Isoflurane Exposure Influence on Sleep Architecture in a Rat Model of Alzheimer's Disease.

Background: A clear understanding of how general anesthesia affects the brain in patients with Alzheimer disease will be crucial to optimize clinical care. We present results from laboratory investigations with a rat model used to study Alzheimer disease (TgF344-AD) to evaluate the effect of isoflurane anesthesia on the early recovery from anesthesia and postanesthesia sleep architecture in animals that exhibit mild symptoms of cognitive decline.

Methods: We used electroencephalogram (EEG) and electromyogram recordings to distinguish WAKE, NREM, and REM sleep in 8 rats from the transgenic model (AD) group and 7 age-matched control (AC) rats, 17 to 18 months of age.

Binaural beat stimulation as a tool to reduce preoperative anxiety in patients undergoing elective surgery and general anesthesia - results from a randomized controlled trial.

Introduction: Pronounced anxiety is increasing in society and is common in patients awaiting surgery. It's associated with increased anesthetic requirements, increased postsurgical pain, and also adverse postoperative outcomes. Binaural beats have been proposed as a non-pharmacological intervention to reduce anxiety in medical settings.

Age-dependent changes in the power spectrum conflate composite scores to assess brain frailty.

Objective: Evaluating age-related dependencies in the electroencephalogram (EEG) during induction of general anesthesia and their impact on composite scores used to assess frailty.

Methods: A composite score was derived from spectral edge frequency, total power, alpha power, and the effect-site concentration (Ce) of propofol. All these parameters are influenced by age, brain health, and dosage and speed of drug administration.

CARDIORESPIRATORY FITNESS PREDICTS EEG-BASED SOMATOSENSORY RESPONSES FOLLOWING NOXIOUS MECHANICAL STIMULATION IN A CONDITIONED PAIN MODULATION MODEL.

Purpose: Existing literature indicates that physical fitness affects endogenous pain modulation capacity, potentially impacting populations with impaired pain modulation ability. However, current evidence remains inconsistent, and there is a lack of studies employing objective measures to examine this relationship. The objective of this study was to assess whether individual physical performance levels can predict endogenous pain modulation variables in the electroencephalogram (EEG).

GAL-201 as a Promising Amyloid-β-Targeting Small-Molecule Approach for Alzheimer's Disease Treatment: Consistent Effects on Synaptic Plasticity, Behavior and Neuroinflammation.

Soluble oligomeric forms of Amyloid-β (Aβ) are considered the major toxic species leading to the neurodegeneration underlying Alzheimer's disease (AD). Therefore, drugs that prevent oligomer formation might be promising. The atypical dipeptide GAL-201 is orally bioavailable and interferes as a modulator of Aβ aggregation.

Spectral Differences of Anesthetic Agents: Addressing Fundamental Problems With New Methods.

Background: Processed electroencephalography parameters are used to guide anesthesia to adequate levels for surgical procedures. Despite known spectral differences between anesthetics, studies often assume similar anesthetic states when titrating to the same target values, presupposing a reductive one-size-fits-all approach for all anesthetic agents. We hypothesize this may introduce bias and aim to characterize the differences using conventional and new approaches.

The Effect of Electroencephalographic Trajectory During Anesthesia Emergence on the Indices Monitoring the Hypnotic Component.

Background: Postoperative neurocognitive disorders (PNDs) are frequent and serious complications that cause an enormous social and economic burden. A previous study demonstrated that certain electroencephalographic (EEG) patterns during emergence from general anesthesia are associated with a higher risk for PND. Compared to patients demonstrating the most favorable trajectory (Traj Ref: delta-dominant slow-wave anesthesia (ddSWA)→spindle-dominant SWA (sdSWA)→non-SWA (nSWA)→wake), patients presenting Traj Abrupt (ddSWA→wake) had 4-fold increased odds to develop PND and patients with Traj High (nSWA→wake) had 8-fold increased odds of developing PND.

EEG features associated with Alzheimer's disease and Frontotemporal dementia are not reflected by processed indices used in anesthesia monitoring.

Patients with dementia face increased risks after general anesthesia. Improved perioperative electroencephalogram (EEG) monitoring techniques could aid in identifying vulnerable patients. However, current technology relies on processed indices to measure "depth-of-anesthesia".

Cortical, subcortical, brainstem and autonomic responses to nociception under total intravenous anesthesia.

Background: Physiological responses to nociception are complex and involve intricate associations between the central, peripheral, and autonomic nervous systems. To optimize intraoperative analgesic titration, several monitoring devices have been developed, each targeting specific physiologic variables. However, existing devices primarily focus on isolated components of the nociceptive response, such as autonomic or cortical activity, without integrating these perspectives comprehensively.

Characterizing Canine Frontal Electroencephalographic Patterns and Cardiovascular Correlates at Different Anesthetic Levels of Sevoflurane.

This study evaluated electroencephalogram [EEG] and cardiovascular correlation of sevoflurane anesthesia in healthy beagle dogs at varying minimum alveolar concentration (MAC) multiples. Processed EEG indices (Patient State Index [PSI], burst suppression ratio [SR], and Spectral Edge Frequency [SEF95], cardiovascular parameters (mean blood pressure [MBP], heart rate [HR]), and responses to noxious (electrical) stimuli were recorded. Deep anesthesia (2.

Evaluating Midazolam's Influence on Bispectral Index and Propofol Concentrations Using Schnider and Eleveld Models in Target-Controlled Infusion General Anesthesia: A Prospective Observational Study.

Background: Midazolam is widely used in clinical anesthesia, but its effects on the Bispectral Index (BIS) and propofol concentration at the effector site (CeP) are underexplored. This study investigates the pharmacodynamic interaction between midazolam and propofol in total intravenous anesthesia (TIVA) with target-controlled infusion (TCI), focusing on Schnider and Eleveld models.

