I don't know if this is the one you mean- but it's worth a try. The film is "Homicidal" and was made in 1961. It's black and white and features an old lady in a wheel chair (among other characters). I can't remember if she uses a brass door knob to communicate but she's definitely mute. The film is famous for two things- both occuring at the end. One is the "fright break", in which a clock appears on the screen just as one of the characters walks towards the creepy, dark, house. The audience is then told that what they are about to see next is so frightening that anyone of a nervous disposition should leave the theatre within the next 45 seconds. (My dad saw the film in a cinema and he told me that a couple of people did indeed walk out). The other is the identity of the murderer which occurs just after the old lady descends from the top of the stairs in a chair lift. If it's not the film you're looking for, it's still worth watching anyway.