What Causes Severe Shaking Of Hands?

My mother (age 70) is facing problem of shaking hands, body imbalance, unclear speech etc from last one month. Dr prescribed medicines Arip MT, Nexito, Clonotril, Valance solution & Pacitane. She is taking all these medicines from last one month. Her uneasiness is reduced but hands are still shaking heavily. Need some suggestions for an early recovery from this problem.