Cortical sources of awake scalp EEG in eating disorders

Electroencephalographic Changes in Pregnant Women with Hyperemesis Gravidarum: A Case-Control Study

OBJECTIVE

Electroencephalogram (EEG), which is frequently used in the clinical practice of neurology, has also been investigated in eating disorders and some cortical dysfunctions have been reported. Based on this, we aimed to investigate EEG changes in pregnant women with hyperemesis gravidarum (HEG).

MATERIALS AND METHODS

This case-control study was conducted on 66 pregnant women who applied to the Umraniye Training and Research Hospital, Department of Obstetrics and Gynecology. The study group consisted of 34 pregnant women diagnosed with HEG. The control group consisted of 32 healthy pregnant women who were matched with the HEG group in terms of age and gestational week. EEGs of the participants were performed with a Micromed Brain Rapid EEG device in the Neurology Department of Umraniye Training and Research Hospital. In EEGs, all channels were selected as bipolar and samples of 18 channels (Fp2-F4, F4-C4, C4-P4, P4-O2, Fp2-F8, F8-T4, T4-T6, T6-O2, Fz-Cz, Cz-Pz, Fp1-F3, F3-C3, C3-P3, P3-O1, Fp1-F7, F7-T3, T3-T5, and T5-O1) were obtained. EEG signals were sampled with a sampling frequency of 200 Hz and digitized with 12-bit resolution. EEG signals were converted to EDF (European Data Format) extension files using the MATLAB software program and analyzed using statistical features on the time and frequency axis. HEG and control groups were compared in terms of signals obtained from these 18 selected channels.

RESULTS

Both groups were similar in terms of mean age, gestational age, and parity (p>0.05). Among the 18 channels, significant changes were detected between the two groups only in the theta, beta, and gamma bands in the C4-P4 channel and the delta, beta, and gamma bands in the T4-T6 channel (p<0.05). No significant changes were detected in the channels and bands.

CONCLUSION

Theta, beta, and gamma band abnormalities in the centro-parietal area of the right hemisphere and delta, beta, and gamma band abnormalities in the temporal area of the right hemisphere were observed on HEG. However, it is unclear whether abnormalities in EEG are primary changes responsible for the development of HEG or secondary to metabolic and hormonal changes resulting from HEG itself.

Complementary and Integrative Medicine and Eating Disorders in Youth: Traditional Yoga, Virtual Reality, Light Therapy, Neurofeedback, Acupuncture, Energy Psychology Techniques, Art Therapies, and Spirituality

Eating disorders (EDs) are a non-heterogeneous group of illnesses with significant physical and mental comorbidity and mortality associated with maladaptive coping. With the exception of lisdexamfetamine (Vyvanse) for binge eating disorder, no medications have been effective for the core symptoms of ED. ED requires a multimodal approach. Complementary and integrative medicine (CIM) can be helpful as an adjunct. The most promising CIM interventions are traditional yoga, virtual reality, eye movement desensitization and reprocessing, Music Therapy, and biofeedback/neurofeedback.

A Systematic Review of Electrophysiological Findings in Binge-Purge Eating Disorders: A Window Into Brain Dynamics

Binge-purge eating disorders (BP-ED), such as bulimia nervosa and binge eating disorder, may share some neurobiological features. Electroencephalography (EEG) is a non-invasive measurement modality that may aid in research and diagnosis of BP-ED. We conducted a systematic review of the literature on EEG findings in BP-ED, seeking to summarize and analyze the current evidence, as well as identify shortcomings and gaps to inform new perspectives for future studies. Following PRISMA Statement recommendations, the PubMed, Embase, and Web of Science databases were searched using terms related to “electroencephalography” and “binge-purge” eating disorders. Of 555 articles retrieved, 15 met predefined inclusion criteria and were included for full-text analysis. Eleven studies investigated EEG by means of event-related potentials (ERP) in BP-ED individuals: 7 using eating disorder-related stimuli (i.e., food, body image) and 4 using non-eating disorder-related stimuli (i.e., facial expressions or auditory clicks). These studies found significant differences in the N200, P200, P300, and LPP components in BP-ED participants compared to controls, indicating that this population exhibits impairments in selective attention, attentional allocation/processing, and allocation of motivational or emotion-based attention. Five studies investigated EEG using frequency analysis; reporting significant differences in beta activity in fronto-temporal and occipito-temporo-parietal areas in BP-ED individuals compared to controls, revealing a dysfunctional brain network. However, the small number of studies, the heterogeneity of samples, study paradigms, stimulus types, and the lack of an adequate assessment of neuropsychological parameters are some limitations of the current literature. Although some EEG data are promising and consistent with neuroimaging and neuropsychological findings in individuals with BP-ED, future studies need to overcome current methodological shortcomings.

