Immediate and long term outcome after infrathalamic and thalamic lesioning for intractable Tourette's syndrome

Comparison of children and adults in deep brain stimulation for Tourette Syndrome: a large-scale multicenter study of 102 cases with long-term follow-up

BACKGROUND

Deep brain stimulation (DBS) is a promising therapy for refractory Gilles de la Tourette syndrome (GTS). However, its long-term efficacy, safety, and recommended surgical age remain controversial, requiring evidence to compare different age categories.

METHODS

This retrospective cohort study recruited 102 GTS patients who underwent DBS between October 2006 and April 2022 at two national centers. Patients were divided into two age categories: children (aged < 18 years; n = 34) and adults (aged ≥ 18 years; n = 68). The longitudinal outcomes as tic symptoms were assessed by the YGTSS, and the YBOCS, BDI, and GTS-QOL were evaluated for symptoms of obsessive-compulsive disorder (OCD), depression, and quality of life, respectively.

RESULTS

Overall, these included patients who finished a median 60-month follow-up, with no significant difference between children and adults (p = 0.44). Overall, the YGTSS total score showed significant postoperative improvements and further improved with time (improved 45.2%, 51.6%, 55.5%, 55.6%, 57.8%, 61.4% after 6, 12, 24, 36, 48, and ≥ 60 months of follow-up compared to baseline, respectively) in all included patients (all p < 0.05). A significantly higher improvement was revealed in children than adults at ≥ 60 months of follow-up in the YGTSS scores (70.1% vs 55.9%, p = 0.043), and the time to achieve 60% improvement was significantly shorter in the children group (median 6 months vs 12 months, p = 0.013). At the last follow-up, the mean improvements were 45.4%, 48.9%, and 55.9% and 40.3%, 45.4%, and 47.9% in YBOCS, BDI, and GTS-QOL scores for children and adults, respectively, which all significantly improved compared to baseline (all p < 0.05) but without significant differences between these two groups (all p > 0.05), and the children group received significantly higher improvement in GTS-QOL scores than adults (55.9% vs. 47.9%, p = 0.049).

CONCLUSIONS

DBS showed acceptable long-term efficacy and safety for both children and adults with GTS. Surgeries performed for patients younger than 18 years seemed to show acceptable long-term efficacy and safety and were not associated with increased risks of loss of benefit compared to patients older than 18 at the time of surgery. However, surgeries for children should also be performed cautiously to ensure their refractoriness and safety.

The intralaminar thalamus: a review of its role as a target in functional neurosurgery

The intralaminar thalamus, in particular the centromedian-parafascicular complex, forms a strategic node between ascending information from the spinal cord and brainstem and forebrain circuitry that involves the cerebral cortex and basal ganglia. A large body of evidence shows that this functionally heterogeneous region regulates information transmission in different cortical circuits, and is involved in a variety of functions, including cognition, arousal, consciousness and processing of pain signals. Not surprisingly, the intralaminar thalamus has been a target area for (radio)surgical ablation and deep brain stimulation (DBS) in different neurological and psychiatric disorders. Historically, ablation and stimulation of the intralaminar thalamus have been explored in patients with pain, epilepsy and Tourette syndrome. Moreover, DBS has been used as an experimental treatment for disorders of consciousness and a variety of movement disorders. In this review, we provide a comprehensive analysis of the underlying mechanisms of stimulation and ablation of the intralaminar nuclei, historical clinical evidence, and more recent (experimental) studies in animals and humans to define the present and future role of the intralaminar thalamus as a target in the treatment of neurological and psychiatric disorders.

Improved depressive symptoms in patients with refractory Gilles de la Tourette syndrome after deep brain stimulation of posteroventral globus pallidus interna

OBJECTIVE

Deep brain stimulation (DBS) has been used on drug-resistant Gilles de la Tourette syndrome (GTS) for more than two decades until now, but the stimulating targets are still under exploration until now. In this study, the authors reported the efficacy of the bilateral posteroventral globus pallidus interna (GPi) DBS on tic severity and neuropsychiatry symptoms of seven individuals with GTS.

METHOD

Seven patients with drug-resistant GTS were enrolled in this study. The severity of these patients was evaluated with Yale Global Tics Severity Scale (YGTSS), Yale Brown Obsessive Compulsive Scale (YBOCS), Hamilton Depression Rating Scale (HAMD), Hamilton Anxiety Rating Scale (HAMA), and Global Assessment of Functioning Scale (GAF). Bilateral posteroventral GPi were selected as the permanent stimulating targets. Follow-up period was at least 5 years after surgery in the enrolled patients.

RESULTS

After surgery, one patient reported no improvement during the follow-up period, and a device removal surgery was performed. The other six patients reported minor to significant improvement. The overall YGTSS, YBOCS, HAMA HAMD, and GAF scores of these patients were changed positively after surgery, but only the improvement of the motor tic and HAMD scores had a statistical difference. No surgical complication was reported.

CONCLUSIONS

Bilateral posteroventral GPi DBS could relieve the motor tics and depressive symptoms of the enrolled patients significantly, but the vocal tics and other psychiatric symptoms presented a progression without statistical difference during the follow-up period. The results of this study suggested that bilateral posteroventral GPi are effective targets for the motor tics in GTS patients, especially with prominent depressive symptoms.

European clinical guidelines for Tourette syndrome and other tic disorders-version 2.0. Part IV: deep brain stimulation

In 2011 the European Society for the Study of Tourette Syndrome (ESSTS) published its first European clinical guidelines for the treatment of Tourette Syndrome (TS) with part IV on deep brain stimulation (DBS). Here, we present a revised version of these guidelines with updated recommendations based on the current literature covering the last decade as well as a survey among ESSTS experts. Currently, data from the International Tourette DBS Registry and Database, two meta-analyses, and eight randomized controlled trials (RCTs) are available. Interpretation of outcomes is limited by small sample sizes and short follow-up periods. Compared to open uncontrolled case studies, RCTs report less favorable outcomes with conflicting results. This could be related to several different aspects including methodological issues, but also substantial placebo effects. These guidelines, therefore, not only present currently available data from open and controlled studies, but also include expert knowledge. Although the overall database has increased in size since 2011, definite conclusions regarding the efficacy and tolerability of DBS in TS are still open to debate. Therefore, we continue to consider DBS for TS as an experimental treatment that should be used only in carefully selected, severely affected and otherwise treatment-resistant patients.

