Reduction Of Dopaminergic Medication Research Articles

An Institutional Experience of Directional Deep Brain Stimulation and a Review of the Literature

IntroductionDirectional deep brain stimulation (dDBS) has been suggested to have a similar therapeutic effect when compared with the traditional omnidirectional DBS, but with an improved therapeutic window that yields optimized clinical effect owing to the ability to better direct, or “steer,” electric current. We present our single-center, retrospective analysis of our experience in the use of dDBS in patients with movement disorders and provide a review of the literature. Materials and MethodsWe identified all patients with Parkinson disease (PD) and essential tremor (ET) who received a dDBS system between 2018 and 2022 and retrospectively examined characteristics of their longitudinal treatment. A total of 70 leads were identified across 42 patients (28 PD, 14 ET). ResultsThree types of systems were implemented (single-segment activation, 45.2% of patients; multiple independent current control, 50.0%; and local field potential sensing-enabled, 4.7%). The subthalamic nucleus or globus pallidus internus was targeted in PD, and the ventral intermediate nucleus of the thalamus in ET. Across the entire cohort (n = 70 leads), at initial programming, 54.2% of leads (n = 38) were programmed using directional stimulation. At the most recent reprogramming, 58.6% of leads (n = 41) implemented directionality. In patients with PD, the average decrease in levodopa-equivalent daily dose at six months after implantation was 35.4% ± 39.2%. Despite the ability to steer current to relieve stimulation-induced side effects, ten leads in six patients required surgical revision owing to electrode malposition. ConclusionsWe show wide adaptability and implementation of directional stimulation, adding to the growing compendium of real-world uses of dDBS therapy. We used directionality to improve clinical response in both patients with PD and patients with ET and found that its programming flexibility was used at high rates long after implantation and initial programming. In patients with PD, dDBS led to a significant reduction in dopaminergic medication, suggesting sustained clinical improvement. Nonetheless, accurate surgical placement remains necessary to ensure optimal clinical outcomes.

Apathy following Bilateral Deep Brain Stimulation of Subthalamic Nucleus and Globus Pallidus Internus in Parkinson's Disease: A Meta-Analysis.

Parkinson's disease (PD) is a progressive neurodegenerative disorder typically manifested by its motor symptoms. In addition, PD patients also suffer from many nonmotor symptoms (NMSs), such as apathy. Bilateral deep brain stimulation (DBS) of the subthalamic nucleus (STN) and the globus pallidus internus (GPi) are recommended as therapeutic interventions for PD, given their pronounced benefit in reducing troublesome dyskinesia. Apathy, a mood disorder recognized as a NMS of PD, has a negative impact on the prognosis of PD patients. However, the effect of STN-DBS and GPi-DBS on apathy is controversial. In the current meta-analysis, we analyzed apathy following bilateral STN-DBS and GPi-DBS in PD patients. Relevant literature was retrieved from public databases, including PubMed, Cochrane Library, and Embase. Studies were included in our analysis based on the following criterion: such studies should report apathy scores presurgery and postsurgery determined by using the Starkstein Apathy Scale or Apathy Evaluation Scale in patients receiving STN or GPi-DBS with at least three months of follow-up. Upon applying this strict criterion, a total of 13 out of 302 studies were included in our study. A mean difference (MD) and 95% confidence interval (CI) were calculated to show the change in apathy scores. We found a statistically significant difference between the presurgery and postsurgery scores in patients receiving STN-DBS (MD = 2.59, 95% CI = 2.23–2.96, P < 0.00001), but not in patients receiving GPi-DBS (MD = 0.32, 95% CI = −2.78–3.41, P=0.84). STN-DBS may worsen the condition of apathy, which may result from the reduction of dopaminergic medication. In conclusion, STN-DBS seems to relatively worsen the condition of apathy compared to GPi-DBS. Further studies should focus on the mechanisms of postoperatively apathy and the degree of apathy in STN-DBS versus GPi-DBS.

