[Static posturography in selected Parkinson syndromes: quantitative analysis of postural control]

Idiopathic Parkinson's disease (IPD) is associated with postural disturbances and falls. The assessment of postural instability by the pull test may lead to inconclusive results. Static posturography measurements may give more reliable information regarding the differential diagnosis of Parkinson syndromes.

We compared results of the pull test and static posturography (sway area in eyes-open/eyes-closed conditions) in healthy controls (C) and patients with akinetic-rigid IPD (n=18), atypical Parkinson syndromes (APS; n=18) and secondary Parkinson syndromes (SPS; n=17).

Static posturography and the pull test results did not differ significantly between controls and patients with akinetic-rigid IPD. APS patients had significantly greater postural sway areas when tested with eyes open compared to controls (APS: 16.89 vs C: 6.89 mm, p≤0.001) and IPD patients (APS: 16.89 vs IPD: 9.55 mm, p=0.005). The correlation in the APS group between the pull test and sway area in the eyes-open condition was significant (r=0.526, p=0.025). With eyes closed, postural instability in APS patients was not significantly increased (+2%, p=.847). SPS patients were more unstable under the eyes-closed condition compared to controls (sway area SPS: 26.29 vs C: 8.79 mm, p≤0.001), IPD patients (sway area SPS: 26.29 vs IPD: 11.06 mm, p≤0.001) and APS patients (sway area SPS: 26.29 vs APS: 17.28 mm, p=0.027), without a significant correlation to the pull test. The sway area in the SPS patients increased significantly by 67% (p=0.001) under the eyes-closed condition.

Static posturography may be a helpful tool for the differentiation of Parkinson syndromes.