The song of Anorexia Nervosa: a specific evoked potential response to musical stimuli in affected participants

PURPOSE

Research applying electroencephalography (EEG) to Anorexia Nervosa (AN) is still limited, even though in other psychiatric disorders EEG has permitted to find out the hallmarks of the disorder. The aim of the study was to explore whether EEG basal activity and reactivity to musical stimulation differ in participants with AN as compared to healthy subjects (HS).

METHODS

Twenty female participants (respectively 10 with AN and 10 healthy controls) were administered a battery of psychometric tests and underwent EEG under three different conditions: (1) at baseline; (2) after a generic music stimulation; and (3) after a favorite musical stimulation.

RESULTS

In participants with AN, basal EEG showed the higher absolute amplitude of cortical slow waves (theta) in the parieto-occipital and temporal derivations, with a deficit in the beta band. In AN, there was a higher N100 latency and a reduced P300 latency compared to HS. While the N100 and P300 latencies were sensitive to the musical stimulus in HS, there was no difference after music stimulation in AN.

CONCLUSION

These data suggest that AN is accompanied by a state of brain hyperarousal with abnormal reactivity to environmental stimuli, similar to the state of HS after musical stimulation. If confirmed, this finding may have treatment implications.

LEVEL OF EVIDENCE

III, Evidence obtained from well-designed cohort or case-control analytic studies.

Brain sources' activity in resting state before a visuo-motor task

Objective In modern neuroscience, the underlying mechanisms of the elaboration and reaction to different kinds of stimuli of the brain hemispheres remain still very challenging to understand, together with the possibility to anticipate certain behaviors to improve the performance. Approach The purpose of the present study was to investigate the brain rhythms characteristics of EEG recordings and in particular, their interhemispheric differences in resting state condition before a visuo-motor task in a population of healthy adults. During the task, subjects were asked to react to a sequence of visual cues as quick as possible. The reaction times (RTs) to the task were measured, collected and correlated with the EEG signals recorded in a resting state condition immediately preceding the task. The EEG data were analyzed in the space of cortical sources of EEG rhythms by the computation of the Global Spectra Power Density (GSPD) in the left and in the right hemisphere, and of an index of brain Laterality L. Main results The results showed a negative correlation between the RTs and the GSPD in the central areas in the left and in the right hemisphere in both eyes open and eyes closed conditions. A close to significant and negative correlation was found in the parietal areas. Furthermore, RTs negatively correlated with L in the central areas in eyes closed condition. The results showed a negative correlation between the RTs and the GSPD in the central areas in the left and in the right hemisphere in both eyes open and eyes closed conditions. Significance The correlations between the brain activity before a task and the RTs to the task can represent an interesting tool for exploring the brain state characterization for the upcoming tasks performance.

Electroencephalographic (EEG) alterations in young women with high subclinical eating pathology levels: a quantitative EEG study

PURPOSE

To explore electroencephalographic (EEG) alterations in young women with different eating disorder (ED) psychopathology levels.

METHODS

Thirty-seven young women completed general and ED psychopathology (i.e., the ED Examination Questionnaire; EDE-Q) measures. EEG power spectra data were investigated in two conditions: (a) 5 min of resting state (RS) and (b) 5 min of RS after a single taste of a milkshake (ML-RS). EEG analyses were performed using exact Low-Resolution Electromagnetic Tomography software (eLORETA).

RESULTS

Cluster analysis performed on the EDE-Q responses revealed a group of 17 women with high levels of ED pathology falling into the subclinical (i.e., sub-threshold) EDs category and a group of 20 women with low levels of ED pathology (controls). In the RS conditions, no significant modifications were observed between groups. Compared to controls, women with subclinical EDs showed an increase in theta activity in the parieto-occipital areas in the ML-RS condition. After controlling for body mass index and general psychopathology, theta activity in these brain structures was positively associated with EDE-Q global and subscale (restraint, shape and weight concern) scores.