Methods: This prospective study included breast surgery patients receiving TIVA-TCI.

Evaluation of different intramuscular injectable anesthetic combinations in rabbits: Impact on anesthetic depth, physiological parameters, and EEG recordings.

Rabbits have a high anesthesia-related mortality rate because of their small size, high metabolic rate and challenging airway management. This study aimed to investigate different combinations of intramuscularly administered anesthetics in New Zealand White rabbits, focusing on their effects on anesthetic depth, physiological parameters, and electroencephalogram (EEG) recordings. Defined doses ketamine (K), esketamine (SK), medetomidine (M), dexmedetomidine (D), midazolam (Mi), and butorphanol (B) were investigated and compared in five different combinations: KM (25/0.

Impact of age on the reliability of GE Entropy™ module indices for guidance of maintenance of anaesthesia in adult patients: a single-centre retrospective analysis.

Background: The GE Entropy™ module uses frontal EEG to compute the processed indices state entropy (SE), response entropy (RE), and burst suppression ratio (BSR) to guide maintenance of anaesthesia by supposedly minimising overly 'deep' or 'light' anaesthesia. It remains unclear whether the manufacturer-recommended index ranges accurately reflect anaesthesia levels or prevent complications such as burst suppression or arousal reactions.

Methods: We retrospectively analysed 15 608 patient records, evaluating 14 770 adult patients (18-90 yr old) undergoing general anaesthesia.

Entropy of difference works similarly to permutation entropy for the assessment of anesthesia and sleep EEG despite the lower computational effort.

EEG monitoring during anesthesia or for diagnosing sleep disorders is a common standard. Different approaches for measuring the important information of this biosignal are used. The most often and efficient one for entropic parameters is permutation entropy as it can distinguish the vigilance states in the different settings.

Electroencephalogram monitoring during anesthesia and critical care: a guide for the clinician.

Perioperative anesthetic, surgical and critical careinterventions can affect brain physiology and overall brain health. The clinical utility of electroencephalogram (EEG) monitoring in anesthesia and intensive care settings is multifaceted, offering critical insights into the level of consciousness and depth of anesthesia, facilitating the titration of anesthetic doses, and enabling the detection of ischemic events and epileptic activity. Additionally, EEG monitoring can aid in predicting perioperative neurocognitive disorders, assessing the impact of systemic insults on cerebral function, and informing neuroprognostication.

Parametrization of the dying brain: A case report from ICU bed-side EEG monitoring.

Background: Cortical high-frequency activation immediately before death has been reported, raising questions about an enhanced conscious state at this critical time. Here, we analyzed an electroencephalogram (EEG) from a comatose patient during the dying process with a standard bedside monitor and spectral parameterization techniques.

Methods: We report neurophysiologic features of a dying patient without major cortical injury.

Aperiodic component of the electroencephalogram power spectrum reflects the hypnotic level of anaesthesia.

Background: Aperiodic (nonoscillatory) electroencephalogram (EEG) activity can be characterised by its power spectral density, which decays according to an inverse power law. Previous studies reported a shift in the spectral exponent α from consciousness to unconsciousness. We investigated the impact of aperiodic EEG activity on parameters used for anaesthesia monitoring to test the hypothesis that aperiodic EEG activity carries information about the hypnotic component of general anaesthesia.

Intraoperative Burst Suppression by Analysis of Raw Electroencephalogram Postoperative Delirium in Older Adults Undergoing Spine Surgery: A Retrospective Cohort Study.

Background: Postoperative delirium is a common complication in older adults, associated with poor outcomes, morbidity, mortality, and higher health care costs. Older age is a strong predictor of delirium. Intraoperative burst suppression on the electroencephalogram (EEG) has also been linked to postoperative delirium and poor neurocognitive outcomes.

Effect of Ketamine on the Bispectral Index, Spectral Edge Frequency, and Surgical Pleth Index During Propofol-Remifentanil Anesthesia: An Observational Prospective Trial.

Background: Ketamine administration during stable propofol anesthesia is known to be associated with an increase in bispectral index (BIS) but a "deepening" in the level of hypnosis. This study aimed to evaluate the association between the effect-site concentration of ketamine (CeK) and 2 electroencephalogram (EEG)-derived parameters, the BIS and spectral edge frequency (SEF95), after the administration of a ketamine bolus. Secondary aims included investigating the BIS and SEF95 variations with time and changes in the surgical pleth index (SPI).

Electroencephalographic and Cardiovascular Assessments of Isoflurane-Anesthetized Dogs.

This study investigated the use of frontal electroencephalography (EEG) to monitor varying levels of isoflurane anesthesia in dogs. The patient state index (PSI), burst suppression ratio (SR), and waveforms, were continuously recorded while mean arterial blood pressure (MBP), heart rate, responses to electric stimuli, and subjective anesthetic "depth" were assessed every 3 min. At deep anesthesia (2.

Changes in Intra- and Cross-hemispheric Directed Functional Connectivity in the Electroencephalographic Signals during Propofol-induced Loss of Consciousness.

Background: Numerous, sometimes conflicting, changes in brain functional connectivity have been associated with the transition from wakefulness to unresponsiveness at induction of general anesthesia. However, relatively few studies have looked at the detailed time evolution of the transition, for different electroencephalogram (EEG) frequency bands, and in the clinical scenario of surgical patients undergoing general anesthesia.

Methods: The authors investigated the changes in the frontal and frontoparietal directed and undirected functional connectivity to multichannel EEG data recorded from 29 adult male surgical patients undergoing propofol-induced loss of consciousness during induction of anesthesia.