If you can move enough to get your heart beating harder, and your doctor says it's OK, make aerobic exercise part of your routine. 30 minutes, 3 times a week increased brain volume and improved memory.
"MRI brain scans and memory tests revealed that aerobic exercise lead in a 16.5 percent increase in hippocampal volume, a 53.7 percent increase in memory, and increased hippocampal resting-state functional connectivity."


Aerobic exercise increases hippocampal volume and improves memory in multiple sclerosis:...
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(2013). Aerobic exercise increases hippocampal volume and improves memory in multiple sclerosis: Preliminary findings. Neurocase. ???aop.label???. doi: 10.1080/13554794.2013.841951