BACKGROUND: Visual snow syndrome is a disorder characterized by the combination of typical perceptual disturbances. The clinical picture suggests an impairment of visual filtering mechanisms and might involve primary and secondary visual brain areas, as well as higher-order attentional networks. On the level of cortical oscillations, the alpha rhythm is a prominent EEG pattern that is involved in the prioritisation of visual information. It can be regarded as a correlate of inhibitory modulation within the visual network.
METHODS: Twenty-one patients with visual snow syndrome were compared to 21 controls matched for age, sex, and migraine. We analysed the resting-state alpha rhythm by identifying the individual alpha peak frequency using a Fast Fourier Transform and then calculating the power spectral density around the individual alpha peak (+/- 1 Hz). We anticipated a reduced power spectral density in the alpha band over the primary visual cortex in participants with visual snow syndrome.
RESULTS: There were no significant differences in the power spectral density in the alpha band over the occipital electrodes (O1 and O2), leading to the rejection of our primary hypothesis. However, the power spectral density in the alpha band was significantly reduced over temporal and parietal electrodes. There was also a trend towards increased individual alpha peak frequency in the subgroup of participants without comorbid migraine.
CONCLUSIONS: Our main finding was a decreased power spectral density in the alpha band over parietal and temporal brain regions corresponding to areas of the secondary visual cortex. These findings complement previous functional and structural imaging data at a electrophysiological level. They underscore the involvement of higher-order visual brain areas, and potentially reflect a disturbance in inhibitory top-down modulation. The alpha rhythm alterations might represent a novel target for specific neuromodulation.
BACKGROUND: we preregistered the study before preprocessing and data analysis on the platform osf.org (DOI: https://doi.org/10.17605/OSF.IO/XPQHF , date of registration: November 19th 2022).

This study investigates eight case reports of spontaneously emerging, brief episodes of vivid altered states of Selfhood (ASoSs) that occurred during mental exercise in six long-term meditators by using a neurophenomenological electroencephalography (EEG) approach. In agreement with the neurophenomenological methodology, first-person reports were used to identify such spontaneous ASoSs and to guide the neural analysis, which involved the estimation of three operational modules of the brain self-referential network (measured by EEG operational synchrony). The result of such analysis demonstrated that the documented ASoSs had unique neurophenomenological profiles, where several aspects or components of Selfhood (measured neurophysiologically and phenomenologically) are affected and expressed differently, but still in agreement with the neurophysiological three-dimensional construct model of the complex experiential Selfhood proposed in our earlier work (Fingelkurts et al. in Conscious Cogn 86:103031. 10.1016/j.concog.2020.103031, 2020).

Die Zwangsstörung hat oftmals einen chronischen Verlauf mit Therapieresistenz gegenüber Psychopharmakotherapie und Psychotherapie. Neue nichtinvasive Hirnstimulationsverfahren könnten helfen, Zwangssymptome zu vermindern. In diesem Fallbericht wird die Behandlung einer Patientin mit Zwangsstörung dargestellt, die mit 10 transkraniellen Wechselstromstimulationen in Gamma-Frequenz (40 Hz) im Rahmen eines Heilversuchs behandelt wurde. Die Yale-Brown Obsessive-Compulsive Scale verminderte sich von 70 auf 59 Punkte, und die Hamilton Depression Rating Scale sank von 25 auf 12 Punkte. Daneben konnte eine Verbesserung des Regensburger Wortflüssigkeitstests, des Pfadfindertests und eines computergestützten n-back-Tests verzeichnet werden. Eine Hypothese für die Verbesserung der Zwangsstörung durch Gamma-Wechselstromstimulation könnte eine Auswirkung auf die bei psychischen Erkrankungen (Depression, Zwangsstörung) veränderte alpha-Frequenz sein. Der hier vorgestellte Fall bestätigt die Ergebnisse einer früheren Fallserie und gibt Anlass zur weiteren Untersuchung dieses Verfahrens.
Die Zwangsstörung hat oftmals einen chronischen Verlauf mit Therapieresistenz gegenüber Psychopharmakotherapie und Psychotherapie. Neue nichtinvasive Hirnstimulationsverfahren könnten helfen, Zwangssymptome zu vermindern. In diesem Fallbericht wird die Behandlung einer Patientin mit Zwangsstörung dargestellt, die mit 10 transkraniellen Wechselstromstimulationen in Gamma-Frequenz (40 Hz) im Rahmen eines Heilversuchs behandelt wurde. Die Yale-Brown Obsessive-Compulsive Scale verminderte sich von 70 auf 59 Punkte, und die Hamilton Depression Rating Scale sank von 25 auf 12 Punkte. Daneben konnte eine Verbesserung des Regensburger Wortflüssigkeitstests, des Pfadfindertests und eines computergestützten n-back-Tests verzeichnet werden. Eine Hypothese für die Verbesserung der Zwangsstörung durch Gamma-Wechselstromstimulation könnte eine Auswirkung auf die bei psychischen Erkrankungen (Depression, Zwangsstörung) veränderte alpha-Frequenz sein. Der hier vorgestellte Fall bestätigt die Ergebnisse einer früheren Fallserie und gibt Anlass zur weiteren Untersuchung dieses Verfahrens.

Virtual reality (VR) systems have been integrated into rehabilitation techniques for phantom limb pain (PLP). In this case report, we used electroencephalography (EEG) to analyze corticocortical coherence between the bilateral sensorimotor cortices during vibrotactile stimulation in conjunction with VR rehabilitation in two PLP patients. As a result, we observed PLP alleviation and increased alpha wave coherence during VR rehabilitation when stimulation was delivered to the cheek and shoulder (referred sensation areas) of the affected side. Vibrotactile stimulation with VR rehabilitation may enhance the awareness and movement of the phantom hand.

