To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure no-reply@cambridge.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
The application of artificial intelligence (AI) to resting-state electroencephalography (EEG) data represents a burgeoning frontier in schizophrenia diagnostics. However, the inferential validity of findings is frequently compromised by methodological heterogeneity. This systematic review rigorously evaluates the diagnostic efficacy and methodological robustness of AI-generated EEG biomarkers by implementing the Prediction model Risk Of Bias Assessment Tool for Artificial Intelligence (PROBAST+AI).
Methods
Following PRISMA guidelines, a systematic search of PubMed, Scopus, and Web of Science identified 43 primary studies encompassing 3,420 patients with schizophrenia or first-episode psychosis and 3,164 healthy controls (total N = 6,584). Methodological quality and validation strategies were assessed using the 34 signaling questions of the PROBAST+AI framework.
Results
The aggregate mean diagnostic accuracy across the literature was 93.38%, with deep learning architectures demonstrating superior metrics relative to classical machine learning (96.83% vs. 87.68%). Critically, external validation was restricted to 4.7% of the included studies. A pronounced performance discrepancy was observed between subject-wise (88.22%) and segment-wise (98.14%) validation protocols, indicating pervasive data leakage. Overall, 76.7% of the analyzed studies were characterized by a high risk of bias, predominantly stemming from suboptimal data partitioning and inadequate independent verification.
Conclusions
Contemporary diagnostic accuracies appear to be artifactually elevated due to structural methodological deficiencies and data leakage. Consequently, current evidence does not support the immediate clinical implementation of AI-EEG biomarkers in schizophrenia. To facilitate translational progress, we propose a standardized methodological framework optimizing validation strategies.
Inappropriate diagnostic testing using electroencephalography (EEG) not only burdens the healthcare system but is especially concerning in Canada, where EEG demand is rising alongside a nationwide shortage of technologists. Understanding factors that influence yield, as well as patterns in requisition quality and completeness, may help improve both clinical utility and resource allocation.
Methods:
We performed a single-center retrospective cohort study analyzing EEGs performed at Kingston Health Sciences Centre from March to August 2024. Demographic and clinical data were collected from paper EEG requisitions and digital reports. Diagnostic yield was assessed across clinical variables, physician specialty and patient setting using descriptive statistics, logistic regressions and odds ratios.
Results:
EEGs detected abnormalities in ∼40% of 1077 EEGs, mostly non-epileptiform. Yield was higher among older adults (60+ years), inpatients in critical care, emergency patients, and those on anti-seizure medications or sedatives. Indications like “neuro-prognostication” and “concern for non-convulsive status epilepticus” had high yield (100%), whereas “syncope/presyncope” had poor yield (12.8%). Sleep-deprived EEGs did not significantly differ in yield compared to routine EEGs. Over half (56%) of the EEG requisition forms were incomplete. Requisition completeness varied by physician specialty: neurologists were found least likely to complete requisition forms compared to other specialties.
Conclusion:
By identifying clinical factors, physician specialties and settings associated with low diagnostic yield, interventions can be tailored to improve requisition practices and guide efficient resource allocation.
Neurological injury is common in neonates undergoing cardiac surgery with cardiopulmonary bypass, yet perioperative neuroimaging and neuromonitoring practices vary across centres. We aimed to characterise current practices and provider perceptions across Pediatric Cardiac Intensive Care Society-affiliated centres.
Methods:
We conducted an online, cross-sectional survey of Pediatric Cardiac Intensive Care Society members between August and October 2024. Part 1, completed by medical directors, assessed institutional characteristics and perioperative practices. Part 2, completed by multidisciplinary providers, evaluated perceptions of utility and sufficiency.
Results:
A total of 143 responses from 60 institutions were analysed, including 38 medical directors. Most centres had a dedicated cardiac ICU (87%) and were academically affiliated (76%). Routine neuroimaging was more common preoperatively than postoperatively (87% vs. 32%), with head ultrasound most frequently used. Near-infrared spectroscopy was the most common neuromonitoring modality, while routine electroencephalography was reported at 18% of centres preoperatively and 50% postoperatively. Physicians were more likely than advanced practice providers and nurses to report practices as sufficient. Neurocritical care teams were present at 42% of centres but were not associated with greater use of neuroimaging or monitoring.
