• Neurology Clinical Trials
• Extrapyramidal & Movement Disorders

• Neurology Clinical Trials
• Extrapyramidal & Movement Disorders
• Neurology

High-frequency deep brain stimulation (DBS) is effective for relief of Parkinson's disease (PD) symptoms. However, studies on the effect of subthalamic nucleus DBS (STN-DBS) on freezing of gait (FOG) have reported inconsistent results, with some suggesting that STN-DBS alleviates FOG [Davis JT et al. Clin Neurol Neurosurg 2006] and others reporting worsening of gait and balance [van Neunen BFL et al. Mov Disord 2008; Krack P et al. N Engl J Med 2003].

The objective of the Vercise Implantable Stimulator for Treating Parkinson's Disease trial [VANTAGE; NCT01221948], presented by Michael T. Barbe, MD, University Hospital, Cologne, Germany, was to evaluate motor function improvement in patients with moderate to severe Parkinson's disease following treatment with bilateral STN-DBS. Prospective and nonrandomized, VANTAGE is open-label interventional trial in which a total of 40 patients underwent STN-DBS. DBS was delivered with the new Vercise DBS System, a multiplesource, eight-contact, constant-current system that is implantable and rechargeable.

FOG was assessed before and after surgery with Unified Parkinson's Disease Rating Scale (UPDRS) II Item 14, the Freezing of Gait Questionnaire (FOGQ), and a videotaped walk test known to provoke FOG (with and without dual tasks). For the postsurgery tests, FOGQ was given at 26 weeks and the walking test at 12, 26, and 52 weeks after implantation. The patients were also assessed with the Core Assessment Program for Surgical Interventional Therapies motor tests, Tremor Rating Scale, Dyskinesia Rating Scale, Parkinson's Disease Questionnaire 39, Short Form 36 Health Survey, and the Schwab and England Activities of Daily Living Scale. Resource utilization was assessed and patient motor diaries collected over 3 days at all subsequent visits.

The cohort was 67.5% male and 32.5% female, with a mean age of 60.2 years. At baseline, 26 of the 38 patients (68%) had FOG. Duration of Parkinson's disease symptoms was 12.6 years in patients with FOG and 9.3 years in those without FOG. The total UPDRS, UPDRS III–meds off, and UPDRS III–meds on scores were similar between patients with and without FOG at baseline. At baseline, the L-dopa equivalent daily dose was 1305.0 mg in the group with FOG and 1653.6 mg in the group without.

At 26 weeks after surgery, the mean total FOGQ score was reduced by >50%. STN-DBS lowered the number of patients with FOG, as defined by FOGQ Item 4, from 26 of 38 patients at baseline to 13 of 38 patients at 26 weeks. The occurrence of FOG as measured with UPDRS II Item 14 declined over 52 weeks. UPDRS III Item 29 results showed that STN-DBS improved gait in this cohort over 52 weeks.

STN-DBS significantly reduced FOG and improved gait in this cohort of patients with Parkinson's disease. Further analysis of the videotaped walking tests might provide additional insights into the effects of STN-DBS on FOG, especially with respect to potential changes in different FOG subtypes and patterns.

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