Symptoms of dementia in cats include:

Acting disoriented or lost

Vocalizing, often at night

Staring off into space while looking at a wall or corner

Forgetting to eat or drink unless food bowls are put in front of them

Going to the bathroom outside the litterbox

Changes in sleep cycle, being awake and active in the middle of the night

Unusual interactions with other pets or family members (becoming more needy, more reactive, or more aloof)

Forgetting that they have just been fed and asking to eat again

Poor grooming habits

Sleeping more than usual