The following can also help distinguish a depressive illness from a dementing illness:
1. Symptoms worse in the morning (dementia has a progressive course)
2. Variable attention span (normal attention span in dementia)
3. Selective (rather than impaired recent and remote) memory impairment
4. Altered psychomotor behaviour (normal psychomotor behaviour in dementia).
Older people with depression may do poorly on cognitive tests, but in general they have more insight into their difficulties and make less effort during a cognitive examination than would a person with dementia. A person with depression may also recognise their memory problems, whereas a person with dementia may deny they have any memory decline.
Mrs Wood's case...
A MMSE score of 22/30 and reports of memory problems may lead you to suspect that Mrs Wood may have early dementia in addition to depression.
If Mrs Woods memory problems persist even when she has received effective treatment for her depression, it would be worth referring her for further cognitive assessment.