Lead Repositioning Guided by Both Physiology and Atlas Based Targeting in Tourette Deep Brain Stimulation

Background:

The centromedian (CM) region of the thalamus is a common target for deep brain stimulation (DBS) treatment for Tourette Syndrome (TS). However, there are currently no standard microelectrode recording or macrostimulation methods to differentiate CM thalamus from other nearby structures and nuclei.

Case Report:

Here we present a case of failed conventional stereotactic targeting in TS DBS. Postoperative local field potential recordings (LFPs) showed features including beta power desynchronization during voluntary movement and thalamo-cortical phase amplitude coupling at rest. These findings suggested that the DBS lead was suboptimally placed in the ventral intermediate (VIM) nucleus of the thalamus rather than the intended CM region. Due to a lack of clinical improvement in tic severity scales three months following the initial surgery, the patient underwent lead revision surgery. Slight repositioning of the DBS leads resulted in a remarkably different clinical outcome. Afterwards, LFPs revealed less beta desynchronization and disappearance of the thalamo-cortical phase amplitude coupling. Follow-up clinical visits documented improvement of the patient’s global tic scores.

Discussion:

This case provides preliminary evidence that combining physiology with atlas based targeting may possibly enhance outcomes in some cases of Tourette DBS. A larger prospective study will be required to confirm these findings.

Highlight:

This report demonstrates a case of failed centromedian nucleus region deep brain stimulation (DBS). We observed suboptimal tic improvement several months following DBS surgery and subsequent lead revision improved the outcome. The neurophysiology provided an important clue suggesting the possibility of suboptimally placed DBS leads. Repeat LFPs during lead revision revealed less beta desynchronization and disappearance of the thalamo-cortical phase amplitude coupling. There was improvement in tic outcome following slight repositioning during bilateral DBS lead revision. This case provides preliminary evidence supporting the use of physiology to augment the atlas based targeting of Tourette DBS cases.

Differentiating tic electrophysiology from voluntary movement in the human thalamocortical circuit

OBJECTIVES

Tourette syndrome is a neurodevelopmental disorder commonly associated with involuntary movements, or tics. We currently lack an ideal animal model for Tourette syndrome. In humans, clinical manifestation of tics cannot be captured via functional imaging due to motion artefacts and limited temporal resolution, and electrophysiological studies have been limited to the intraoperative environment. The goal of this study was to identify electrophysiological signals in the centromedian (CM) thalamic nucleus and primary motor (M1) cortex that differentiate tics from voluntary movements.

METHODS

The data were collected as part of a larger National Institutes of Health-sponsored clinical trial. Four participants (two males, two females) underwent monthly clinical visits for collection of physiology for a total of 6 months. Participants were implanted with bilateral CM thalamic macroelectrodes and M1 subdural electrodes that were connected to two neurostimulators, both with sensing capabilities. MRI scans were performed preoperatively and CT scans postoperatively for localisation of electrodes. Electrophysiological recordings were collected at each visit from both the cortical and subcortical implants.

RESULTS

Recordings collected from the CM thalamic nucleus revealed a low-frequency power (3-10 Hz) increase that was time-locked to the onset of involuntary tics but was not present during voluntary movements. Cortical recordings revealed beta power decrease in M1 that was present during tics and voluntary movements.

CONCLUSION

We conclude that a human physiological signal was detected from the CM thalamus that differentiated tic from voluntary movement, and this physiological feature could potentially guide the development of neuromodulation therapies for Tourette syndrome that could use a closed-loop-based approach.

Deep brain stimulation for Tourette's syndrome

Tourette syndrome (TS) is a childhood-onset neuropsychiatric disorder characterized by the presence of multiple motor and vocal tics. TS usually co-occurs with one or multiple psychiatric disorders. Although behavioral and pharmacological treatments for TS are available, some patients do not respond to the available treatments. For these patients, TS is a severe, chronic, and disabling disorder. In recent years, deep brain stimulation (DBS) of basal ganglia-thalamocortical networks has emerged as a promising intervention for refractory TS with or without psychiatric comorbidities. Three major challenges need to be addressed to move the field of DBS treatment for TS forward: (1) patient and DBS target selection, (2) ethical concerns with treating pediatric patients, and (3) DBS treatment optimization and improvement of individual patient outcomes (motor and phonic tics, as well as functioning and quality of life). The Tourette Association of America and the American Academy of Neurology have recently released their recommendations regarding surgical treatment for refractory TS. Here, we describe the challenges, advancements, and promises of the use of DBS in the treatment of TS. We summarize the results of clinical studies and discuss the ethical issues involved in treating pediatric patients. Our aim is to provide a better understanding of the feasibility, safety, selection process, and clinical effectiveness of DBS treatment for select cases of severe and medically intractable TS.

Connections between the zona incerta and superior colliculus in the monkey and squirrel

The zona incerta contains GABAergic neurons that project to the superior colliculus in the cat and rat, suggesting that it plays a role in gaze changes. However, whether this incertal connection represents a general mammalian pattern remains to be determined. We used neuronal tracers to examine the zona incerta connections with the midbrain tectum in the gray squirrel and macaque monkey. Collicular injections in both species revealed that most incertotectal neurons lay in the ventral layer, but anterogradely labeled tectoincertal terminals were found in both the dorsal and ventral layers. In the monkey, injections of the pretectum also produced retrograde labeling, but mainly in the dorsal layer. The dendritic fields of incertotectal and incertopretectal cells were generally contained within the layer inhabited by their somata. The macaque, but not the squirrel, zona incerta extended dorsolaterally, within the external medullary lamina. Zona incerta injections produced retrogradely labeled neurons in the superior colliculus of both species. In the squirrel, most cells inhabited the lower sublamina of the intermediate gray layer, but in the monkey, they were scattered throughout the deeper layers. Labeled cells were present among the pretectal nuclei in both species. Labeled terminals were concentrated in the lower sublamina of the intermediate gray layer of both species, but were dispersed among the pretectal nuclei. In summary, an incertal projection that is concentrated on the collicular motor output layers and that originates in the ventral layer of the ipsilateral zona incerta is a common mammalian feature, suggesting an important role in collicular function.

