***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: Abstract Preliminary reports in patients with Parkinson 's disease ( PD ) showed that subthalamic nucleus ( STN ) stimulation was able to reverse parkinsoniam state . Since 1998 we evaluated the safety and the efficacy of STN stimulation in 7 patients affected by advanced PD . All patients were included using CAPIT protocol .  Motor functions and quality of life were evaluated , before and after surgery , with UPDRS and PDQ38 , respectively . At the 6-month follow-up , the off medication/on stimulation UPDRS motor score improved by 50.6 % and the on medication/on stimulation by 20.3 % . Motor fluctuations were reduced by 57.2 % and dyskinesias by 73.5 % . The total D-dopa equivalent daily dose was reduced by 40.7 % . PDQ38 ameliorated by 49.9 % . We did not observe any perioperatory complication and only mild and tolerable side effects after stimulation A series of 24 consecutive PD patients were prospect ively studied prior to and within 6 months postoperatively for mood , motor , and cognitive status to investigate the effects on mood of subthalamic deep brain stimulation ( DBS ) in PD . In six patients ( 25 % ) , mood state worsened significantly , and three were transiently suicidal despite clear motor improvement . Caregivers and patients should be educated about the potential impact of this neurosurgical procedure on mood OBJECTIVE To evaluate the effects of bilateral deep brain stimulation in the subthalamic nucleus for symptomatic relief of advanced idiopathic Parkinson 's disease .  DESIGN Prospect i ve cohort study . SETTING Patients were assessed and received medical treatment at the Kingston Centre , Southern Health , Melbourne . Surgery took place at Melbourne Neuroscience Centre , The Royal Melbourne Hospital . Both are tertiary public institutions . SUBJECTS 14 patients with Parkinson 's disease with intact cognition and difficult to manage motor symptoms who were referred to Kingston Centre between 1996 and 2000 and were eligible for surgical intervention . INTERVENTIONS All patients were assessed both after 12 hours ' withdrawal from and while taking their levodopa medication on two occasions before surgery . Further assessment s were carried out one , three , six and 12 months after surgery . MAIN OUTCOME MEASURES The Unified Parkinson 's Disease Rating Scale motor exam and gait parameters , such as stride length and velocity , were compared at six months after surgery with neither stimulation nor medication , with stimulation only , with medication only , and with stimulation and medication . RESULTS Stimulators were explanted in one patient after intracranial haemorrhage and relocated to the thalamus in a second . Extraneous factors prevented two patients from attending at six-month follow-up . Motor performance improved significantly with stimulation alone in the 10 remaining patients . Further significant gains were seen with stimulation and medication combined , with an apparent reduction in side-effects such as dyskinesia . CONCLUSIONS Bilateral deep brain stimulation of the subthalamic nucleus significantly improves motor performance in advanced Parkinson 's disease , despite a rather high complication rate OBJECTIVES Deep brain stimulation of the basal ganglia has become a promising treatment option for patients with Parkinson 's disease who have side effects from drugs . Which is the best target — globus pallidus internus ( GPi ) or subthalamic nucleus (STN)—is still a matter of discussion . The aim of this prospect i ve study is to compare the long term effects of GPi and STN stimulation in patients with severe Parkinson 's disease . PATIENTS AND METHODS Bilateral deep brain stimulators were implanted in the  GPi in six patients and in the STN in 12 patients with severe Parkinson 's disease . Presurgery and 3 , 6 , and 12 months postsurgery patients were scored according to the CAPIT protocol . RESULTS Stimulation of the STN increased best Schwab and Engl and scale score significantly from 62 before surgery to 81 at 12 months after surgery ; GPi stimulation did not have an effect on the Schwab and Engl and scale . Stimulation of the GPi reduced dyskinesias directly whereas STN stimulation seemed to reduce dyskinesias by a reduction of medication . Whereas STN stimulation increased the unified Parkinson 's disease rating scale ( UPDRS ) motor score , GPi stimulation did not have a significant effect . Fluctuations were reduced only by STN stimulation and STN stimulation suppressed tremor very effectively . CONCLUSION Stimulation of the GPi reduces medication side effects , which leads to a better drug tolerance . There was no direct improvement of bradykinesia or tremor by GPi stimulation . Stimulation of the STN