Commentary: Out-of-Body Experience during Awake Craniotomy

Out-of-body illusion induced by visual-vestibular stimulation

Out-of-body experiences (OBEs) are characterized by the subjective feeling of being located outside one's physical body and perceiving one's own body from an elevated perspective looking downwards. OBEs have been correlated with abnormal integration of bodily signals, including visual and vestibular information. In two studies, we used mixed reality combined with a motion platform to manipulate visual and vestibular integration in healthy participants. Behavioral data and questionnaires show that congruent visual-vestibular stimulation in a self-centered reference frame induced an OBE-like illusion characterized by elevated self-location and feelings of disembodiment and lightness. The OBE-like illusion was also modulated by individuals' visual field dependency assessed by the Rod and Frame Test. These results show that the manipulation of visual-vestibular stimulation in the present study induces various aspects of OBEs and further link OBE to congruency mechanisms between visual and vestibular gravitational and self-motion cues.

Anesthesia for awake craniotomy: a case report

Awake craniotomy (AC) is a neurosurgical technique that enables the precise localization of functional neural networks through intraoperative brain mapping and real-time monitoring. This operative method has been popularized in recent years due to decreased postoperative morbidities. We present a case of 31-year-old female who was presented with episodes of generalized tonic colonic seizures. She had a history of recurring seizures. Upon further investigations, she was diagnosed with brain space-occupying lesions initially suspected as low-grade glioma. Considering the lesion site, the patient was deemed a suitable candidate for an AC. To achieve conscious sedation, the patient received infusions of remifentanil and propofol at varying rates. During the procedure, the patient was under sedation and was regularly tested for response to predetermined commands. The tumor was successfully excised by using a combination of local anesthesia on the scalp and by the administration of propofol and boluses through a systemic infusion.

Awake craniotomy for brain tumor resection: Patient experience and acceptance in an Asian population

INTRODUCTION

Awake craniotomy is well-established for resection of brain tumor in the eloquent areas. Previous studies from Western countries have reported good level of patient tolerance and acceptance. However, its acceptability in non-Western populations, with different ethnic, social, cultural, religious, and linguistic backgrounds, has not been studied systematically. This study aims to evaluate the experience of patients from an Asian population who underwent awake craniotomy for tumor resection.

METHODS

Data on patient experience were collected by interviewing patients using a structured questionnaire at follow-up appointment. Data on patient demographics and diagnosis were collected from medical records.

RESULTS

Eighteen patients (age 16-68 years) who underwent 20 awake craniotomies were recruited. Preoperatively, all (100%) patients understood the indication for awake craniotomy. Almost all felt fully counseled by the neurosurgeon (90%), anesthetist (100%), and neuropsychologist (95%). Ninety-five percent reported their family to be supportive of awake craniotomy. Seventy-five percent felt adequately prepared on operation day. Intraoperatively, most patients did not experience pain/discomfort (55%) or anxiety (65%). Nearly all found intraoperative motor and language testing to be easy (100% and 90%, respectively). Postoperatively, 100% were satisfied with their care. One hundred percent rated their overall experience as good or excellent. Eighty percent were willing to undergo awake craniotomy again if indicated.

CONCLUSION

Awake craniotomy is well-accepted in an Asian population. All patients had good-to-excellent overall experience, with most willing to undergo awake craniotomy again. Our findings underscore the generalizability of awake craniotomy across different socio-cultural backgrounds and support its utilization in countries with a significant Asian population.

Psychedelic-assisted therapy for functional neurological disorders: A theoretical framework and review of prior reports

Functional neurological disorders (FNDs), which are sometimes also referred to as psychogenic neurological disorders or conversion disorder, are common disabling neuropsychiatric disorders with limited treatment options. FNDs can present with sensory and/or motor symptoms, and, though they may mimic other neurological conditions, they are thought to occur via mechanisms other than those related to identifiable structural neuropathology and, in many cases, appear to be triggered and sustained by recognizable psychological factors. There is intriguing preliminary evidence to support the use of psychedelic‐assisted therapy in a growing number of psychiatric illnesses, including FNDs. We review the theoretical arguments for and against exploring psychedelic‐assisted therapy as a treatment for FNDs. We also provide an in‐depth discussion of prior published cases detailing the use of psychedelics for psychosomatic conditions, analyzing therapeutic outcomes from a contemporary neuroscientific vantage as informed by several recent neuroimaging studies on psychedelics and FNDs.

Dissociation of the subjective and objective bodies: Out-of-body experiences following the development of a posterior cingulate lesion

An out‐of‐body experience (OBE) is a phenomenon whereby an individual views his/her body and the world from a location outside the physical body. Previous studies have suggested that the temporoparietal junction (TPJ), the brain region responsible for integrating multisensory signals, is responsible for OBE development. Here, however, we first present a case of OBE after brain tumour development in the posterior cingulate cortex (PCC). The patient was a 46‐year‐old right‐handed female; she underwent brain surgery. She reported that she had experienced OBEs several times monthly (during daily life) before surgery but never after surgery. She defined her OBEs explicitly; she drew pictures. Her OBEs exhibited phenomenological, overt dissociation of the subjective and objective bodies. We discuss the mechanisms underlying this phenomenon and the relationship between OBEs and the PCC in terms of anatomical and functional brain connectivity. Our case sheds some light on the mechanism involved in creating spatial (dis)unity between the self and the body.

Vestibular Stimulation Modulates Neural Correlates of Own-body Mental Imagery

There is growing evidence that vestibular information is not only involved in reflexive eye movements and the control of posture but it also plays an important role in higher order cognitive processes. Previous behavioral research has shown that concomitant vestibular stimuli influence performance in tasks that involve imagined self-rotations. These results suggest that imagined and perceived body rotations share common mechanisms. However, the nature and specificity of these effects remain largely unknown. Here, we investigated the neural mechanisms underlying this vestibulocognitive interaction. Participants (n = 20) solved an imagined self-rotation task during caloric vestibular stimulation. We found robust main effects of caloric vestibular stimulation in the core region of the vestibular network, including the rolandic operculum and insula bilaterally, and of the cognitive task in parietal and frontal regions. Interestingly, we found an interaction of stimulation and task in the left inferior parietal lobe, suggesting that this region represents the modulation of imagined body rotations by vestibular input. This result provides evidence that the inferior parietal lobe plays a crucial role in the neural integration of mental and physical body rotation.