Deep Brain Stimulation of the H Fields of Forel Alleviates Tics in Tourette Syndrome

The current rationale for target selection in Tourette syndrome revolves around the notion of cortico-basal ganglia circuit involvement in the pathophysiology of the disease. However, despite extensive research, the ideal target for deep brain stimulation (DBS) is still under debate, with many structures being neglected and underexplored. Based on clinical observations and taking into account the prevailing hypotheses of network processing in Tourette syndrome, we chose the fields of Forel, namely field H1, as a target for DBS. The fields of Forel constitute the main link between the striatopallidal system and the thalamocortical network, relaying pallidothalamic projections from core anatomical structures to the thalamic ventral nuclear group. In a retrospective study we investigated two patients suffering from chronic, medically intractable Tourette syndrome who underwent bilateral lead implantation in field H1 of Forel. Clinical scales revealed significant alleviation of tics and comorbid symptoms, namely depression and anxiety, in the postoperative course in both patients.

Deep brain stimulation for Tourette syndrome: a single-center series

OBJECTIVE Tourette syndrome (TS) is a complex neuropsychiatric disorder characterized by multiple motor and phonic tics. While pharmacological and behavioral therapy can be effective in most patients, a subset of patients remains refractory to treatment. Increasing clinical evidence from multiple centers suggests that deep brain stimulation (DBS) of the medial thalamus can be effective in many cases of refractory TS. METHODS The authors retrospectively reviewed outcomes in 13 patients with refractory TS who underwent medial thalamic DBS performed by their team over a 7-year period. Patients were evaluated by a multidisciplinary team, and preoperative objective assessments were performed using the Yale Global Tic Severity Scale (YGTSS) and Yale-Brown Obsessive Compulsive Scale. YGTSS scores were calculated at visits immediately postoperatively and at the most recent follow-up in patients with a minimum of 6 months of postoperative follow-up. Coordinates of the active DBS contacts were calculated and projected onto each patient's pre- and postoperative images. RESULTS Patients showed an average decrease of 37% (p = 0.0063) in the total tic severity at their first postoperative visit. At their latest visit, their scores achieved significance, decreasing from preoperative scores by an average of 50% (p = 0.0014). The average position of the active contact was noted to be at the junction of the posterior ventralis oralis internus/centromedian-parafascicular nuclei. Device-related complications occurred in 2 patients, necessitating additional surgeries. All patients continued to use the system at last follow-up. CONCLUSIONS The authors' data are consistent with the small but growing body of literature supporting DBS of the ventralis oralis internus/centromedian-parafascicular thalamus as an effective and relatively safe treatment for severe, refractory TS.

Dystonic tics induced by deep brain stimulation of the posterior subthalamic area for essential tremor

OBJECTIVE The posterior subthalamic area (PSA) is a promising target of deep brain stimulation (DBS) for medication-refractory essential tremor (ET). This case series describes a novel adverse effect manifesting as dystonic tics in patients with ET undergoing DBS of the PSA. METHODS Six patients with ET received electrode implants for DBS of the dorsal and caudal zona incerta subregions of the PSA. RESULTS Five of the 6 patients developed dystonic tics soon after clinical programming. These tics were of varying severity and required reduction of the electrical stimulation amplitude. This reduction resolved tic occurrence without significantly affecting ET control. Dystonic tics were not observed in 39 additional patients who underwent DBS of the same brain regions for controlling non-ET movement disorders. CONCLUSIONS The pathophysiology of tic disorders is poorly understood and may involve the basal ganglia and related cortico-striato-thalamo-cortical circuits. This series is the first report of DBS-induced tics after stimulation of any brain target. Although the PSA has not previously been implicated in tic pathophysiology, it may be a candidate region for future studies.

Updates in medical and surgical therapies for Tourette syndrome

Tourette syndrome is a complex neurobehavioral disorder defined by multiple motor and at least 1 vocal tic, persisting over 1 year, waxing and waning in severity, and not explained by another condition. The condition may range from mild nuisance to debilitating and disabling in severity. Management includes counseling and reassurance, behavioral interventions, pharmacologic, and rarely, surgical interventions. Traditionally, alpha-2 agonists and dopamine receptor antagonists have been utilized. In addition, a number of different pharmacotherapies have been implemented in the search for improved management of tics with better tolerability. In rare, severely disabling cases, neuromodulation with deep brain stimulation may be indicated. Optimal brain targets and candidate selection are still in evolution. This article will review the evidence for current medical and surgical therapies with a focus on recent updates.

[Surgery for behavioral disorders: the state of the art]

BACKGROUND

Surgery for behavioral disorders (SBD) is becoming a more common treatment since the development of neuromodulation techniques.

METHODS

This article is a non-systematic review of the history, current indications, techniques and surgical targets of SBD. We divide its history into 3 eras: the first era starts in the beginning of psychosurgery and finishes with the development of stereotactic techniques, when the second one starts. It is characterized by the realization of stereotactic lesions. We are traveling through the third era, which begins when deep brain stimulation (DBS) starts to be used for SBD.

RESULTS

In spite of the serious mistakes committed in the past, nowadays, SBD is reawakening. The psychiatric disorders which are most frequently treated by surgery are: treatment-resistant depression, obsessive-compulsive disorder and Tourette syndrome. Furthermore, some patients with abnormal aggression were surgically treated. There are several stereotactic targets described for these disorders. Vagus nerve stimulation may be also used for depression.

