I have a fairly strict definition of early infantile autism. That is not to say that people who don't meet that classic description don't have autism, but we might do well to narrow our definitions, and our samples, down to groups that are very similar, because I think you're more likely to find the cause.

When you first try to learn to ride a bike, you work very carefully at keeping your balance, and trying to keep one pedal in front of the other, and all that, and all of a sudden, ah, you know, I got it. And that's true of skiing, or it's true of all kinds of things.

Savant syndrome, characteristically, consists of left hemisphere dysfunction coupled with right hemisphere emergence, and what you see in the savant are basically right brain skills.

The term syndrome generally appears to be a constellation, or collection, of similar traits or behaviors within an individual. So, savants do have sort of a constellation of symptoms, which is characterized by some spectacular skill, or skills, coupled with this massive memory which is grafted on to some underlying disability. So those three conditions quantify, in my mind, the term syndrome.

Savant syndrome is not a disorder in the same way as autism is a disorder or dementia is a disorder. Savant syndrome are some conditions that are superimposed and grafted on to some underlying disability. So savant syndrome is not a disease or disorder in and of itself. It is a collection of characteristics, or symptoms, or behaviors that have grafted on to the underlying disability.

The ways in which acquired savants show up are usually the same ways that congenital, or non-acquired, savant syndrome shows up. They tend to show up in the same areas: music, art, math, visual, spatial skills, and calendar calculating, although calendar calculating probably isn't quite as prominent in that group. They tend to show up quite quickly, or sort of explode on the scene and they then tend to have an obsessive sort of forceful quality about them in the same way as savant skills. So they tend to show up in the same ways.

There are some cases that have come to my attention where there's been a head injury, or getting struck by lightning and surviving, with really no disability or residual. So there are cases that I'm aware of where there's been some incident which triggered the acquired savant ability, but is not associated with long term disability, so that can occur. But I think that's probably the exception rather than the rule in that I think many of the acquired savants do end up with some residual disability.