Electroencephalogram-based pharmacodynamic measures: a review

Review: bioavailability and efficacy of 'free' curcuminoids from curcumagalactomannoside (CGM) curcumin formulation

The golden spice turmeric with its main bioactive component curcumin is one of the most popular and extensively studied nutraceuticals. Despite numerous pre-clinical studies reporting positive pharmacodynamics of turmeric extracts and curcumin, the main issues in translating the pharmacological effects to clinical efficacy have been to overcome its poor pharmacokinetics and to deliver significant amounts of the biologically relevant forms of the actives to various tissues. This review is aimed at providing a first critical evaluation of the current published literature with the novel curcumagalactomannoside (CGM) formulation of curcumin using fenugreek galactomannan dietary fibre, specifically designed to address curcumin poor pharmacokinetics. We describe CGM and its technology as a food-grade formulation to deliver 'free' unconjugated curcuminoids with enhanced bioavailability and improved pharmacokinetic properties. The therapeutic relevance of improving bioavailability of 'free' curcuminoids and some of the technical challenges in the measurement of the 'free' form of curcuminoids in plasma and tissues are also discussed. A total of twenty-six manuscripts are reviewed here, including fourteen pre-clinical and twelve clinical studies that have investigated CGM pharmacokinetics, safety and efficacy in various animal models and human conditions. Overall current scientific evidence suggests CGM formulation has improved bioavailability and tissue distribution of the biologically relevant unconjugated forms of turmeric actives called 'free' curcuminoids that may be responsible for the superior clinical outcomes reported with CGM treatments in comparison with unformulated standard curcumin across multiple studies.

Assessment of electroencephalography modification by antipsychotic drugs in patients with schizophrenia spectrum disorders using frontier orbital theory: A preliminary study

AIM

Schizophrenia is characterized by an abnormality in electroencephalography (EEG), which can be affected by antipsychotic drugs. Recently, the mechanism underlying these EEG alterations in schizophrenia patients was reframed from the perspective of redox abnormalities. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) can be calculated using a computational method and may be useful for evaluating the antioxidant/prooxidant effect of antipsychotic drugs. Thus, we examined the association between the effects of antipsychotic monotherapy on quantitative EEG and HOMO/LUMO energy.

METHODS

We used medical report data including EEG results of psychiatric patients admitted to Hokkaido University Hospital. We extracted the EEG records of patients diagnosed with a schizophrenia spectrum disorder undergoing antipsychotic monotherapy during the natural course of treatment (n = 37). We evaluated the HOMO/LUMO energy of all antipsychotic drugs using computational methods. Multiple regression analyses were used to examine the relationship between the HOMO/LUMO energy of all antipsychotic drugs and spectral band power in all patients. Statistical significance was set at p < 6.25 × 10^-4 adjusted with Bonferroni correction.

RESULTS

We showed that the HOMO energy of all antipsychotic drugs had weak positive correlations with delta- and gamma-band power (e.g., standardized β = 0.617 for delta in the F3 channel, p = 6.6 × 10^-5 ; standardized β = 0.563 for gamma in the O1 channel, p = 5.0 × 10^-4 ).

CONCLUSION

Although there may be unexpected bias and confounding factors, our findings suggest that the effect of antipsychotic drugs on EEG may be related to their antioxidant actions.

Clinical application of BIS combined with LCR in assessing brain function and prognosis of patients with severe carbon monoxide poisoning

BACKGROUND

This study investigated the value of the bispectral index (BIS) and lactate clearance rate (LCR) in the assessment of cerebral neurological injury and prognosis in acute severe carbon monoxide poisoning (ASCOP) patients.

METHODS

A retrospective study was conducted on 86 ASCOP patients admitted to our hospital from November 2019 to March 2021. The patients' prognosis neurological function of the brain after 3 months of treatment was observed. The patients were divided into good (48) and poor (38) groups according to the different prognoses. The GCS-Pittsburgh score (G-P score) was performed on the patients after admission. BIS and LCR were recorded at admission, 6 h, 24 h, 48 h, and 72 h after admission. We conducted correlation and multivariate regression analysis for each factor. ROC curves were used to assess the diagnostic efficacy of each index on prognosis.

RESULTS

The two different prognosis groups showed that there were no significant differences for gender, age, treatment-free period, and APACHE II score at admission (P > 0.05); the G-P score, the BIS, and LCR at different times of admission was significantly higher in the good group than in the poor group (all P < 0.05). Both the 24 h of BIS and the LCR were diagnostically superior to the G-P score (P < 0.05); the diagnostic efficacy of the two combined was not superior to that of the individual factors (AUC=0.787), but had a high specificity (93.8 %).

