asterixis

[ăs′tə-rĭksĭs]
n.
  1. An abnormal tremor consisting of involuntary jerking movements, especially in the hands, frequently occurring with impending hepatic coma and other forms of metabolic encephalopathy.flapping tremor
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.