Conclusions:
Significant variability exists in perioperative practices and provider perceptions, highlighting the need for multidisciplinary alignment and standardised guidelines.
Lennox-Gastaut syndrome (LGS) is characterized by drug-resistant seizures, cognitive impairment, and significant comorbidities, requiring lifelong care. Despite therapeutic advances, real-world management and system-level barriers in Canada are not well defined. A national survey was conducted to examine Canadian practices in LGS diagnostic approaches, therapies, comorbidity management, counseling practices, and transition services, aiming to identify gaps and guide quality improvement initiatives.
Methods:
Following a literature review, a 41-item web-based survey was developed and distributed to neurologists and allied health workers via the Canadian League Against Epilepsy and the Canadian Neurological Sciences Federation.
Results:
Among 111 respondents (77% physicians; 79% academic practice), diagnostic confidence was limited: 46% believed LGS is both over- and underdiagnosed, and only 5% felt most patients are accurately identified. Adult diagnosis was considered particularly challenging (46%). Genetic testing for unknown etiologies was routine for 67% and, however, was more common among pediatric than adult neurologists (81% vs 41%, p < 0.001). Valproic acid (98%), clobazam (82%), and lamotrigine (75%) were the most common first-line anti-seizure medications (ASMs), yet 67% rated available treatments as inadequate. Reported treatment barriers included limited ASM efficacy (68%), adverse effects (38%), and comorbidity management challenges (37%). Corpus callosotomy was perceived as underutilized (71% overall), suggesting access disparities. Time and resource limitations hindered comorbidity screening. Only 23% reported access to formal transition programs.
Conclusions:
Significant gaps remain in the diagnosis and management of LGS in Canada, particularly in treatment, comorbidity screening, and transition care. National guidelines, standardized pathways, and improved access to multidisciplinary services are needed to enhance outcomes.
Equids slaughtered for human consumption in many countries are stunned with penetrating captive bolt (PCB) to produce an irreversible state of unconsciousness to prevent pain and distress before exsanguination. This topic is much-studied for the most commonly slaughtered species, while literature remains limited on Equidae, particularly donkeys (Equus asinus). This study, in a Mexican commercial abattoir, examined the effectiveness of pneumatic PCB stunning with electroencephalographic (EEG) and behavioural signs in 13 donkeys. Forty-six percent (6/13) of donkeys had periods of ‘normal-like’ EEG after PCB stunning, between 1 to 9 s in duration. However, in all animals, this changed to either ‘transitional’ EEG or ‘isoelectric’ waveforms. The normal-like EEG phases were characterised by increased theta, alpha and beta activity in the EEG power spectrum. Just one donkey showed behavioural signs of incomplete concussion after stunning, showing both rhythmic breathing and spontaneous blinking, alongside normal-like EEG. In addition, four animals did not reach isoelectric EEG during the 30 s of recording. Shot position frequently deviated caudally from the suggested position and this was significantly associated with the presence of normal-like EEG and behavioural signs. These results highlight welfare concerns related to delayed or incomplete loss of consciousness in these animals, indicating the need for species-specific stunning guidelines. In conclusion, EEG is a useful research tool to substantially assist in understanding the risks of a potential return of consciousness after stunning. This could help to refine ideal airline pressure, shot position and validate behavioural signs that better evaluate consciousness in donkeys.
Major depressive disorder (MDD) and bipolar disorder (BD) exhibit overlapping depressive presentations, making early differentiation difficult and misdiagnosis clinically consequential. Entropy-based resting-state electroencephalography (EEG) markers were evaluated for differentiating drug-naïve patients with stable MDD, converted BD, and diagnosed BD.
Methods
Resting-state EEG was acquired from 92 drug-naïve patients: 50 with stable MDD, 16 who converted to bipolar II disorder over 3 years, and 26 with diagnosed BD. Band-scale entropy and cross-sample entropy (CSE) were analyzed. Group differences were tested by analysis of covariance adjusted for depressive severity; classification was evaluated by nested cross-validation with permutation testing.
