Ataxic breathing during alternating forearm movements of various frequencies in cerebellar patients.

Breathing was analyzed at rest and during sinusoidal tracking movements of the forearm of the dominant side at various frequencies in 11 patients with a cerebellar impairment and in 9 healthy subjects. In the patients, breathing movements were always rhythmical as in normal subjects during rest, but sometimes were interrupted by intermittent breathing-arrests during tracking (breathing ataxia). In 9 of the 11 cerebellar patients, the normal phase relationships between breathing and forearm movements at target frequencies in the spontaneous breathing rate range were absent. Thus patients with cerebellar lesions not only show disturbed skeletomotor movements, but also show an impaired coordination between breathing and limb movements.