Can postural abnormality really respond to levodopa in Parkinson's disease?

OBJECTIVE

Abnormal postures affect motor function in Parkinson's disease (PD), potentially compromising the quality of life. The clinical efficacy of dopaminergic medications remains uncertain. Knowing what type of abnormal posture clearly responds to dopaminergic medication would facilitate the clinical management of PD. We investigated whether abnormal posture responded to dopamine challenge testing.

METHODS

We studied 24 consecutive patients with PD who had anterior trunk flexion (ATF) (n=13), antecollis (n=4), or lateral trunk flexion (LTF) (n=7). Levodopa was infused intravenously over the course of 30min. Before and after the levodopa infusion, the angle of the posture was measured with the use of "Image J" software.

RESULTS

After the infusion of levodopa, the angle of the overall abnormal posture significantly decreased (p<0.001). The angle of the abnormal posture significantly decreased in both natural position (p<0.001, p=0.002) and in a position with the back averted (p=0.003, p=0.029) in patients with ATF or antecollis, but did not change significantly in patients with LTF (p=0.099). The change in the angle differed significantly between patients with ATF and those with antecollis (p=0.017) and between patients with antecollis and those with LTF (p=0.008), but did not differ significantly between patients with ATF and those with LTF (p=0.052). The change in the angle in patients with abnormal posture related to the 'off' state was significantly greater than that in patients without abnormal posture related to the 'off' state (p<0.001).

CONCLUSION

Patients with LTF and some patients with ATF poorly respond to levodopa. Two phenotypes of levodopa-responsiveness exist in patients with abnormal posture, and this observation is associated with an 'off' state, especially in patients with ATF.