Phone question to help my 86 yr. old mother

[Swimmer]

Are thier phones or phone accessories that one can attach to an elderly persons phone such as a light that flashes when they receive a call. Half the time, my mother who is deaf as a haddock, she doesn't hear the ringing phone, but would see a light come on and go off that coincides with a ringer to signify a call. Is thier such a device out there? Just trying to help mom out.