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Héléna Cassol

18 papers in the library · 984 citations · publishing 2017-2024

Papers

DMT Models the Near-Death Experience

Frontiers in Psychology August 15, 2018 Christopher Timmermann, Leor Roseman, L. Williams et al. 228 citations

Near-death experiences (NDEs) share striking phenomenological similarities with the effects of the psychedelic drug DMT. In a placebo-controlled, within-subjects study, 13 healthy participants received DMT and placebo, then completed a standard NDE measure. DMT significantly increased NDE-like features compared to placebo. NDE scores were linked to DMT-induced ego-dissolution and mystical experiences, as well as baseline traits of absorption and delusional ideation. Nearly all NDE features overlapped between DMT-induced experiences and a matched group of actual NDE experiencers. These results indicate a remarkable similarity between the DMT state and NDEs, warranting further research.

Qualitative thematic analysis of the phenomenology of near-death experiences

PLoS ONE February 14, 2018 Héléna Cassol, Benoît Pétré, Sophie Degrange et al. 131 citations

Near-death experiences (NDEs) are profound psychological events that can significantly affect experiencers' lives. Previous research shows NDE memories are phenomenologically rich. This study analyzed the narratives of 34 cardiac arrest survivors to extract common themes. A qualitative thematic analysis identified 10 'time-bounded' themes—isolated events during the NDE—and 1 'transversal' theme that characterizes the entire narrative, often as a retrospective self-reflective comment. The division into themes provides detailed vocabulary used by experiencers and enables a rigorous description of the phenomenon, ensuring all self-reported manifestations are included.

Neurochemical models of near-death experiences: A large-scale study based on the semantic similarity of written reports.

Consciousness and cognition March 1, 2019 Charlotte Martial, Héléna Cassol, Vanessa Charland-Verville et al. 98 citations

Near-death experiences (NDEs) share consistent features across cultures, suggesting a common neurobiological basis. Analyzing semantic similarity between about 15,000 reports from 165 psychoactive substances and 625 NDE narratives, the NMDA receptor antagonist ketamine produced reports most similar to NDEs, followed by Salvia divinorum and serotonergic psychedelics like DMT. The similarity was driven by concepts of self and environmental consciousness, as well as therapeutic, ceremonial, and religious aspects of drug use. Ketamine may serve as a safe experimental model for NDE phenomenology, and endogenous NMDA antagonists might be released near death.

Near-Death Experience as a Probe to Explore (Disconnected) Consciousness

Trends in Cognitive Sciences January 22, 2020 Charlotte Martial, Héléna Cassol, Steven Laureys et al. 90 citations

Near-death experiences (NDEs) occur during comatose states, challenging the common view that consciousness disappears when the brain shuts down. A new framework distinguishing awareness, wakefulness, and connectedness is needed to understand the phenomenon. Classical NDEs represent internal awareness experienced in unresponsive conditions, constituting an episode of disconnected consciousness. This proposal points toward new directions for NDE research and consciousness science more broadly.

Temporality of Features in Near-Death Experience Narratives

Frontiers in Human Neuroscience June 13, 2017 Charlotte Martial, Héléna Cassol, Georgios Antonopoulos et al. 85 citations

Near-death experiences (NDEs) often follow a common sequence: an out-of-body experience, moving through a tunnel, seeing a bright light, then feeling peace. However, this sequence occurred in only a small number of experiencers, suggesting that the order of NDE features varies widely among individuals. The study analyzed 154 written NDE narratives from French speakers, using text analysis to infer the timing and frequency of core features. The findings indicate that while a typical pattern exists, it is not universal, and understanding the relationships between features may improve scientific definitions of NDEs.

Fantasy Proneness Correlates With the Intensity of Near-Death Experience

Frontiers in Psychiatry June 7, 2018 Charlotte Martial, Héléna Cassol, Vanessa Charland-Verville et al. 70 citations

People who report near-death experiences (NDEs) without facing a life-threatening situation score higher on fantasy proneness than those who have NDEs during actual danger, those whose experiences do not meet NDE criteria, and healthy controls. In contrast, individuals who have classical NDEs (during a life-threatening event) show no difference in fantasy proneness compared to matched controls. The intensity of the reported experience correlates positively with engagement in fantasy. These findings suggest that strong fantasy proneness may make some individuals more likely to report NDE-like experiences under suitable physiological or psychological conditions, such as meditation or syncope.