CONCLUSION

BIS monitoring and LCR have clinical value in the assessment of neurological damage and prognostic in ASCOP patients.

The association of bispectral index values and metrics of cerebral perfusion during cardiopulmonary bypass

STUDY OBJECTIVE

Low bispectral index (BIS) values have been associated with adverse postoperative outcomes. However, trials of optimizing BIS by titrating anesthetic administration have reported conflicting results. One potential explanation is that cerebral perfusion may also affect BIS, but the extent of this relationship is not clear. Therefore, we examined whether BIS would be associated with cerebral perfusion during cardiopulmonary bypass, when anesthetic concentration was constant.

DESIGN

Observational cohort study.

SETTING

Cardiac operating room.

PATIENTS

Seventy-nine patients with cardiopulmonary bypass surgery were included.

MEASUREMENTS

Continuous BIS, mean arterial blood pressure (MAP), cerebral blood flow velocity (CBFV), and regional cerebral oxygen saturation (rSO₂) were monitored, with analysis during a period of constant anesthetic. Mean flow index (Mx) was calculated as Pearson correlation between MAP and CBFV. The lower limit of autoregulation (LLA) was identified as the MAP value at which Mx increased >0.4 with decreasing blood pressure. Postoperative delirium was assessed using the 3D-Confusion Assessment Method.

RESULTS

Mean BIS was lower during periods of MAP < LLA compared with BIS when MAP>LLA (mean 49.35 ± 10.40 vs. 50.72 ± 10.04, p = 0.002, mean difference = 1.38 [standard error: 0.42]). There was a dose response effect, with the BIS proportionately decreasing as MAP decreased below LLA (β = 0.15, 95% CI for the average slope across all patients 0.07 to 0.23, p < 0.001). In contrast, BIS was relatively unchanged when MAP was above LLA (β = 0.03, 95% CI for the average slope across all patients -0.02 to 0.09, p = 0.22). Additionally, increasing CBFV and rSO₂ were associated with increasing BIS. Patients with postoperative delirium had lower mean BIS and higher percentage of time duration with BIS <45 compared to patients without delirium.

CONCLUSIONS

There was an association of BIS and metrics of cerebral perfusion during a period of constant anesthetic administration, but the absolute magnitude of change in BIS as MAP decreased below the LLA was small.

Quantitative Resting State Electroencephalography in Patients with Schizophrenia Spectrum Disorders Treated with Strict Monotherapy Using Atypical Antipsychotics

OBJECTIVE

The effect of antipsychotic drugs on quantitative electroencephalography (EEG) has been mainly examined by the administration of a single test dose or among patients using combinations of other psychotropic drugs. We therefore investigated the effects of strict monotherapy with antipsychotic drugs on quantitative EEG among schizophrenia patients.

METHODS

Data from 2,364 medical reports with EEG results from psychiatric patients admitted to the Hokkaido University Hospital were used. We extracted EEG records of patients who were diagnosed with schizophrenia spectrum disorders and who were either undergoing strict antipsychotic monotherapy or were completely free of psychotropic drugs. The spectral power was compared between drug-free patients and patients using antipsychotic drugs. We also performed multiple regression analysis to evaluate the relationship between spectral power and the chlorpromazine equivalent daily dose of antipsychotics in all the patients.

RESULTS

We included 31 monotherapy and 20 drug-free patients. Compared with drug-free patients, patients receiving antipsychotic drugs demonstrated significant increases in theta, alpha and beta power. When patients taking different types of antipsychotics were compared with drug-free patients, we found no significant change in any spectrum power for the aripiprazole or blonanserin groups. Patients taking risperidone demonstrated significant increases in alpha and beta power. Patients taking clozapine and olanzapine demonstrated significant slow wave increases. Multiple regression analysis revealed that the chlorpromazine equivalent dose was positively associated with theta power.

CONCLUSION

Use of any antipsychotic drug by patients was associated with a dose-dependent increase in theta power. However, each type of antipsychotic demonstrated different spectral power changes.

The effects of oral administration of curcumin-galactomannan complex on brain waves are consistent with brain penetration: a randomized, double-blinded, placebo-controlled pilot study

OVERVIEW

A novel highly bioavailable curcumin-galactomannan (CGM) formulation was shown to have improved blood-brain-barrier (BBB) permeability of free curcuminoids in animal models; however, this has not been established in humans. The present study was conducted to determine the functional effects of CGM on brain waves in healthy individuals, owing to its BBB permeability.

