Disease Rating Scale Motor Subscale Research Articles

Differential response of speed, amplitude, and rhythm to dopaminergic medications in Parkinson's disease

Although movement impairment in Parkinson's disease includes slowness (bradykinesia), decreased amplitude (hypokinesia), and dysrhythmia, clinicians are instructed to rate them in a combined 0-4 severity scale using the Unified Parkinson's Disease Rating Scale motor subscale. The objective was to evaluate whether bradykinesia, hypokinesia, and dysrhythmia are associated with differential motor impairment and response to dopaminergic medications in patients with Parkinson's disease. Eighty five Parkinson's disease patients performed finger-tapping (item 23), hand-grasping (item 24), and pronation-supination (item 25) tasks OFF and ON medication while wearing motion sensors on the most affected hand. Speed, amplitude, and rhythm were rated using the Modified Bradykinesia Rating Scale. Quantitative variables representing speed (root mean square angular velocity), amplitude (excursion angle), and rhythm (coefficient of variation) were extracted from kinematic data. Fatigue was measured as decrements in speed and amplitude during the last 5 seconds compared with the first 5 seconds of movement. Amplitude impairments were worse and more prevalent than speed or rhythm impairments across all tasks (P < .001); however, in the ON state, speed scores improved exclusively by clinical (P < 10(-6) ) and predominantly by quantitative (P < .05) measures. Motor scores from OFF to ON improved in subjects who were strictly bradykinetic (P < .01) and both bradykinetic and hypokinetic (P < 10(-6) ), but not in those strictly hypokinetic. Fatigue in speed and amplitude was not improved by medication. Hypokinesia is more prevalent than bradykinesia, but dopaminergic medications predominantly improve the latter. Parkinson's disease patients may show different degrees of impairment in these movement components, which deserve separate measurement in research studies. © 2011 Movement Disorder Society.

A randomized, double‐blind, placebo‐controlled trial of levetiracetam for dyskinesia in Parkinson's disease

This randomized double blind, placebo-controlled crossover study investigated the antidyskinetic effects of levetiracetam in Parkinson's disease. Sixteen participants with levodopa-induced dyskinesia were enrolled. Hourly videotaped dyskinesia assessments scored by the Goetz method and hourly Unified Parkinson's Disease Rating Scale motor subscale scoring were conducted on 1 day at the end of each treatment period. Dyskinesia was slightly less on placebo (P = .26). Patient diary records also showed less dyskinesia on placebo (P = .10). Parkinsonism was a little worse on levetiracetam, at borderline statistical significance (P = .05). Levetiracetam was well tolerated at doses up to 2000 mg per day, but we did not detect any antidyskinetic properties.

Deep Brain Stimulation in “On”-State Parkinson Hyperpyrexia

Parkinsonism hyperpyrexia syndrome (PHS) is a life-threatening condition seen in Parkinson disease (PD) characterized by high fever, muscle rigidity, elevated creatine phosphokinase (CPK), autonomic instability, and altered consciousness. Serious complications, such as rhabdomyolysis, renal failure, disseminated intravascular coagulation, and infections, are common.1,–,3 Withdrawal from dopamine replacement therapy (DRT), infection, injury, surgery, dehydration, and metabolic abnormalities can provoke PHS.4 Treatment includes increasing the frequency of DRT and management of systemic complications. Mortality is 4% if treated and 16% if untreated.5,6 Among survivors, 30% have worsening of symptoms of parkinsonism and never return to their baseline. A 52-year-old woman with a 17-year history of PD was referred for deep brain stimulation (DBS) surgery. She had bilateral tremor, rigidity, gait impairment, postural instability, motor fluctuations with dyskinesias, and wearing off symptoms of limb dystonia and freezing. Medications included carbidopa/levodopa (CD/LD) and amantadine. The Unified Parkinson's Disease Rating Scale–motor subscore (UPDRS-III) in a challenged “on” state was 27 (video 1 on the Neurology ® Web site at www.neurology.org). Off medication (>12 hours) she had such severe tremor and rigidity in the waiting area that a physician passing by …

