A 50-year-old gentleman presents to the emergency department h | Neurology collections 2020

A 50-year-old gentleman presents to the emergency department having had a fall.
Examination revealed ataxia and some mild extrapyramidal signs. He was receiving treatment for suspected
Parkinson's disease following a fall he had had six months ago when he demonstrated extrapyramidal signs.
His symptoms had been noted to have improved with the medication. Tilt table testing was performed and
found to be positive.
What is the likely diagnosis?