The Near-Death Experience Content (NDE-C) scale: Development and psychometric validation

Consciousness and Cognition November 1, 2020 Charlotte Martial, Jessica Simon, Ninon Puttaert et al. 69 citations

Two scales for measuring near-death experiences (NDEs) were evaluated. The original NDE scale showed several weaknesses. A new 20-item Near-Death Experience Content (NDE-C) scale was developed and validated, revealing a five-factor structure covering relevant dimensions. The NDE-C scale demonstrated very good internal consistency (Cronbach α = 0.85) and concurrent validity (correlations above 0.76). This new reliable scale should facilitate future research on NDEs.

A systematic analysis of distressing near-death experience accounts

Memory June 12, 2019 Héléna Cassol, Charlotte Martial, Jitka Annen et al. 60 citations

Near-death experiences (NDEs) are typically positive, but about 14% of 123 NDE accounts were distressing. These distressing NDEs included inverse, hellish, or void types, with inverse and hellish each appearing 8 times and void once. A higher proportion of suicide survivors reported distressing NDEs compared to classical ones. Memories of distressing NDEs were as phenomenologically detailed as those of classical NDEs. The findings suggest distressing NDEs require careful attention to help experiencers integrate them into their identity.

Losing the Self in Near-Death Experiences: The Experience of Ego-Dissolution.

Brain sciences July 14, 2021 Charlotte Martial, Géraldine Fontaine, Olivia Gosseries et al. 37 citations

People who have had a near-death experience often report a disturbed sense of having a distinct self. In a survey of 100 individuals who scored 27 or higher out of 80 on the Near-Death-Experience Content scale, 80 had their experience in a life-threatening situation and 20 did not. Participants completed inventories measuring ego dissolution and ego inflation during their NDE, as well as a scale of nature-relatedness. Ego-dissolution scores were higher than ego-inflation scores. Total NDE intensity positively correlated with ego dissolution and, more weakly, with ego inflation and nature-relatedness. Ego dissolution also correlated with the intensity of out-of-body experiences and a sense of unity. The findings suggest that dissolved ego-boundaries are a common feature of NDEs.

Neurophenomenology of near-death experience memory in hypnotic recall: a within-subject EEG study.

Scientific reports October 1, 2019 Charlotte Martial, Armand Mensen, Vanessa Charland-Verville et al. 36 citations

A proof-of-concept study induced near-death experience (NDE)-like features in five volunteers who had previously had a pleasant NDE by having them recall the memory under hypnosis while their brain activity was recorded with high-density EEG. The hypnosis protocol recreated NDE-like features without adverse effects and increased absorption and dissociation compared to normal consciousness recall. Recalling the NDE phenomenology was associated with increased alpha brain activity in frontal and posterior regions. The methodology offers a controlled way to prospectively study NDE-like features and their EEG correlates.

Intensity and memory characteristics of near-death experiences

Consciousness and Cognition July 8, 2017 Charlotte Martial, Vanessa Charland-Verville, Héléna Cassol et al. 24 citations

Memories of near-death experiences (NDEs) are detailed and stable over time, yet their rich phenomenology lacks a satisfactory explanation. In 152 individuals who reported a classical NDE during life-threatening conditions, the intensity of the NDE was positively correlated with phenomenological characteristics of the memory, such as sensory details, personal importance, and frequency of reactivation. Those who described more intense NDEs also reported more vivid and detailed memories of the event.

Memories of near-death experiences: are they self-defining?

Neuroscience of Consciousness January 1, 2019 Héléna Cassol, Arnaud D’Argembeau, Vanessa Charland‐verville et al. 16 citations

People who report near-death experiences (NDEs) often consider those memories central to their identity, regardless of whether the experience occurred during actual physical danger. Among 71 participants screened with the Greyson NDE scale, 48 had real NDEs and 23 had NDE-like experiences without life threat. Those who recalled their NDE (41 total) rated it as more central to their identity than other self-defining memories. Richer NDE memories were associated with greater centrality. The findings suggest that the self-defining nature of NDEs relates more to their phenomenological content than to the circumstances of occurrence, highlighting the importance of integrating these memories into personal identity.