Clinical expression of LRRK2 G2019S mutations in the elderly

Mutations in the leucine-rich repeat kinase 2 gene (LRRK2, PARK8) are the most commonly identified monogenic etiology of Parkinson disease (PD). Over-represented in the Ashkenazi Jewish population, these mutations are transmitted in an autosomal dominant manner with age-dependent reduced penetrance. The natural history and penetrance of these mutations in the elderly is controversial and inadequately studied. We conducted a nested cohort study in a community-based aging study (the Einstein Aging Study). Six elderly, initially nonmanifesting carriers (NMC) of the LRKK2 G2019S mutation were identified (average age 82.1 ± 7.0, range 72.7-90.8), and five had available longitudinal data. We matched five noncarrier controls to each NMC and followed them for an average of 4.7 years with annual cognitive and motor examinations. PD was identified in one NMC at age 95 and in no control subjects. The remaining carriers did not differ from controls on motor scores at baseline or follow-up. The baseline Unified Parkinson's Disease Rating Scale motor subscore (UPDRS-III) in cases was 6.2 ± 6.9 (range 1-19) and in controls was 4.5 ± 6.6 (1-30), P = 0.6; the mean difference in UPDRS-III slopes over time between cases and controls was 0.1 ± 1.3 and was not statistically significant. Our data, while limited by a small sample size, show that in LRKK2 G2019S mutation carriers, phenoconversion to PD can occur late in life. However, most NMC have motor decline which is indistinguishable from their age mates, suggesting that the larger subset of elderly NMC is not on the motor trajectory to disease.

Effects of Medication on Turning Deficits in Individuals with Parkinson's Disease

People with Parkinson's disease often have difficulty executing turns. To date, most studies of turning have examined subjects ON their anti-Parkinson medications. No studies have examined what specific aspects of turning are modified or remain unchanged when medication is administered. The purpose of this study was to determine how anti-Parkinson medications affect temporal and spatial features of turning performance in individuals with Parkinson's disease. We examined turning kinematics in 10 people with Parkinson's disease who were assessed both OFF and ON medication. For both conditions, participants were evaluated with the Unified Parkinson's Disease Rating Scale motor subscale, rated how well their medication was working on a visual analog scale, and performed straight-line walking and 180-degree in-place turns. We determined the average walking velocity, time and number of steps to execute turns, sequence of yaw rotation onsets of the head, trunk, and pelvis during turns, and amplitudes of yaw rotation of the head, trunk, and pelvis during turns. Medication significantly improved the Unified Parkinson's Disease Rating Scale scores (P = 0.02), visual analog scale ratings (P = 0.03), and walking velocity (P = 0.02). Although improvements in turning were not statistically significant, medication did reduce the time and number of steps required to turn, slightly increased the amplitudes of yaw rotation of the various segments, and increased the rotation of the head relative to the other segments. Medication did not improve the timing of segment rotations, which showed en bloc turn initiation in both the OFF and ON medication conditions. These results suggest that only certain aspects of turning may be responsive to anti-Parkinson medications. As such, additional rehabilitative approaches to address turning are needed because turning may not be effectively addressed by pharmacologic approaches. These results should be interpreted cautiously given the small sample size.

Four‐week trunk‐specific rehabilitation treatment improves lateral trunk flexion in Parkinson's disease

People with Parkinson's disease (PD) often have a posture characterized by lateral trunk flexion poorly responsive to antiparkinsonian drugs. To examine the effects of a rehabilitation programme (daily individual 90-minute-sessions, 5-days-a-week for 4-consecutive weeks) on lateral trunk flexion and mobility, 22 PD patients with mild to severe lateral trunk flexion, and 22 PD patients without trunk flexion were studied. Patients were evaluated using the Unified Parkinson's Disease Rating Scale motor subscale (UPDRS-III) score, and the kinematic behavior of the trunk was recorded by means of an optoelectronic system to determine: a) trunk flexion, inclination and rotation values in the erect standing posture; b) ranges of trunk flexion and inclination during trunk movements. After the treatment, significant decreases in trunk flexion [24 degrees (4) vs. 14 degrees (3), P < 0.001] and inclination in the static condition [23 degrees (5) vs. 12 degrees (4), P < 0.001)] were observed, both of which were maintained at the 6-month follow up. During the trunk flexion task, a significantly increased range of trunk flexion [64 degrees (15) vs. 83 degrees (15), P < 0.001] was observed; similarly, during the lateral bending task, the range of trunk inclination was found to be significantly increased, both toward the side of the trunk deviation [29 degrees (8) vs. 42 degrees (13), P < 0.01] and toward the contralateral side [14 degrees (6) vs 29 degrees (11), P < 0.01]. No further significant changes were observed at the 6-month follow-up. Trunk flexion and inclination values in the upright standing posture correlated slightly with the UPDRS-III score. Our findings show that significant improvements in axial posture and trunk mobility can be obtained through the 4-week rehabilitation programme described, with a parallel improvement in clinical status.