CONCLUSIONS

Our results may reflect the neurophysiological substrate of ED psychopathology core features like shape/weight concerns. Previous brain imaging and qEEG studies with full-syndrome ED patients also underscored the involvement of parieto-occipital areas in ED pathophysiology. These studies also found brain alterations in the RS condition, not observed here. This is notable given that full-syndrome and subclinical EDs are considered as different manifestations of the same disease along a severity spectrum.

LEVEL OF EVIDENCE

Level V, cross-sectional, electroencephalographic, descriptive study.

Brain Rate Parameter in Children with General Anxiety Disorder

INTRODUCTION

Brain rate is parameter correlated to brain electric and metabolic activity.

AIM

The aim of this study was to analyze the results obtained for brain rate parameter as an indicator for general mental arousal in anxious patients and to compare them with results of healthy young people matched in age and gender, as well as with anorectic and hyperactive children.

MATERIAL AND METHODS

The diagnosis for all examinees was made according two statistic manuals (DMSIV- R and ICD-10), medical history, neuropsychological assessment, biochemical analysis and QEEG. In this study we examined the spectra power of the brain waves through quantified EEG (QEEG). The obtained results were exported to brain rate software and then calculated for each region separately. The QEEG spectra power data and the brain rate data were analyzed using Statistica software.

RESULTS

According to sagittal and lateral topography maximal values of brain rate parameter were obtained in group of healthy individuals and in group of anorectic patients. The lowest results were obtained in group of hyperactive children for all three regions.

CONCLUSIONS

The general conclusion will be that pathological conditions in childhood, analyzed in this research, can be defined as conditions of hypoarausal and this can be specific sign of brain dysfunction.

EEG neurofeedback effects in the treatment of adolescent anorexia nervosa

A pre-post design including 22 females was used to evaluate the effectiveness of neurofeedback in the treatment of adolescent anorexia nervosa. Resting EEG measures and a psychological test-battery assessing eating behavior traits, clinical symptoms, emotionality, and mood were obtained. While both the experimental (n = 10) and control group (n = 12) received their usual maintenance treatment, the experimental group received 10 sessions of individual alpha frequency training over a period of 5 weeks as additional treatment. Significant training effects were shown in eating behavior traits, emotion regulation, and in relative theta power in the eyes closed condition. Although the results are limited due to the small sample size, these are the first empirical data demonstrating the benefits of neurofeedback as a treatment adjunct in individuals with anorexia nervosa.

Increased frontal electroencephalogram theta amplitude in patients with anorexia nervosa compared to healthy controls

OBJECTIVE

To conduct a blind study of quantitative electroencephalogram-band amplitudes in patients with anorexia nervosa (AN) and healthy controls.

METHODS

Twenty-one patients with AN and 24 controls were examined with eyes-closed 16-channel electroencephalogram. Main variables were absolute alpha, theta, and delta amplitudes in frontal, temporal, and posterior regions.

RESULTS

There were no significant differences between the AN patients and controls regarding absolute regional band amplitudes in μV. Borderline significance was found for anterior theta (P=0.051). Significantly increased left and right frontal electrode theta amplitude was found in AN patients (F3, P=0.014; F4, P=0.038) compared to controls. Significant differences were also observed for secondary variables: lower values for relative parietooccipital delta and frontocentral alpha activity among AN patients than among controls.

CONCLUSION

We observed slight excess frontal theta and lower relative alpha and delta amplitudes among AN patients than among controls. This pattern is possibly related to a slight frontal lobe dysfunction in AN, or it may reflect increased attention/vigilance or another state-related change in patients with AN compared to healthy controls.

Electroencephalography in eating disorders

Clinical applications of electroencephalography (EEG) are used with different objectives, EEG being a noninvasive and painless procedure. In respect of eating disorders, in the 1950s a new line of study about the neurological bases of anorexia nervosa was started and has since been developed. The purpose of this review is to update the existing literature data on the main findings in respect of EEG in eating disorders by means of a search conducted in PubMed. Despite the fact that weight gain tends to normalize some brain dysfunctions assessed by means of EEG, the specific effect of gaining weight remains controversial. Different studies have reported that cortical dysfunctions can be found in patients with anorexia nervosa even after weight gain, whereas others have reported a normalization of EEG in respect of the initial reduced alpha/ increased beta power in those patients with refeeding. Findings of studies that have analyzed the possible relationship between eating disorders and depression, based on sleep EEG disturbances, do not support the idea of eating disorders as a variant of depression or affective disorders. Some EEG findings are very consistent with previous neuroimaging results on patients with anorexia nervosa, reporting neural disturbances in response to stimuli that are relevant to the pathology (eg, stimuli like food exposure, different emotional situations, or body images).

