Grace S. Liang

Impaired olfaction and other prodromal features in the Parkinson At-Risk Syndrome Study.

To test the association between impaired olfaction and other prodromal features of PD in the Parkinson At‐Risk Syndrome Study. The onset of olfactory dysfunction in PD typically precedes motor features, suggesting that olfactory testing could be used as a screening test. A combined strategy that uses other prodromal nonmotor features, along with olfactory testing, may be more efficient than hyposmia alone for detecting the risk of PD. Individuals with no neurological diagnosis completed a mail survey, including the 40‐item University of Pennsylvania Smell Identification Test, and questions on prodromal features of PD. The frequency of reported nonmotor features was compared across individuals with and without hyposmia. A total of 4,999 subjects completed and returned the survey and smell test. Of these, 669 were at or below the 15th percentile based on age and gender, indicating hyposmia. Hyposmics were significantly more likely to endorse nonmotor features, including anxiety and depression, constipation, and rapid eye movement sleep behavior disorder symptoms, and to report changes in motor function. Twenty‐six percent of subjects with combinations of four or more nonmotor features were hyposmic, compared to 12% for those reporting three or fewer nonmotor features (P < 0.0001). Hyposmia is associated with other nonmotor features of PD in undiagnosed individuals. Further assessment of hyposmic subjects using more specific markers for degeneration, such as dopamine transporter imaging, will evaluate whether combining hyposmia and other nonmotor features is useful in assessing the risk of future neurodegeneration.

Subthalamic nucleus deep brain stimulation for severe idiopathic dystonia: impact on severity, neuropsychological status, and quality of life

OBJECT Medically refractory dystonia has recently been treated using deep brain stimulation (DBS) targeting the globus pallidus internus (GPI). Outcomes have varied depending on the features of the dystonia. There has been limited literature regarding outcomes for refractory dystonia following DBS of the subthalamic nucleus (STN). METHODS Four patients with medically refractory, predominantly cervical dystonia underwent STN DBS. Intraoperative assessments with the patients in a state of general anesthesia were performed to determine the extent of fixed deformities that might predict outcome. Patients were rated using the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) preoperatively and 3 and 12 months following surgery by a rater blinded to the study. Mean changes and standard errors of the mean in scores were calculated for each subscore of the two scales. Scores were also analyzed using analysis of variance and probability values were generated. Neuropsychological assessments and quality of life ratings using the 36-Item Short Form Health Survey (SF-36) were evaluated longitudinally. RESULTS Significant improvements were seen in motor (p = 0.04), disability (p = 0.02), and total TWSTRS scores (p = 0.03). Better outcomes were seen in those patients who did not have fixed deformities. There was marked improvement in the mental component score of the SF-36. Neuropsychological function was not definitively impacted as a result of the surgery. CONCLUSIONS Deep brain stimulation of the STN is a novel target for dystonia and may be an alternative to GPI DBS. Further studies need to be performed to confirm these conclusions and to determine optimal candidates and stimulation parameters.

Effect of creatine monohydrate on clinical progression in patients with Parkinson disease: a randomized clinical trial.

IMPORTANCE There are no treatments available to slow or prevent the progression of Parkinson disease, despite its global prevalence and significant health care burden. The National Institute of Neurological Disorders and Stroke Exploratory Trials in Parkinson Disease program was established to promote discovery of potential therapies. OBJECTIVE To determine whether creatine monohydrate was more effective than placebo in slowing long-term clinical decline in participants with Parkinson disease. DESIGN, SETTING, AND PATIENTS The Long-term Study 1, a multicenter, double-blind, parallel-group, placebo-controlled, 1:1 randomized efficacy trial. Participants were recruited from 45 investigative sites in the United States and Canada and included 1741 men and women with early (within 5 years of diagnosis) and treated (receiving dopaminergic therapy) Parkinson disease. Participants were enrolled from March 2007 to May 2010 and followed up until September 2013. INTERVENTIONS Participants were randomized to placebo or creatine (10 g/d) monohydrate for a minimum of 5 years (maximum follow-up, 8 years). MAIN OUTCOMES AND MEASURES The primary outcome measure was a difference in clinical decline from baseline to 5-year follow-up, compared between the 2 treatment groups using a global statistical test. Clinical status was defined by 5 outcome measures: Modified Rankin Scale, Symbol Digit Modalities Test, PDQ-39 Summary Index, Schwab and England Activities of Daily Living scale, and ambulatory capacity. All outcomes were coded such that higher scores indicated worse outcomes and were analyzed by a global statistical test. Higher summed ranks (range, 5-4775) indicate worse outcomes. RESULTS The trial was terminated early for futility based on results of a planned interim analysis of participants enrolled at least 5 years prior to the date of the analysis (n = 955). The median follow-up time was 4 years. Of the 955 participants, the mean of the summed ranks for placebo was 2360 (95% CI, 2249-2470) and for creatine was 2414 (95% CI, 2304-2524). The global statistical test yielded t1865.8 = -0.75 (2-sided P = .45). There were no detectable differences (P < .01 to partially adjust for multiple comparisons) in adverse and serious adverse events by body system. CONCLUSIONS AND RELEVANCE Among patients with early and treated Parkinson disease, treatment with creatine monohydrate for at least 5 years, compared with placebo did not improve clinical outcomes. These findings do not support the use of creatine monohydrate in patients with Parkinson disease. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00449865.