METHODS

A total of 18 healthy volunteers aged 35-65 were randomly assigned to consume 500 mg CGM, Unformulated curcumin (UC) or Placebo capsules twice daily for 30 days. Electroencephalogram (EEG) measurements, audio-visual reaction time tests and a working memory test were conducted at baseline and after 30 days.

RESULTS

Supplementation of CGM resulted in a significant increase in α- and β-waves (p < 0.05) as well as a significant reduction in α/β ratio in comparison with unformulated curcumin and placebo groups. Furthermore, the CGM showed significant reduction in the audio-reaction time (29.8 %; p < 0.05) in comparison with placebo and 24.6% (p < 0.05) with unformulated curcumin. The choice-based visual-reaction time was also significantly decreased (36%) in CGM as compared to unformulated curcumin and placebo which produced 15.36% and 5.2% respectively.

CONCLUSION

The observed increase in α and β waves and reduction in α/β ratio in the CGM group suggest that CGM can influence the brain waves in healthy subjects in a manner consistent with penetration of the blood-brain-barrier. The EEG results correlated with improved audio-visual and working memory tests which further support the role of CGM on memory improvements and fatigue reduction.

Deep learning and feature based medication classifications from EEG in a large clinical data set

The amount of freely available human phenotypic data is increasing daily, and yet little is known about the types of inferences or identifying characteristics that could reasonably be drawn from that data using new statistical methods. One data type of particular interest is electroencephalographical (EEG) data, collected noninvasively from humans in various behavioral contexts. The Temple University EEG corpus associates thousands of hours of de-identified EEG records with contemporaneous physician reports that include metadata that might be expected to show a measurable correlation with characteristics of the recorded signal. Given that machine learning methods applied to neurological signals are being used in emerging diagnostic applications, we leveraged this data source to test the confidence with which algorithms could predict, using a patient’s EEG record(s) as input, which medications were noted on the matching physician report. We comparatively assessed deep learning and feature-based approaches on their ability to distinguish between the assumed presence of Dilantin (phenytoin), Keppra (levetiracetam), or neither. Our methods could successfully distinguish between patients taking either anticonvulsant and those taking no medications; as well as between the two anticonvulsants. Further, we found different approaches to be most effective for different groups of classifications.

A MEG Study of Acute Arbaclofen (STX-209) Administration

Several electrophysiological parameters, including the auditory evoked response component M50/M100 latencies and the phase synchrony of transient and steady-state gamma-band oscillations have been implicated as atypical (to various extents) in autism spectrum disorder (ASD). Furthermore, some hypotheses suggest that an underlying neurobiological mechanism for these observations might be atypical local circuit function indexed by atypical levels of inhibitory neurotransmitter, GABA. This study was a randomized, placebo-controlled, double-blind, escalating-dose, acute investigation conducted in 25 14–18 year-old adolescents with ASD. The study assessed the sensitivity of magnetoencephalography (MEG) and MEGAPRESS “GABA” magnetic resonance spectroscopy (MRS) to monitor dose-dependent acute effects, as well as seeking to define properties of the pre-drug “baseline” electrophysiological and GABA signatures that might predict responsiveness to the GABA-B agonist, arbaclofen (STX-209). Overall, GABA levels and gamma-band oscillatory activity showed no acute changes at either low (15 mg) or high (30 mg) dose. Evoked M50 response latency measures tended to shorten (normalize), but there was heterogeneity across the group in M50 latency response, with only a subset of participants (n = 6) showing significant M50 latency shortening, and only at the 15 mg dose. Findings thus suggest that MEG M50 latency measures show acute effects of arbaclofen administration in select individuals, perhaps reflecting effective target engagement. Whether these subjects have a greater trend towards clinical benefit remains to be established. Finally, findings also provide preliminary support for the use of objective electrophysiological measures upon which to base inclusion for optimal enrichment of populations to be included in full-scale clinical trials of arbaclofen.

Clinical Trial of the Potassium Channel Activator Diazoxide for Major Depressive Disorder Halted Due to Intolerability

BACKGROUND

Some glutamatergic modulators have demonstrated rapid and relatively sustained antidepressant properties in patients with major depressive disorder. Because the potassium channel activator diazoxide increases glutamate uptake via potassium channel activation, we hypothesized that it might exert antidepressant effects by increasing the removal of glutamate from the synaptic cleft, thereby reducing excessive glutamate transmission.