CONCLUSION

The results of DBS in these disorders seem to be encouraging. However, more randomized trials are needed in order to establish the effectiveness of SBD. It must be taken in mind that a proper patient selection will help us to perform a safer procedure as well as to achieve better surgical results, leading SBD to be more accepted by psychiatrists, patients and their families. Further research is needed in several topics such as: physiopathology of behavioral disorders, indications of SBD and new surgical targets.

Deep brain stimulation for Tourette syndrome

Gilles de la Tourette syndrome is a movement disorder characterized by repetitive stereotyped motor and phonic movements with varying degrees of psychiatric comorbidity. Deep brain stimulation (DBS) has emerged as a novel therapeutic intervention for patients with refractory Tourette syndrome. Since 1999, more than 100 patients have undergone DBS at various targets within the corticostriatothalamocortical network thought to be implicated in the underlying pathophysiology of Tourette syndrome. Future multicenter clinical trials and the use of a centralized online database to compare the results are necessary to determine the efficacy of DBS for Tourette syndrome.

Predictors during childhood of future health-related quality of life in adults with Gilles de la Tourette syndrome

BACKGROUND

Gilles de la Tourette syndrome (GTS) is a chronic neurodevelopmental disorder characterised by multiple motor and phonic tics and behavioural problems. Patients with GTS of all ages often report a poor health-related quality of life (HR-QOL). The diagnosis of GTS is usually established in childhood but little is known about factors that predict the long-term well-being of patients, especially in the presence of co-morbid behavioural problems.

AIM

To investigate the childhood predictors of HR-QOL in a cohort of adult patients with GTS.

METHODS

Forty-six patients with GTS aged 6-16 years underwent a baseline standardised clinical assessment of both tics and behavioural symptoms at a specialist GTS clinic. The same patients were re-assessed aged 16 years and above, with a mean follow-up period of 13 years (range 3-25 years), when they completed the Gilles de la Tourette Syndrome-Quality of Life Scale (GTS-QOL), a disease-specific measure of HR-QOL.

RESULTS

Tic severity, premonitory urges and family history of GTS were identified as predictors during childhood of a poorer HR-QOL in adults with GTS by multiple linear regression analysis. Specifically, tic severity significantly predicted poor outcome across physical, psychological and cognitive domains of the GTS-QOL, reflecting widespread effects on HR-QOL.

CONCLUSION

Young patients with severe tics associated with characteristic premonitory urges and a family history of tic disorders appear to be at higher risk for poorer HR-QOL as adults. Further prospective research into HR-QOL in GTS is required in order to inform long-term strategic resource allocation.

Surgical treatment of Tourette syndrome

In severely affected, treatment resistant patients with Tourette syndrome (TS) new therapeutic strategies are urgently needed. Since 1999, 34 studies including more than 90 patients have been performed to investigate the efficacy and safety of deep brain stimulation (DBS) in the treatment of tics resulting in the vast majority of patients in an improvement of tics and in some patients even of comorbidities. Both surgery-related (e.g., bleeding, infection) and stimulation-related adverse events (e.g., loss of energy, blurred vision) seem to occur only in a minority of patients and not to cause significant impairment, respectively. Since randomized controlled studies including a larger number of patients are still lacking, up to now, no definite conclusion can be drawn. Therefore, at present time DBS is recommended only in adult, treatment resistant, and severely affected patients. However, most experts have no doubt that DBS is indeed effective in the treatment of tics. Future studies should aim to identify which target in which patient is optimal depending on the individual symptomatology.

Pediatric indications for deep brain stimulation

PURPOSE

Based on the success of deep brain stimulation (DBS) in the treatment of adult disorders, it is reasonable to assume that the application of DBS in the pediatric population is an emerging area worthy of study. The purpose of this paper is to outline the current movement disorder indications for DBS in the pediatric population, and to describe areas of investigation, including possible medically refractory psychiatric indications.

METHODS

We performed a structured review of the English language literature from 1990 to 2011 related to studies of DBS in pediatrics using Medline and PubMed search results.

RESULTS

Twenty-four reports of DBS in the pediatric population were found. Based on published data on the use of DBS for pediatric indications, there is a spectrum of clinical evidence for the use of DBS to treat different disorders. Dystonia, a disease associated with a low rate of remission and significant disability, is routinely treated with DBS and is currently the most promising pediatric application of DBS. We caution the application of DBS to conditions associated with a high remission rate later in adulthood, like obsessive-compulsive disorder and Tourette's syndrome. Moreover, epilepsy and obesity are currently being investigated as indications for DBS in the adult population; however, both are associated with significant morbidity in pediatrics.

CONCLUSION

While currently dystonia is the most promising application of DBS in the pediatric population, multiple conditions currently being investigated in adults also afflict children and adolescents, and thus warrant further research.

Surgery for Tourette syndrome

Tourette syndrome is a chronic neuropsychiatric disorder characterized by motor and vocal tics. In the majority of cases, tics are associated by behavioral disorders such as obsessive-compulsive behavior. First symptoms typically appear in early childhood. Mostly symptoms disappear when adulthood is reached. Treatment options consist of behavioral therapy and medication. In refractory cases, surgery may be an option. In the past, several attempts have been made to treat therapy-refractory patients through neurosurgical ablative procedures. In 1999, deep brain stimulation was introduced as a novel treatment option for patients with intractable Tourette syndrome. Up until now, five brain areas have been used or suggested as potential target areas for deep brain stimulation in Tourette syndrome. In the majority of the published cases, there is a clear effect on tics but most studies consist of only a limited number of patients. A strict patient selection is absolutely mandatory. There is a need for double-blinded multicenter trials with inclusion of more patients.

