MRCP2-3542

A 75 year old male presents with a low frequency irregular tremor of the right hand and ataxia. The tremor is present at rest and when he holds his arms outstretched. The frequency of the tremor ranges from 3-4 Hz and is enhanced with posture and aggravated with movement. On neurological examination patient was found to have an ataxic gait with mild right arm weakness (power 4/5). He had a past medical history of type 2 diabetes mellitus, hypertension and previous stroke. What is the most likely diagnosis for his tremor?