Should Deep Brain Stimulation Programs Be Halted During the COVID-19 Pandemic? Balancing the Risk of COVID-19 Infection Against the Survival Benefits of DBS

To the Editor: The COVID-19 pandemic has rapidly spread over the world. Numerous infections and fatalities have been reported in almost all countries. Facing the challenge of steadily increasing patients, limited amount of protection equipment and ventilators, resources have been relocated towards emergency departments and intensive care units. Nonemergency elective procedures such as deep brain stimulation (DBS) for patients with Parkinson’s disease have been postponed. It has been discussed that most functional neurosurgery patients are vulnerable to the COVID-19 pandemic and at a higher risk for becoming critically ill infected. Therefore, most centers have halted their DBS programs. Undisputed is that hardware infections and battery replacements require urgent action to prevent sepsis, neuroinfections or akinetic crisis and death, eventually (1.Miocinovic S Ostrem JL Okun MS Bullinger KL Riva-Posse P Gross RE Buetefisch CM. Recommendations for deep brain stimulation device management during a pandemic.J Parkinsons Dis. 2020; 10 (https://doi.org/10.3233/JPD-202072.): 903-910Crossref PubMed Scopus (34) Google Scholar,2.Gross RE et al.Letter: evaluation and surgical treatment of functional neurosurgery patients with implanted deep brain stimulation and vagus nerve stimulation pulse generators during the COVID-19 pandemic.Neurosurgery. 2020; 87: E222-E226Crossref PubMed Scopus (8) Google Scholar). We would like to highlight the fact that Parkinson’s disease (PD) itself is a condition with high mortality rate and complement the rationale that for any functional neurosurgery procedure, and DBS for PD in particular, we should always weigh the imminent risk of a COVID-19 infection against the long term clinical benefits of the procedure. As it remains unclear how long the pandemic will last, and if there will be a second peak, this becomes crucially important. Despite progress in medical management of PD, it does not appear to have altered the mortality rate nor significantly delayed the onset of nonmotor symptoms. Life expectancy remains decreased with the main cause of death being respiratory failure from aspiration pneumonia caused by dysphagia due to brady- or dyskinesia and rigidity of the muscles involved in the act of swallowing. Other causes of death include the deterioration of general condition, cardiovascular disease, traumatic injuries due to postural instability and sepsis. Co-evolving depression and dementia as well as the need for admittance to residential care facilities are associated with higher mortality and increased risk of suicide. All in all, 11 years is the median duration from the onset of PD until death (3.Duarte J García Olmos LM Mendoza A Clavería LE. The natural history of Parkinson’s disease in the province of Segovia: mortality in a longitudinal study (20-year follow-up).Acta Neurol. Scand. 2013; 127 (https://doi.org/10.1111/ane.12003.): 295-300Crossref PubMed Scopus (27) Google Scholar). DBS of the subthalamic nucleus has become an established pillar of the therapy continuum of patients with beginning motor fluctuations and suboptimal medical management, mainly improving motor symptoms (4.Deuschl G Schade-Brittinger C Agid Y EARLYSTIM Study GroupNeurostimulation for Parkinson’s disease with early motor complications.N Engl J Med. 2013; 368: 2038Google Scholar). Moreover, it has shown to improve survival rates in PD patients. A prospective, open-labeled, nonrandomized study by Ngoga et al. followed 147 patients who were offered a DBS procedure by a joint medical/surgical movement disorders clinic over the course of a 10 years period; 106 patients underwent DBS procedure whilst 41 patients prefered medical management. The mortality rate of patients who underwent DBS was significantly lower (17%) compared to patients who received medical management (41.5%), so was admittance to residential nursing care (5.7% vs. 36.6%) (5.Ngoga D Mitchell R Kausar J Hodson J Harries A Pall H. Deep brain stimulation improves survival in severe Parkinson’s disease.J Neurol Neurosurg Psychiatry. 2014; 85 (https://doi.org/10.1136/jnnp-2012-304715.): 17-22Crossref PubMed Scopus (69) Google Scholar). It has been widely discussed whether improvement of survival is related to ameliorated mobility and axial motor functions, perceived improvement in swallowing ability or reduction in dopaminergic medication and drug-related side effects. DBS could prevent the development of motor complications at a much earlier time-point and before long-term sequelae occur, such as psychosocial limitations and deterioration of quality of life. Given all these factors, we strongly believe that PD patients with motor fluctuations should not be treated as nonurgent but interdisciplinary teams of neurologists and neurosurgeons should carefully balance the risk of nosocomial COVID-19 infection against the long-term survival benefits. Conflict of Interest: None for all authors. Dr. Bara developed the idea and wrote the manuscript. Prof. Maciaczyk supervised the work and performed the revisions. Both authors approved the final manuscript.

