The is another disorder, whereby the brain retains too much cerebral/spinal fluid, eg. a plumbing problem as well.
Called Normal Pressure Hydrocephalus, or NPH, is often undiagnosed or misdiagnosed, as mere "aging," dementia etc. But it is treatable.
Symptoms are called Wobbly, Wet and Weird. Wobbly as in gait disturbance, wet as in mildly to severely incontinent, and weird as in memory loss.