Results
Relative to stable MDD, diagnosed BD showed higher theta- and alpha-band entropy in frontal and central regions and lower values for selected intra- and inter-regional CSE measures. Two CSE measures correlated positively with non-planning impulsiveness in diagnosed BD. Converted BD showed intermediate values without significant pairwise differences. Prospective discrimination of stable MDD versus converted BD was modest (balanced accuracy, 65.4%; area under the receiver operating characteristic curve [ROC-AUC], 0.661). Classification was strongest for stable MDD versus diagnosed BD, yielding 78.9% pooled accuracy, 76.6% balanced accuracy, and an ROC-AUC of 0.832 when entropy features were combined with depressive severity; combined entropy outperformed either single-family configuration.
Conclusions
Entropy-derived EEG measures differentiated stable MDD from diagnosed BD and suggested a weaker, intermediate profile in converted BD. They may serve as candidate adjunctive biomarkers for mood disorder differentiation, although larger prospective cohorts are required to clarify their value in predicting conversion to bipolar II disorder.
Subspecialty neurology fellowship training is becoming increasingly more common and a requirement to practice at academic institutions. This is especially true for electroencephalography (EEG) and epilepsy, as neurology residency does not usually provide adequate exposure to this complex field. Little is known about the availability and content of epilepsy fellowships in Canada. This study aims to identify this information and characterize available programs. Eight pediatric and eight adult epilepsy fellowship programs were identified. There was a wide range in the availability of resources in many centers, but all centers provided exposure to core EEG and epilepsy skills.
Alterations in reward responsiveness represent a key mechanism implicated in youth depression risk. However, not all youth with these alterations develop depression, suggesting the presence of factors that may moderate risk patterns. As socioeconomic disadvantage is also related to youth depression risk, particularly for youth exhibiting altered reward function, this study examined whether indices of family- and neighborhood-level disadvantage interacted with electrocortical reward responsivity to predict depression symptom trajectories across childhood and adolescence.
Methods
Participants included 76 youth (ages 9–16 years) at low and high risk for depression based on maternal history of depression. At baseline, youth completed a monetary reward-guessing task while electroencephalography was recorded to measure the reward positivity (RewP), an event-related potential indexing reward responsiveness. Family and neighborhood disadvantage were assessed using the income-to-needs (ITN) ratio and Area Deprivation Index (ADI), respectively. Self-reported and clinician-rated depression symptoms were assessed across a multiwave, 18-month follow-up.
Results
RewP interacted with family- and neighborhood-level disadvantage to predict self-reported depression symptom trajectories. Specifically, blunted RewP predicted self-reported depression symptom increases for youth with a lower ITN ratio and higher ADI score. A blunted RewP also predicted clinician-rated depression symptom increases for youth living in neighborhoods with higher ADI scores.
Conclusions
Findings suggest that reduced reward responsiveness is a mechanism implicated in future depression risk among youth, specifically in the context of family- and neighborhood-level socioeconomic disadvantage. Interventions that enhance reward response among youth exposed to higher levels of socioeconomic disadvantage may be particularly effective in preventing depression emergence.
Neurons generate electromagnetic fields as they communicate with each other. Chapter 9 introduces the electromagnetic field as a key concept overarching different electrophysiological brain activities. The concept corrects common misconceptions (e.g. "EEG is the sum of action potentials") and provides a common basis for data analysis of field signals. Basic properties of the field signal, amplitude, phase and frequency, are explained in plain language.
In addition, two major noninvasive techniques for measuring field activity, electroencephalography (EEG) and magnetoencephalography (MEG), are introduced. The advantages and disadvantages of the methods are discussed with a brief history of the techniques.
