Improvement of both dystonia and tics with 60 Hz pallidal deep brain stimulation

Deep brain stimulation has been utilized in both dystonia and in medication refractory Tourette syndrome. We present an interesting case of a patient with a mixture of disabling dystonia and Tourette syndrome whose coexistent dystonia and tics were successfully treated with 60 Hz-stimulation of the globus pallidus region.     

Battery life following pallidal deep brain stimulation (DBS) in children and young people with severe primary and secondary dystonia

Background

The finite life of non-rechargeable batteries powering implantable pulse generators (IPG) necessitates their periodic replacement. Children receiving deep brain stimulation (DBS) may require frequent battery changes over their treatment lifetime.

Objectives

We aimed to determine the battery life of IPGs used in pallidal DBS for the treatment of dystonia in children and young people.

Methods

We make use of a review of case notes of all children and young people undergoing DBS surgery at our institution from June 2005 to May 2010.

Results

A total of 54 children and young people underwent surgery on at least one occasion, with a total of 76 IPGs implanted. Replacement IPGs due to battery failure were required in 15 out of 54 (27.8%). The average time to battery failure was 24.5?±?2.9?months (95% confidence interval), with a range of 13–39?months. Battery life was significantly longer in primary compared to subsequent IPGs. No difference in longevity was seen between different IPG devices.

Conclusions

IPG battery life may be short in children and young people receiving treatment for dystonia. These findings highlight the potential benefits of the recently introduced rechargeable neurostimulators.     

Risperidone-responsive segmental dystonia and pallidal deep brain stimulation

A 67-year-old man with risperidone-responsive segmental dystonia underwent bilateral deep brain stimulation (DBS) of the globus pallidus internus. Prospectively, the authors assessed the Burke-Fahn-Marsden Dystonia Rating Scale in medication (M) and stimulation (S) "on"/"off" states. With DBS at 9 months, the score improved by 86% to 8.5 in M-"on"/S-"on" and 12.5 in M-"off"/S-"on." Studies of the effects of DBS and concomitant medication may be warranted in selected patients treated by DBS for dystonia.     

The effects of frequency in pallidal deep brain stimulation for primary dystonia

Abstract. The effect of stimulation frequency for pallidal deep brain stimulation in five patients with either generalized or segmental dystonia was evaluated three to twelve months postoperatively via a randomized, double-blind paradigm. The quality of life and the severity of dystonic symptoms improved by approximately 60% and 43% respectively using a frequency of 130 Hz. Compared with 130 Hz a significant further clinical improvement was observed at frequencies of 180 and 250 Hz, which contrasted with a significant deterioration at lower frequencies (5, 50 Hz) compared to 130 Hz.     

Long-term outcome of bilateral pallidal deep brain stimulation for primary cervical dystonia

Ten patients with severe cervical dystonia (CD) unresponsive to medical treatment underwent bilateral globus pallidus internus (GPi) deep brain stimulation (DBS) and were followed for 31.9 +/- 20.9 months. At last follow-up, the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) severity score improved by 54.8%, the TWSTRS disability score improved by 59.1%, and the TWSTRS pain score improved by 50.4%. Bilateral GPi DBS is an effective long-term therapy in patients with CD.     

Treatment of severe tardive dystonia with pallidal deep brain stimulation

In five patients with medically refractory tardive dystonia, continuous bilateral high-frequency stimulation of the globus pallidus internus was associated with a rapid (within 12 to 72 hours) and substantial (mean 87%, 10.7 SD of the motor part of the Burke-Fahn-Marsden Dystonia Rating Scale) improvement of dystonia and functional disability without adverse events.     

Battery lifetime in pallidal deep brain stimulation for dystonia

Background and Purpose: The aim of the study was to analyse the lifetime of Soletra implantable pulse generators (IPG) in deep brain stimulation (DBS) of the globus pallidus internus (GPi) for dystonia, depending on stimulation parameters and the total electrical energy delivered (TEED) by the IPG. Methods: In a prospective series of 20 patients with GPi DBS for dystonia, we recorded IPG longevity and stimulation parameters over time. An evaluation of the TEED was performed using the previously suggested equation [(voltage² × pulse width × frequency)/impedance] × 1 s. Results: During median follow‐up of 57 months (range 23–79 months), 64 IPGs were replaced because of battery depletion or end of life signal. We found a mean IPG longevity of 25.1 ± 10.1 (range 16–60) months, which was inversely correlated with the TEED (r = −0.72; P < 0.001). IPG longevity was not different between bipolar and monopolar stimulation (24.9 ± 10.8 vs. 25.4 ± 9.0 months, P = 0.76). Incongruously, the mean TEED applied throughout the lifetime cycle was significantly higher in patients with bipolar compared with monopolar stimulation (584 ± 213 vs. 387 ± 121 Joule; P < 0.01). Conclusions: Battery lifetime in GPi DBS for dystonia is substantially shorter compared with that reported in DBS for Parkinson’s disease, caused by a considerably higher voltage and greater pulse width and therefore a higher TEED applied during the battery lifetime cycle. The commonly used equation to calculate TEED, however, seems to be correct only for monopolar, but not bipolar stimulation.     

