Change in fatigue after bilateral subthalamic nucleus deep brain stimulation for Parkinson's disease

BackgroundBilateral subthalamic nucleus (STN) deep brain stimulation (DBS) improves motor function in patients with medically intractable Parkinson’s disease (PD), but the effects of STN DBS on fatigue are unknown. The purpose of this study was to examine the effects of STN DBS on fatigue scores in patients with PD.MethodsTwenty PD patients underwent bilateral STN DBS surgery at our institution from 2007 to 2009. Only data from the 17 patients who completed the Parkinson Fatigue Scale (PFS) and Unified PD Rating Scale (UPDRS) before and approximately 6 months after surgery were analyzed. Other evaluations included the Geriatric Depression Scale (GDS), Apathy Evaluation Scale (AES), and Epworth Sleepiness Scale (ESS).ResultsWhen the cohort was analyzed as a whole, there was no significant change in the mean or binary PFS score from baseline to the 6 month evaluation. However, the fatigue response of individual subjects was variable. Six of 12 subjects with fatigue before surgery were not fatigued post-operatively, while 3/5 subjects without fatigue before surgery became fatigued after DBS surgery. Fatigue in 8 subjects remained unchanged. Change in fatigue scores correlated significantly with change in the motor UPDRS, GDS and AES. Improvement in PFS also correlated with a higher PFS baseline score and higher baseline UPDRS motor off score.ConclusionsChanges in fatigue severity were not observed in our cohort as a whole, but there were changes in fatigue on an individual level. These changes appear to be related to the effects of STN DBS on motor improvement and mood.     

Mood response to deep brain stimulation of the subthalamic nucleus in Parkinson's disease

Deep brain stimulation of the subthalamic nucleus (STN DBS) in Parkinson's disease (PD) improves motor functioning but has variable effects on mood. Little is known about the relationship between electrode contact location and mood response. The authors identified the anatomical location of electrode contacts and measured mood response to stimulation with the Visual Analog Scale in 24 STN DBS PD patients. Participants reported greater positive mood and decreased anxiety and apathy with bilateral and unilateral stimulation. Left DBS improved mood more than right DBS. Right DBS-induced increase in positive mood was related to more medial and dorsal contact locations. These results highlight the functional heterogeneity of the STN.     

Neuropsychiatric symptoms three years after subthalamic DBS in PD patients

Objective

To evaluate neuropsychiatric symptoms in PD patients submitted to bilateral deep brain stimulation of the subthalamic nucleus (DBS-STN) by comparison with a control group of PD patients not treated with DBS.

Methods

25 consecutive PD patients bilaterally implanted for DBS of STN (DBS group) were compared to a control group of 25 not operated PD patients (CT group) for mood, anxiety and personality traits. The two group were matched for age, sex, duration and severity of the illness. DBS PD patients were assessed three years after surgery. Mood was evaluated through the Beck Depression Inventory (BDI). Anxiety was measured by means of the State-Trait Anxiety Inventory (STAI X1-X2) and personality traits were evaluated with the Structured Clinical Interview for the DSM-IIIR Axis II Disorders (SCID II).

Results

Comparing the DBS group and the CT group, no significant differences were found for mood (BDI) or state and trait anxiety scores (STAI X1-X2). Obsessive-compulsive traits scores were found to be significantly lower in the DBS group (p < 0.03).

Conclusions

The results of this case-control study suggest that STN DBS does not lead to relevant modifications of mood, anxiety and personality provided that PD patients are well selected for the surgical treatment.     

Medication dose reductions after pallidal versus subthalamic stimulation in patients with Parkinson's disease