Deep brain stimulation: current and future clinical applications

Deep brain stimulation (DBS) has developed during the past 20 years as a remarkable treatment option for several different disorders. Advances in technology and surgical techniques have essentially replaced ablative procedures for most of these conditions. Stimulation of the ventralis intermedius nucleus of the thalamus has clearly been shown to markedly improve tremor control in patients with essential tremor and tremor related to Parkinson disease. Symptoms of bradykinesia, tremor, gait disturbance, and rigidity can be significantly improved in patients with Parkinson disease. Because of these improvements, a decrease in medication can be instrumental in reducing the disabling features of dyskinesias in such patients. Primary dystonia has been shown to respond well to DBS of the globus pallidus internus. The success of these procedures has led to application of these techniques to multiple other debilitating conditions such as neuropsychiatric disorders, intractable pain, epilepsy, camptocormia, headache, restless legs syndrome, and Alzheimer disease. The literature analysis was performed using a MEDLINE search from 1980 through 2010 with the term deep brain stimulation, and several double-blind and larger case series were chosen for inclusion in this review. The exact mechanism of DBS is not fully understood. This review summarizes many of the current and potential future clinical applications of this technology.

European clinical guidelines for Tourette syndrome and other tic disorders. Part IV: deep brain stimulation

Ten years ago deep brain stimulation (DBS) has been introduced as an alternative and promising treatment option for patients suffering from severe Tourette syndrome (TS). It seemed timely to develop a European guideline on DBS by a working group of the European Society for the Study of Tourette Syndrome (ESSTS). For a narrative review a systematic literature search was conducted and expert opinions of the guidelines group contributed also to the suggestions. Of 63 patients reported so far in the literature 59 had a beneficial outcome following DBS with moderate to marked tic improvement. However, randomized controlled studies including a larger number of patients are still lacking. Although persistent serious adverse effects (AEs) have hardly been reported, surgery-related (e.g., bleeding, infection) as well as stimulation-related AEs (e.g., sedation, anxiety, altered mood, changes in sexual function) may occur. At present time, DBS in TS is still in its infancy. Due to both different legality and practical facilities in different European countries these guidelines, therefore, have to be understood as recommendations of experts. However, among the ESSTS working group on DBS in TS there is general agreement that, at present time, DBS should only be used in adult, treatment resistant, and severely affected patients. It is highly recommended to perform DBS in the context of controlled trials.

Deep brain stimulation therapy for treatment-refractory Tourette's syndrome: A review

Tourette's syndrome is a chronic neurobehavioral disorder that can demonstrate refractoriness to conservative treatments, or to invasive nonsurgical treatments such as botulinum toxin infiltration, or to psychobehavioral treatments. In these cases, the surgical option is often proposed, either with lesional interventions, or more recently with deep brain stimulation (DBS). This latter modality is currently preferred because of its reversibility and modularity. Some relevant issues, however, still persist in terms of appropriate indication to treatment, selection of target, and follow-up evaluation.

Lack of benefit of accumbens/capsular deep brain stimulation in a patient with both tics and obsessive-compulsive disorder

LAY SUMMARY: This case report illustrates lack of clinical efficacy of deep brain stimulation (DBS) for control of tics in a case of mild Tourette syndrome (TS) with severe comorbid obsessive-compulsive disorder (OCD). The brain target for stimulation was the anterior limb internal capsule (ALIC).

OBJECTIVE

To investigate the effect of anterior limb of internal capsule/nucleus accumbens (ALIC-NA) DBS on mild motor and vocal tics in a Tourette syndrome (TS) patient with severe OCD.

BACKGROUND

The optimum target to address symptoms of TS with DBS remains unknown. Earlier lesional therapy utilized thalamic targets and also the ALIC for select cases which had been diagnosed with other psychiatric disorders. Evidence regarding the efficacy of DBS for the symptoms of TS may aid in better defining a brain target's suitability for use. We report efficacy data on ALIC-NA DBS in a patient with severe OCD and mild TS.

METHODS

A 33-year-old man underwent bilateral ALIC-NA DBS. One month following implantation, a post-operative CT scan was obtained to verify lead locations. Yale Global Tic Severity Scales (YGTSS) and modified Rush Videotape Rating scales (MRVRS) were obtained throughout the first 6 months, as well as careful clinical examinations by a specialized neurology and psychiatry team. The patient has been followed for 30 months.

RESULTS

YGTSS scores worsened by 17% during the first 6 months. MRVRS scores also worsened over 30 total months of follow-up. There was a lack of clinically significant tic reduction although subjectively the patient felt tics improved mildly.

CONCLUSION

DBS in the ALIC-NA failed to effectively address mild vocal and motor tics in a patient with TS and severe comorbid OCD.

From psychosurgery to neuromodulation: deep brain stimulation for intractable Tourette syndrome

Tourette syndrome is a neuropsychiatric disorder characterized by motor and vocal tics. It is often associated with depression, obsessive-compulsive symptoms, self-injurious behaviour and attention deficit-hyperactivity disorder (ADHD). In intractable patients, neuromodulation using deep brain stimulation (DBS) has widely replaced psychosurgery. Three different key structures are defined for DBS, the medial portion of the thalamus, the globus pallidus internus and the anterior limb of the internal capsule/nucleus accumbens. This is a comprehensive overview on the effect of DBS on motor and non-motor symptoms using different case series and two larger studies.

Neurosurgical treatment for Gilles de la Tourette syndrome: the Italian perspective

Despite the availability of both pharmacological and behavioral therapies for Gilles de la Tourette Syndrome (GTS), a subgroup of patients suffer intractable disease and require treatment through non-conservative means. Since 1955, various neurosurgical procedures have been considered as a potential resort for this severely affected sub-group; this article reviews the neurosurgical treatment for GTS, with in-depth discussion on deep brain stimulation (DBS). Internationally, 39 cases of GTS undergoing DBS treatment have been published. Yet, despite the small numbers of patients assessed in centers involved and the inconsistency of postoperative assessment between centres, DBS has been considered the most promising neurosurgical procedure. Patients resorting to surgical measures often carry the additional burden of a diverse range of behavioral disturbances found to significantly impair health-related quality of life; comorbid psychopathologies must be considered when postoperatively evaluating the benefits of DBS. The authors acknowledge that out of the 39 documented cases of GTS treated with DBS, 18 cases originate from Italy; thus, it seems both relevant and pertinent to recount and present the lived Italian experience of that subgroup of GTS treated by DBS, for the first time. Recommendations from such experience are presented.

