Mixed results for GPi-DBS in the treatment of cranio-facial and cranio-cervical dystonia symptoms

Abstract

The aim of the study is to determine clinical outcomes in patients undergoing Globus Pallidus Internus Deep Brain Stimulation (GPi-DBS) for cranio-facial and cranio-cervical dystonia (Meige) symptoms. A total of 6 patients seen between 2002 and 2010 with cranio-facial and cranio-cervical dystonia symptoms were identified from the University of Florida Institutional Review Board approved database. Patients were videotaped using a standardized protocol, and tapes were randomized and blindly reviewed by a movement disorders neurologist. The Unified Dystonia Rating Scale improved 31.6 ± 23.2% (range: 3.4-63.2%) at 6 months and 63.7 ± 35.3% (range: 6.3-100%) at 12 months. The Burke-Fahn-Marsden Dystonia Rating Scale improved 45.3 ± 29.5% (range: 4.7-75.0%) at 6 months and 61.8 ± 30.9% (range: 16.6-100%) at 12 months. One patient significantly had a very large improvement with little evidence of residual dystonia. Blepharospasm improved in all patients, whereas speech and swallowing did not improve in this cohort. Two patients improved with unilateral GPi-DBS, although one required a contralateral DBS later in the disease course. Two patients were managed with low frequency stimulation (<100 Hz). Two patients had less than 20% benefit. GPi-DBS for cranio-facial and cranio-cervical symptoms is an effective strategy to manage a subset of patients who remain unresponsive to optimized medical management. Unilateral stimulation may be an option for some patients, but it remains unclear whether response to single-sided stimulation will be sustainable. The mixed results of this GPi-DBS case series highlight the need for a careful re-examination of selection criteria, alternative brain targets, and possibly rescue leads for patients who are non-responders to the GPi target.

Dystonia rating scales: Critique and recommendations

“…The FMDRS has been used in numerous studies to determine the treatment effects of deep brain stimulation, including childhood‐onset dystonia …”

The focal dystonias: Current views and challenges for future research

“…This approach is offered when medical therapy fails or when BL is accompanied by dystonia elsewhere. BL responds in some, but not others . Curiously, orbicularis oculi spasms and apparent apraxia can be induced by DBS in some patients in whom they did not previously exist .…”

Deep brain stimulation for dystonia

“…Apart from cervical dystonia, the data regarding other forms of focal dystonia are limited to small series of mixed cases or individual reports and should be interpreted with caution, as some patients showed excellent improvement (up to 70%)38–40 and others had little or no benefit 41. In most cases, bilateral GPi stimulation was used.…”

“…28 30 42 44–50 Blepharospasm improved in most patients, but the results on speech and swallowing were not so good 41. In a homogeneous series of patients with craniocervical and brachial segmental dystonia with oromandibular involvement,51 there was little effect on speech/swallowing scores at 6 months, but there was an improvement in function at 3 years follow-up (60%) even in patients who were almost anarthric before the procedure 51.…”

“…Beneficial effects could be obtained with low stimulation intensity (1.5 V, 90 μs, 130 Hz),49 lower frequency (100 Hz)41 or cyclic stimulation mode, with the stimulator being programmed to turn off automatically during nighttime sleep 40. Sustained long-term benefit was observed on follow-up of 49±43.7 (mean±SD) months 49 51 53…”