Rajesh Pahwa

Movement Disorder Society-Sponsored Revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS): Scale Presentation and Clinimetric Testing Results

We present a clinimetric assessment of the Movement Disorder Society (MDS)‐sponsored revision of the Unified Parkinsons Disease Rating Scale (MDS‐UPDRS). The MDS‐UDPRS Task Force revised and expanded the UPDRS using recommendations from a published critique. The MDS‐UPDRS has four parts, namely, I: Non‐motor Experiences of Daily Living; II: Motor Experiences of Daily Living; III: Motor Examination; IV: Motor Complications. Twenty questions are completed by the patient/caregiver. Item‐specific instructions and an appendix of complementary additional scales are provided. Movement disorder specialists and study coordinators administered the UPDRS (55 items) and MDS‐UPDRS (65 items) to 877 English speaking (78% non‐Latino Caucasian) patients with Parkinsons disease from 39 sites. We compared the two scales using correlative techniques and factor analysis. The MDS‐UPDRS showed high internal consistency (Cronbachs alpha = 0.79–0.93 across parts) and correlated with the original UPDRS (ρ = 0.96). MDS‐UPDRS across‐part correlations ranged from 0.22 to 0.66. Reliable factor structures for each part were obtained (comparative fit index > 0.90 for each part), which support the use of sum scores for each part in preference to a total score of all parts. The combined clinimetric results of this study support the validity of the MDS‐UPDRS for rating PD.

Pallidal versus subthalamic deep-brain stimulation for Parkinson's disease

BACKGROUND Deep-brain stimulation is the surgical procedure of choice for patients with advanced Parkinsons disease. The globus pallidus interna and the subthalamic nucleus are accepted targets for this procedure. We compared 24-month outcomes for patients who had undergone bilateral stimulation of the globus pallidus interna (pallidal stimulation) or subthalamic nucleus (subthalamic stimulation). METHODS At seven Veterans Affairs and six university hospitals, we randomly assigned 299 patients with idiopathic Parkinsons disease to undergo either pallidal stimulation (152 patients) or subthalamic stimulation (147 patients). The primary outcome was the change in motor function, as blindly assessed on the Unified Parkinsons Disease Rating Scale, part III (UPDRS-III), while patients were receiving stimulation but not receiving antiparkinsonian medication. Secondary outcomes included self-reported function, quality of life, neurocognitive function, and adverse events. RESULTS Mean changes in the primary outcome did not differ significantly between the two study groups (P=0.50). There was also no significant difference in self-reported function. Patients undergoing subthalamic stimulation required a lower dose of dopaminergic agents than did those undergoing pallidal stimulation (P=0.02). One component of processing speed (visuomotor) declined more after subthalamic stimulation than after pallidal stimulation (P=0.03). The level of depression worsened after subthalamic stimulation and improved after pallidal stimulation (P=0.02). Serious adverse events occurred in 51% of patients undergoing pallidal stimulation and in 56% of those undergoing subthalamic stimulation, with no significant between-group differences at 24 months. CONCLUSIONS Patients with Parkinsons disease had similar improvement in motor function after either pallidal or subthalamic stimulation. Nonmotor factors may reasonably be included in the selection of surgical target for deep-brain stimulation. (ClinicalTrials.gov numbers, NCT00056563 and NCT01076452.)

Randomized, double-blind trial of glial cell line-derived neurotrophic factor (GDNF) in PD

Objective: To assess the safety, tolerability, and biological activity of glial cell line-derived neurotrophic factor (GDNF) administered by an implanted intracerebroventricular (ICV) catheter and access port in advanced PD. Background: GDNF is a peptide that promotes survival of dopamine neurons. It improved 6-OHDA- or MPTP-induced behavioral deficits in rodents and monkeys. Methods: A multicenter, randomized, double-blind, placebo-controlled, sequential cohort study compared the effects of monthly ICV administration of placebo and 25, 75, 150, 300, and 500 to 4,000 μg of GDNF in 50 subjects with PD for 8 months. An open-label study extended exposure up to an additional 20 months and maximum single doses of up to 4,000 μg in 16 subjects. Laboratory testing, adverse events (AE), and Unified Parkinson’s Disease Rating Scale (UPDRS) scoring were obtained at 1- to 4-week intervals throughout the studies. Results: Twelve subjects received placebo and seven or eight subjects were assigned to each of the other GDNF dose groups. “On” and “off” total and motor UPDRS scores were not improved by GDNF at any dose. Nausea, anorexia, and vomiting were common hours to several days after injections of GDNF. Weight loss occurred in the majority of subjects receiving 75 μg or larger doses of GDNF. Paresthesias, often described as electric shocks (Lhermitte sign), were common in GDNF-treated subjects, were not dose related, and resolved on discontinuation of GDNF. Asymptomatic hyponatremia occurred in over half of subjects receiving 75 μg or larger doses of GDNF; it was symptomatic in several subjects. The open-label extension study had similar AE and lack of therapeutic efficacy. Conclusions: GDNF administered by ICV injection is biologically active as evidenced by the spectrum of AE encountered in this study. GDNF did not improve parkinsonism, possibly because GDNF did not reach the target tissues—putamen and substantia nigra.

