Dyskinesias and motor symptoms onset in Parkinson disease.

Purpose: To assess, using a longitudinal follow-up study design, the relationship between the body site of motor symptoms onset and that of dyskinesias (LID) onset in 70 PD patients in whom LID were absent at the baseline but appeared at one of the follow-up visits; to investigate the demographic and clinical features associated with different sites of LID onset.

Methods: Motor symptoms onset was retrospectively determined by asking patients which body part had first been affected by motor impairment. The site of LID onset was determined objectively in one of the follow-up visits.

Results: Motor symptoms started in the limbs in all patients (unilaterally in 91.4% and bilaterally in 8.6% of the patients). LID started unilaterally in the limbs in 25.8%, bilaterally in the limbs in 7.1%, in the cranio-cervical-axial region in 40% and in both the cranio-cervical-axial region and limbs in 27.1% of the patients. No significant association emerged between the site of motor symptoms onset and that of LID onset; a correlation did emerge between the site of motor symptoms onset and that of LID onset in patients with unilateral onset of both motor symptoms and LID. No differences were detected when the subgroups of patients with LID onset in different body regions were compared.

Conclusions: The partial association between the body site of motor symptoms and of LID onset likely reflects pathophysiological mechanisms underlying LID.