Cryonics is the low-temperature preservation of the deceased, as rapidly as possible after death so as to preserve the fine structure of the brain before it can be damaged or decay. The body, or at least the head, are also preserved - but that is largely incidental to the real purpose, which is to store the mind encoded in the structure of neural tissue. For so long as that mind exists in low-temperature storage it has time to wait out progress in technology, the dawn of an age of medical molecular nanotechnology, and advanced tissue engineering capable of restoring that brain to live in a new body. If you have the technology to de-vitrify a brain whilst maintaining its mind, so the thinking goes, then building a body from stem cells is pretty straightforward by comparison.
In any case, my point here is the the focus of cryonics is the brain, its structure, and the mind. Threats to the fabric of the mind are of greater importance than threats to the rest of the body in this way of looking at the world, as there exist a range medical conditions that can destroy your mind well prior to death, placing you just as far beyond help as if you burned to death, were lost at sea, or simply buried. Earlier this month, the folk of the Institute for Evidence Based Cryonics hosted a symposium on cryonics and dementia. Here is a report:
The recent symposium on cryonics and brain-threatening disorders was a major success. On Saturday, July 7, 2012, around 30 people attended the first ever symposium on dementia and cryonics in Portland, Oregon. The symposium started with a brief introduction by Institute for Evidence Based Cryonics President Aschwin de Wolf, who emphasized why people with cryonics arrangements have a clear interest in understanding and avoiding dementia. The first speaker, Chana de Wolf, introduced the audience to the topic of adult neurogenesis, the two areas in the brain where it occurs, and how little we still understand about it. Aubrey de Grey then talked about the SENS approach to rejuvenation and how some emerging damage repair bio-technologies might be able to also reverse neurodegenerative diseases such as Alzheimer's disease. Cryonics Institute President Ben Best followed Aubrey's presentation with a technical introduction about the pathophysiology of Alzheimer's disease and the treatments that are currently being investigated.