Most cognitive processes decline with age
It does appear that most component processes of cognition decline with advanced age if the difficulty level is sufficiently high. For example, the following processes have all shown age effects:
Articles
Stimulating activities
A 5-year study1 involving 488 people age 75 to 85 found that, for the 101 people who developed dementia, the greater the number of stimulating activities (reading, writing, doing crossword puzzles, playing board or card games, having group discussions, and playing music) they engaged in, the longer rapid memory loss was delayed. Similarly, a study2 involving 1321 randomly selected people aged 70 to 89, of whom 197 had mild cognitive impairment, has found that reading books, playing games, participating in compute
Montessori education
Maria Montessori (1870-1952) was an Italian physician. After working with retarded children in a psychiatric clinic attached to the University of Rome, she applied the ideas she had developed to children in a slum district in Rome. This was the first Casa dei Bambini ("children's house"). It opened in 1907. Two years later she set out her methods and principles in a book, which was translated as The Montessori Method in 1912.
I don’t often talk about motor or skill memory — that is, the memory we use when we type or drive a car or play the piano. It’s one of the more mysterious domains of memory. We all know, of course, that this is a particularly durable kind of memory. It’s like riding a bicycle, we say — meaning that it’s something we’re not likely to have forgotten, something that will come back to us very readily, even if it’s been a very long time since we last used the skill.
A Scientific American article talks about a finding that refines a widely-reported association between self-regulation and academic achievement. This association relates to the famous ‘marshmallow test’, in which young children were left alone with a marshmallow, having been told that if they could hold off eating it until the researcher returns, they would get two marshmallows.
A New Yorker cartoon has a man telling his glum wife, “Of course I care about how you imagined I thought you perceived I wanted you to feel.” There are a number of reasons you might find that funny, but the point here is that it is very difficult to follow all the layers. This is a sentence in which mental attributions are made to the 6th level, and this is just about impossible for us to follow without writing it down and/or breaking it down into chunks.
When we are presented with new information, we try and connect it to information we already hold. This is automatic. Sometimes the information fits in easily; other times the fit is more difficult — perhaps because some of our old information is wrong, or perhaps because we lack some of the knowledge we need to fit them together.
Prevalence
Vascular dementia, as its name suggests, is caused by poor blood flow, produced by a single, localized stroke, or series of strokes.
It is the second most common dementia, accounting for perhaps 17% of dementias. It also co-occurs with Alzheimer's in 25-45% of cases. Although there are other types of dementia that also co-occur with Alzheimer's, mixed dementia generally refers to the co-occurrence of Alzheimer's and vascular dementia.
Some personal experience
I have two sons. One of them was a colicky baby. Night after night my partner would carry him around the room while I tried to get a little sleep. One night, for his own amusement, my partner chose a particular CD to play. Magic! As the haunting notes of the hymns of the 12th century abbess Hildegard of Bingen rang through the room, the baby stopped crying. And stayed stopped. As long as the music played. Experimentation revealed that our son particularly liked very early music (plainchant from the 15th century Josquin des Pres was another favorite).
Prevalence of Parkinson's Disease
After Alzheimer's disease, the second most common neurodegenerative disorder is Parkinson’s disease. In the U.S., at least 500,000 are believed to have Parkinson’s, and about 50,000 new cases are diagnosed every year1 (I have seen other estimates of 1 million and 1.5 million — and researchers saying the numbers are consistently over-estimated while others that they are consistently under-estimated!). In the U.K., the numbers are 120,000 and 10,0002.