The increased consumption of tobacco products in recent years has been linked, among other factors, to the presence of added flavors. Although flavors are important in explaining consumption, their effects in the brain have until now been unexplored. In the present study, we investigated how electrophysiology can serve to dissociate the effects of nicotine and flavor. Participants attended 4 sessions (2-by-2 factorial design, with flavor and nicotine as within-subject factors), in each session an oddball task was performed before and after smokeless tobacco consumption. We explored the dissociation of neural responses to flavor and nicotine. While event-related potentials did not show modulation due to flavors, time-frequency showed a flavor-nicotine dissociation. Low-frequency activity (delta, theta and alpha) showed only effects of nicotine, and high-frequency activity (beta1, beta2 and gamma) showed effects only susceptible to flavor. Flavors in smokeless tobacco not only made the product more desirable but also triggered the allocation of cognitive resources. This long-lasting effect of flavor may enhance the addictive potential of the tobacco product. Further research is being developed to determine the precise role of flavors in contributing to addiction. This is the first study investigating the neural effects of flavor (specifically wintergreen) in smokeless tobacco products. By understanding the effects of flavors in the brain we can explain the precipitants of tobacco consumption behaviors, and the addictive potential of flavors. Regulators will be able to determine if and in which amount flavors should be allowed in tobacco products.

The alpha peak frequency (APF) of the human electroencephalogram (EEG) is a reliable neurophysiological marker for cognitive abilities. In these case series, we document a shift of the APF towards the lower end of the EEG spectrum in two completely locked-in ALS patients. In not completely locked-in ALS patients, the alpha rhythm lies within the common frequency range. We discuss potential implications of this shift for the largely unknown cognitive state of completely locked-in ALS patients.

In this report, we describe the case of a patient who sustained extremely severe traumatic brain damage with diffuse axonal injury in a traffic accident and whose recovery was monitored during 6 years. Specifically, we were interested in the recovery dynamics of 3-dimensional components of selfhood (a 3-dimensional construct model for the complex experiential selfhood has been recently proposed based on the empirical findings on the functional-topographical specialization of 3 operational modules of brain functional network responsible for the self-consciousness processing) derived from the electroencephalographic (EEG) signal. The analysis revealed progressive (though not monotonous) restoration of EEG functional connectivity of 3 modules of brain functional network responsible for the self-consciousness processing, which was also paralleled by the clinically significant functional recovery. We propose that restoration of normal integrity of the operational modules of the self-referential brain network may underlie the positive dynamics of 3 aspects of selfhood and provide a neurobiological mechanism for their recovery. The results are discussed in the context of recent experimental studies that support this inference. Studies of ongoing recovery after severe brain injury utilizing knowledge about each separate aspect of complex selfhood will likely help to develop more efficient and targeted rehabilitation programs for patients with brain trauma.

We report the case of a 37-year-old female patient who required 22 surgeries following a pedestrian versus car accident. She was enrolled in a clinical study investigating emergence from anesthesia. In 10 of her 22 surgeries, we assessed her cognitive status in the postanesthesia care unit (PACU) using the Confusion Assessment Method. We observed PACU delirium in all 4 cases in which the patient received sevoflurane, but only in 1 of 6 cases in which she received propofol. The patient showed EEG α-band activity similar to that of an elderly patient who may reflect a greater risk of PACU delirium.

It has been argued that complex subjective sense of self is linked to the brain default-mode network (DMN). Recent discovery of heterogeneity between distinct subnets (or operational modules - OMs) of the DMN leads to a reconceptualization of its role for the experiential sense of self. Considering the recent proposition that the frontal DMN OM is responsible for the first-person perspective and the sense of agency, while the posterior DMN OMs are linked to the continuity of \'I\' experience (including autobiographical memories) through embodiment and localization within bodily space, we have tested in this study the hypothesis that heterogeneity in the operational synchrony strength within the frontal DMN OM among patients who are in a vegetative state (VS) could inform about a stable self-consciousness recovery later in the course of disease (up to six years post-injury). Using EEG operational synchrony analysis we have demonstrated that among the three OMs of the DMN only the frontal OM showed important heterogeneity in VS patients as a function of later stable clinical outcome. We also found that the frontal DMN OM was characterized by the process of active uncoupling (stronger in persistent VS) of operations performed by the involved neuronal assemblies.

Anorexia nervosa has been related to alterations in brain activity in terms of hyperactive EEG patterns. This case report illustrates the principles and results of a five-week neurofeedback treatment in a 29-year-old woman suffering from anorexia nervosa. A neurofeedback protocol to enhance alpha activity (8 - 12 Hz) was developed and conducted additionally to the standardized treatment for eating disorders in training sessions twice a week. Pre- and post-test measurements included resting state EEG measurements and a psychological test battery. The results show improvements from pre- to post-test in eating disorder psychopathology including psychological wellbeing, emotional competence, and eating behavior traits. In addition, a decrease in theta power (4 - 7 Hz), a well-known trait marker of anorexia nervosa, was measured. However, our data should be interpreted with caution because this is a single case study. Nevertheless, this report documents the practicability and method of neurofeedback as treatment adjunct in eating disorders from the clinical perspective. Although the use of neurofeedback in the treatment of anorexia nervosa is recommended in literature, empirical studies are still lacking. Randomized controlled trials to evaluate short- and long-term effects of neurofeedback are needed.