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

Freezing of gait is a symptom of Parkinson's disease (PD) that becomes more evident with the evolution of the disease, and which presents an important difference compared to the other signs and symptoms: does not respond adequately to dopaminergic therapy, which calls into question its pathophysiology. In this sense, and through empirical experience, it has been noted that freezing responds to cueing techniques (visual, sensory motor, auditory tricks, among others) which suggests a similarity with dystonic pathology. This similarity could be the basis of a common response to botulinum toxin (BT). Objectives: This study aims to understand whether BT is an effective therapy for freezing gait in patients with Parkinson's disease. Methodology: This is a prospective parallel study with therapeutic intervention, controlled by placebo, double blind. The randomization of groups will be stratified. The population will be recruited from from the CHLC movement disorders consultation, and that meets the following inclusion criteria: Parkinson's disease with freezing of gait, scoring \> 1 at point 2.13 on the scale MDS-UPDRS and be responsive to cueing techniques, with severity of Parkinson's disease rated 3 or 4 on the Hoehn \& Yahr scale. 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.