ameliorated all parkinsonian symptoms . Daily drug intake was reduced by STN stimulation . The STN is the target of choice for treating patients with severe Parkinson 's disease who have side effects from drugs Background The main advantage of deep brain stimulation ( DBS ) in the treatment of PD is that the electrical setting s can be adjusted to optimize benefits and minimize adverse effects . The main objective of this study was to discover how varying these electrical parameters impacted on parkinsonian motor signs . Methods Twelve patients with PD with chronic bilateral subthalamic nucleus ( STN ) stimulation were selected . The authors evaluated the effects of a variation in the voltages , frequencies , and pulse widths on tremor , bradykinesia , and rigidity using two different paradigms : one in which the total electrical energy delivered was held constant , and one in which this was varied . Up to 26 parameter conditions were tested under double blind r and omized conditions . Results Voltages ≥3 V and frequencies ≥130 Hz led to the greatest improvement in all three parkinsonian signs . A rate of 5 Hz significantly worsened akinesia . The combination of the highest voltage with the narrowest pulse width was most effective . Conclusions This study confirms that the most beneficial effects induced by STN stimulation are obtained at high frequencies and that voltage is the most critical factor to obtain adequate alteration in STN activity . The mechanisms by which STN DBS  improves parkinsonism remain speculative Abstract Bilateral deep brain stimulation is an effective treatment for most motor signs of Parkinson 's disease ( PD ) , but the effects on cognitive functions are less clear . We therefore examined the effects of bilateral deep brain stimulation on central information processing , using the event-related auditory P300 potential as an electrophysiological index of mental chronometry . Eight PD patients with bilateral stimulators within the subthalamic nuclei ( STN ) and eight age-matched controls participated . Patients were examined after overnight withdrawal of antiparkinson medication  , both “ on ” and “ off ” stimulation ( in r and om sequence ) . The P300 and reaction times were recorded using an auditory oddball paradigm  . P300 latencies were prolonged in PD patients off stimulation ( 440 ± 45 ms ) compared to controls ( 397 ± 16 ms ; P < 0.05 ) . STN stimulation significantly reduced clinical disease severity ( as indexed by the Unified Parkinson 's Disease Rating Scale ) and markedly improved reaction times , but did not improve the prolonged P300 latencies in PD patients ( 429 ± 36 ms ) . These results confirm that P300 latencies are prolonged in PD . Significantly , bilateral STN stimulation did not improve this electrophysiological measure of cognitive impairment , even though motor disability was markedly reduced . This suggests that some dopa-responsive features are resistant to STN stimulation , possibly due to involvement of dopaminergic deficits outside the nigrostriatal pathway , which are not influenced by outflow from the STN Abstract . Thirty patients with idiopathic Parkinson 's disease were treated with deep brain stimulation electrode in the subthalamic nucleus . After surgery , the patients ' best mean Unified Parkinson 's Disease Rating Scale ( UPDRS III ) scores ( medictionOFF-stimulatorON versus preoperative medicationOFF ) were 77±14 % at 3 months ( n=20 patients ) and 72±14 % at 12 months follow-up ( n=16 ) . The mean reduction in therapy ( expressed in levodopa dose equivalents in mg ) was 68±25 % at 12 months . Postoperative complications were rare , mostly mild , and reversible . Therapeutic success depends on a multidisciplinary team approach , meticulous patient selection , including patients ' cognitive , psychic , and behavioral status , and patient and family lifestyles CONTEXT This study was part of a large double-blind sham surgery-controlled trial design ed to determine the effectiveness of transplantation of human embryonic dopamine neurons into the brains of persons with advanced Parkinson 's disease . This portion of the study investigated the quality of life ( QOL ) of participants during the 1 year of double-blind follow-up . OBJECTIVES To determine whether QOL improved more in the transplant group than in the sham surgery group and to investigate outcomes at 1 year based on perceived treatment ( the type of surgery patients thought they received ) . DESIGN Participants were r and omly assigned to receive either the transplant or sham surgery . Reported results are from the 1-year double-blind period . SETTING Participants were recruited from across the United States and Canada . Assessment and surgery were conducted at 2 separate