Effectiveness of Botulinum Toxin in Freezing of Gate in Parkinson's Disease Walking in Parkinson's Disease.

The BT injection will be performed by a doctor with experience in this therapy, with 100 Units (U) of type A BT, bilaterally, in the flexor muscle of the thigh, once, with replacement of the same ampoules with saline in controls. To the Patient assessments will take place over 4 months, weekly by telephone using a questionnaires on freezing and the notion of clinical improvement (FOGQ and SCGIC, respectively) and monthly in person with objective assessments using the MDS-UPDRS scales - part III motor assessment, Timed Up \& Go and Two Minute Walk.