Subthalamic nucleus deep brain stimulation: summary and meta-analysis of outcomes.

Subthalamic nucleus (STN) deep brain stimulation (DBS) is currently the most common therapeutic surgical procedure for patients with Parkinsons disease (PD) who have failed medical management. However, a recent summary of clinical evidence on the effectiveness of STN DBS is lacking. We report the results of such a systematic review and meta‐analysis. A comprehensive review of the literature using Medline and Ovid databases from 1993 until 2004 was conducted. Estimates of change in absolute Unified Parkinsons Disease Rating Scale (UPDRS) scores after surgery were generated using random‐effects models. Sources of heterogeneity were explored with meta‐regression models, and the possibility of publication bias was evaluated. Patient demographics, reduction in medication requirements, change in dyskinesia, daily offs, quality of life, and a ratio of postoperative improvement from stimulation compared to preoperative improvement by medication from each study were tabulated and average scores were calculated. Adverse effects from each study were summarized. Thirty‐seven cohorts were included in the review. Twenty‐two studies with estimates of standard errors were included in the meta‐analysis. The estimated decreases in absolute UPDRS II (activities of daily living) and III (motor) scores after surgery in the stimulation ON/medication off state compared to preoperative medication off state were 13.35 (95% CI: 10.85–15.85; 50%) and 27.55 (95% CI: 24.23–30.87; 52%), respectively. Average reduction in L‐dopa equivalents following surgery was 55.9% (95% CI: 50%–61.8%). Average reduction in dyskinesia following surgery was 69.1% (95% CI: 62.0%–76.2%). Average reduction in daily off periods was 68.2% (95% CI: 57.6%–78.9%). Average improvement in quality of life using PDQ‐39 was 34.5% ± 15.3%. Univariable regression showed improvements in UPDRS III scores were significantly greater in studies with higher baseline UPDRS III off scores, increasing disease duration prior to surgery, earlier year of publication, and higher baseline L‐dopa responsiveness. Average baseline UPDRS III off scores were significantly lower (i.e., suggesting milder disease) in later than in earlier studies. In multivariable regression, L‐dopa responsiveness, higher baseline motor scores, and disease duration were independent predictors of greater change in motor score. No evidence of publication bias in the available literature was found. The most common serious adverse event related to surgery was intracranial hemorrhage in 3.9% of patients. Psychiatric sequelae were common. Synthesis of the available literature indicates that STN DBS improves motor activity and activities of daily living in advanced PD. Differences between available studies likely reflect differences in patient populations and follow‐up periods. These data provide an estimate of the magnitude of the treatment effects and emphasize the need for controlled and randomized studies.

Deep Brain Stimulation for Parkinson Disease: An Expert Consensus and Review of Key Issues

OBJECTIVE To provide recommendations to patients, physicians, and other health care providers on several issues involving deep brain stimulation (DBS) for Parkinson disease (PD). DATA SOURCES AND STUDY SELECTION An international consortium of experts organized, reviewed the literature, and attended the workshop. Topics were introduced at the workshop, followed by group discussion. DATA EXTRACTION AND SYNTHESIS A draft of a consensus statement was presented and further edited after plenary debate. The final statements were agreed on by all members. CONCLUSIONS (1) Patients with PD without significant active cognitive or psychiatric problems who have medically intractable motor fluctuations, intractable tremor, or intolerance of medication adverse effects are good candidates for DBS. (2) Deep brain stimulation surgery is best performed by an experienced neurosurgeon with expertise in stereotactic neurosurgery who is working as part of a interprofessional team. (3) Surgical complication rates are extremely variable, with infection being the most commonly reported complication of DBS. (4) Deep brain stimulation programming is best accomplished by a highly trained clinician and can take 3 to 6 months to obtain optimal results. (5) Deep brain stimulation improves levodopa-responsive symptoms, dyskinesia, and tremor; benefits seem to be long-lasting in many motor domains. (6) Subthalamic nuclei DBS may be complicated by increased depression, apathy, impulsivity, worsened verbal fluency, and executive dysfunction in a subset of patients. (7) Both globus pallidus pars interna and subthalamic nuclei DBS have been shown to be effective in addressing the motor symptoms of PD. (8) Ablative therapy is still an effective alternative and should be considered in a select group of appropriate patients.