Evidente VGH, Premkumar AP, Adler CH, Caviness JN, Driver‐Dunckley E, Lyons MK. Medication dose reductions after pallidal versus subthalamic stimulation in patients with Parkinson’s disease.
Acta Neurol Scand: 2011: 124: 211–214.
© 2010 John Wiley & Sons A/S. Objective – To compare the medication dose reduction between deep brain stimulation (DBS) of the globus pallidus interna (GPi) vs subthalamic nucleus (STN) in matched patients with Parkinson’s disease (PD). Materials and methods – Records of 12 patients with PD who underwent GPi‐DBS at our institution from 2002 to 2008 were matched by pre‐operative PD medication doses and pre‐operative motor Unified Parkinson’s Disease Rating Scale (UPDRS) scores to 12 cases of STN‐DBS. PD medication doses were converted to levodopa equivalent doses (LEDs). Results – GPi and STN groups had similar mean pre‐operative LEDs and motor UPDRS scores. At 6 months post‐DBS, there was no significant difference in percent reduction in LEDs between the GPi (47.95%) and STN (37.47%) groups (P = 0.52). The mean post‐operative ‘medication off/stimulation on’ motor UPDRS scores did not differ significantly between GPi (15.33) and STN (16.25) groups (P = 0.74). The mean percent reduction in motor UPDRS scores was also similar between GPi (58.44%) and STN (58.98%) patients (P = 0.94). Conclusions – We conclude that in disease‐matched patients with PD undergoing DBS, both GPi and STN may result in similar reduction in PD medication doses.     

Neural correlates of STN DBS-induced cognitive variability in Parkinson disease

BACKGROUND: Although deep brain stimulation of the subthalamic nucleus (STN DBS) in Parkinson disease (PD) improves motor function, it has variable effects on working memory (WM) and response inhibition (RI) performance. The purpose of this study was to determine the neural correlates of STN DBS-induced variability in cognitive performance. METHODS: We measured bilateral STN DBS-induced blood flow changes (PET and [(15)O]-water on one day) in the supplementary motor area (SMA), dorsolateral prefrontal cortex (DLPFC), anterior cingulate cortex (ACC), and right inferior frontal cortex (rIFC) as well as in exploratory ROIs defined by published meta-analyses. STN DBS-induced WM and RI changes (Spatial Delayed Response and Go-No-Go on the next day) were measured in 24 PD participants. On both days, participants withheld PD medications overnight and conditions (OFF vs. ON) were administered in a counterbalanced, double-blind manner. RESULTS: As predicted, STN DBS-induced DLPFC blood flow change correlated with change in WM, but not RI performance. Furthermore, ACC blood flow change correlated with change in RI but not WM performance. For both relationships, increased blood flow related to decreased cognitive performance in response to STN DBS. Of the exploratory regions, only blood flow changes in DLPFC and ACC were correlated with performance. CONCLUSIONS: These results demonstrate that variability in the effects of STN DBS on cognitive performance relates to STN DBS-induced cortical blood flow changes in DLPFC and ACC. This relationship highlights the need to further understand the factors that mediate the variability in neural and cognitive response to STN DBS.     

Utilizing 7-Tesla Subthalamic Nucleus Connectivity in Deep Brain Stimulation for Parkinson Disease

BackgroundDeep brain stimulation (DBS) of the subthalamic nucleus (STN) is a highly effective surgical treatment for patients with advanced Parkinson disease (PD). Combining 7.0-Tesla (7T) T2- and diffusion-weighted imaging (DWI) sequences allows for selective segmenting of the motor part of the STN and, thus, for possible optimization of DBS.Materials and Methods7T T2 and DWI sequences were obtained, and probabilistic segmentation of motor, associative, and limbic STN segments was performed. Left- and right-sided motor outcome (Movement Disorders Society Unified Parkinson’s Disease Rating Scale) scores were used for evaluating the correspondence between the active electrode contacts in selectively segmented STN and the clinical DBS effect. The Bejjani line was reviewed for crossing of segments.ResultsA total of 50 STNs were segmented in 25 patients and proved highly feasible. Although the highest density of motor connections was situated in the dorsolateral STN for all patients, the exact partitioning of segments differed considerably. For all the active electrode contacts situated within the predominantly motor-connected segment of the STN, the average hemi-body Unified Parkinson’s Disease Rating Scale motor improvement was 80%; outside this segment, it was 52% (p < 0.01). The Bejjani line was situated in the motor segment for 32 STNs.ConclusionThe implementation of 7T T2 and DWI segmentation of the STN in DBS for PD is feasible and offers insight into the location of the motor segment. Segmentation-guided electrode placement is likely to further improve motor response in DBS for PD. However, commercially available DBS software for postprocessing imaging would greatly facilitate widespread implementation.     