Letter: Evaluation and Surgical Treatment of Functional Neurosurgery Patients With Implanted Deep Brain Stimulation and Vagus Nerve Stimulation Pulse Generators During the COVID-19 Pandemic.

Author(s): Gross, Robert E; Buetefisch, Cathrin M; Miocinovic, Svjetlana; Bullinger, Katie L; Okun, Michael S; Ostrem, Jill L; Foote, Kelly D; Starr, Phillip A

Management of Impulse Control Disorders with Subthalamic Nucleus Deep Brain Stimulation in Parkinson’s Disease

Impulse Control Disorders (ICDs) and related disorders are common side effects of dopaminergic treatment in Parkinson's Disease (PD) and are associated with negative effects on mental and physical health, quality of life and interpersonal relationships. Current management options are limited, as a reduction of dopaminergic medication often leads to worsening of motor symptoms or dopamine agonist withdrawal syndrome. The aim of this review was to investigate if ICDs improve, worsen, or remain stable after Subthalamic Nucleus Deep Brain Stimulation (STN-DBS). We reviewed retrospective, prospective and randomized-controlled studies published between 2000 and 2019 examining the effect of STN-DBS on one or more ICDs. The number of participants, time of follow-up, methods used to measure ICDs, type of ICDs, the incidence of ICDs before STN-DBS, the incidence of improvement (remission or reduction) of ICDs after STN-DBS, the incidence of de novo ICDs after STN-DBS, stimulation parameters, lead position, change in motor score and change in medication are reported for each study. Available studies suggest that ICDs improve after STN-DBS in most patients and that persisting new-onset ICDs induced by STN-DBS are rare. However, more randomized-controlled studies are needed to confirm the findings and to further investigate the underlying mechanisms.

Modulation of Nigrofugal and Pallidofugal Pathways in Deep Brain Stimulation for Parkinson Disease.

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a well-established surgical therapy for patients with Parkinson disease (PD). To define the role of adjacent white matter stimulation in the effectiveness of STN-DBS. We retrospectively evaluated 43 patients with PD who received bilateral STN-DBS. The volumes of activated tissue were analyzed to obtain significant stimulation clusters predictive of 4 clinical outcomes: improvements in bradykinesia, rigidity, tremor, and reduction of dopaminergic medication. Tractography of the nigrofugal and pallidofugal pathways was performed. The significant clusters were used to calculate the involvement of the nigrofugal and pallidofugal pathways and the STN. The clusters predictive of rigidity and tremor improvement were dorsal to the STN with most of the clusters outside of the STN. These clusters preferentially involved the pallidofugal pathways. The cluster predictive of bradykinesia improvement was located in the central part of the STN with an extension outside of the STN. The cluster predictive of dopaminergic medication reduction was located ventrolateral and caudal to the STN. These clusters preferentially involved the nigrofugal pathways. Improvements in rigidity and tremor mainly involved the pallidofugal pathways dorsal to the STN. Improvement in bradykinesia mainly involved the central part of the STN and the nigrofugal pathways ventrolateral to the STN. Maximal reduction in dopaminergic medication following STN-DBS was associated with an exclusive involvement of the nigrofugal pathways.