Mitochondrial Polymorphisms Significantly Reduce the Risk of Parkinson Disease

Mitochondrial (mt) impairment, particularly within complex I of the electron transport system, has been implicated in the pathogenesis of Parkinson disease (PD). More than half of mitochondrially encoded polypeptides form part of the reduced nicotinamide adenine dinucleotide dehydrogenase (NADH) complex I enzyme. To test the hypothesis that mtDNA variation contributes to PD expression, we genotyped 10 single-nucleotide polymorphisms (SNPs) that define the European mtDNA haplogroups in 609 white patients with PD and 340 unaffected white control subjects. Overall, individuals classified as haplogroup J (odds ratio [OR] 0.55; 95% confidence interval [CI] 0.34-0.91; P=.02) or K (OR 0.52; 95% CI 0.30-0.90; P=.02) demonstrated a significant decrease in risk of PD versus individuals carrying the most common haplogroup, H. Furthermore, a specific SNP that defines these two haplogroups, 10398G, is strongly associated with this protective effect (OR 0.53; 95% CI 0.39-0.73; P=.0001). SNP 10398G causes a nonconservative amino acid change from threonine to alanine within the NADH dehydrogenase 3 (ND3) of complex I. After stratification by sex, this decrease in risk appeared stronger in women than in men (OR 0.43; 95% CI 0.27-0.71; P=.0009). In addition, SNP 9055A of ATP6 demonstrated a protective effect for women (OR 0.45; 95% CI 0.22-0.93; P=.03). Our results suggest that ND3 is an important factor in PD susceptibility among white individuals and could help explain the role of complex I in PD expression.

Age at onset in two common neurodegenerative diseases is genetically controlled.

To identify genes influencing age at onset (AAO) in two common neurodegenerative diseases, a genomic screen was performed for AAO in families with Alzheimer disease (AD; n=449) and Parkinson disease (PD; n=174). Heritabilities between 40%--60% were found in both the AD and PD data sets. For PD, significant evidence for linkage to AAO was found on chromosome 1p (LOD = 3.41). For AD, the AAO effect of APOE (LOD = 3.28) was confirmed. In addition, evidence for AAO linkage on chromosomes 6 and 10 was identified independently in both the AD and PD data sets. Subsequent unified analyses of these regions identified a single peak on chromosome 10q between D10S1239 and D10S1237, with a maximum LOD score of 2.62. These data suggest that a common gene affects AAO in these two common complex neurodegenerative diseases.

Validation of the questionnaire for impulsive-compulsive disorders in Parkinson's disease.

As no comprehensive assessment instrument for impulse control disorders (ICDs) in Parkinsons disease (PD) exists, the aim of this study was to design and assess the psychometric properties of a self‐administered screening questionnaire for ICDs and other compulsive behaviors in PD. The Questionnaire for Impulsive‐Compulsive Disorders in Parkinsons Disease (QUIP) has 3 sections: Section 1 assesses four ICDs (involving gambling, sexual, buying, and eating behaviors), Section 2 other compulsive behaviors (punding, hobbyism, and walkabout), and Section 3 compulsive medication use. For validation, a convenience sample of 157 PD patients at 4 movement disorders centers first completed the QUIP, and then was administered a diagnostic interview by a trained rater blinded to the QUIP results. A shortened instrument (QUIP‐S) was then explored. The discriminant validity of the QUIP was high for each disorder or behavior (receiver operating characteristic area under the curve [ROC AUC]: gambling = 0.95, sexual behavior = 0.97, buying = 0.87, eating = 0.88, punding = 0.78, hobbyism = 0.93, walkabout = 0.79). On post hoc analysis, the QUIP‐S ICD section had similar properties (ROC AUC: gambling = 0.95, sexual behavior = 0.96, buying = 0.87, eating = 0.88). When disorders/behaviors were combined, the sensitivity of the QUIP and QUIP‐S to detect an individual with any disorder was 96 and 94%, respectively. Scores on the QUIP appear to be valid as a self‐assessment screening instrument for a range of ICDs and other compulsive behaviors that occur in PD, and a shortened version may perform as well as the full version. A positive screen should be followed by a comprehensive, clinical interview to determine the range and severity of symptoms, as well as need for clinical management.

Surgical and hardware complications of subthalamic stimulation A series of 160 procedures

Objective: To assess the surgical and hardware complications in a series of 81 consecutive patients undergoing subthalamic (STN) deep brain stimulation (DBS) for Parkinson disease (PD). Methods: The authors prospectively documented surgical and hardware complications occurring at the time of surgery and at subsequent neurologic and surgical evaluations for an average of 17 months, ranging from 1 to 54 months. Results: No patient had a serious surgical complication resulting in death or permanent neurologic deficit. One patient had an intracranial hemorrhage but with no permanent deficit. In follow-up, 2.5% had infections requiring system removal, 3.7% had infections requiring implantable pulse generator (IPG) removal, 12.5% had misplaced leads, and 26.2% had hardware complications including lead migration, lead fracture, extension erosion, extension fracture, and IPG malfunction. Conclusion: Serious complications leading to permanent neurologic deficit are rare after STN DBS for advanced PD. However, long-term follow-up demonstrated that hardware complications are relatively common, having occurred in approximately 26% of these patients.

Basic algorithms for the programming of deep brain stimulation in Parkinson's disease.

The clinical success of deep brain stimulation (DBS) for treating Parkinsons disease (PD) critically depends on the quality of postoperative neurological management. Movement disorder specialists becoming involved with this therapy need to acquire new skills to adapt optimally stimulation parameters and medication after implantation of a DBS system. At first glance, the infinite number of theoretically possible parameter combinations seems to make programming a complex and time‐consuming art. This article outlines a stepwise and standardized approach, reducing the possible parameter settings in DBS to a few relevant combinations. The basic programming algorithms for thalamic, subthalamic, and pallidal stimulation in PD are explained and summarized in flowcharts.