Bilateral subthalamic nucleus stimulation in the treatment of advanced Parkinson's disease. Five years' personal experience

Background and purposeThe objective of the study was to assess bilateral subthalamic nucleus (STN) deep brain stimulation (DBS) for patients with advanced Parkinson disease (PD).Material and methodsThe study population included 5 patients with bilateral STN DBS who completed a 5-year postoperative follow-up period. In all patients electrodes (Model 3387 or 3389) were stereotactically bilaterally inserted into the STN using a Leksell stereotactic G frame. The clinical rating tests included Unified Parkinson's Disease Rating Scale (UPDRS) and two motor-timed tests derived from CAPIT (rapid movements between two points and stand-walk-sit test). All patients were assessed in off and on condition before implantation and 1, 3 and 5 years in medication on and off condition and stimulation on condition and stimulation off condition. To compare preoperative to postoperative UPDRS scores, only mean values and standard deviations are presented because of the small study population.ResultsThe stimulation effect was noted in the off state, resulting in a 59% improvement in motor scores of UPDRS at 5-year follow-up, when compared to preoperative scores. In the on state the stimulation improved motor scores by 17%. At 5-year follow-up, reduction of daily levodopa dose was 50%.ConclusionsBilateral STN DBS is an effective and safe treatment for patients with advanced PD. Bilateral STN DBS contributes to improvement of parkinsonian symptoms in the off state and levodopa-induced dyskinesia. This can be correlated with a 50% reduction of daily levodopa dose 5 years postoperatively.     

Unilateral vs. bilateral STN DBS effects on working memory and motor function in Parkinson disease

Bilateral subthalamic nucleus deep brain stimulation (STN DBS) can reduce working memory while improving motor function in Parkinson disease (PD), but findings are variable. One possible explanation for this variability is that the effects of bilateral STN DBS on working memory function depend in part on functional or disease asymmetry. The goal of this study was to determine the relative contributions of unilateral DBS to the effects seen with bilateral DBS. Motor (Unified Parkinson Disease Rating Scale Part III, UPDRS) and working memory function (Spatial Delayed Response, SDR) were measured in 49 PD patients with bilateral STN DBS while stimulators were Both-off, Left-on, Right-on and Both-on in a randomized, double-blind manner. Patients were off PD medications overnight. Effects of unilateral DBS were compared to effects of bilateral STN DBS. Mean UPDRS and SDR responses to Left-on vs. Right-on conditions did not differ (p>.20). However, improvement in contralateral UPDRS was greater and SDR performance was more impaired by unilateral DBS in the more affected side of the brain than in the less affected side of the brain (p=.008). The effect of unilateral DBS on the more affected side on contralateral UPDRS and SDR responses was equivalent to that of bilateral DBS. These results suggest that motor and working memory function respond to unilateral STN DBS differentially depending on the asymmetry of motor symptoms.     

Subthalamic deep brain stimulation for the treatment of Parkinson disease

Background and purposeThe role of subthalamic nucleus deep brain stimulation (STN DBS) in the treatment of Parkinson disease (PD) is well established. The authors present a group of patients diagnosed with PD who were treated with STN DBS.Material and methodsBetween 2008 and 2009, 32 female and 34 male patients with PD were treated with STN DBS. Mean age at implantation was 57 ± 12 years. PD lasted from 6 to 21 years (mean 10 years). Patients were qualified for the surgery according to the CAPSIT-PD criteria. The STN was identified with direct and indirect methods. Macrostimulation and microrecording for STN identification were used in all cases. A unilateral STN DBS system was implanted in two cases and bilateral implantation was performed among rest of the group. Outcome was assessed six months after implantation.ResultsThe mean reduction of UPDRS III score among 51 patients who underwent follow-up was 45% (5-89%). Reduction of levodopa consumption varied from 15 to 100%. Infection forced the authors to remove the DBS system in one case four months after implantation. Skin erosion above the internal pulse generator was noted in four cases.ConclusionsCardinal symptoms of Parkinson's disease can be safely and effectively treated with STN DBS in selected group of patients.     

