This is the first of two lectures on anomalies of the aging brain. In this lecture, we’ll be discussing
dementias as well as delirium. We’ve all had the experience of walking in to the other room
and wondering what did I ever come in here for. It’s natural that that sort of pattern
will increase slightly with age. Normal forgetfulness is normal forgetfulness. It doesn’t really cause
too many deep-rooted problems. However, if that sort of thing progresses to a decline in reasoning
and judgement as well as memory, so we see progressive loss beyond the usual, we see that
there is development of dementia. There are a number of different kinds of dementia.
Dementias are most common in individuals over 65 years old. So, there’s normal memory loss
and then there’s excessive memory loss which might involve loss of reasoning and judgement.
People start to seem a little bit loopy. Anyway, Alzheimer’s is probably the one that you’d think of
most clearly when you think about dementia. That’s probably because about 60% of dementias
are accounted for by Alzheimer’s. Alzheimer’s, you’re probably familiar is a neurodegenerative disorder.
It has some hereditary association but we haven’t quite deciphered the multifactorial pieces
associated with that. What we do know is that it is associated with development of plaques
and tangles in the brain. At that level, you probably already understand this.
We don’t know if the tangles and plaques are a cause of the dementia or whether they result from
the development of dementia. We just know that they are associated with that. So, cause or effect,
that’s pretty much unclear at the moment. But let’s take a closer look at the regions of the brain
that could be associated with Alzheimer’s. Generally, it’ll start in the temporal lobe.
In the temporal lobe, if that is the area associated with damage, the individual is more likely
to forget things. If the damage is primarily in the frontal cortex, the individual might have trouble
planning things. Really, it depends on the region of the brain that’s most affected
where Alzheimer’s shows up first. It does have a classic sort of progression.
I’ll lead you through that shortly.