Deep Brain Stimulation for Parkinson's Disease

There is a long history of surgical treatment for Parkinson's disease (PD). Formerly, ablative stereotactic procedures such as thalamotomy or pallidotomy were performed. Currently, deep brain stimulation (DBS) is the most promising surgical treatment option for patients with medically refractory PD. DBS modulates neurological function of the target region using implanted medical devices to deliver electrical stimulation to the brain. Currently, the most common target of DBS for PD is the subthalamic nucleus (STN). The appropriate surgical candidate for STN-DBS suffers from motor complications from levodopa such as fluctuations and dyskinesia. STN-DBS significantly improves motor function in the medication-off state, motor fluctuations and dyskinesia with reduction of dopaminergic medication. Long-term outcomes are favorable for cardinal motor symptoms such as tremor, rigidity, and bradykinesia. However, refractory axial symptoms concerning speech, swallowing, gait and postural stability gradually deteriorated with progression of disease. New strategy to treat these axial symptoms is the future subject.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guideline on Subthalamic Nucleus and Globus Pallidus Internus Deep Brain Stimulation for the Treatment of Patients With Parkinson's Disease: Executive Summary.

Is bilateral subthalamic nucleus deep brain stimulation (STN DBS) more, less, or as effective as bilateral globus pallidus internus deep brain stimulation (GPi DBS) in treating motor symptoms of Parkinson's disease, as measured by improvements in Unified Parkinson's Disease Rating Scale, part III (UPDRS-III) scores? Given that bilateral STN DBS is at least as effective as bilateral GPi DBS in treating motor symptoms of Parkinson's disease (as measured by improvements in UPDRS-III scores), consideration can be given to the selection of either target in patients undergoing surgery to treat motor symptoms. (Level I). Is bilateral STN DBS more, less, or as effective as bilateral GPi DBS in allowing reduction of dopaminergic medication in Parkinson's disease? When the main goal of surgery is reduction of dopaminergic medications in a patient with Parkinson's disease, then bilateral STN DBS should be performed instead of GPi DBS. (Level I). Is bilateral STN DBS more, less, or as effective as bilateral GPi DBS in treating dyskinesias associated with Parkinson's disease? There is insufficient evidence to make a generalizable recommendation regarding the target selection for reduction of dyskinesias. However, when the reduction of medication is not anticipated and there is a goal to reduce the severity of "on" medication dyskinesias, the GPi should be targeted. (Level I). Is bilateral STN DBS more, less, or as effective as bilateral GPi DBS in improving quality of life measures in Parkinson's disease? When considering improvements in quality of life in a patient undergoing DBS for Parkinson's disease, there is no basis to recommend bilateral DBS in 1 target over the other. (Level I). Is bilateral STN DBS associated with greater, lesser, or a similar impact on neurocognitive function than bilateral GPi DBS in Parkinson disease? If there is significant concern about cognitive decline, particularly in regards to processing speed and working memory in a patient undergoing DBS, then the clinician should consider using GPi DBS rather than STN DBS, while taking into consideration other goals of surgery. (Level I). Is bilateral STN DBS associated with a higher, lower, or similar risk of mood disturbance than GPi DBS in Parkinson's disease? If there is significant concern about the risk of depression in a patient undergoing DBS, then the clinician should consider using pallidal rather than STN stimulation, while taking into consideration other goals of surgery. (Level I). Is bilateral STN DBS associated with a higher, lower, or similar risk of adverse events compared to GPi DBS in Parkinson's disease? There is insufficient evidence to recommend bilateral DBS in 1 target over the other in order to minimize the risk of surgical adverse events. The full guideline can be found at: https://www.cns.org/guidelines/deep-brain-stimulation-parkinsons-disease.

Apathy following Bilateral Deep Brain Stimulation of Subthalamic Nucleus in Parkinson's Disease: A Meta-Analysis.