Eleven-Year Outcomes of Deep Brain Stimulation in Early-Stage Parkinson Disease

ObjectiveThe deep brain stimulation (DBS) in early-stage Parkinson's disease (PD) pilot clinical trial randomized 30 patients (Hoehn & Yahr II off; medication duration 0.5–4 years; without dyskinesia/motor fluctuations) to optimal drug therapy (ODT) (early ODT) or bilateral subthalamic nucleus (STN) DBS plus ODT (early DBS+ODT). This study aims to report the 11-year outcomes of patients who completed the DBS in early-stage PD pilot clinical trial.Materials and MethodsAttempts were made to contact all 29 subjects who completed the two-year trial to participate in an 11-year follow-up study. Mixed-effects models compared overall trend in outcomes for randomization groups (fixed-effects: assigned treatment, year, their interaction; random-effect: subject) to account for repeated measures.ResultsTwelve subjects participated in this 11-year follow-up study (n = 8 early ODT, n = 4 early DBS+ODT). Participating subjects were 70.0 ± 4.8 years old with a PD medication duration of 13.7 ± 1.7 years (early DBS duration 11.5 ± 1.3 years, n = 4). Three early ODT subjects received STN-DBS as standard of care (DBS duration 6.5 ± 2.0 years). Early ODT subjects had worse motor complications (Unified Parkinson’s Disease Rating Scale [UPDRS]–IV) than early DBS+ODT subjects over the 11-year follow-up period (between-group difference = 3.5 points; p_interaction = 0.03). Early DBS+ODT was well-tolerated after 11 years and showed comparable outcomes to early ODT for other UPDRS domains, Parkinson Disease Questionnaire–39 (PDQ-39), and levodopa equivalent daily dose (LEDD).ConclusionsEleven years after randomization, early DBS+ODT subjects had fewer motor complications than early ODT subjects. These results should be interpreted with caution because only 40% of pilot trial subjects participated in this 11-year follow-up study. The Food and Drug Administration has approved the conduct of a pivotal clinical trial evaluating DBS in early-stage PD (IDEG050016).Clinical Trial RegistrationThe Clinicaltrials.gov registration number for the study is NCT00282152.     

Unilateral subthalamic nucleus deep brain stimulation improves sleep quality in Parkinson's disease

BackgroundSleep disturbances are common in Parkinson’s disease (PD). Bilateral subthalamic nucleus (STN) deep brain stimulation (DBS) is superior to best medical therapy in the treatment of motor symptoms in advanced PD, and observational studies suggest that bilateral STN DBS improves sleep in these patients as well. Unilateral STN DBS also improves motor function in PD, but its effects on sleep have not been extensively investigated.MethodsWe report the effects of unilateral STN DBS on subjective sleep quality as measured by the Pittsburgh Sleep Quality Index (PSQI) in 53 consecutive PD patients. These subjects completed the PSQI prior to surgery and at 3 and 6 months post-operatively. The primary outcome measure was the change in the global PSQI at 6 months post-operatively versus the pre-operative baseline, measured with repeated measures analysis of variance (ANOVA).ResultsPatients with PD who underwent unilateral STN DBS had a significant improvement in PSQI at 6 months post-operatively (baseline 9.30 ± 0.56 (mean ± SEM), 6 months: 7.93 ± 0.56, p = 0.013). Supplemental analyses showed that subjects selected for STN DBS placed on the right had worse baseline subjective sleep quality and more improvement in PSQI at 6 months compared to patients who received left STN DBS.ConclusionThis prospective case series study provides evidence that unilateral STN DBS improves subjective sleep quality in patients with PD at up to 6 months post-operatively as measured by the PSQI.     