Severe neuropathy with leaky connexin32 hemichannels

X‐linked Charcot‐Marie‐Tooth disease is one of a set of diseases caused by mutations in gap junction proteins called connexins. We identified a connexin32 missense mutation (F235C) in a girl with unusually severe neuropathy. The localization and trafficking of the mutant protein in cell culture was normal, but electrophysiological studies showed that the mutation caused abnormal hemichannel opening, with excessive permeability of the plasma membrane and decreased cell survival. Abnormal leakiness of connexin hemichannels is likely a mechanism of cellular toxicity in this and perhaps other diseases caused by connexin mutations. Ann Neurol 2005;57:749–754

Long-Term Outcomes of Bilateral Subthalamic Nucleus Stimulation in Patients with Advanced Parkinson’s Disease

Background: In patients with advanced Parkinson’s disease (PD), deep brain stimulation (DBS) of the subthalamic nucleus (STN) has been shown to improve motor function and decrease medication requirements in the short term. However, the long-term benefits of DBS are not yet established. Objective: It was the aim of this study to evaluate long-term outcomes of patients with PD treated with bilateral DBS of the STN. Design and Methods: Thirty-three subjects who had bilateral STN DBS were followed prospectively after surgery. We evaluated subjects, using the Unified Parkinson’s Disease Rating Scale (UPDRS), preoperatively, 12 months after surgery and at a long-term follow-up visit. Ratings were performed on and off dopaminergic medications. We compared postoperative UPDRS scores, dyskinesia ratings and medication dosages with preoperative values. Results: Twenty-seven subjects had evaluations beyond 18 months (median 33.7 months). Total UPDRS scores in the ‘medication-off’ state were improved by 37% (p < 0.001) at 12 months and 17.7% (p = 0.0051) at the long-term evaluation. Medication-off state UPDRS part III scores were significantly improved at both 1 year and at the last evaluation (37.6 and 29.3%; p < 0.001). Dopaminergic medication requirements were decreased by 35.3% (p < 0.001) during the first postoperative year and remained below preoperative levels at the long-term evaluation. Average duration of ‘off’ time remained decreased by about 40% at both 1 year and at the time of last evaluation. Subjects had a sustained reduction in dyskinesia severity (88.6% at 1 year and 68.8% at last evaluation). Conclusions: In this cohort of subjects with advanced PD, bilateral STN stimulation improved ‘off’ medication motor function, reduced time spent in the medication-off state and reduced medication requirements for up to 4 years after surgery. We conclude that STN DBS is an effective long-term therapy for selected patients with advanced PD.

Long-term effects of bilateral subthalamic nucleus stimulation on health-related quality of life in advanced Parkinson's disease