P2.134 Differential response of bradykinesia and hypokinesia to levodopa in Parkinson's disease

Eighty-five PD patients (Table 1) performed UPDRS-directed finger tapping, hand grasping, and pronation/supination tasks in the OFF (12-15 hours after dopaminergic drug withdrawal) and ON states while wearing wireless six-degree-of-freedom motion sensors (KinetiSenseTM, CleveMed) on the index finger and thumb (Figure 1). Each motion sensor contains three orthogonal accelerometers for measuring linear acceleration and three orthogonal gyroscopes for measuring angular velocity. A Modified Bradykinesia Rating Scale (MBRS) was used to assess separately speed and amplitude during the tasks on a 0 – 4 scale (Table 2). Quantitative variables representing speed (root-mean-square [RMS] angular velocity) and amplitude (RMS excursion angle) were extracted from kinematic data, correlated with clinical MBRS scores, and used to classify patients as hypokinetic, bradykinetic, both, or neither. Although slowness (bradykinesia) and decreased amplitude (hypokinesia) of movements may be associated with differential impairment and disability in Parkinson’s disease (PD), clinicians are asked to rate rapid alternating movements into a combined 0 – 4 severity scale through the Unified Parkinson’s Disease Rating Scale motor subscale (UPDRS-III). Clinical raters consider multiple aspects of movement including speed, amplitude, hesitations, fatiguing, and arrests in movement. Previous research has shown that individual clinicians weigh individual components of bradykinesia differently, thus creating a considerable degree of variability across clinicians. The objective of this study is to evaluate the motor function and response to dopaminergic drugs in patients with PD with various impairments in speed and amplitude of movement. Speed and amplitude are evaluated separately to determine if bradykinesia and hypokinesia should deserve separate clinical assessment.

QUETIAPINE IMPROVES VISUAL HALLUCINATIONS IN PARKINSON DISEASE BUT NOT THROUGH NORMALIZATION OF SLEEP ARCHITECTURE: RESULTS FROM A DOUBLE-BLIND CLINICAL-POLYSOMNOGRAPHY STUDY

Polysomnographic studies of Parkinson's disease (PD) patients with visual hallucinations (VH) usually reveal short, fragmented rapid eye movement (REM) sleep, with lower sleep efficiency and reduced total REM sleep. Quetiapine has been demonstrated in open-label trials to be effective for the treatment of insomnia and VH in PD. To confirm quetiapine's efficacy in improving VH, and to determine whether the mechanism was due to its effect on REM sleep architecture, we performed a pilot, double-blind, placebo-controlled study. Sixteen PD patients experiencing VH were recruited. Eight patients were randomized to quetiapine and eight patients to placebo. Patients underwent pre- and post-treatment polysomnography. The Clinical Global Impression Scale (CGIS), Brief Psychiatric Rating Scale (BPRS), and Unified Parkinson Disease Rating Scale (UPDRS) motor subscale were obtained. There were no differences in baseline characteristics between the treatment arms except that the placebo group had more sleep in stage REM (74.7 min vs. 40.1 min; p < .001). Data were imputed for all patients who prematurely discontinued (four quetiapine and one placebo) in an intention-to-treat analysis. The average quetiapine dose was 58.3 mg/day. While there was no significant difference in the change in REM duration pre- vs. post-treatment in either arm, patients randomized to quetiapine improved on the CGIS (p = .03) and the hallucination item of the BPRS (p = .02). No difference was noted in the UPDRS motor scores. Despite the small sample, this is the first double-blind trial to show quetiapine's efficacy over placebo in controlling VH in the PD population. However, normalization of sleep architecture was not supported as the mechanism.

The relationship between impairment of voluntary movements and cognitive impairment in Huntington’s disease

The relationship between motor symptoms and cognitive impairment in Huntington's disease (HD) is still discussed. We analysed 45 HD patients in various stages using Unified Huntington's Disease Rating Scale motor subscale (voluntary and involuntary components were evaluated separately), verbal memory and executive functions tests. Partial correlations controlling for HD duration and age were used to estimate the relationships among factor scores for motor and cognitive impairment. Voluntary components of motor performance were found to be significantly correlated with verbal short-term memory disturbances (r = -0.361, P = 0.03), with tests of executive functions more dependent on motor performance (r = 0.640, P < 0.01) and also with tests of executive functions less dependent on motor performance (r = 0.461, P < 0.01). Involuntary components did not correlate significantly with any part of cognitive performance.