Long‐term results of a multicenter study on subthalamic and pallidal stimulation in Parkinson's disease

We report the 5 to 6 year follow‐up of a multicenter study of bilateral subthalamic nucleus (STN) and globus pallidus internus (GPi) deep brain stimulation (DBS) in advanced Parkinson's disease (PD) patients. Thirty‐five STN patients and 16 GPi patients were assessed at 5 to 6 years after DBS surgery. Primary outcome measure was the stimulation effect on the motor Unified Parkinson's Disease Rating Scale (UPDRS) assessed with a prospective cross‐over double‐blind assessment without medications (stimulation was randomly switched on or off). Secondary outcomes were motor UPDRS changes with unblinded assessments in off‐ and on‐medication states with and without stimulation, activities of daily living (ADL), anti‐PD medications, and dyskinesias. In double‐blind assessment, both STN and GPi DBS were significantly effective in improving the motor UPDRS scores (STN, P < 0.0001, 45.4%; GPi, P = 0.008, 20.0%) compared with off‐stimulation, regardless of the sequence of stimulation. In open assessment, both STN‐ and GPi‐DBS significantly improved the off‐medication motor UPDRS when compared with before surgery (STN, P < 0.001, 50.5%; GPi, P = 0.002, 35.6%). Dyskinesias and ADL were significantly improved in both groups. Anti‐PD medications were significantly reduced only in the STN group. Adverse events were more frequent in the STN group. These results confirm the long‐term efficacy of STN and GPi DBS in advanced PD. Although the surgical targets were not randomized, there was a trend to a better outcome of motor signs in the STN‐DBS patients and fewer adverse events in the GPi‐DBS group. © 2010 Movement Disorder Society     

GPi and STN deep brain stimulation can suppress dyskinesia in Parkinson's disease

ObjectivesTo compare subthalamic nucleus (STN) to globus pallidus internus (GPi) deep brain stimulation (DBS) for control of motor fluctuations and for potential dyskinesia-suppressing qualities.MethodsWe conducted a retrospective database review of all patients who underwent GPi or STN DBS for idiopathic Parkinson's disease. Direct dyskinesia suppression (dDS) was defined as improvement in dyskinesia subscore of the Unified Parkinson's Disease Rating Scale (UPDRS) part IV (items 32–34), despite lack of reduction in dopaminergic medication dosage. We analyzed the data using methods appropriate for a case–control study.ResultsA total of 133 patients were evaluated. At the last evaluation Dyskinesia scores and motor fluctuations significantly improved in both the GPi (p < 0.0001) and STN groups (p < 0.0001). The GPi group was more likely than the STN group to experience dDS (odds ratio = 1.95, 95% CI = 0.556, 3.21). However, the association between DBS target and dDS was not statistically significant (Pearson chi-square = 2.286, p = 0.131).ConclusionsThe overall clinical outcome of STN and GPi DBS for control of dyskinesia and motor fluctuations was similar. STN and GPi DBS both had some direct dyskinesia suppression effects.     

Greater improvement in quality of life following unilateral deep brain stimulation surgery in the globus pallidus as compared to the subthalamic nucleus

While deep brain stimulation (DBS) surgery is a well-accepted treatment for Parkinson disease (PD) that improves overall quality of life (QoL), its effects across different domains of QoL are unclear. The study reported here directly compared the effects of unilateral DBS in subthalamic nucleus (STN) or globus pallidus (GPi) on QoL in 42 non-demented patients with medication-refractory PD. Patients were enrolled in the COMPARE trial, a randomized clinical trial of cognitive and mood effects of STN versus GPi DBS conducted at the University of Florida Movement Disorders Center. Patients underwent motor, mood, verbal fluency and QoL (Parkinson disease questionnaire: PDQ-39) measures before and 6 months following surgery. Groups experienced motor and mood improvements that did not differ by target. Patients with STN DBS evidenced a slight decrement on letter fluency. On average, all patients endorsed better overall QoL after surgery. However, despite similar motor and mood improvements, GPi patients improved more than STN patients (38 vs. 14%, respectively; P = 0.03). Patients reported better QoL on subscales of mobility, activities of daily living (ADLs), emotional well-being, stigma, cognition and discomfort, but not on those of social support and communication. Improvements on the mobility, ADLs, stigma and social support subscales were greater amongst GPi patients. In regression analyses, only depression changes independently predicted changes in overall QoL as well as emotional well-being and social support changes. Within the STN group only, declining category fluency scores correlated with poorer QoL on the communication subscale. Unilateral DBS in both STN and GPi improved QoL overall and in disparate domains 6 months after surgery. Patients receiving GPi DBS reported greater improvements that cannot be explained by differential mood or motor effects; however, verbal fluency changes may have partially contributed to lesser QoL improvements amongst STN patients.     