Tourette's syndrome, trichotillomania, and obsessive-compulsive disorder: how closely are they related?

The question of whether Tourette's syndrome (TS) and trichotillomania (TTM) are best conceptualized as obsessive-compulsive spectrum disorders was raised by family studies demonstrating a close relationship between TS and obsessive-compulsive disorder (OCD), and by psychopharmacological research indicating that both TTM and OCD respond more robustly to clomipramine than to desipramine. A range of studies have subsequently allowed comparison of the phenomenology, psychobiology, and management of TS and TTM, with that of OCD. Here we briefly review this literature. The data indicate that there is significant psychobiological overlap between TS and OCD, supporting the idea that TS can be conceptualized as an OCD spectrum disorder. TTM and OCD have only partial overlap in their phenomenology and psychobiology, but there are a number of reasons for why it may be useful to classify TTM and other habit disorders as part of the obsessive-compulsive spectrum of disorders.

Neurosurgical strategies for Gilles de la Tourette's syndrome

Tourette's syndrome (TS) is a neurological disorder characterized by motor and vocal tics that typically begin in childhood and often are accompanied by psychiatric comorbidities. Symptoms of TS may be socially disabling and cause secondary medical complications. Pharmacological therapies remain the mainstay of symptom management. For the subset of patients in whom TS symptoms are medically recalcitrant and do not dissipate by adulthood, neurosurgery may offer an alternative treatment strategy. Greater understanding of the neuroanatomic and pathophysiologic basis of TS has facilitated the development of surgical procedures that aim to ameliorate TS symptoms by lesions or deep brain stimulation of cerebral structures. Herein, the rationale for the surgical management of TS is discussed and neurosurgical experiences since the 1960s are reviewed. The necessity for neurosurgical strategies to be performed with appropriate ethical considerations is highlighted.

Lesion of the centromedian thalamic nucleus in MPTP-treated monkeys

The caudal intralaminar nuclei are a major source of glutamatergic afferents to the basal ganglia. Experiments in the 6-hydroxydopamine rat model have shown that the parafascicular nucleus is overactive and its lesion alleviates basal ganglia neurochemical abnormalities associated with dopamine depletion. Accordingly, removal of this excitatory innervation of the basal ganglia could have a beneficial value in the parkinsonian state. To test this hypothesis, unilateral kainate-induced chemical ablation of the centromedian thalamic nucleus (CM) has been performed in MPTP-treated monkeys. Successful lesions restricted to the CM boundaries (n = 2) without spreading over other neighboring thalamic nuclei showed an initial, short-lasting, and mild change in the parkinsonian motor scale but no effect against levodopa-induced dyskinesias. The lack of significant and persistent motor improvement leads us to conclude that unilateral selective lesion of the CM alone cannot be considered as a suitable surgical approach for the treatment of PD or levodopa-induced dyskinesias. The role of the caudal intralaminar nuclei in the pathophysiology of movement disorders of basal ganglia origin remains to be clarified.

Pearls in patient selection for deep brain stimulation

BACKGROUND

Deep brain stimulation (DBS) has emerged as an important treatment for medication refractory movement and neuropsychiatric disorders. General neurologists and even general practitioners may be called upon to screen potential candidates for DBS. The patient selection process plays an important role in this procedure.

REVIEW SUMMARY

In this article, we discuss "pearls" for the clinician who may be called upon to identify appropriate candidates for DBS. Additionally, we will discuss the important points that should be considered when referring patients for surgical intervention.

CONCLUSION

Diagnosis, response to levodopa, cognitive status, psychiatric status, access to care, and patient expectations are all essential elements of the patient selection process for DBS. These areas must be adequately addressed prior to any surgical procedure.

Surgery for other movement disorders: dystonia, tics

PURPOSE OF REVIEW

Various movement disorders are now treated with stereotactic procedures, particularly deep brain stimulation. We review the neurosurgical treatment of dystonias and tics, focusing mainly on the surgical aspects and outcome of deep brain stimulation.

RECENT FINDINGS

Pallidal stimulation is nowadays the mainstay surgical treatment for patients with dystonia, particularly generalized dystonia. Various well designed recent clinical trials support the efficacy of the procedure. Improvements of 40-80% have been reported in primary generalized, segmental and cervical dystonia. For secondary dystonia, a similar outcome has been described in patients with tardive dystonia and pantothenate kinase-associated neurodegeneration. In patients with Tourette's syndrome, the results of the first trials with thalamic and pallidal deep brain stimulation have been very promising. Improvements of 70-90% in the frequency of tics have been reported with surgery in both targets.

SUMMARY

Deep brain stimulation has become an established therapy for dystonia and is currently being used to treat Tourette's syndrome. With accumulation of experience, clinical features that are more responsive to surgery and the best surgical candidates will be revealed. This will likely improve even further the outcome of surgery for the treatment of these disorders.

Cortical control of zona incerta

The zona incerta (ZI) is at the crossroad of almost all major ascending and descending fiber tracts and targets numerous brain centers from the thalamus to the spinal cord. Effective ascending drive of ZI cells has been described, but the role of descending cortical signals in patterning ZI activity is unknown. Cortical control over ZI function was examined during slow cortical waves (1-3 Hz), paroxysmal high-voltage spindles (HVSs), and 5-9 Hz oscillations in anesthetized rats. In all conditions, rhythmic cortical activity significantly altered the firing pattern of ZI neurons recorded extracellularly and labeled with the juxtacellular method. During slow oscillations, the majority of ZI neurons became synchronized to the depth-negative phase ("up state") of the cortical waves to a degree comparable to thalamocortical neurons. During HVSs, ZI cells displayed highly rhythmic activity in tight synchrony with the cortical oscillations. ZI neurons responded to short epochs of cortical 5-9 Hz oscillations, with a change in the interspike interval distribution and with an increase in spectral density in the 5-9 Hz band as measured by wavelet analysis. Morphological reconstruction revealed that most ZI cells have mediolaterally extensive dendritic trees and very long dendritic segments. Cortical terminals established asymmetrical synapses on ZI cells with very long active zones. These data suggest efficient integration of widespread cortical signals by single ZI neurons and strong cortical drive. We propose that the efferent GABAergic signal of ZI neurons patterned by the cortical activity can play a critical role in synchronizing thalamocortical and brainstem rhythms.