Bilateral deep brain stimulation of subthalamic nucleus (STN-DBS) has proven effective in improving motor symptoms in Parkinson's disease (PD) patients. However, psychiatric changes after surgery are controversial. In this study, we specifically analyzed apathy following bilateral STN-DBS in PD patients using a meta-analysis. Relevant articles utilized for this study were obtained through literature search on PubMed, ScienceDirect, and Embase databases. The articles included were those contained both pre- and postsurgery apathy data acquired using the Starkstein Apathy Scale or Apathy Evaluation Scale with patient follow-up of at least three months. A total of 9 out of 86 articles were included in our study through this strict screening process. Standardized mean difference (SMD), that is, Cohen's d, with a 95% confidence interval (CI) was calculated to show the change. We found a significant difference between the presurgery stage and the postsurgery stage scores (SMD = 0.35, 95% CI: 0.17∼0.52, P < 0.001). STN-DBS seems to relatively worsen the condition of apathy, which may result from both the surgery target (subthalamic nucleus) and the reduction of dopaminergic medication. Further studies should focus on the exact mechanisms of possible postoperative apathy in the future.

Personality, dopamine, and Parkinson's disease: Insights from subthalamic stimulation.

Subthalamic stimulation improves the motor and neuropsychiatric symptoms of Parkinson's disease. However, the impact of this treatment on impulse control and personality is the subject of heavy debate. The objective of this study was to investigate personality changes after subthalamic stimulation. Using Cloninger's biosocial model, we assessed personality in 73 Parkinson's disease patients before and 12 months after subthalamic stimulation accompanied by a drastic reduction in dopaminergic medication. Changes in psychobehavioral symptoms were measured using a battery of validated clinical scales (apathy, depression, anxiety, hyperemotionality, mania, psychosis, punding, and impulse control behaviors). One year after surgery, the harm avoidance personality domain total score increased compared with the baseline (+2.8; 34 patients; P < 0.001), as did 3 of its 4 subdomains: anticipatory worry (+0.7; 10 patients; P = 0.005), shyness (+0.6; 7 patients; P = 0.03), and fatigability (+1.1; 10 patients; P = 0.0014). Evolution of the shyness personality trait correlated with the decrease in dopaminergic medication. Total scores in the other personality domains remained unchanged, except for extravagance, a subdomain of novelty seeking, and persistence, a subdomain of reward dependence, which both decreased following surgery (-0.3; 7 patients; and -0.6; 9 patients; P = 0.03 and P = 0.0019, respectively). Although apathy increased, other psychobehavioral symptoms, including impulse control behaviors and neuropsychiatric nonmotor fluctuations, improved. Depression and anhedonia remained stable. Scores in hypodopaminergia and neuropsychiatric nonmotor OFF correlated with harm avoidance. Scores in hyperdopaminergia and neuropsychiatric nonmotor ON correlated with novelty seeking. When subthalamic stimulation is applied in Parkinson's disease, significant changes in personality traits are observed, which may be related to postoperative tapering of dopaminergic treatment. © 2017 International Parkinson and Movement Disorder Society.

Five-Year Outcomes of Bilateral Subthalamic Nucleus Stimulation in Japanese Patients with Parkinson’s Disease

Background: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is widely performed for medically refractory Parkinson’s disease (PD). Several western studies have examined the long-term outcomes of STN DBS. However, the long-term outcomes in Japanese patients have not been reported. Methods: We studied the long-term outcomes of STN DBS in Japanese patients with PD. Fifty-five consecutive patients treated with bilateral STN DBS were followed for 5 years after surgery. Each patient underwent Unified Parkinson’s Disease Rating Scale assessments preoperatively and 1 and 5 years after surgery. Results: Twelve patients (22%) were lost to follow up within 5 years. Among them, 7 died and 5 became bed ridden because of PD deterioration. In the 43 patients followed for 5 years, STN DBS significantly improved motor function. The cardinal motor symptoms of tremor, rigidity, and bradykinesia in medication-on periods were significantly better than baseline 5 years after DBS. However, axial motor symptoms of speech, gait and postural stability gradually deteriorated and significantly worsened 5 years after DBS. Motor complications, including dyskinesia and motor fluctuations, significantly improved after DBS with a marked reduction in dopaminergic medication. These effects were maintained 5 years after DBS. Frequently, persisting adverse effects included apraxia of eyelid opening and dysarthria. Conclusions: STN DBS significantly improved motor symptoms in patients with advanced PD. These effects were maintained over 5 years in most patients. However, some showed rapid PD progression even after STN DBS. Other treatments for the axial symptoms and disease progression are needed in long-term PD treatment.

