To Örebro University

Objective: To investigate variability of spatial and temporal performance of Parkinson’s disease (PD) patients and healthy elderly subjects during spirography tasks.

Background: A total of 105 subjects were recruited, comprising of 65 patients with advanced PD (mean 6 sd age; 65 6 11), 15 patients intermediate stage patients experiencing motor fluctuations (65 6 6), 15 clinically stable patients (65 6 6) and 10 healthy elderly subjects (61 6 7). Thirty of the 65 advanced patients switched from oral to continuous administration of treatment via pump. The subjects used a telemetry touch screen device in their home environment settings. On each test occasion, they were asked to trace pre-drawn Archimedes spirals as accurately and fast as possible.

Methods: Spatial and temporal variability were measured by computing four intra-individual measures of drawing displacement and speed, respectively. Combined scores were derived by applying principal component analysis on these measures and retaining the first component. One-way ANOVA test followed by Tukey multiple comparisons test was used to assess differences between the groups.

Results: Patients with advanced PD had slower drawing speed and more spatial variability than moderate patients, stable patients and healthy elderly subjects with a mean increase of 76%, 89% and 90% (p<0.001), respectively. The spatial variability of stable patients did not differ from healthy elderly subjects. In contrast, the mean temporal variability did not differ between healthy subjects, stable patients and advanced patients. Moderate patients had higher temporal variability than other groups.

Conclusions: The findings suggest that patients with PD can be best discriminated from healthy subjects on measures of spatial variability rather than temporal variability. Spatial variability measures are not useful for diagnosing PD but can be used for measuring the severity of symptoms.