Suggestions for talking watches or clocks to help my mom with Parkinson's?

My Mom has Parkinson's, and I think she is also starting to develop dementia. One of her biggest problems is staying oriented in time. She can no longer make sense of clocks or calendars. (Her eyes are in good shape--problem is in her brain.)

I'd like to get her a watch or a small, portable clock that would tell her the time, day, and date at the push of a button. Ideally, it would be atomic so it would fix itself if she messed up the setting. B/C of the Parkinson's and dementia, it also needs to be extremely easy to use (e.g., one big button instead of several little ones, etc.)

There are a lot of options available on the Web. Has anyone had experience--positive or negative--that would be helpful in guiding my choice?

Thanks!