Language and other cognitive abilities interact with each other in a complex fashion. This interaction affects how we understand and develop models of cognitive function, interpret data reflecting neural activation and connectivity, and diagnose and treat language and cognitive conditions. The goal of this chapter is to provide a cohesive narrative introduction to major cognitive processes and some of the ways in which they interact with language processing. The chapter addresses four key non-linguistic cognitive processes: attention, memory, working memory, and executive function. Each process is discussed in terms of current thinking and prominent models regarding how it functions, its neural substrates, and how it affects and is affected by language function. While the cognitive processes discussed are presented separately, they share underlying relationships, and some models of cognition conceptualize the divisions between constructs differently. This chapter offers a clear but somewhat simplified overview in the interest of providing a basis for conceptualizing the interactive nature of language and other cognitive skills.
In response to the prevailing trend of an aging society and the increasing requirements of rehabilitation, this paper presents an approach involving brain-machine interaction (BMI) for a single-degree-of-freedom (1-DOF) sit-to-stand transfer robot. Based on a 1-DOF rehabilitation robot, three experiment paradigms involving motor imagery (MI), action observation of motor imagery (AO-MI) and motor execution are designed using both electroencephalography (EEG) and electromyography (EMG). To enhance motion intention recognition accuracy, a Gumbel-ResNet-KANs decoding model is established. The Gumbel-ResNet-KANs model integrates the Gumbel-Softmax method with the ResNet-KANs network module and demonstrates strong decoding capability, as demonstrated by comparative tests in this paper. To validate the effect of robotic assistance, EEG and EMG coherence are analyzed to assess the impact of robotic assistance on rehabilitation from a neuromuscular perspective in both assisted and unassisted conditions. We assessed the effect of robotics on rehabilitation from an emotional perspective by analyzing the difference between the differential entropy of the right and left brain. The proposed study also reveals that the movement-related cortical potentials in AO-MI are beneficial for promoting the performance of BMI in sit-to-stand training, which provides a possible approach for the development of new types of robots for lower limb rehabilitation.
Neurophysiology is a broad discipline involved in the recording and analysis of biological signals of multiple modalities relevant to the nervous system. Neurophysiological studies have contributed substantially to the understanding of the neurobiological underpinnings of psychiatric disease. In clinical psychiatry, EEG and other studies are secondary to the clinical assessment for a reliable diagnosis and prognostication of psychiatric disease, and should not be interpreted in isolation. However, in some clinical situations, such as non-epileptic seizures, they can be confirmatory of the diagnosis. In this chapter, we start with an overview of basic principles in neurophysiology, from cellular and molecular to systems neuroscience. We then describe the technical aspects, rationale, indications and limitations of the most commonly used neurophysiological tests in clinically psychiatry. We outline the main neurophysiological abnormalities present in primary psychiatric disorders and in their differential diagnoses (delirium, epilepsy, dementia, focal cerebral lesions and sleep disorders), as well as the neurophysiological effect of psychotropic medications. We also describe recent advances in neuromodulation techniques, linking diagnosis to therapy.
This paper reports the methods and preliminary findings of Germina, an ongoing cohort study to identify biomarkers and trajectories of executive functions and language development in the first 3 years of life. 557 mother-infant dyads (mean age of mothers 33.7 years, 65.2% white, 48.7% male infants) have undergone baseline and are currently collecting data for other timepoints. A linear regression was used to predict baseline Bayley-III using scores derived from data-driven sparse partial least squares utilizing a multiple holdout framework of 15 domains. Significant associations were found between socioeconomic/demographic characteristics (B = 0.29), epigenetics (B = 0.11), EEG theta (B = 0.14) and beta activity (B = 0.11), and microbiome functional pathways (B = 0.08) domains, and infant development measured by the Bayley-III at T1, suggesting potential interventions to prevent impairments.
Based on facial expression experiments, childhood adversity may be associated with threat-related information processing bias. Yet, it is unclear whether this generalizes to other threat-related stimuli, such as social and non-social visual scenes.
Methods
We combined fast periodic visual stimulation with frequency-tagging electroencephalography (EEG) and eye-tracking to assess automatic and implicit neural discrimination, neural salience and preferential looking towards negative versus neutral social and non-social visual scenes in young adults aged 16–24 years (51 with childhood adversity and psychiatric symptoms and 43 controls).