Deep brain stimulation in neurologic disorders

Deep brain stimulation (DBS) is an effective surgical therapy for well-selected patients with medically intractable Parkinson's disease (PD) and essential tremor (ET). The purpose of this review is to describe the success of DBS in these two disorders and its promising application in dystonia, Tourette Syndrome (TS) and epilepsy. In the last 10 years, numerous short- and intermediate-term outcome studies have demonstrated significant relief to patients with PD and ET. A few long-term follow-up studies have also reported sustained benefits. When successful, DBS greatly reduces most of parkinsonian motor symptoms and drug-induced dyskinesia, and it frequently improves patients' ability to perform activities of daily living with less encumbrance from motor fluctuations. Quality of life is enhanced and many patients are able to significantly reduce the amount of antiparkinsonian medications required to still get good pharmacological benefit. Overall, adverse effects associated with DBS tend to be transient, although device-related and other postoperative complications do occur. DBS should be considered the surgical procedure of choice for patients who meet strict criteria with medically intractable PD, ET and selected cases of dystonia.

Novel surgical therapies for Tourette syndrome

Tourette syndrome is a common neurologic disorder with close ties to obsessive-compulsive disorder and attention-deficit hyperactivity disorder (ADHD). The majority of patients improve spontaneously as they near adulthood. Most others are effectively treated with pharmacologic agents, although these therapies fail for an unfortunate few. For patients debilitated by the disease despite medical therapy, surgery can become an important option.

Increased midbrain gray matter in Tourette's syndrome

OBJECTIVE

To investigate cerebral structure in Tourette's syndrome (TS).

METHODS

Voxel-based morphometry study of high-resolution MRIs in 31 TS patients compared with 31 controls.

RESULTS

Increased gray matter mainly in the left mesencephalon in 31 TS patients.

INTERPRETATION

This result constitutes strong and direct evidence supporting Devinsky's hypothesis (Devinsky O. Neuroanatomy of Gilles de la Tourette's syndrome. Possible midbrain involvement. Arch Neurol 1983;40:508-514) according to which midbrain disturbances play an important pathogenic role in TS.

Efficient internal pallidal stimulation in Gilles de la Tourette syndrome: a case report

The usefulness of deep brain stimulation (DBS) of thalamic nuclei in Gilles de la Tourette syndrome (GTS) has recently been advocated. We report on a 14-month follow-up study of a patient with intractable GTS in whom bilateral DBS of the internal globus pallidus was carried out. Tic frequency per minute decreased by 73% in the postoperative phase and in particular the vocal tics became less intense. Pronation/ supination bradykinesia of the left extremities was a well-tolerated, permanent side effect. Pallidal DBS could become a valuable rescue therapy for otherwise intractable GTS.

Abnormal thalamic volume in treatment-naïve boys with Tourette syndrome

OBJECTIVE

Thalamic abnormality has been implicated in the pathophysiology of Tourette's syndrome (TS). We examined the presence of aberrant thalamic volume from the treatment-naïve boys with TS using magnetic resonance imaging (MRI).

METHOD

Volumetric MRI was performed on 18 treatment-naïve boys with TS, aged 7-14 years, and 16 healthy comparison subjects. The anatomical boundaries were then manually parcellated to measure the thalamic volume.

RESULTS

Tourette's syndrome subjects had a significantly larger left thalamus in comparison with those of healthy subjects. On the contrary, no group difference was observed from the right thalamic volume. TS subjects also showed a significant reduction in rightward asymmetry in thalamic volume compared with the healthy subjects.

CONCLUSION

Our findings provide new evidence of abnormal thalamic volume in pediatric TS.

Neurosurgical interventions for neuropsychiatric syndromes

Psychosurgical procedures have been used for the treatment of intractable mental illness for more than 50 years. With improvements in surgical techniques, including new implantable stimulators, advances in functional neuroimaging, and progress in our fundamental understanding of the pathophysiology of mental illness there is a renewed interest in neurosurgical treatment of refractory psychiatric illness. This article will review the history of psychosurgery and recent developments in surgical techniques and implantable devices used in this context. The results of psychosurgery for the treatment of several psychiatric conditions and neuropsychiatric symptoms will be presented, including obsessive-compulsive disorder, Tourette's syndrome, depression, anxiety, aggression, self-injurious behavior, and schizophrenia. Lastly, a perspective on the current and future role of psychosurgery for the treatment of mental illnesses will be discussed.

Surgery in Tourette syndrome

Tourette syndrome (TS) is a neuropsychiatric disorder with onset in early childhood. It is characterized by tics and often accompanied by disturbances in behavior, such as obsessive-compulsive disorder (OCD). In most cases, the disorder is self-limited or can be treated by medication or behavioral therapy. In a small percentage, however, symptoms are intractable to any conservative treatment. Since 1955, various attempts have been made to treat these patients through neurosurgical procedures. The target sites have been diverse and include the frontal lobe (prefrontal lobotomy and bimedial frontal leucotomy), the limbic system (limbic leucotomy and anterior cingulotomy), the thalamus, and the cerebellum. Combined approaches have also been tried such as anterior cingulotomies plus infrathalamic lesions. The results have often been unsatisfactory or major side effects have occurred, such as hemiplegia or dystonia. Our review of the literature from 1960 until 2003 revealed 21 reports and 3 descriptions in textbooks covering about 65 patients in total who had undergone ablative procedures for intractable TS, the first being reported in 1962. In 1999, deep brain stimulation (DBS) was introduced as a new approach for intractable TS. To date, 3 patients have been reported who underwent bilateral thalamic stimulation, with promising results on tics and obsessive-compulsive symptoms.

