My mom has started - a few months ago now - tapping her foot almost all the time. It's like a person who's impatiently waiting for something, but she's not impatient when she's doing it. It's like a tick, and she never had any before. She stops if she's engrossed in something on TV, but not always - sometimes if she's talking or watching a show or something that should distract her from that, she keeps doing it. Is it a symptom?