METHODS

This randomized, double-blind, placebo-controlled, crossover, single-site inpatient clinical study was conducted at the National Institute of Mental Health to assess the efficacy and safety of a 3-week course of diazoxide (200-400 mg daily, twice a day) versus a 3-week course of placebo in 6 participants with treatment-refractory major depressive disorder. The primary clinical outcome measure was change in Montgomery-Asberg Depression Rating Scale score from baseline to posttreatment. Quantitative insulin sensitivity check index, as well as concomitant imaging measures (electroencephalography, proton magnetic resonance spectroscopy, magnetoencephalography), were used as potential surrogate markers of target (KATP channel) engagement.

RESULTS

The study was halted due to severe adverse effects. Given the small sample size, statistical evaluation of the effect of diazoxide on Montgomery-Asberg Depression Rating Scale scores or the imaging measures was not pursued. Visual inspection of the quantitative insulin sensitivity check index test revealed no evidence of target engagement.

CONCLUSIONS

Although the results are negative, they are an important addition to the literature in this rapidly changing field.

Drugs in space: Pharmacokinetics and pharmacodynamics in astronauts

Space agencies are working intensely to push the current boundaries of human spaceflight by sending astronauts deeper into space than ever before, including missions to Mars and asteroids. Spaceflight alters human physiology due to fluid shifts, muscle and bone loss, immune system dysregulation, and changes in the gastrointestinal tract and metabolic enzymes. These alterations may change the pharmacokinetics and/or pharmacodynamics of medications used by astronauts and subsequently might impact drug efficacy and safety. Most commonly, medications are administered during space missions to treat sleep disturbances, allergies, space motion sickness, pain, and sinus congestion. These medications are administered under the assumption that they act in a similar way as on Earth, an assumption that has not been investigated systematically yet. Few inflight pharmacokinetic data have been published, and pharmacodynamic and pharmacokinetic/pharmacodynamic studies during spaceflight are also lacking. Therefore, bed-rest models are often used to simulate physiological changes observed during microgravity. In addition to pharmacokinetic/pharmacodynamic changes, decreased drug and formulation stability in space could also influence efficacy and safety of medications. These alterations along with physiological changes and their resulting pharmacokinetic and pharmacodynamic effects must to be considered to determine their ultimate impact on medication efficacy and safety during spaceflight.

EEG Source Reconstruction in Male Nonsmokers after Nicotine Administration during the Resting State

Modern psychopharmacological research in humans focuses on how specific psychoactive molecules modulate oscillatory brain activity. We present state-of-the-art EEG methods applied in a resting-state drug study. Thirty healthy male nonsmokers were randomly allocated either to a nicotine group (14 subjects, 7 mg transdermal nicotine) or a placebo group (16 subjects). EEG activity was recorded in eyes-open (EO) and eyes-closed (EC) conditions before and after drug administration. A source reconstruction (minimum norm algorithm) analysis was conducted within a frequency range of 8.5-18.4 Hz subdivided into three different frequency bands. During EO, nicotine reduced the power of oscillatory activity in the 12.5- to 18.4-Hz frequency band in the left middle frontal gyrus. In contrast, in the EC condition, nicotine reduced the power in the 8.5- to 10.4-Hz frequency band in the superior frontal gyri and in the 10.5- to 12.4-Hz and 12.5- to 18.4-Hz frequency bands in the supplementary motor areas. In summary, nicotine reduced the power of the 12.5- to 18.4-Hz band in the left middle frontal gyrus during EO, and it reduced power from 8.5 to 18.4 Hz in a brain area spanning from the superior frontal gyri to the supplementary motor areas during EC. In conclusion, the results suggest that nicotine counteracts the phenomenon of anteriorization of α activity, hence potentially increasing the level of vigilance.