Factors predicting improvement in primary generalized dystonia treated by pallidal deep brain stimulation

Despite the beneficial effects of Globus Pallidus internus (GPi) deep brain stimulation (DBS) in patients with primary generalized dystonia (PGD), the degree of improvement varies from one patient to another. The objective of this study was to examine the effects of clinical, anatomical (volume of the GPi), and electrical variables on the postoperative Burke‐Fahn‐Marsden Dystonia rating scale (BFMDRS) motor score to identify which factors may be predictive of the degree of improvement. We reviewed retrospectively the clinical records of 40 steady‐state patients with PGD who had been treated by bilateral GPi lead implantation. The follow‐up period was 2 to 8 years. The correlation between the electrical parameters (voltage, impedance, and current) and the clinical outcome was studied. An analysis of covariance was performed to identify factors predictive of the magnitude of improvement. The most influential factors according to the model are as follows: the preoperative BFMDRS score (P < 0.0001); age at surgery (P < 0.0001); the right GPi volume (P = 0.002); the left stimulated GPi volume (P = 0.005). No significant correlation was found between the electrical parameters used and the mean motor scores in steady state. © 2009 Movement Disorder Society     

Long-term benefit to pallidal deep brain stimulation in a case of dystonia secondary to pantothenate kinase-associated neurodegeneration.

Pantothenate kinase-associated neurodegeneration (PKAN) is a rare autosomal recessive disorder with onset in childhood and rapid progression. There is no causative and insufficient symptomatic drug therapy. Deep brain stimulation (DBS) of the internal pallidum (GPi) has been reported to improve motor function. Most case reports, however, are limited to short observational periods. The impact of DBS on the progression and life expectancy in PKAN is unknown. We present a 5-year outcome and video documentation of bilateral GPi-DBS of an adolescent patient suffering from genetically defined PKAN.     

A practical guide to troubleshooting pallidal deep brain stimulation issues in patients with dystonia

High frequency deep brain stimulation (DBS) of the internal portion of the globus pallidus has, in the last two decades, become a mainstream therapy for the management of medically-refractory dystonia syndromes. Such increasing uptake places an onus on movement disorder physicians to become familiar with this treatment modality, in particular optimal patient selection for the procedure and how to troubleshoot problems relating to sub-optimal efficacy and therapy-related side effects.Deep brain stimulation for dystonic conditions presents some unique challenges. For example, the frequent lack of immediate change in clinical status following stimulation alterations means that programming often relies on personal experience and local practice rather than real-time indicators of efficacy. Further, dystonia is a highly heterogeneous disorder, making the development of unifying guidelines and programming algorithms for DBS in this population difficult. Consequently, physicians may feel less confident in managing DBS for dystonia as compared to other indications e.g. Parkinson's disease.In this review, we integrate our years of personal experience of the programming of DBS systems for dystonia with a critical appraisal of the literature to produce a practical guide for troubleshooting common issues encountered in patients with dystonia treated with DBS, in the hope of improving the care for these patients.     

Focal childhood‐onset,action induced primary hip dystonia treated with pallidal deep brain stimulation

Focal proximal lower limb dystonias are rare. Unlike the adult form, focal lower limb dystonias in children usually become generalized. The condition is often unrecognized and the patient often receives orthopedic or psychiatric treatment for years before the diagnosis eventually made. Previously reported cases of isolated lower limb dystonias have been managed nonsurgically. We present a case of a childhood‐onset action‐induced primary hip dystonia that has remained focal even in adulthood and which responded successfully to pallidal deep brain stimulation. Additionally, our results suggest that neurons representing the leg lie within the most ventral aspect of the globus pallidus interna. © 2008 Movement Disorder Society     

Bilateral pallidal deep brain stimulation in primary Meige syndrome

Primary Meige syndrome is an idiopathic movement disorder that manifests as craniofacial and often cervical dystonias. Deep brain stimulation (DBS) of the globus pallidus internus (GPi) has emerged as a powerful surgical option in the treatment of primary generalized or segmental dystonia. However, the experience with GPi-DBS in Meige syndrome is limited. We followed 5 patients with disabling Meige syndrome treated by bilateral GPi-DBS for 49?±?43.7 (mean?±?SD) months. All patients were assessed before surgery and at the last follow-up after surgery using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) which includes both the movement and disability scales. Bilateral GPi-DBS produced a sustained and long-lasting improvement in dystonia symptoms associated with Meige syndrome. At?the last follow-up, the mean scores of BFMDRS movement and disability scales improved significantly by 84?±?6.8% (range, 75-94%) and 89?±?8.1% (range, 80-100%), respectively. Bilateral pallidal stimulation is a beneficial therapeutic option for long-term relief of the disabling dystonia symptoms in Meige syndrome.     

