False
Is an Unapproved Device?:
None
Is a PPSD?:
None
Is a US Export?:
None
Is an FDA AA801 Violation?:
None