How do Christian apologists defend the soul's existence when neurodegenerative diseases like Alzheimer's seem to erode human personhood?

Let me start by quoting a [question](https://philosophy.stackexchange.com/q/111993/104300) and top [answer](https://philosophy.stackexchange.com/a/112012/104300) from a different site: > **Is Alzheimer’s disease evidence for the non-existence of the soul?** > > As Alzheimer's disease kills off neurons, a person's personality and cognitive abilities gradually fade away. Doesn't this suggest that the self or "soul" is simply an emergent property of the brain's physical structure and function, rather than some immaterial essence or spirit that exists independently of the body? > > The classical notion of the soul as an immaterial, eternal essence that exists independently of the physical body is challenged by the way Alzheimer's systematically dismantles a person's mental faculties and sense of identity over time. As the disease destroys neurons and neural connections, the patient's personality, memories, and very "self" seem to disintegrate, suggesting that these aspects of the human experience are products of the brain's physical structure and function, rather than some non-physical soul. > Alzheimer's disease (and other brain disorders with some observable > physical effect along with psychology and neuroscience generally) does > seem to make the existence of an immaterial soul much less plausible > and less useful or necessary for explaining anything. > > Science tells us that: > > - Different parts of the brain correspond to different neural functions. > - Physical changes in the brain affects your memories, your emotions, your ability to reason, etc. > - People consistently behave in certain ways given certain environments and stimuli (which isn't direct evidence against a soul, > but does support the claim that we're merely the result of our biology > and environment). > - Etc. > > But the existence of a soul is ultimately unfalsifiable, so someone > can accept all of that and still hold that there's an immaterial soul > by saying roughly either of the following: > > - The soul sort-of mirrors the brain, with some unclear connection between the two (which seems to render the soul completely unnecessary > as a hypothesis) > - There's some separate part of your being that is your soul (but we have no reason to think such a part exists, we don't know what that > part would do, and we already know parts of your physical brain > affects memories and emotions and your reasoning ability, so does the > soul exclude all of that?) > > Also, if one accepts evolution and common descent, the human-only soul > is also a lot less plausible, given the unclear line between humans > and other apes. [Related > answer](https://philosophy.stackexchange.com/questions/110085/does-it-matter-if-certain-professions-have-a-lower-rate-of-theism-and-if-so-wh/110089#110089) . **What arguments do Christian apologists use to defend the soul's existence against the materialist challenge posed by Alzheimer's disease?**