How can I keep my wandering mother off the stairs?

Thank you for the helpful suggestions! Just to clarify, moms bedroom is on the first floor. She has a day program she can still go to and and a caregiver who helps out while my husband and i work from home. Night wandering isn't an issue, but 4:30 pm wandering while her caregiver is cooking and I'm trying to finish work is! :) A black rug combined with an accordion door may work. I appreciate the help.

Locking her in her room at night is probably not even legal. Eldercare laws in most people require that there is escape in case of fire, flood or another bad thing.

If you can't use an actual door, would an accordian-style folding door be a possibility? It can be fixed to the wall then locked to the railing.
Or maybe a high gate with lock?
Is your mother's bedroom on the first floor, or does she have the whole first floor like an apartment?
If it's only that her bedroom is on the first floor, put a lock on the outside of the door and lock her in at night.

Without seeing your staircase it would be hard to tell u what you can do. Can a childs gate be used? The two I had could be hinged so you could open them like a gate but keep them secure.

My Moms room was in the lower level of our split level. The staircase was enclosed so I was able to place a gate on the first step to keep her in her room. It was too high for her to climb over.

Just read the curtain idea. Have it the same color as the walls that way it blends in. The reason the rug suggested works is because of depth perception, they lose it. I don't think the rug has to be round, just black. When Mom lived with me, my daughter recommended I get one of those memory foam rugs for her bath. They don't tend to move. The rubber on the bottom is different.

I used a heavy over stuffed chair on casters to limit my MIL’s access to a second floor, but her dementia very quickly escalated to the need for full time supervision. I’d slide the chair across the opening to the stairs, and her fading perceptual abilities kept her from figuring out how to surmount the obstacle.

Is she supervised on the first floor? If you’re sure she’s still safe there, this may be a good time to consider other alternatives for her as they inevitably become necessary.

Could she remove baby gates? If not that may be the simplest solution.

Is it possible to put some hooks on the ceiling and hang a curtain rod, then hang a big, wide, thick curtain that would fully cover the stair entrance and sides, enough to hide the stairs, so your mom won't see it?

Sometimes, if a round black rug is put down in front of an area you wish to keep a dementia patient out of, they'll avoid that area believing the rug to be a black hole they'll fall into if they step on it. Of course, a throw rug is also a potential trip hazard, so there's that to keep in mind as well.

You should consider hiring an Occupational Therapist to come into your home to evaluate what needs to be done to make it a safe environment for your mother to live and thrive in. She can give you a bunch of ideas & recommendations including devices mom should use to keep her steady on her feet, ie: a walker or rollator. Having a dementia patient living in your home can be even trickier than having a toddler, what with things they can get into. You can use the same devices we used for our kids to baby proof the house, like the cabinet and drawer locks to keep mom out of areas that have chemicals or cleaning supplies in them. You can also install locks (high up) on the doors to outside so mom can't get out of the house and wander away at night. The OT can give you other ideas as well.

Best of luck to you!