Axial apraxia in Parkinson's disease.

Attention is drawn to certain disorders of posture and movement such as kneeling, turning around in the recumbent position, arising and walking which form a separate group of motor disabilities in Parkinson patients. Levodopa therapy is far less effective for these axial motor abnormalities than for hypokinesia, tremor, rigidity and manual dexterity. Inappropriate function of the axial musculature leads to debilitating situations. It is argued that the disordered axial movements are not the result of an akinetic mechanism but share the criteria applied to apraxic phenomena and the term axial apraxia is proposed. Thus far axial apraxia has resisted conventional physiotherapeutic treatment, but some patients overcome their apraxic disability using alternative motor strategies.