Results
Controls showed enhanced negative-neutral neural discrimination within a social versus non-social context. However, this facilitating effect of social content was absent in those with adversity, suggesting a selective alteration in social threat processing. Moreover, individual differences in adversity severity, and more specifically threat experiences (but not neglect experiences), were associated with decreased neural discrimination of negative versus neutral social scenes, corresponding to similar findings in facial expression processing, indicating the robustness of adversity-related deficits in threat-safety discrimination across social visual stimuli.
Conclusions
The adversity-related decreased threat-safety discrimination might impact individuals’ perception of social cues in daily life and relate to poor social functioning and future development of psychopathology.
Recent neuroimaging studies have demonstrated that the heterogeneous antidepressant responsiveness in patients with major depressive disorder (MDD) is associated with diverse resting-state functional brain network (rsFBN) topology; however, only limited studies have explored the rsFBN using electroencephalography (EEG). In this study, we aimed to identify EEG-derived rsFBN-based biomarkers to predict pharmacotherapeutic responsiveness.
Methods
The resting-state EEG signals were acquired for demography-matched three groups: 98 patients with treatment-refractory MDD (trMDD), 269 those with good-responding MDD (grMDD), and 131 healthy controls (HCs). The source-level rsFBN was constructed using 31 sources as nodes and beta-band power envelope correlation (PEC) as edges. The degree centrality (DC) and clustering coefficients (CCs) were calculated for various sparsity levels. Network-based statistic and one-way analysis of variance models were employed for comparing PECs and network indices, respectively. The multiple comparisons were controlled by the false discovery rate.
Results
Patients with trMDD were characterized by the altered dorsal attention network and salience network. Specifically, they exhibited hypoconnection between eye fields and right parietal regions (p = 0.0088), decreased DC in the right supramarginal gyrus (q = 0.0057), and decreased CC in the reward circuit (qs < 0.05). On the other hand, both MDD groups shared increased DC but decreased CC in the posterior cingulate cortex.
Conclusions
We confirmed that network topology was more severely deteriorated in patients with trMDD, particularly for the attention-regulatory networks. Our findings suggested that the altered rsFBN topologies could serve as potential pathologically interpretable biomarkers for predicting antidepressant responsiveness.
Nearly 25% of people with intellectual disability (PwID) have epilepsy compared to 1% of the UK general population. PwID are commonly excluded from research, eventually affecting their care. Understanding seizures in PwID is particularly challenging because of reliance on subjective external observation and poor objective validation. Remote electroencephalography (EEG) monitoring could capture objective data, but particular challenges and implementation strategies for this population need to be understood.
Aim
This co-production aimed to explore the accessibility and potential impact of a remote, long-term EEG tool (UnEEG 24/7 SubQ) for PwID and epilepsy.
Method
We conducted six, 2-hour long workshops; three with people with mild intellectual disability and three with families/carers of people with moderate–profound intellectual disability. Brief presentations, easy read information and model demonstrations were used to explain the problem and device. A semi-structured guide developed by a communication specialist and art-based techniques facilitated discussion with PwID. For family/carers, active listening was employed. All conversations were recorded and transcribed. Artificial intelligence-based coding and thematic analysis (ATLAS.ti and ChatGPT) were synthesised with manual theming to generate insights.
Results
Co-production included four PwID, five family members and seven care professionals. Three main themes were identified: (1) perceived benefits for improving seizure understanding, informing care and reducing family and carer responsibility to accurately identify seizures; (2) the device was feasible for some PwID but not all; and (3) appropriate person-centred communication is essential for all stakeholders to reduce concerns.
Conclusions
The workshops identified key benefits and implementing barriers to SubQ in PwID.