Short duration, intensive tango dancing for Parkinson disease: An uncontrolled pilot study

The goal of this pilot study was to determine the effects of short duration, intensive tango lessons on functional mobility in people with Parkinson disease. This study employed a within-subject, prospective, repeated measures design. Fourteen people with idiopathic Parkinson disease participated. All balance and gait assessments were performed in a laboratory, but dance classes took place in a large, open classroom. Participants completed ten 1.5-h long Argentine tango dance lessons within 2 weeks. Their balance, gait and mobility were assessed before and after the training sessions. Measures included the Berg Balance Scale, the Unified Parkinson Disease Rating Scale, gait velocity, functional ambulation profile, step length, stance and single support percent of gait, Timed Up and Go, and the 6 min walk. Participants significantly improved on the Berg Balance Scale (effect size (ES)=0.83, p=0.021), Unified Parkinson Disease Rating Scale Motor Subscale III (ES=-0.64, p=0.029), and percent of time spent in stance during forward walking (ES=0.97, p=0.015). Non-significant improvements were noted on the Timed Up and Go (ES=-0.38, p=0.220) and 6 min walk (ES=0.35, p=0.170). Frequent social dance lessons completed within a short time period appear to be appropriate and effective for these individuals with mild-moderately severe Parkinson disease.

ELECTRODE POSITION DETERMINED BY FUSED IMAGES OF PREOPERATIVE AND POSTOPERATIVE MAGNETIC RESONANCE IMAGING AND SURGICAL OUTCOME AFTER SUBTHALAMIC NUCLEUS DEEP BRAIN STIMULATION

The electrode position is important to the surgical outcome after subthalamic nucleus (STN) deep brain stimulation (DBS). The aim of this study was to compare the surgical outcome of bilateral STN DBS with the electrode position estimated using fused magnetic resonance imaging. Bilateral STN DBS was performed in 60 patients with advanced Parkinson's disease. Patients were evaluated with the Unified Parkinson's Disease Rating Scale, Hoehn and Yahr staging, Schwab and England Activities of Daily Living, L-dopa equivalent dose, and Short Form-36 Health Survey before and at 3 and 6 months after surgery. Brain magnetic resonance imaging (1.5-T) was performed in 53 patients at 6 months after STN DBS. The electrode position was estimated in the fused pre- and postoperative magnetic resonance images and correlated with the surgical results. As a group, the Unified Parkinson's Disease Rating Scale, Hoehn and Yahr staging, Schwab and England Activities of Daily Living, and Short Form-36 Health Survey scores improved at 3 and 6 months after STN DBS. The L-dopa equivalent dose decreased by 60% at 3 and 6 months after STN DBS. The electrode position was divided into 6 types according to its relationship to the STN and the red nucleus. Most off-medication Unified Parkinson's Disease Rating Scale motor subscale scores improved regardless of the type of electrode position. The off-medication speech subscale score improved only in the patients whose electrodes were correctly positioned in the STN bilaterally. The electrodes accurately positioned in the STN led to improved speech after bilateral STN DBS. An effort should be made in each patient to document the electrode position to monitor surgical performance and to improve the surgical outcome after STN DBS.

PET study of brain acetylcholinesterase in cerebellar degenerative disorders

To elucidate characteristic changes of brain acetylcholinesterase (AChE) in cerebellar degenerative disorders. Eight patients with the cerebellar variant of multiple system atrophy (MSA-C), 7 patients with spinocerebellar ataxia type-3 (SCA-3), 3 patients with SCA-6, and 13 healthy age-matched volunteers participated in this study. Brain AChE activity was measured by [(11)C] N-methylpiperidin-4-yl propionate PET in all subjects. Brain AChE activities were significantly decreased in the thalamus (-27%) and the posterior lobe of cerebellar cortex (-36%) in patients with MSA-C and in the thalamus (-23%) in patients with SCA-3 compared with healthy controls (P < 0.01). Thalamic AChE activities of SCA-3 patients were negatively correlated with the unified Parkinson's disease rating scale motor subscore (P < 0.001). AChE activities were not significantly altered in the cerebral cortex in any disease group. Reduction of AChE activities in the thalamus and cerebellum in MSA and in the thalamus in SCA-3 suggest that cholinergic modulating drugs may have a role in the treatment of ataxia and other symptoms in these disorders.