Deep brain stimulation improves survival in severe Parkinson's disease

ObjectivesLevodopa and other dopaminergic treatments have not had the expected effect on survival in Parkinson's disease (PD). Bilateral subthalamic nucleus deep brain stimulation (STN-DBS) has been shown to improve motor...

Psychostimulant effect of levodopa: reversing sensitisation is possible

BackgroundLevodopa therapy in Parkinson's disease (PD) is associated with non-motor complications resulting from sensitisation of the ventral striatum system. Recent studies showed an improvement in non-motor complications in PD patients...

Temporary deterioration of executive function after subthalamic deep brain stimulation in Parkinson's disease

ObjectiveSelective impairment of executive function has been shown in Parkinson's Disease (PD) patients undergoing Deep Brain Stimulation (DBS) of the Subthalamic Nucleus (STN). However, some patients experience difficulties in daily life, such as dissension in interpersonal relationships or a loss of lifestyle balance, in the short term after surgery. Our hypothesis is that these difficulties might be related to executive dysfunction. To elucidate the involvement of executive dysfunction in these difficulties, we assessed motor and executive function in the short term and long term after surgery. MethodsWe examined motor function and executive function in 30 patients who underwent bilateral STN–DBS for medically refractory PD. Patients were evaluated for executive function 1 month before surgery, 1 month after surgery, and 12 months after surgery using the Trail Making Test (TMT), the Modified Stroop Color Word Interference Test (MST) and tests of Verbal Fluency (VF). ResultsTMT-B, TMT (B/A), MST-B, VF-phonemic and VF-semantic scores were significantly poorer 1 month after STN–DBS. TMT-B, TMT (B/A) and VF-phonemic recovered to preoperative levels by 12 months after surgery. A reduction in dopaminergic medication 1 month after surgery was significantly correlated with deterioration of TMT (B/A). ConclusionTemporary deterioration of executive function may occur in the short term after STN–DBS, whereas motor function is usually improved. PD patients undergoing STN–DBS should be managed during this period to better predict temporary executive dysfunction. Excessive reduction of dopaminergic medication after surgery might, at least in part, result in this deterioration of executive function.

P.07 The role of amantadine in motor complications after deep brain stimulation for Parkinson's disease

Subthalamic deep brain stimulation (STN DBS) for Parkinson's disease typically enables a 50% reduction in dopaminergic medication postoperatively. This reduction in medication is accompanied by a 60% reduction in dyskinesia...

Suicide Attempts after Subthalamic Nucleus Stimulation for Parkinson’s Disease

A higher risk of suicidal attempt after subthalamic nucleus deep brain stimulation (STN-DBS) for Parkinson’s disease (PD) has been consistently reported. We retrospectively analyzed 3 PD patients with suicide attempts after STN-DBS. All patients had normal pre- and immediate postoperative psychopathological and cognitive evaluations, with STN-DBS yielding a good motor benefit. Levodopa medication was markedly reduced. Albeit there was a significant reduction in dopaminergic medication, there was also a considerable time lag to suicide attempt. Impulsive behavior could have played a higher role, going unnoticed in punctual psychopathological examinations. STN-DBS patients need a closer postoperative psychiatric and behavioral follow-up.