Depression is transmitted within families, but the mechanisms involved in such transmission are not clearly defined. A potential marker of familial risk is the neural response to errors, which may play a role in depression symptoms and is known to be partially heritable. Here, 97 mother-daughter dyads completed a Flanker task while electroencephalography markers of error monitoring were recorded: the error-related negativity (ERN) and response-locked delta and theta power. We assessed whether these measures of neural response to errors 1) were associated with history of recurrent major depressive disorder (MDD) and current depression symptoms among mothers, 2) were correlated among mother-daughter dyads, and 3) were associated with maternal history of recurrent MDD and maternal symptoms of depression among daughters. A history of recurrent MDD was associated with blunted delta and increased theta among mothers. Across mothers, delta and theta were negatively and positively associated, respectively, with current depression symptoms. Mothers’ and daughters’ ERN were positively correlated. Finally, current maternal depression symptoms were negatively associated with delta power in daughters. These results suggest that neural responses to errors may be implicated in the intergenerational transmission of depression. These results also support the relevance of delta oscillations to understanding pathways to depression.
The Hierarchical Taxonomy of Psychopathology (HiTOP) offers a promising framework to identify the neurobiological mechanisms of psychopathology. Many forms of psychopathology are characterized by dysfunctional emotional reactivity. The late positive potential (LPP) is an event-related potential component that provides an index of neurobiological emotional reactivity. Several categorical disorders have demonstrated a similar association with the emotion-modulated LPP. It is possible that higher-order dimensional representations of psychopathology might explain the comparable results. The present study examined the association between HiTOP-consistent pathological personality dimensions across multiple levels of the hierarchy and neurobiological emotional reactivity.
Methods
The sample included 215 18–35-year-old adults (86% female) who were oversampled for psychopathology. Participants completed the emotional interrupt task while electroencephalography was recorded to examine the LPP. Participants also completed the Comprehensive Assessment of Traits relevant to Personality Disorders to assess pathological personality.
Results
At the spectra level, higher negative emotionality was associated with a larger emotion-modulated LPP, while higher detachment was associated with a smaller emotion-modulated LPP. There were no associations between higher-order psychopathology levels and the emotion-modulated LPP. Compared to categorical diagnoses, spectra-level personality pathology dimensions significantly improved the prediction of the emotion-modulated LPP.
Conclusions
The present study indicates that HiTOP spectra levels of negative emotionality and detachment demonstrate unique associations with neurobiological emotional reactivity. The study highlights the utility of examining dimensional and hierarchical, rather than categorical, representations of psychopathology in the attempt to identify the neurobiological origins of psychopathology.
Schizotypal traits include abnormalities in cognition, behavior, and interpersonal relationships that are similar, yet less severe than psychotic symptomology. It is estimated that approximately 5% of the general population displays psychotic symptoms and experiences that can be considered schizotypal in nature, but there is little research examining the neurological correlates of these traits. The mismatch negativity (MMN) event-related potential is an objective measure of auditory change detection derived from electroencephalography. The current study contributes to the limited body of evidence examining the neurobiological underpinnings of schizotypy in a non-clinical sample using the MMN. Participants were recruited from the general population and divided into high and low-schizotypy groups for comparison. Individuals with high schizotypal traits displayed reduced MMN amplitudes in response to frequency and location deviants, and longer MMN latencies in response to location deviants. Specific sub-traits of schizotypy were uniquely related to frequency and location amplitudes, suggesting the previously reported inconsistencies in the literature may be due to diverse samples and differing deviant tone types. Finally, impulsivity and sensation-seeking likely contributed to the slower processing seen in location deviance detection. Ultimately, the current results provide evidence that the neurobiological abnormalities seen in clinical populations of schizotypal personality disorder and psychosis also extend to non-clinical populations.
The electroencephalographic (EEG) signal is the electric potential recorded on the scalp, and it is believed to originate from the combined activity of large populations of neurons. In forward models of EEG signals, one typically (i) represents neuronal sources in terms of effective current dipoles, (ii) defines a head model, which is a specification of the conductivity profile for the medium between the sources and the recording position (brain tissue, cerebrospinal fluid, skull, scalp), and (iii) uses volume-conductor theory to compute the resulting electric potential at the scalp. In this chapter, we introduce the key theory and computational frameworks for modeling EEG signals. We illustrate how biophysically detailed models of neurons can be reduced to approximate equivalent dipoles, and we discuss further ways to simplify neural simulations in order to reduce the computational cost. Using a combination of computational modeling and analytical approximations, we analyze how various factors are involved in shaping the EEG signal.