Quantitative Analysis of Pursuit Ocular Movements in Parkinson’s Disease by Using a Video-Based Eye Tracking System

The purpose of this study is to assess the efficacy and the tolerability of a new vision-based non-intrusive eye tracker in a population composed of normal controls and in patients affected by nonadvanced Parkinson’s disease (PD). PD patients characteristically have difficulty in sustaining repetitive motor actions. Previous studies showed a progressive bradykinesia and hypokinesia of pursuit ocular movements (POM) in advanced PD. We found that the values of POM were lower in PD patients than in normal controls (p < 0.001). In PD patients, the values correlated closely with Hoehn and Yahr stage and Unified Parkinson Disease Rating Scale motor subscore (p < 0.001, for both). Our data suggest that deficit in POM occurs also in nonadvanced PD patients and it is closely correlated with clinical scores. Thus, this vision-based system can be considered a new method to provide, noninvasively, measures of POM dysfunctions and can be used as reliable indices of disease severity in PD patients.

Intrastriatal Implantation of Human Retinal Pigment Epithelial Cells Attached to Microcarriers in Advanced Parkinson Disease

Human retinal pigment epithelial (RPE) cells produce levodopa and can be isolated from postmortem human eye tissue, grown in culture, and implanted into the brain attached to microcarriers. These implants ameliorated the motor deficits in rodent and nonhuman primate models of Parkinson disease. To evaluate the safety and efficacy of unilateral implantation of human RPE cells attached to gelatin microcarriers into the putamen contralateral to the more symptomatic side of patients with Parkinson disease. Open-label pilot study. A tertiary referral center for movement disorders. Six patients with advanced Parkinson disease. We performed stereotactic intrastriatal implantation of approximately 325,000 RPE cells on microcarriers. Change from baseline to 12 months in the Unified Parkinson's Disease Rating Scale motor subscore with the patients in the practically defined off state (not taking antiparkinsonian medications for at least 12 hours overnight). The implants were well tolerated. We observed an average improvement of 48% at 12 months after implantation in the Unified Parkinson's Disease Rating Scale motor subscore with the patient in the off state, which was sustained through 24 months. Improvement was also observed in activities of daily living, quality of life, and motor fluctuations. No off-state dyskinesias were observed. Implants of human RPE cells attached to gelatin microcarriers appear to be safe and well tolerated, and they improved motor symptoms in patients with Parkinson disease. On the basis of these results, a randomized, double-blind, placebo-controlled study has been initiated.

Poster 26: Efficacy of a Multidisciplinary Treatment Program on Long-Term Outcomes of Individuals With Parkinson’s Disease.

Objective: To assess the efficacy of a multidisciplinary treatment approach to the management of Parkinson’s disease (PD) over a 1- to 3-year period. Design: Prospective, longitudinal study. Setting: A regional Parkinson’s Disease Research, Education and Clinical Center (PADRECC) within the Veteran’s Health System. Participants: 49 consecutive individuals with neurologist-confirmed PD who were followed for 1 to 3 years. Intervention: Treatment in a comprehensive, multidisciplinary PD clinic, including neurologist, physiatrist, psychologist, neurosurgeon, biomedical engineer, and nurse, was compared to PD research consortium-adopted expected neurologic progression on standard treatment medications. Team meetings were held to discuss patient care and team functioning. Rehabilitation interventions included medication management; exercise prescription; prescription of adaptive equipment; patient and family education; formalized balance, gait, and pain assessment; and referral to necessary therapy services. Main Outcome Measures: Unified Parkinson’s Disease Rating Scale (UPDRS) motor subscale was employed to assess disease progression (range, 0–108, where a lower score represents improving motor function). Results: 49 participants averaged 71.7 years of age, were all male, and 71% were white with the remaining 29% being African American. Patients were diagnosed on average 71 months prior to PADRECC initial assessment. Initial UPDRS scores were in the moderately impaired range (mean ± SD, 28.8±13.03; range, 4–67). Overall, there was a mean UPDRS, motor subscale improvement for the entire study sample (decrease of .65 points/mo change over a mean follow-up period of 18.6mo of treatment). While 12 (24%) subjects did demonstrate disease progression, their worsening (.24 points/mo) was lower than the expected historical controls (>.33 points/mo; P<.05). Conclusions: As with other geriatric and neurologic-related disabilities, PD is well managed in a multidisciplinary treatment setting that includes attention to physical and psychologic functioning.

