Neuroplasticity is the brain's ability to reorganize itself by forming new neural connections. I feel it may not depend on aging ; an active brain will reorganize at any age. But illness like dementia, Alzhimiers, depression etc will affect the reorganization badly. In old age, the brain will work with less magnitude of potential.

I can't answer your question, and suspect no one can at present, but I will put up a warning flag. There is substantial bias against old brains. Some while ago there was an article in Science that traced brain activation during a particular test between childhood and early adulthood. The finding that the brain went from activating unilaterally to bilaterally was interpreted as representing "maturation" of the brain. Two weeks later Science published a similar study that compared young adult and old brains with a similar result. Bilateralization was interpreted as "compensation" for deterioration of the brain. Bear in mind that short term recall in older brains is slower but more accurate than in younger brains, and that older brains have larger vocabularies and construct grammatically more complex sentences.

would not trust any definitive answer to your question- aging has no

scientific evidence as a cause- answers for limits posed by specific

individual impairments most helpful for assessing system impairments

and how to correct- aging issues mostly apt for statistical population

discussions-