Changes in cognitive‐emotional and physiological symptoms of depression following STN‐DBS for the treatment of Parkinson’s disease

Background and purpose: Subthalamic nucleus deep brain stimulation (STN‐DBS) has been shown to have beneficial effects on the motor features of Parkinson’s disease (PD), but its impact on non‐motor symptoms, most notably mood, has not been fully explored. Methods: In the first study to independently compare the emotional‐cognitive and somatic/physiological symptoms of depression, we examined mood differences in 17 bilateral STN‐DBS and 22 matched non‐surgical PD patients at baseline and 6 months. Results: The STN‐DBS group reported higher levels of depression at baseline with significant endorsement of physical symptomatology. Postoperatively, no significant between‐group differences in physical symptoms of depression were found. In contrast, a significant group by time interaction for cognitive‐emotional symptoms of depression was found, with the STN‐DBS group reporting an increase in psychological symptoms of distress. The STN‐DBS group also reported an increase in anxiety following surgery. The suicide rate of 5% found in our study is consistent with other postoperative studies in PD. The impact of changes in levodopa and psychotropic medication are also explored. Conclusions: Preliminary results suggest that the motor improvement often observed in patients with PD following bilateral STN‐DBS may be partially offset by an increase in affective‐cognitive symptoms of depression.     

Electrophysiologic Evidence That Directional Deep Brain Stimulation Activates Distinct Neural Circuits in Patients With Parkinson Disease

ObjectivesDeep brain stimulation (DBS) delivered via multicontact leads implanted in the basal ganglia is an established therapy to treat Parkinson disease (PD). However, the different neural circuits that can be modulated through stimulation on different DBS contacts are poorly understood. Evidence shows that electrically stimulating the subthalamic nucleus (STN) causes a therapeutic effect through antidromic activation of the hyperdirect pathway—a monosynaptic connection from the cortex to the STN. Recent studies suggest that stimulating the substantia nigra pars reticulata (SNr) may improve gait. The advent of directional DBS leads now provides a spatially precise means to probe these neural circuits and better understand how DBS affects distinct neural networks.Materials and MethodsWe measured cortical evoked potentials (EPs) using electroencephalography (EEG) in response to low-frequency DBS using the different directional DBS contacts in eight patients with PD.ResultsA short-latency EP at 3 milliseconds originating from the primary motor cortex appeared largest in amplitude when stimulating DBS contacts closest to the dorsolateral STN (p < 0.001). A long-latency EP at 10 milliseconds originating from the premotor cortex appeared strongest for DBS contacts closest to the SNr (p < 0.0001).ConclusionsOur results show that at the individual patient level, electrical stimulation of different nuclei produces distinct EP signatures. Our approach could be used to identify the functional location of each DBS contact and thus help patient-specific DBS programming.Clinical Trial RegistrationThe ClinicalTrials.gov registration number for the study is NCT04658641.     

丘脑底核脑深部电刺激治疗帕金森病合并抑郁障碍的长期疗效

目的研究丘脑底核（STN）脑深部电刺激（DBS）治疗帕金森病（PD）合并抑郁障碍的长期疗效并探讨其神经机制。方法对15例合并抑郁障碍的PD患者实施STN脑深部电极植入，术后3个月、6个月和12个月进行随访和临床评价。结果术后运动功能症状如肢体僵硬、震颤、运动迟缓和姿势平衡障碍改善良好，停药后PD分级量表运动评分显著下降（P〈0．01）。术后抑郁障碍症状如焦虑、绝望和激越症状改善良好，停药后汉密尔顿抑郁量表评分显著下降（P〈0．05）。结论STN-DBS能显著改善PD的抑郁障碍症状，STN在PD抑郁障碍神经机制中起重要作用。     

Correspondence of optimal stimulation and beta power varies regionally in STN DBS for Parkinson disease