university medical centers . PARTICIPANTS A volunteer sample of 40 persons with idiopathic Parkinson 's disease participated in the transplant ( " parent " ) study , and 30 agreed to participate in the related QOL study : 12 received the transplant and 18 received sham surgery . INTERVENTIONS Interventions in the parent study were transplantation and sham brain surgery . Assessment s of QOL were made at baseline and 4 , 8 , and 12 months after surgery . MAIN OUTCOME MEASURES Comparison of the actual transplant and sham surgery groups and the perceived treatment groups on QOL and medical outcomes . We also investigated change over time . RESULTS There were 2 differences or changes over time in the transplant and sham surgery groups . Based on perceived treatment , or treatment patients thought they received , there were numerous differences and changes over time . In all cases , those who thought they received the transplant reported better scores . Blind ratings by medical staff showed similar results . CONCLUSIONS The placebo effect was very strong in this study , demonstrating the value of placebo-controlled surgical trials OBJECTIVE Deep brain stimulation ( DBS ) of the globus pallidus internus ( GPi ) and subthalamic nucleus ( STN ) has been reported to be effective in alleviating the symptoms of advanced Parkinson 's disease ( PD ) . Although recent studies suggest that STN stimulation may be superior to GPi stimulation , a r and omized , blinded comparison has not been reported . The present study was design ed to provide a preliminary comparison of the safety and efficacy of DBS at either site . METHODS Ten patients with idiopathic PD , L-dopa-induced dyskinesia , and response fluctuations were r and omized to implantation of bilateral GPi or STN stimulators . Neurological condition was assessed preoperatively with patients on and off L-dopa and on DBS at 10 days and 3 , 6 , and 12 months after implantation . Patients and evaluating clinicians were blinded to stimulation site throughout the study period . Complete follow-up data were analyzed for four GPi patients and five STN patients . RESULTS When off-L-dopa , both GPi and STN groups demonstrated a similar response , with approximately 40 % improvement in Unified PD Rating Scale motor scores after 12 months of DBS . Rigidity , tremor , and bradykinesia improved in both groups . In combination with L-dopa , Unified PD Rating Scale motor scores were more improved by GPi stimulation than by STN stimulation . On-L-dopa axial symptoms were clinical ly improved in the GPi but not the STN group . L-Dopa-induced dyskinesia was reduced by DBS at either site , although medication requirement was reduced only in the STN group . There were no serious intraoperative complications among patients in either group . CONCLUSION Pallidal and STN stimulation appears to be safe and efficacious for the management of advanced PD . A larger study is needed to investigate further the differences in symptom response and the interaction of L-dopa with stimulation at either site BACKGROUND Although the short-term benefits of bilateral stimulation of the subthalamic nucleus in patients with advanced Parkinson 's disease have been well documented , the long-term outcomes of the procedure are unknown . METHODS We conducted a five-year prospect i ve study of the first 49 consecutive patients whom we treated with bilateral stimulation of the subthalamic nucleus . Patients were assessed at one , three , and five years with levodopa ( on medication ) and without levodopa ( off medication ) , with use of the Unified Parkinson 's Disease Rating Scale . Seven patients did not complete the study : three died , and four were lost to follow-up . RESULTS As compared with base line , the patients ' scores at five years for motor function while off medication improved by 54 percent ( P<0.001 ) and those for activities of daily living improved by 49 percent ( P<0.001 ) . Speech was the only motor function for which off-medication scores did not improve . The scores for motor function on medication did not improve one year after surgery , except for the dyskinesia scores . On-medication akinesia , speech , postural stability , and freezing of gait worsened between year 1 and year 5 ( P<0.001 for all comparisons ) . At five years , the dose of dopaminergic treatment  and the duration and severity of levodopa-induced dyskinesia were reduced , as compared with base line ( P<0.001 for each comparison ) . The average scores for cognitive performance remained un 
    Output:
    
Bilateral subthalamic nucleus stimulation is effective in the treatment of PD .
Further refinements in patient selection and surgical technique may lessen the incidence of complications associated with this procedure