Intermuscular coherence as biomarker for pallidal deep brain stimulation efficacy in dystonia

ObjectiveFinding a non-invasive biomarker for Globus Pallidus interna Deep Brain Stimulation (GPi-DBS) efficacy. Dystonia heterogeneity leads to a wide variety of clinical response to GPi-DBS, making it hard to predict GPi-DBS efficacy for individual patients.MethodsEEG-EMG recordings of twelve dystonia patients who received bilateral GPi-DBS took place pre- and 1 year post-surgery ON and OFF stimulation, during a rest, pinch, and flexion task. Dystonia severity was assessed using the BFMDRS and TWSTRS (pre- and post-surgery ON stimulation). Intermuscular coherence (IMC) and motorcortex corticomuscular coherence (CMC) were calculated. Low frequency (4–12 Hz) and beta band (13–30 Hz) peak coherences were studied.ResultsDystonia severity improved after 1 year GPi-DBS therapy (BFMDRS: 30%, median 7.8 (IQR 3–10), TWSTRS: 22%, median 6.8 (IQR 4–9)). 86% of IMC were above the 95% confidence limit. The highest IMC peak decreased significantly with GPi-DBS in the low frequency and beta band. Low frequency and beta band IMC correlated partly with dystonia severity and severity improvement. CMC generally were below the 95% confidence limit.ConclusionsPeak low frequency IMC functioned as biomarker for GPi-DBS efficacy, and partly correlated with dystonia severity.SignificanceIMC can function as biomarker. Confirmation in a larger study is needed for use in clinical practice.     

Effect of electrode contact location on clinical efficacy of pallidal deep brain stimulation in primary generalised dystonia

Objectives

To determine the effect of electrode contact location on efficacy of bilateral globus pallidus internus (GPi) deep brain stimulation (DBS) for primary generalised dystonia (PGD).

Subjects and methods

A consecutive series of 15 patients with PGD (10 females, mean age 42 years, seven DYT1) who underwent bilateral GPi DBS, were assessed using the Burke–Fahn–Marsden (BFM) dystonia scale before and 6 months after surgery. The position of the stimulated electrode contact(s) was determined from the postoperative stereotactic MRI. Contralateral limb and total axial BFM subscores were compared with the location of the stimulated contact(s) within the GPi.

Results

The mean total BFM score decreased from 38.9 preoperatively to 11.9 at 6 months, an improvement of 69.5% (p<0.00001). Cluster analysis of the stimulated contact coordinates identified two groups, distributed along an anterodorsal to posteroventral axis. Clinical improvement was greater for posteroventral than anterodorsal stimulation for the arm (86% vs 52%; p<0.05) and trunk (96% vs 65%; p<0.05) and inversely correlated with the y coordinate. For the leg, posteroventral and anterodorsal stimulation were of equivalent efficacy. Overall clinical improvement was maximal with posteroventral stimulation (89% vs 67%; p<0.05) and inversely correlated with the y (A‐P) coordinate (r = −0.62, p<0.05).

Conclusion

GPi DBS is effective for PGD but outcome is dependent on contact location. Posteroventral GPi stimulation provides the best overall effect and is superior for the arm and trunk. These results may be explained by the functional anatomy of GPi and its outflow tracts.Primary generalised dystonia (PGD) is a movement disorder characterised by involuntary muscle contractions causing abnormal postures and spasms.¹ The failure of medical treatment has led to renewed interest in functional neurosurgical approaches to its treatment. Earlier positive reports of ablative pallidal surgery in dystonia² and the subsequent observations of improvement of dystonia in Parkinson''s disease (PD) with posteroventral pallidotomy and DBS led to the first attempts to treat dystonia using globus pallidus internus (GPi) deep brain stimulation (DBS) by Coubes et al in 1996.³ Since then, GPi DBS has emerged as an effective treatment for PGD.^4,5 Despite this progress and the more widespread acceptance of the technique, there is still debate about the optimal target within the GPi to achieve the best effect in dystonia. Most surgeons target the posteroventral portion of the GPi, the classical target for pallidotomy developed by Leksell and Laitinen.⁶ However, to date there have been few data to support the superiority of this target in dystonia, or whether within this region there may be an optimal zone to achieve the best effect.We sought to explore the relationship between the precise location of the therapeutically stimulated electrode contact and the magnitude of clinical benefit in a consecutive series of patients with PGD who all underwent bilateral GPi DBS. We were interested to determine if within the GPi there is any regional stratification of the efficacy of stimulation for dystonia.