Stimulation cérébrale profonde et troubles de la marche dans la maladie de Parkinson

Gait disorders and freezing of gait (FOG) are seen in most patients with advanced Parkinson disease. Response to levodopa and deep brain stimulation is variable across patients

Subthalamic nucleus versus pedunculopontine nucleus stimulation in Parkinson disease: synergy or antagonism?

Stimulation of the subthalamic nucleus (STN) improves the cardinal features of Parkinson disease (PD). However, its efficacy on gait disorders is less satisfying in the long term. In recent years, the pedunculopontine (PPN) nucleus has emerged as a possible promising deep brain stimulation target for gait disorders in PD. In this review, we examine whether STN and PPN act synergistically or antagonistically. Results suggest that the combination of STN and PPN stimulations leads to a significant further improvement in gait as compared with STN stimulation alone, but additive effects on the classical motor triad are questionable. Thus, they highlight the specificity of STN stimulation over PPN's for the PD cardinal features and the specificity of PPN stimulation over STN for gait disorders. In addition, low-frequency stimulation of the PPN may improve alertness. The additive rather than potentiating effects of STN and PPN stimulations suggest that they may be mediated by distinct pathways. Nevertheless, considering the inconsistencies in published results regarding the influence of PPN stimulation on gait disorders, work is still needed before one can know whether it will convert into a standard surgical treatment and to decipher its place beside STN stimulation

Effects of subthalamic nucleus stimulation and levodopa on freezing of gait in Parkinson disease

OBJECTIVE: We studied the effects of subthalamic nucleus (STN) stimulation vs levodopa on freezing of gait (FOG) and gait impairments in a large consecutive series of patients with Parkinson disease with bilateral STN stimulation. METHODS: One hundred twenty-three patients performed the Stand Walk Sit Test before and 1 year after surgery both off and on levodopa and off and on stimulation. RESULTS: Before surgery, 25 patients displayed FOG episodes and 48 were unable to complete the Stand Walk Sit Test when off levodopa. Both symptoms were alleviated by levodopa. After surgery, STN stimulation reproduced the improvement induced by levodopa before surgery in all but two patients with FOG and five others unable to walk. In 11 patients, FOG or inability to perform the test first occurred after surgery. In all patients but those experiencing FOG during the Stand Walk Sit Test before surgery, the benefit of STN stimulation did not reach that of levodopa before surgery. In patients with FOG before surgery, the effect of STN stimulation did not differ from that of levodopa either before or after surgery. CONCLUSIONS: Overall, subthalamic nucleus stimulation improved levodopa-responsive freezing of gait in most patients, although it was not always as effective as levodopa to improve gait impairments. In addition, surgery can induce gait problems in some patients

Effects of pedunculopontine nucleus area stimulation on gait disorders in Parkinson's disease

Gait disturbances are frequent and disabling in advanced Parkinson's disease. These symptoms respond poorly to usual medical and surgical treatments but were reported to be improved by stimulation of the pedunculopontine nucleus. We studied the effects of stimulating the pedunculopontine nucleus area in six patients with severe freezing of gait, unresponsive to levodopa and subthalamic nucleus stimulation. Electrodes were implanted bilaterally in the pedunculopontine nucleus area. Electrode placement was checked by postoperative magnetic resonance imaging. The primary outcome measures were a composite gait score, freezing of gait questionnaire score and duration of freezing episodes occurring during a walking protocol at baseline and one-year follow-up. A double-blind cross-over study was carried out from months 4 to 6 after surgery with or without pedunculopontine nucleus area stimulation. At one-year follow-up, the duration of freezing episodes under off-drug condition improved, as well as falls related to freezing. The other primary outcome measures did not significantly change, nor did the results during the double-blind evaluation. Individual results showed major improvement of all gait measures in one patient, moderate improvement of some tests in four patients and global worsening in one patient. Stimulation frequency ranged between 15 and 25 Hz. Oscillopsia and limb myoclonus could hinder voltage increase. No serious adverse events occurred. Although freezing of gait can be improved by low-frequency electrical stimulation of the pedunculopontine nucleus area in some patients with Parkinson's disease our overall results are disappointing compared to the high levels of expectation raised by previous open label studies. Further controlled studies are needed to determine whether optimization of patient selection, targeting and setting of stimulation parameters might improve the outcome to a point that could transform this experimental approach to a treatment with a reasonable risk-benefit ratio