Parkinson disease

To determine the proportion of individuals in a clinic-based setting that present with asymmetric Parkinson disease (PD) and identify predictive factors associated with asymmetric symptoms. The authors examined right vs left difference scores on the Unified Parkinson Disease Rating Scale motor subscale in a consecutive clinical series of 1,277 individuals diagnosed with PD. Predictors of asymmetry included sex, symptomatic disease duration, age at onset, initial motor symptom laterality, handedness, and medical history variables (e.g., family history of PD). Nearly half the sample (46%) met criteria for asymmetric disease based on a right vs left difference score of > or =5 points, and 12% of the sample had a difference score of > or =10 (difference score: mean = 4, SD = 3.4). All three cardinal features of PD showed characteristics of asymmetric disease presentation. Multiple regression analyses showed that an increased discrepancy between right- and left-sided symptoms was significantly associated with a shorter disease duration, younger age at symptomatic onset, asymmetric initial symptom onset, hand dominance, and a positive self-reported family history of "other" neurodegenerative disorder. Hand dominance was related to the side of asymmetric disease such that left-handed individuals tended to have more severe disease on the left side of the body. Asymmetric presentation of Parkinson disease features was a common occurrence in the clinical cohort. Asymmetry was reliably predicted by several clinical characteristics, although the moderate level of explained variance (i.e., between 16 and 23%) highlighted the need for additional research examining predictive models of asymmetric disease. Recommendations for the classification and measurement of asymmetric disease are discussed.

Effects of pallidotomy and levodopa on walking and reaching movements in Parkinson's disease

We examined the effects of levodopa and unilateral pallidotomy on quantitative measures of walking and reaching in Parkinson's disease (PD). We also compared quantitative measures of movement with standard clinical rating scales. We used kinematic measures and the Unified Parkinson's Disease Rating Scale (UPDRS) motor subscale (subscale III) to evaluate the movement of 10 people with PD. Subjects were tested after withholding PD medications for at least 8 hours and again 30 to 45 minutes after taking the first morning dose of levodopa. They were studied in this manner before unilateral pallidotomy and then 3.5 to 10 months after surgery. The UPDRS motor subscale was performed in each state. Kinematic data were collected as subjects reached to a target and walked. The UPDRS motor subscale ratings were similar to those reported in the literature: pallidotomy improved the overall motor score and the contralateral bradykinesia + rigidity score, but not the gait + posture score. In contrast, kinematic measures demonstrated that levodopa and pallidotomy had different effects on walking and reaching speed. Both treatments improved walking speed, and the effect was additive. Levodopa improved reaching speed before pallidotomy but did not improve it as much after pallidotomy. Additionally, pallidotomy had inconsistent effects on reaching; some subjects were faster and others were slower. The subjects who initially reached more slowly improved after pallidotomy; the subjects who initially reached more normally (faster) worsened after pallidotomy. On the basis of our results, we speculate that basal ganglia output pathways that control walking and reaching may be distinct, such that bilateral projections to the pedunculopontine area influence walking, whereas ipsilateral thalamocortical projections influence reaching.

Motor, cognitive, and behavioral performance following unilateral ventroposterior pallidotomy for Parkinson disease.

To evaluate the effects of ventroposterior pallidotomy on motor disability and on behavior and cognition in patients with medically intractable idiopathic Parkinson disease. Detailed motor testing both while receiving and discontinuing levodopa medication, posturography, and neurocognitive and behavioral assessments were performed before and 3 to 6 months after unilateral ventroposterior pallidotomy. University-based movement disorder program. Thirty-two patients without dementia with medically refractory idiopathic Parkinson disease were studied. Motor function and disability were measured using the Unified Parkinson's Disease Rating Scale, Hoehn and Yahr stage, and the Schwab and England Activities of Daily Living Scale. Dynamic balance was measured by sway (amplitude and velocity) using the Chattecx Balance System. Detailed cognitive and behavioral assessments were also performed both before and after surgery. Eighty-three percent of patients experienced improvement of their total Unified Parkinson's Disease Rating Scale score at 3 to 6 months after surgery. Significant improvements were also seen in the contralateral Unified Parkinson's Disease Rating Scale motor subscore (78%) as well as in the contralateral Unified Parkinson's Disease Rating Scale total score both during the on and off period (78% and 79%, respectively). The Hoehn and Yahr stage, Schwab and England Activities of Daily Living Scale score, and dynamic balance when standing on foam also improved following unilateral pallidotomy in many patients. Cognitive performance remained relatively unchanged following surgery with the exception of category fluency, which exhibited a modest decline (P < .04). A significant improvement in depression was found on the Beck Depression Inventory. Ventroposterior pallidotomy significantly improves motor performance and daily level of function in Parkinson disease. Cognition and behavior are not adversely affected in patients without dementia, and a cognitive screening battery is proposed.