No firm evidence of benefit for any treatment or approach
A systematic review has examined the best 32 randomised controlled trials (RCTs) investigating treatments for cognitive decline, including drug treatments, hormone therapies, nutritional supplements, physical activity and cognitive exercises. The authors looked comprehensively at pharmacological treatments and non-pharmacological treatments in healthy adults. The study was recently published in the Journal of the Canadian Medical Association.
There was no firm evidence that pharmacological treatments – such as cholinesterase inhibitors, NMDA (N-methyl-D-aspartate) receptor antagonists or vitamin pills – are of any benefit for preventing cognitive decline. Oestrogen therapies may actually cause a decline in memory.
Contrary to other research, there was only inconsistent evidence concerning the benefits of physical activity for preventing cognitive decline. The authors discovered some evidence (from only three studies) that brain training exercises might help prevent cognitive decline; as measured in terms of auditory memory (for spoken information) and attention.
The authors conclude that most treatments and approaches for preventing cognitive decline do not appear to work (or may occasionally be harmful), and that even the benefits of cognitive training remain uncertain. The studies examined so far have been variable in quality, so further high-quality research is needed.