Chronic bilateral thalamic stimulation: a new therapeutic approach in intractable Tourette syndrome

✓✓ Based on the results of thalamotomies described by Hassler in 1970, the authors performed bilateral thalamic highfrequency stimulation (HFS) in three patients with intractable Tourette syndrome (TS). In this report they describe the long-term effects.

Three male patients (42, 28, and 45 years of age) had manifested motor and vocal tics since early childhood. The diagnosis of TS was made according to the criteria of the Tourette Syndrome Classification Study Group. Any drug or alternative treatment had been either ineffective or only temporarily effective in all three patients. There was no serious comorbidity. The target for stimulation was chosen at the level of the centromedian nucleus, substantia periventricularis, and nucleus ventrooralis internus. After 2 weeks of test stimulation, the pulse generators were implanted. After a follow-up period of 5 years in the patient in Case 1, 1 year in the patient in Case 2, and 8 months in the patient in Case 3, all major motor and vocal tics had disappeared and no serious complications had occurred. When stimulation was applied at the voltage necessary to achieve an optimal result on the tics, a slight sedative effect was noted in all three patients. In the patients in Cases 1 and 3 there were stimulation-induced changes in sexual behavior.

Chronic thalamic HFS may be an effective and safe treatment for medically intractable TS in adult patients. Unwanted stimulation-induced side effects may occur.

Electrical stimulation of the posterior subthalamic area for the treatment of intractable proximal tremor

OBJECT

Tremors, including its proximal component, are often refractory to standard thalamic surgery. In the 1960s the posterior part of the subthalamic white matter was reported to be a promising target in treating various forms of tremor, but was also found to be associated with adverse effects. Advances involving a less invasive method, that is, deep brain stimulation (DBS), has led to a reappraisal of this target.

METHODS

Eight patients with severe essential tremor involving the proximal arm were treated using unilateral stimulation of the posterior part of the subthalamic white matter. The tentative target was situated in the area lateral to the red nucleus and posteromedial to the subthalamic nucleus. Macrostimulation was used to find the optimal site to suppress tremor. Through a quadripolar DBS lead, somatosensory evoked potentials (SSEPs) were recorded. Improvement of tremor was evaluated based on a modified clinical tremor rating scale. Anatomical locations of all contacts were assessed using stereotactic guidance and represented on the Schaltenbrand-Wahren atlas.

CONCLUSIONS

A characteristic diphasic pattern of SSEPs reaffirmed the electrophysiological endorsement of this target. Tremors, both proximal and distal, were remarkably improved in all patients. The rate of improvement, as indicated by the total tremor score, was a mean of 81%. Axial tremors in the legs and head were also improved. Most of the contacts associated with remarkable improvement were located in the posterior part of the subthalamic white matter (the zona incerta and prelemniscal radiation). Neither major complications nor neurological deterioration was observed. The authors concluded that DBS of the posterior part of the subthalamic white matter together with SSEP recording is a safe and effective method to ameliorate severe intractable tremors.

Tourette's Syndrome in Children

This paper will provide a review of the Tourette's syndrome (TS) in children, focusing on treatment options, including a drug-by-drug evaluation of available pharmacologic agents and other treatments. Despite increasing knowledge of the neurophysiologic basis of the tics of TS, ideal and universally effective treatments do not yet exist. Affected children may present a wide variety of phenotypes, which are best managed in a case-by-case manner, with the well-informed patient and family weighing the risks and benefits of interventions together with a knowledgeable and committed clinician. The clinician treating TS will encounter a wide range of tic severity, comorbidity, adherence to treatment, and treatment response. The clinician's most important task is to identify the main sources of distress and impairment, and set priorities for their management. Common treatment may involve education and reassurance, psychosocial and school interventions, and choices from an array of pharmacologic agents. Decisions regarding treatment ought to be made collaboratively with the clinician and family, after a careful discussion of symptom extent and severity, psychosocial impact, desired outcome, and realistic treatment expectations and side effects. Given the waxing and waning course of tics in TS, clinicians often monitor each patient for several weeks before starting a somatic treatment, based on a judgement that even when tics are at their best, they are severe enough to warrant pharmacotherapy. With children for whom the decision has been taken to target tics with medication, the authors recommend beginning with guanfacine or clonidine, especially when there are any hyperactivity symptoms. The next choice would be a low-dose neuroleptic. Patience and close ongoing monitoring of efficacy and side effects is necessary, whenever a clinical trial of medications is undertaken, to achieve an acceptable balance between tic control and side effects. Treatments should be targeted at specific symptoms and comorbidities, such as attention deficit hyperactivity disorder and obsessive-compulsive disorder. Clinicians tend to treat comorbid conditions first because they may be the greatest sources of difficulty. On occasion, the successful treatment of a comorbid condition will lead to an amelioration of tics.

The treatment of Tourette's syndrome: current opinions

Correct education of the patient is one of the most important aspects in the treatment of Tourette's syndrome. Pharmacotherapy is often unsatisfactory and therefore should be limited to those patients who are significantly impaired. Therapy must be individualised and the most troublesome symptom should be targeted first. In the treatment of tics, dopamine receptor blocking agents are currently the most effective drugs. It is currently unknown whether classic neuroleptics, such as pimozide, selective dopamine receptor antagonists, such as sulpiride, or newer atypical antipsychotics, such as risperidone, have the best adverse effect profile. Tiapride can be used as an alternative, particularly in children. Selective serotonin-re-uptake inhibitors are recommended for the treatment of obsessive-compulsive behaviour. In children suffering from attention deficit hyperactivity disorder, psychostimulants, such as methylphenidate, are the treatment of choice. Recent studies have provided increasing evidence that stimulants do not cause a significant increase in tics in the majority of patients.