“Reality” of near-death-experience memories: evidence from a psychodynamic and electrophysiological integrated study

Abstract

The nature of near-death-experiences (NDEs) is largely unknown but recent evidence suggests the intriguing possibility that NDEs may refer to actually “perceived,” and stored, experiences (although not necessarily in relation to the external physical world). We adopted an integrated approach involving a hypnosis-based clinical protocol to improve recall and decrease memory inaccuracy together with electroencephalography (EEG) recording in order to investigate the characteristics of NDE memories and their neural markers compared to memories of both real and imagined events. We included 10 participants with NDEs, defined by the Greyson NDE scale, and 10 control subjects without NDE. Memories were assessed using the Memory Characteristics Questionnaire. Our hypnosis-based protocol increased the amount of details in the recall of all kind of memories considered (NDE, real, and imagined events). Findings showed that NDE memories were similar to real memories in terms of detail richness, self-referential, and emotional information. Moreover, NDE memories were significantly different from memories of imagined events. The pattern of EEG results indicated that real memory recall was positively associated with two memory-related frequency bands, i.e., high alpha and gamma. NDE memories were linked with theta band, a well-known marker of episodic memory. The recall of NDE memories was also related to delta band, which indexes processes such as the recollection of the past, as well as trance states, hallucinations, and other related portals to transpersonal experience. It is notable that the EEG pattern of correlations for NDE memory recall differed from the pattern for memories of imagined events. In conclusion, our findings suggest that, at a phenomenological level, NDE memories cannot be considered equivalent to imagined memories, and at a neural level, NDE memories are stored as episodic memories of events experienced in a peculiar state of consciousness.

Epistemological implications of near-death experiences and other non-ordinary mental expressions: Moving beyond the concept of altered state of consciousness

“…The pattern of EEG during the recall of imagined events was significantly different from the one observed when recalling their NDEs. More specifically, NDE memories were linked to theta band, a well-known marker of true episodic memory, suggesting that NDE memories cannot be simply considered as memories of imagined events (28).…”

Characterization of near death experiences using text mining analyses: A preliminary study

“…In fact, the technique could allow for group comparisons among etiology leading to the NDE but also to compare NDEs with other modified and dissociative states of consciousness that have been shown to include elements similar to a NDE (e.g. ketamine use [53], REM sleep [14,54], meditation [2], hypnosis [55], syncope [56]. The analyses could thus permit to test the hypotheses arguing that NDEs can be comparable to other altered states of consciousness [57].…”

Non-Ordinary Mental Expressions (NOMEs): Clues on the Nature of the Human Mind

“…Besides studying NDEs in real time as soon as the patients regains consciousness, a possible way to study NDEs is by reliving them during hypnosis, as in the case of OBEs. Palmieri et al (2014) have used hypnosis and EEG monitoring to improve recall and decrease memory inaccuracy in patients with previous NDEs, as well as check their neural markers compared to memories of both real and imagined events. NDE memories were similar to real memories as regards detail richness, self-referential, and emotional information and differed from memories of imagined events.…”