Dopaminergic Loss and Pain in Parkinson's Disease

Evaluation of Radioligand Uptake (FP-CIT) of Dopamine Transporters in Patients Suffering From Parkinson's Disease With or Without Pain

About 46% of patients suffering from Parkinson's disease present pain disorders. Parkinson disease is characterized by loss of dopaminergic neurons. The aim of this study is to assess the relationship between the loss of dopaminergic neurons and the existence of pain in Parkinson's disease. Using single photon emission computerized tomography (SPECT) imaging (123I FP-CIT, which binds dopamine transporter) and the determination of subjective pain threshold, the investigators will establish correlations between dopaminergic degeneration and pain perception.

Parkinson's disease is a frequent neurodegenerative disease leading to motor handicap, cognitive and pain disorders. These pain disorders could be correlated to dopaminergic loss.

The clinical trial will be conducted in a single center (Neurology Department, Purpan Hospital, Toulouse, France). The study is classified as a physiopathology one. Twenty patients with Parkinson's disease, presenting pain disorders or not, will be selected. This clinical trial will last one year. All the exams, including image acquisition will be done the same day. These will take about 6 hours for each patient.

Expected results: Binding of 123I FP-CIT to dopamine transporters should negatively correlate with pain intensity and also with thermal pain thresholds in patients suffering from Parkinson's disease.

Inclusion Criteria:

• Patients with clinically established Parkinson's disease according to the UKPDSBB (UK Parkinson's Disease Society Brain Bank) (Gibb et Less, 1998; Hugues et al, 1992).
• Male or Female patients, aged from 30 to 70 years.
• Patients must benefit from the French Social security system.
• Patients must give a written informed consent.
• Female fertile patients must use an efficient method of contraception.

If patients suffer from chronic pain, pain must be related to Parkinson's disease.

Exclusion Criteria:

• Patients with a syndrome other than the idiopathic Parkinson's disease.
• Patients suffering from important trembling during the OFF periods or abnormal involuntary movements (dyskinesia) during the ON periods, not allowing the imagery exam to be performed.
• Patients suffering from another disease causing chronic pain.
• Patients suffering from cancer.
• Patients with cognitive dysfunction.
• Patients not able to complete the scales.
• Pregnant, breastfeeding or fertile female patients not using an efficient method of contraception.
• Patients not willing to participle in the trial.