Challenges in developing drugs for pediatric CNS disorders: A focus on psychopharmacology

Many psychiatric and behavioral disorders manifest in childhood (attention deficit hyperactivity disorder, obsessive compulsive disorder, anxiety, depression, schizophrenia, autism spectrum disorder, etc.) and the opportunity for intervening early may attenuate full development of the disorder and lessen long term disability. Yet, pediatric drug approvals for CNS indications are limited, and pediatric testing generally occurs only after establishing adult efficacy, more as an afterthought rather than with the initial goal of developing the medication for a pediatric CNS indication. With pharmaceutical companies decreasing funding of their neuroscience research divisions overall, the prospects for moving promising investigational drugs forward into pediatrics will only decline. The goal of this review is to highlight important challenges around pediatric drug development for psychiatric disorders, specifically during clinical development, and to present opportunities for filling these gaps, using new strategies for de-risking investigational drugs in new clinical trial designs/models. We will first present the current trends in pediatric drug efficacy testing in academic research and in industry trials, we will then discuss the regulatory landscape of pediatric drug testing, including policies intended to support and encourage more testing. Obstacles that remain will then be presented, followed by new designs, funding opportunities and considerations for testing investigational drugs safely.

Increased power of resting-state gamma oscillations in autism spectrum disorder detected by routine electroencephalography

Experimental studies suggest that increased resting-state power of gamma oscillations is associated with autism spectrum disorder (ASD). To extend the clinical applicability of this finding, we retrospectively investigated routine electroencephalography (EEG) recordings of 19 patients with ASD and 19 age- and gender-matched controls. Relative resting-state condition gamma spectral power was variable, but on average significantly increased in children with ASD. This effect remained when excluding electrodes associated with myogenic gamma activity. These findings further indicate that increased resting-state gamma activity characterizes a subset of ASD and may also be detected by routine EEG as a clinically accessible and well-tolerated investigation.

Electroencephalography and analgesics

To assess centrally mediated analgesic mechanisms in clinical trials with pain patients, objective standardized methods such as electroencephalography (EEG) has many advantages. The aim of this review is to provide the reader with an overview of present findings in analgesics assessed with spontaneous EEG and evoked brain potentials (EPs) in humans. Furthermore, EEG methodologies will be discussed with respect to translation from animals to humans and future perspectives in predicting analgesic efficacy. We searched PubMed with MeSH terms 'analgesics', 'electroencephalography' and 'evoked potentials' for relevant articles. Combined with a search in their reference lists 15 articles on spontaneous EEG and 55 papers on EPs were identified. Overall, opioids produced increased activity in the delta band in the spontaneous EEG, but increases in higher frequency bands were also seen. The EP amplitudes decreased in the majority of studies. Anticonvulsants used as analgesics showed inconsistent results. The N-methyl-D-aspartate receptor antagonist ketamine showed an increase in the theta band in spontaneous EEG and decreases in EP amplitudes. Tricyclic antidepressants increased the activity in the delta, theta and beta bands in the spontaneous EEG while EPs were inconsistently affected. Weak analgesics were mainly investigated with EPs and a decrease in amplitudes was generally observed. This review reveals that both spontaneous EEG and EPs are widely used as biomarkers for analgesic drug effects. Methodological differences are common and a more uniform approach will further enhance the value of such biomarkers for drug development and prediction of treatment response in individual patients.

Altered cortical causality after remifentanil administration in healthy volunteers: a novel approach for pharmaco-EEG

Alterations in cortical causality information flow induced by remifentanil infusion in healthy volunteers was investigated in a placebo-controlled double-blind cross-over study. For each of the 21 enrolled male subjects, 2.5 minutes of resting electroencephalography (EEG) data were collected before and after infusion of remifentanil and placebo. Additionally, to assess cognitive function and analgesic effect, continuous reaction time (CRT) and bone pressure and heat pain were assessed, respectively. The causality information was extracted from the EEG by phase slope index (PSI). Among the features being reproducible between the two baseline recordings, several PSI features were altered by remifentanil administration in comparison to placebo. Furthermore, several of the PSI features altered by remifentanil were correlated to changes in both CRT and pain scores. The results indicate that remifentanil administration influence the information flow between several brain areas. Hence, the EEG causality approach offers the potential to assist in deciphering the cortical effects of remifentanil administration.

Use of PD biomarkers to drive dose selection and early clinical decision making

A major challenge facing the development of new therapies is the high level of compound attrition in late-stage clinical studies. A key factor in reducing these unsustainable levels of attrition is the successful evaluation of the level of drug effect on its target pathway in early development, otherwise known as testing the compound mechanism. Incorporation of PD biomarkers into Phase I/II trials to demonstrate compound binding to its molecular target and the subsequent modulation of downstream pathways enables early testing of compound mechanism and provides a data-driven framework for decisions on compound progression. This review will discuss the identification and validation of such 'fit-for-purpose' PD biomarkers, and case studies illustrating their use and value in dose selection and accelerating the clinical development of small-molecule drugs will be described.