Gait disorders in Parkinson's disease - Gait arrests and falls. Therapeutic aspects

Gait arrests: They affect the evolution of the disease. This freezing pheno menon which induces falls sometimes constitutes an initial sign. Like the g ait initiation failure, freezing can be controlled by sensory stimulation, notably visual inputs, but also by more sustained attention. Falls are mainly connected with both postural instability and rigidity: The y are poorly influenced by dopaminergic therapies. The progressive decrease of step width represents a main factor in their occurrence. Precocity of gait disorders is unusual in Parkinson's disease: Other parkin sonian syndromes such as progressive supranuclear palsy, multiple system at rophy and vascular parkinsonian syndrome must then be evoked. Their associa tion with a cognitive impairment and abnormal sphincter behaviour infers a diagnosis of normal pressure hydrocephalus. Gait improves with L-dopa therapy: Speed, step length and duration of the s wing phase are increased without change of cadence. Progressive loss of L-d opa efficiency on gait and postural stability contrasts with the persistent effect on tremor, rigidity and bradykinesia; a functional abnormality of n ondopaminergic systems can explain these symptoms. In the following stages, gait troubles increased by motor fluctuations and abnormal involuntary mov ements are less controlled by L-dopa therapy. Physical therapy plays a major role in therapeutic management: An individua l or collective rehabilitation project must be established according to the stage of evolution; the exercises aim to protect postural control and coor dination. Visual or sound rhythmic inputs can be employed in the case of ga it initiation failure. The effects of functional neurosurgery are in the course of evaluation: The rmolesion and chronic electrical stimulation of deep brain structures have opposite effects on gait troubles. Bilateral thalamotomy or pallidotomy are sometimes a source of disequilibrium. Chronic thalamic stimulation does no t induce either benefits or adverse effects. On the other hand, stimulation of the internal pallidum improves gait kinematic parameters; improved post ural adjustments have also been reported. The effect of subthalamic nucleus stimulation is comparable to that of L-dopa, however the long-term effect remains to be evaluated.