The characteristics of acute deterioration in truncal movements, posture and gait were studied in patients admitted with acute non-neurological disease. Reversible gait abnormalities with characteristics of a 'lower-half parkinsonism' were associated with a disorder of axial movement, disability (as assessed by an activities of daily living score), and low mental test score. There was no association of gait dysfunction with tests of upper limb apraxia. An 'at risk' sub-group of elderly patients was identified who during an acute illness lose their walking independence, of whom some also have great difficulty performing axial movements. Furthermore, any assessment of locomotor and axial movement in elderly patients must consider that any impairment may be the result of an acute medical illness.