Electroencephalographic Signature of Out-of-Body Experiences Induced by Virtual Reality: A Novel Methodological Approach.

Journal of cognitive neuroscience September 1, 2023 Charlotte Martial, Héléna Cassol, Mel Slater et al. 13 citations

Out-of-body experiences (OBEs) can be partially induced in a virtual reality setup. Seven healthy participants wore a VR headset and saw their virtual body from a ceiling viewpoint; in one condition their real movements were mirrored onto the virtual body, in the other they were not. Participants reported strong sensations of floating and being high up, but only weak to moderate feelings of being out of their body. Brain activity recorded with 128 electrodes showed that these subjective experiences were linked to increased delta and decreased alpha power, reduced theta complexity, and increased beta-2 connectivity, supporting the idea that delta activity plays a prominent role in certain conscious states.

Personality traits and pattern of beliefs of near-death(-like) experiencers

Frontiers in Human Neuroscience April 28, 2023 Aminata Bicego, Héléna Cassol, Jessica Simon et al. 13 citations

Spiritual beliefs, Openness to experience, and Fantasy proneness are associated with recalling a near-death experience (NDE) or an NDE-like experience (similar phenomenology without a life-threatening context). In a retrospective study of 181 people divided into four groups—NDE experiencers, NDE-like experiencers, controls who faced a life-threatening situation without an NDE, and controls with neither—multivariate logistic regression showed that spiritual beliefs predicted NDE-like recall, while Openness and Fantasy proneness predicted NDE recall. A discriminant analysis using these variables correctly classified only 35% of cases, indicating other factors also play a role.

EEG signature of near-death-like experiences during syncope-induced periods of unresponsiveness.

NeuroImage September 1, 2024 Charlotte Martial, Andrea Piarulli, Olivia Gosseries et al. 10 citations

During fainting, some people have dream-like experiences with extraordinary, mystical features similar to near-death experiences. In 22 healthy volunteers who fainted under controlled conditions, eight reported such near-death-like features. Their brain activity showed higher electrical activity in delta, theta, and beta2 frequency bands in temporal and frontal regions, including the insula, right temporoparietal junction, and cingulate cortex. The richer the experience, the stronger the activity in these areas. The brains of those with near-death-like experiences also showed more complex, more connected, and more integrated neural networks compared to those without such experiences. These surges of neural activity may mark disconnected consciousness during fainting.

Phenomenological memory characteristics and impact of near-death experience in critically ill survivors: Observations at discharge and after a 1-year follow-up.

International journal of clinical and health psychology : IJCHP January 1, 2024 Charlotte Martial, Pauline Fritz, Héléna Cassol et al. 3 citations

One year after a prolonged intensive care unit (ICU) stay, survivors who reported a near-death experience (NDE) retained vivid, stable memories with many phenomenological details such as visual features and emotions. Among 126 adult ICU survivors, 19 (15%) reported an NDE as identified by the Greyson scale. The most common NDE features were altered time perception, heightened senses, and life review; Greyson scores did not change over the year. One year later, 18% of the NDE group and 24% of the non-NDE group were less afraid of death. The findings suggest that clinicians should interview all ICU patients about their memories.

Chinese translation and validation of the Near-Death Experience Content scale.

Frontiers in psychiatry January 1, 2023 Yan Li, Yan Chen, Charlotte Martial et al.

A Chinese version of the Near-Death Experience Content (NDE-C) scale was translated and validated on 79 near-death experience testimonies. The translation used Brislin's back-translation model, and the scale showed good internal consistency (Cronbach's α = 0.846). Confirmatory factor analysis supported the scale's structure. This new Chinese NDE-C scale is now available to screen people who have had near-death experiences or near-death-like experiences (e.g., from meditation) and to quantify their subjective experiences, enabling further research on this phenomenon in Eastern cultural contexts.