The paper by Stolze et al 1 (this issue, pp 289–297) substantially contributes to an improved diagnosis of often occurring gait disorders. The study compares the kinematics of gait in patients with Parkinson's disease before and after treatment with levodopa and those with normal pressure hydrocephalus before and after CSF tapping, as well as with and without external cues.

Clinically, the movement disorder of the two patient groups is usually difficult to diagnose appropriately. Up to now there existed no direct comparative gait analysis between the two diseases, especially in respect to the effects of treatment. …