IntroductionSubthalamic nucleus deep brain stimulation (STN DBS) for Parkinson disease (PD) normalizes neuronal hypersynchrony in the beta frequency range (13–30 Hz). The spatial correspondence of maximal beta power to the site of optimal stimulation along the DBS lead trajectory has been debated.MethodsWe determined the trajectory locations of the active contact, maximal beta power, and the dorsal border of the STN (DB-STN) in DBS patients. Beta power profiles were measured during intraoperative microelectrode recording (MER). Active contact locations were assigned during blinded, postoperative DBS programming. The DB-STN was identified both electrophysiologically during MER and anatomically on MRI. After grouping DBS trajectories into quadrants relative to the anatomic STN midpoint, we examined regional variations in the relative trajectory locations of the three entities.ResultsSTN DBS significantly improved motor performance for all 13 DBS patients, with active contacts at the DB-STN. Along trajectories passing posterior-medial to the STN midpoint, maximal beta power co-localized with active contacts at the DB-STN (difference Δ = 0.4 ± 1.6 mm, p = 0.57). By contrast, in posterior-lateral trajectories, maximal beta arose within the STN, ventral to active contacts (Δ = 1.9 ± 1.3 mm, p = 0.002). For trajectories anterior to the STN midpoint, maximal beta power co-localized with the DB-STN, while active contacts were ventral to peak beta power (p = 0.05).ConclusionOur findings indicate that co-localization of optimal stimulation and beta power varies by anatomical region in STN DBS for Parkinson disease.     

Two‐year follow‐up on the effect of unilateral subthalamic deep brain stimulation in highly asymmetric Parkinson's disease

Although bilateral subthalamic deep brain stimulation (STN DBS) provides greater relief from the symptoms of Parkinson's disease (PD) than unilateral STN DBS, it has been suggested that unilateral STN DBS may be a reasonable treatment option in selected patients, especially those with highly asymmetric PD. In previous studies on the effect of unilateral STN DBS, the asymmetry of PD symptoms was not prominent and the mean follow‐up durations were only 3 to 12 months. In this study, we report our findings in a series of 8 patients with highly asymmetric PD who were treated with unilateral STN DBS and were followed for 24 months. Serial changes in Unified Parkinson's Disease Rating Scale (UPDRS) motor score and subscores in the ipsilateral, contralateral, and axial body parts were analyzed. Unilateral STN DBS improved the UPDRS motor score and the contralateral subscore in the on‐medication state for 5 nonfluctuating patients and in the off‐medication state for 3 fluctuating patients. However, the ipsilateral subscore progressively worsened and reversed asymmetry became difficult to manage, which led to compromised medication and stimulator adjustment. At 24 months, all the patients were considering the second‐side surgery. Our results suggest that bilateral STN DBS should be considered even in highly asymmetric PD. © 2008 Movement Disorder Society     

Acute psychotropic effects of bilateral subthalamic nucleus stimulation and levodopa in Parkinson's disease.

High-frequency deep brain stimulation (DBS) of the subthalamic nucleus (STN) improves the motor symptoms of Parkinson's disease (PD). Opposite changes in mood, such as mania or depression, have been reported after surgery, but it is not known whether these side effects are specifically related to STN DBS. To learn whether STN DBS also influences the limbic loop, we investigated acute subjective psychotropic effects related to levodopa or bilateral STN DBS. After a median postoperative follow-up of 12 months, 50 PD patients completed the Addiction Research Center Inventory (ARCI), assessing subjective psychotropic effects in four conditions: off-drug/on-stimulation; off-drug/off-stimulation; on-drug/off-stimulation; and on-drug/on-stimulation. Both levodopa and STN DBS improved all the ARCI subscales, indicating subjective feelings of well being, euphoria, increase in motivation, and decrease in fatigue, anxiety, and tension. A suprathreshold dose of levodopa was significantly more effective than STN DBS, using the same electrical parameters as for chronic stimulation, on four of the five ARCI subscales. We concluded that 1) both STN DBS and levodopa have synergistic acute beneficial psychotropic effects in PD, 2) the psychotropic effects of both treatments need to be considered in the long-term management of chronic STN DBS, and 3) the results indicate an involvement of the limbic STN in mood disorders of PD.