Foot Dystonia Treatment by Botulinum Toxin Injections in Parkinson Disease : Efficiency of Injections Made in Extrinsic Muscle (Flexor Digitorum Longus Muscle) Compared to Intrinsic Muscle (Flexor Digitorum Brevis or Quadratus Plantae Muscles)

Overview

Foot dystonia is frequently observed in patients suffering from Parkinson'disease. It is characterized by an abnormal involuntary movement which is very uncomfortable (difficult to walk) and painful for the patient. Botulinum toxin injections seem to be efficient to treat this dystonia. However studies on this topic are few and very imprecise (many muscle injected, especially the Flexor digitorum longus, different doses used, heterogeneous population with many types of dystonia included, open studies).

Study progress : After an inclusion visit, patients are randomized in one of the 3 following groups : * First group (PL : placebo) : * J0 : Patient will receive 1 injection of placebo in the Flexor digitorum longus and 1 injection of placebo in the Flexor digitorum brevis or in the quadratus plantae * J+1month : First evaluation * J+3 months : Patient will receive again 1 injection of placebo in the Flexor digitorum longus and 1 injection of placebo in the Flexor digitorum brevis or in the quadratus plantae * J+4 months : Last evaluation * Second group (ME : Extrinsic muscle) * J0 : Patient will receive 1 injection of Botulinum toxin (100U) in the Flexor digitorum longus and 1 injection of placebo in the Flexor digitorum brevis or in the quadratus plantae * J+1 month : First evaluation * J+3 months : Patient will receive again 1 injection of Botulinum toxin (100U) in the Flexor digitorum longus and 1 injection of placebo in the Flexor digitorum brevis or in the quadratus plantae * J+4 months : Last evaluation * Third group (MI : Intrinsic muscle) * J0 : Patient will receive 1 injection of placebo in the Flexor digitorum longus and 1 injection of Botulinum toxin (100U) in the Flexor digitorum brevis or in the quadratus plantae * J+1 month : First evaluations * J+3 months : Patient will receive again 1 injection of placebo in the Flexor digitorum longus and 1 injection of Botulinum toxin (100U) in the Flexor digitorum brevis or in the quadratus plantae * J+4 months : Last evaluations During injections (J0 and J+3M), we will measure the pain induced by injections (EVA) For each evaluation (J+1M and J+4M), following evaluations will be made: clinical improvement (CGI), dystonia evaluation (duration and severity, Burke scale), pain (EVA) and quality of life (PDQ39).