CEREBRAL dysfunction and movement disorders have been recognized in patients with chronic respiratory insufficiency.1-3 The mental dysfunction has been described as disorientation, confusion, incoherence, somnolence, obstreperousness, combativeness, bewilderment, and carbon dioxide intoxication and narcosis. In addition, fine tremors, asterixis, myoclonic jerks, sustained myoclonus, and seizures have been found.
A flapping tremor which was elicited by maintenance of certain postures, particularly by dorsiflexing the wrists with the arms outstretched, was seen by Adams and Foley in patients with impending hepatic coma who also manifested inappropriate behavior, mental confusion, somnolence, and slow waves in the electroencephalogram.4 They coined "asterixis" from the Greek "asteriktos," meaning unstable, to designate the tremor. These authors also saw the flapping tremor in patients with confusion related to uremia, polycythemia and heart failure, and hypokalemia.5 Austen, Carmichael, and Adams 6 and Conn7 noted asterixis and mental dysfunction in patients with severe pulmonary insufficiency.
The incidence of neurologic manifestations