Tratamiento de la psicosis parkinsoniana

Parkinson's disease (PD) is a chronic idiopathic neurodegenerative disorder in which there is a dopamine deficit that produces motor and other disturbances, such as autonomic, sensory and neuropsychiatric disorders, including psychosis. Psychosis in PD, which is characterised by the existence of hallucinations and delusions, is a frequent and disabling problem for the patient; it is stressing for caregivers and difficult to manage for the physician, since it predisposes the patient to higher rates of morbidity and mortality and to institutionalisation.To carry out a review of the literature on the treatment of psychosis in PD.In this paper we review several different aspects of psychosis in PD, such as the diagnostic criteria, pathophysiology, predisposing factors, clinical features and, above all, management, which includes the use of atypical antipsychotics (after attempts have been made to reduce the antiparkinson medication to a limit marked by the loss of motor autonomy). Additionally, we also review the evidence that is currently available on other pharmaceuticals for use to treat psychosis in PD (anticholinesterases, drugs that act on serotonin receptors and so forth).Psychosis in PD is a problem that is difficult to treat, with a poorly understood pathophysiology, in which the most important means of combating it (in addition to prevention and reduction of dopaminergic medication, if possible) is the use of atypical antipsychotics. Other treatments which are now offering still very preliminary, but promising, results could well end up becoming the first line of treatment for this condition in the near future.

Rapid Resolution of Dopamine Dysregulation Syndrome (DDS) After Subthalamic DBS for Parkinson Disease (PD)

To describe how subthalamic deep brain stimulation (STN-DBS) and reduction in dopamine replacement therapy (DRT) allowed rapid resolution of dopamine dysregulation syndrome (DDS) with severe behavioral disorder in a patient with late stage Parkinson disease (PD). DDS was recently defined as compulsive use of dopaminergic drugs, associated with severe behavioral symptoms, and impaired social functioning, occurring in about 4% of PD patients under DRT. STN-DBS is an effective treatment for late stage PD with treatment resistant motor fluctuations, which frequently allows also to reduce DRT. A late stage PD patient referred to our center for STN-DBS, suffering from severe DDS necessitating in-ward psychiatric management, was comprehensively assessed preoperatively and postoperatively for motor, cognitive, and psychiatric status. Following subthalamic DBS procedure and medication reduction, we observed a rapid and dramatic resolution of DDS and associated psychiatric symptoms, allowing discharge from a 2-year stay in a psychiatric institution. DDS occurring in late stage PD patients may be dramatically improved by STN-DBS, possibly in relation with the reduction of dopaminergic medication. In contrast to other psychiatric symptoms, DDS should not be considered as an obstacle to DBS procedure in late stage PD patients.

STN DBS in PD

Brain stimulation in the awake patient was systematically used by Penfield to map cortical functions during epilepsy and tumor surgery.1 Although it was initially thought that such stimulation activated circuits much like turning on a tape recorder, electrophysiologic mapping during stereotactic surgery showed that high-frequency stimulation could temporarily disrupt normal neural activity and produce a functional lesion.2 This eventually led to the use of deep brain stimulation (DBS) to replace Vim thalamotomy for the treatment of tremor.3 Now hailed as the holy grail of treatment for advanced Parkinson disease (PD), dystonia, and tremor, but also applied to the treatment of chronic pain, Tourette syndrome, depression, Huntington disease, obsessive-compulsive disorder, and epilepsy, DBS is established as a major technique in functional neurosurgery. The pathophysiologic basis of DBS is proposed to be the induction of a functional lesion, a cancellation of error messages, or perhaps the liberation of transmitter either locally or at a distance from the point stimulated.4 Subthalamic nucleus (STN) DBS allows the reduction of dopaminergic medication by approximately 50% and provides long-term improvement of motor symptoms.5 Stimulation of other brain targets (e.g., the globus pallidus internus) is of less benefit and does not reduce the need for dopaminergic medication.6 This raises the question as to whether (and to what extent) STN DBS activates dopaminergic …