70 yr female- diagnosed small vessel brain disease, cerebral athropy - stroke 10yrs ago balance and walking bad need cane what is prognosis ?

Not enough info: What you describe sounds like advanced, severe small vessel disease and atrophy that are beyond what is normally expected for age. If the stroke 10 years ago affected the back of the brain, cerebellum, it may explain the difficulty with balance and walking. Probably will not improve. Since there are other causes of imbalance, i would follow up with your neurologist.

Manage risks: Cerebrovascular small vessel disease builds over decades; we can't reverse it, but we can manage risk factors that caused it. Keep blood pressure on target. Manage blood sugar, prevent diabetes. Keep cholesterol & lipids on target. Do aerobic exercise at least 3 days/ week, more is better. Limit alcohol to 1 drink a day or less. Eat a healthy diet; limit fats, sodium & sweets. Good luck!