Vascular dementia is the second most common form of dementia (after Alzheimer's disease) in older adults. It is caused by a number of small strokes (transient ischaemic attacks -TIA), where the blood flow to the brain is cut off briefly. These may cause damage to areas of the brain, affecting for example, movement, speech and cognitive function, including memory.
Alzheimer's disease is caused by the loss of connections between brain cells, loss of brain cells themselves, a jumble of neurofibrillary tangles (a prtoein called tau) and the accumulation of amyloid plaques. While the cause and progression are not yet well understood, it is an age-related disease, with most diagnoses in people over 65, though early-onset Alzheimer's can occur in the 30s and 40s.
Alzheimer's disease disrupts the way electrical charges travel within brain cells (neurones) and the activity of neurotransmitters. Connections between neurones are lost; the type of connection lost relates to the symptoms. Loss of strong 'sticky connections affects long-term memory, while loss of less strong connections affects short-term memory. This explains why short-term memory is usually affected first; later there will be effects on behaviour, judgement, personality and functionality.
Normal: forgetting names of acquaintances, missing appointments. Not normal: can't remember the name of someone close, or remembering what happened yesterday. Normal: to be slower at mental calculation as you get older. Not normal: being flummoxed by household finances when previously ok. Normal to search occasionally for a word. Not normal: frequent searches for a word and verbal substitution. Normal: Worry about memory. Not normal: having problems but not being aware of it.
A few facts are emerging but much research is still needed. Bright children stand the best chance of a bright old age (perhaps they have more or better brain cells connections, so cope with any loss for longer before damage shows?). Staying physically fit helps deliver oxygen to the brain. Keeping the brain active (crosswords, jigsaw puzzles, etc) seems to help.
Don't smoke - it narrows bloods vessels, so more risk of strokes. It seems that repeated head trauma (e.g. boxers, American football players, etc.) may also be a risk factor. There is also a genetic aspect, but this is thought to be due to inheriting risk genes rather than direct genes for Alzheimer's.
Music therapy appears to help. Music involves many areas of the brain; rhythm, melody, harmony, pitch, timbre and accent are experienced in various areas not just one, so provide many clues. There are also emotional and historical elements associated with specific pieces of music. Even with massive dementia, physically able sufferers can still beat time. Sufferers respond to music almost to the end of their lives.
Where Memories Go by Sally Magnusson, pub by Two Roads, Hodder & Stoughton, 2014.
