Botulinum Toxin Type A (Botox) in the Management of Levodopa-Induced Peak-Dose Dyskinesias in Parkinson's Disease

Inclusion Criteria: 1. Patients must have idiopathic PD (by standard clinical criteria). 2. Patients must have persistence of LID despite optimization of anti-Parkinsonian medication (duration of LID \> 1 \[duration of at least 1-25% of the waking time\] on item 32 of the United Parkinson's Disease Rating Scale \[UPDRS\]). 3. Patients must have severity of LID \> 1 \[mildly disabling\] on item 33 of the UPDRS. 4. Patients must have a Mini-Mental State score of \> 24. 5. Patients must be willing and able to give consent. Exclusion Criteria: 1. Patients who are older than 75 years of age. 2. Patients who have a Parkinsonian syndrome that is unresponsive or weakly responsive to levodopa (improvement \< 30%). 3. Patients who require concurrent use of warfarin or other anticoagulating agents. 4. Uncontrolled clinically significant medical condition other than the condition under evaluation 5. Known allergy or sensitivity to any of the components in the study medication. 6. Concurrent participation in another investigational drug or device study or participation in the 30 days immediately prior to study enrollment. 7. Any medical condition that may put the subject at an increased risk with exposure to Botox including diagnosed myasthenia gravis, Eaton-Lambert syndrome, amyotrophic lateral sclerosis, or any other disorder that might interfere with neuromuscular function. 8. Evidence of recent alcohol or drug abuse. 9. Infection or skin disorder at an anticipated injection site (if applicable). 10. Any condition or situation that, in the investigator's opinion, may put the subject at significant risk, confound the study results, or interfere significantly with the subject's participation in the study.