Tonic pain and continuous EEG: prediction of subjective pain perception by alpha-1 power during stimulation and at rest

OBJECTIVE

Pain neurophysiology has been chiefly characterized via event-related potentials (ERPs), which are exerted using brief, phase-locked noxious stimuli. Striving for objectively characterizing clinical pain states using more natural, prolonged stimuli, tonic pain has been recently associated with the individual peak frequency of alpha oscillations. This finding encouraged us to explore whether alpha power, reflecting the magnitude of the synchronized activity within this frequency range, will demonstrate a corresponding relationship with subjective perception of tonic pain.

METHODS

Five-minute-long continuous EEG was recorded in 18 healthy volunteers under: (i) resting-state; (ii) innocuous temperature; and (iii) psychophysically-anchored noxious temperature. Numerical pain scores (NPSs) collected during the application of tonic noxious stimuli were tested for correlation with alpha-1 and alpha-2 power.

RESULTS

NPSs and alpha power remained stable throughout the recording conditions (Ps⩾0.381). In the noxious condition, alpha-1 power obtained at the bilateral temporal scalp was negatively correlated with NPSs (Ps⩽0.04). Additionally, resting-state alpha-1 power recorded at the bilateral temporal scalp was negatively correlated with NPSs reported during the noxious condition (Ps⩽0.038).

CONCLUSIONS

Current findings suggest alpha-1 power may serve as a direct, objective and experimentally stable measure of subjective perception of tonic pain. Furthermore, resting-state alpha-1 power might reflect individuals' inherent tonic pain responsiveness.

SIGNIFICANCE

The relevance of alpha-1 power to tonic pain perception may deepen the understanding of the mechanisms underlying the processing of prolonged noxious stimulation.

Brain dysfunction in anorexia nervosa: cause or consequence of under-nutrition?

PURPOSE OF REVIEW

Imaging studies that demonstrate loss of brain substance help explain why people with anorexia nervosa have cognitive deficits and may help to elucidate the cognitive style found in many patients. It is not known whether a neurobiological vulnerability predisposes to anorexia nervosa or if this is associated with maintenance of symptoms once the illness develops.

RECENT FINDINGS

Evidence emerging from functional neuro-imaging studies raise the possibility of a biological abnormality that may predispose to anorexia nervosa. Studies have found abnormal functioning in the frontal, limbic, occipital, striatal and cerebellar regions that may persist after recovery. However, most recent cross-sectional and prospective studies indicate improved cerebral activity and mixed findings in regards to neurocognitve function with recovery from anorexia nervosa.

SUMMARY

The elucidation of the neurobiology of anorexia nervosa has benefited from recent advances in neuro-imaging and cognitive neuroscience. Further research is needed to examine the degree to which abnormalities are a consequence of starvation or are caused by a putative anorexia nervosa endophenotype.

EEG in adolescent anorexia nervosa: impact of refeeding and weight gain

OBJECTIVE

To examine resting awake EEG in adolescent AN participants before and after refeeding to determine if EEG abnormalities in Anorexia Nervosa (AN) are reversible.

METHOD

In 37 adolescent first admission AN patients and 45 healthy controls, EEG was recorded during short duration "eyes open" and "eyes closed" awake resting conditions. Repeat testing occurred in 28 AN participants after refeeding and subsequent weight gain.

RESULTS

In "eyes open," underweight AN participants exhibit reduced relative alpha power and increased beta power in frontal brain regions. A significant increase in alpha, and decrease in beta and delta power was observed within participants after refeeding. In "eyes closed", underweight AN participants had elevated theta in parietal-occipital regions which remained after refeeding.

DISCUSSION

EEG abnormalities (reduced alpha/increased beta power) in AN normalizes with refeeding, while increased theta power persists in parietal-occipital regions in an eyes closed context.