What kind of exercises can I do with my Mom to help her cognitive impairment?

There may not be much that helps a lot. I Googled cognitive rehabilitation memory elderly and found an entire into the literature here: www.ncbi.nlm.nih.gov/pubmed/17166312. Any physical exercise may also help. I know with my mom and her vascular dementia, she had some partial benefit from speech therapy for her aphasia, but there was not anything that could really help the judgment and thinking skills, or even teach her a sequence of steps for a complex activity. Sorry there are not better answers.