ABSTRACT
Postural instability, causing unsteadiness when standing and walking, is a cardinal feature of Parkinson's disease (PD), and is particularly associated with disease onset after the age of 70 years. Whether or not these patients have a different underlying pathology is still unclear, although co-morbidity – in particular cerebrovascular disease – is likely to be the explanation in at least some of these patients. The challenge for clinicians is therefore twofold: first, to decide whether the patient with the all-too-common presentation of falls and 'off his/her legs' really does have idiopathic PD; and second, to determine the best form of treatment. During normal quiet standing, balance is maintained when the vertical projection of the centre of mass on the ground is kept within the support base provided by the feet. Freezing tends to be a later feature of PD, but analysis of the DATATOP study reveals that it may occur in the early stages of idiopathic PD.
