Doctors say there is a 25% chance a frozen brain or body could be revived in the future: survey

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Next they were asked to imagine a scenario where a patient is preserved within minutes of his or her heart stopping, and where imaging and brain biopsies show “intact brain structures down to the synaptic level.”

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How likely would it be, the doctors were asked, that a “significant amount of the neurally-encoded information required for long-term memory and personality is still preserved in their brain, such that it may be technologically possible to revive this patient, even in the distant future?”

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Overall, they said there was a 25.5 per cent chance.

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Neurosurgeons rated the possibility that psychological information would remain after revival at 72 per cent, the highest of the group. Most of the other specialities were more skeptical.

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Blood clots that form shortly after cardiac arrest can seriously hamper preservation’s probability of success, the authors said. When asked whether it should be allowable to give blood thinners to an “imminently terminal patient” who wishes to be preserved after death — which, to the best of the team’s knowledge, is not currently legally permissible anywhere in the world — 70.7 per cent said the practice should “probably” or “definitely” be allowed

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Roughly 44 per cent said that, in cases of medically assisted dying, it should be legal to begin preservation procedures for those who want it after the patient is unconscious, but not yet dead.

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“A lot of physician hesitancy may come from simple unfamiliarity with the scientific basis of modern preservation methods,” Zeleznikow-Johnston said in a news release.

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“The doctors who have actually thought about this — and who regularly sit with dying patients — tend to be more receptive, not less.”

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Experiments freezing and reviving fish date back to 1665. More recently, German scientists reported in March that they succeeded in restoring some activity in previously frozen slices of an adult mouse brain.

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Zeleznikow-Johnston and his co-authors said that the plausibility of it working with humans gains some support from procedures like deep hypothermic circulatory arrest, where patients undergoing complex surgeries on blood vessels around the heart or in the brain are cooled to the point where blood stops circulating and their heart and brain activity ceases, so that surgeons can do the delicate repairs in a bloodless field. Their bodies are then slowly warmed again after surgery.

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While patients “routinely recover full neurological function” after 30 minutes of cardiac arrest, that’s a short-term form of preservation, and skeptics of the preserve-restore-revival promise of cryonics are plentiful.

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The cost isn’t cheap, upwards of $200,000 for whole body freezing and storage. Given what’s known about how the dying process damages brain tissue due to lack of oxygen, in addition to any further damage sustained from freezing, it’s “next to impossible” to believe brain preservation and restoration would ever work, no matter how advanced the science, bioethicist Arthur Caplan told National Post in 2023. The risk of adverse events like dementia or severe cognitive impairment “are just huge,” Caplan added.

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How, and in what form, people will “reawaken” is unknown: Their brain still attached to their now freshly, biologically restored body, or uploaded to a digital form that’s placed inside a robot? Whatever form, “if the memories and experiences which define us are held on to, a person has survived,” Zeleznikow-Johnston said in an interview with the Guardian. “A robotic or digital brain, if done right, I’d argue, is still you.”

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Payments to doctors for filling out the survey (US$28 for primary care physicians and US$48 for specialists) was supported by a a grant from CryoDAO, an organization that funds research in cryopreservation.

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National Post

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