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What is a near-death experience?

Charlotte Martial
Charlotte Martial
Researcher at Université de Liège
Key takeaways
  • Near-death experiences (NDEs) are altered states of consciousness that can affect anyone.
  • Testimonies almost universally attest to an out-of-body sensation or an encounter with entities; these are referred to as prototypical elements.
  • NDEs can be experienced in a variety of states: coma, anaesthesia, syncope or even orgasm.
  • The phenomenon is still poorly understood, but scientists today explain it as the synergy of a spike in cerebral electrical activity and the release of certain hormones.
  • Explaining near-death experiences would provide a better understanding of consciousness, its origin and its construction.

Out-of-body expe­ri­ences, meet­ing deceased loved ones, see­ing a light at the end of a tun­nel… These images and sen­sa­tions are recount­ed by peo­ple who have come close to the bound­ary between life and death. Near-death expe­ri­ences only became of real inter­est to sci­ence in the 1970s, yet they are not that uncom­mon and they say some­thing about our con­scious­ness. After the pub­li­ca­tion of the book Life After Life, writ­ten by the Amer­i­can doc­tor Ray­mond Moody in 1975, the first sci­en­tif­ic stud­ies were pub­lished. Inter­est in this phe­nom­e­non has peaked over the last ten years. The Coma Sci­ence Group team has been study­ing near-death expe­ri­ences for a decade, with the aim of gain­ing a bet­ter under­stand­ing of consciousness.

Near-death expe­ri­ences (NDEs) are altered states of con­scious­ness that can affect any­one, regard­less of age, sex or reli­gious belief or lack there­of. The team gath­ered around 2,000 tes­ti­monies from all over the world, with greater rep­re­sen­ta­tion from French and Eng­lish speak­ing coun­tries, in order to obtain a more pre­cise def­i­n­i­tion. NDEs are rich and intense sub­jec­tive expe­ri­ences, with clear pro­to­typ­i­cal ele­ments: an out-of-body sen­sa­tion, encoun­ters with enti­ties, some­times deceased peo­ple, and the vision of a tun­nel with a light at the end. Each expe­ri­ence is per­son­al and unique, but there are recur­ring ele­ments. It is these pro­to­typ­i­cal aspects that dif­fer­en­ti­ate NDEs from oth­er sub­jec­tive states, such as dream­ing, which is infi­nite­ly vari­able. Usu­al­ly, these are pos­i­tive expe­ri­ences, despite the context.

Major consequences for people’s lives

A wide vari­ety of states can lead to an NDE. Most often, the per­son is clin­i­cal­ly dead, i.e. in car­diac arrest, but coma, trau­ma, anaes­the­sia or stroke can some­times be the cause of a near-death expe­ri­ence. Indi­vid­u­als may expe­ri­ence this phe­nom­e­non in oth­er con­texts where their life is not in dan­ger: dur­ing faint­ing, in med­i­ta­tive states, dur­ing intense anx­i­ety or orgasm. In addi­tion, peo­ple with a ten­den­cy to expe­ri­ence dis­so­cia­tive states are more prone to these phe­nom­e­na. For exam­ple, they may per­form an action mechan­i­cal­ly, with­out real­is­ing it, until they reach a more intense state, a feel­ing of leav­ing their body.

Near-death expe­ri­ences have a sig­nif­i­cant impact on people’s lives, and for the most part they are large­ly pos­i­tive. Peo­ple report a reduced fear of death and a more altru­is­tic, less mate­ri­al­is­tic and more spir­i­tu­al­ly ori­ent­ed state of mind. How­ev­er, 10–15% of tes­ti­monies attest to neg­a­tive con­se­quences. The expe­ri­ence of an NDE is too extra­or­di­nary to be inte­grat­ed into one’s life after­wards. This can lead to anx­i­ety and post-trau­mat­ic stress. The num­ber of neg­a­tive NDEs may be under­es­ti­mat­ed, as they are not nec­es­sar­i­ly shared. 

The Coma Sci­ence Group’s first task is there­fore to deter­mine the pre­cise char­ac­ter­is­tics of near-death expe­ri­ences. The lab­o­ra­to­ry is also inter­est­ed in under­stand­ing the poten­tial neu­ro­phys­i­o­log­i­cal or cog­ni­tive basis for these phe­nom­e­na. What hap­pens in the brain dur­ing a near-death expe­ri­ence? Imme­di­ate­ly after car­diac arrest, there is a peak in elec­tri­cal activ­i­ty in the brain, which emits faster waves in cer­tain spe­cif­ic regions, includ­ing the tem­poro-pari­etal region, the area asso­ci­at­ed with con­scious­ness. The brain would be in great pain, but just before and after the heart stopped, a spike in elec­tri­cal activ­i­ty would allow an NDE to be gen­er­at­ed. This could be a defence mech­a­nism or a way for the brain to cope with this phys­i­o­log­i­cal suf­fer­ing. At the same time, cer­tain hor­mones or neu­ro­trans­mit­ters, such as endor­phins, seem to con­tribute to the feel­ing of well-being. How­ev­er, most of these expla­na­tions are mere­ly hypothe­ses. Although the phe­nom­e­non is becom­ing bet­ter under­stood, there is still a great deal of research to be done to prove it.

Similar effects observed with psychedelic drugs

To gain a bet­ter under­stand­ing of what hap­pens in the brain dur­ing clin­i­cal death, the research team stud­ied the elec­troen­cephalo­grams (EEGs) of patients between life and death. The sci­en­tists then gath­er tes­ti­monies from sur­viv­ing patients. In the lab­o­ra­to­ry, they also work with psy­che­del­ic sub­stances to try to repro­duce sub­jec­tive expe­ri­ences that resem­ble IMEs. To do this, healthy par­tic­i­pants (with no par­tic­u­lar dis­or­ders and who have nev­er expe­ri­enced an NDE) are giv­en a dose of dimethyl­trypt­a­mine (DMT), psilo­cy­bin or ket­a­mine. By cross-ref­er­enc­ing the results with those of a study car­ried out by experts in psy­che­delics at Impe­r­i­al Col­lege Lon­don, the sci­en­tists observed sig­nif­i­cant over­laps between expe­ri­ences under DMT and dur­ing an NDE. The same images and sen­sa­tions recur, such as encoun­ters with enti­ties or a feel­ing of har­mo­ny with one’s envi­ron­ment. How­ev­er, one dif­fer­ence was not­ed: dur­ing an IME, peo­ple have the feel­ing of being on a fron­tier, par­tic­u­lar­ly that of death. This feel­ing is less preva­lent with DMT.

Accord­ing to cur­rent research, an NDE is a form of hal­lu­ci­na­tion. It is a men­tal expe­ri­ence with per­cep­tions dis­so­ci­at­ed from the phys­i­cal envi­ron­ment. Nev­er­the­less, despite their recur­rent nature, there are still many unknown ele­ments about the brain, death and con­scious­ness. This def­i­n­i­tion could there­fore be called into ques­tion tomor­row. Explain­ing near-death expe­ri­ences would give us a bet­ter under­stand­ing of con­scious­ness, its ori­gin and its construction.

Sirine Azouaoui

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