We evaluated the long‐term effects of subthalamic nucleus (STN) stimulation on health‐related quality of life (HRQL) in patients with advanced Parkinsons disease (PD). STN stimulation improves motor function and decreases medication requirements in patients with advanced PD. The impact of STN stimulation on HRQL is less well established, especially beyond 1 year after surgery. We report HRQL outcomes for 18 patients with advanced PD. Patients were evaluated with the Parkinsons Disease Questionnaire‐39 (PDQ‐39), the Medical Outcome Study Short Form (SF‐36), and the EuroQol visual analogue scale (VAS) before surgery, 6 months postoperatively, and at a long‐term follow‐up visit (mean, 35.9 months; range, 18–57 months after surgery). Preoperative scores on HRQL measures were compared to results obtained at short‐ and long‐term follow‐up evaluations. The VAS and all domains of the PDQ‐39 except for cognition, communication, and social support showed marked improvements at 6 months after surgery. At the long‐term follow‐up, there were sustained improvements in the VAS (63% improvement; P = 0.0009) and in several domains of the PDQ‐39 [mobility: 20%, P = 0.01; activities of daily living (ADL): 29%, P = 0.005; emotional well‐being: 26%, P = 0.02; stigma: 43%, P = 0.003; and bodily discomfort: 35%, P = 0.007]. At the long‐term evaluation, only the vitality domain of the SF‐36 was significantly improved from baseline (16%; P = 0.01). In this selected group of patients, many of the short‐term gains in HRQL persist beyond 18 months after STN implantation. Benefits in nonmotor aspects of HRQL such as bodily discomfort and stigma appear to be among the most durable.

KINECT 3: A Phase 3 Randomized, Double-Blind, Placebo-Controlled Trial of Valbenazine for Tardive Dyskinesia

OBJECTIVE Tardive dyskinesia is a persistent movement disorder induced by dopamine receptor blockers, including antipsychotics. Valbenazine (NBI-98854) is a novel, highly selective vesicular monoamine transporter 2 inhibitor that demonstrated favorable efficacy and tolerability in the treatment of tardive dyskinesia in phase 2 studies. This phase 3 study further evaluated the efficacy, safety, and tolerability of valbenazine as a treatment for tardive dyskinesia. METHOD This 6-week, randomized, double-blind, placebo-controlled trial included patients with schizophrenia, schizoaffective disorder, or a mood disorder who had moderate or severe tardive dyskinesia. Participants were randomly assigned in a 1:1:1 ratio to once-daily placebo, valbenazine at 40 mg/day, or valbenazine at 80 mg/day. The primary efficacy endpoint was change from baseline to week 6 in the 80 mg/day group compared with the placebo group on the Abnormal Involuntary Movement Scale (AIMS) dyskinesia score (items 1-7), as assessed by blinded central AIMS video raters. Safety assessments included adverse event monitoring, laboratory tests, ECG, and psychiatric measures. RESULTS The intent-to-treat population included 225 participants, of whom 205 completed the study. Approximately 65% of participants had schizophrenia or schizoaffective disorder, and 85.5% were receiving concomitant antipsychotics. Least squares mean change from baseline to week 6 in AIMS dyskinesia score was -3.2 for the 80 mg/day group, compared with -0.1 for the placebo group, a significant difference. AIMS dyskinesia score was also reduced in the 40 mg/day group (-1.9 compared with -0.1). The incidence of adverse events was consistent with previous studies. CONCLUSIONS Once-daily valbenazine significantly improved tardive dyskinesia in participants with underlying schizophrenia, schizoaffective disorder, or mood disorder. Valbenazine was generally well tolerated, and psychiatric status remained stable. Longer trials are necessary to understand the long-term effects of valbenazine in patients with tardive dyskinesia.

Design innovations and baseline findings in a long-term parkinson’s trial: The national institute of neurological disorders and stroke exploratory trials in parkinson’s disease long-term study-1

Based on the preclinical data and the results of a phase II futility study, creatine was selected for an efficacy trial in Parkinsons disease (PD). We present the design rationale and a description of the study cohort at baseline. A randomized, multicenter, double‐blind, parallel‐group, placebo‐controlled phase III study of creatine (10 g daily) in participants with early, treated PD, the Long‐term Study–1 (LS‐1), is being conducted by the National Institute of Neurological Disorders and Stroke Exploratory Trials in Parkinsons Disease network. The study utilizes a global statistical test (GST) encompassing five clinical rating scales to provide a multidimensional assessment of disease progression. A total of 1,741 PD participants from 45 sites in the United States and Canada were randomized 1:1 to either 10 g of creatine/day or matching placebo. Participants are being evaluated for a minimum of 5 years. The LS‐1 baseline cohort includes participants treated with dopaminergic therapy and generally mild PD. LS‐1 represents the largest cohort of patients with early treated PD ever enrolled in a clinical trial. The GST approach should provide high power to test the hypothesis that daily administration of creatine (10 g/day) is more effective than placebo in slowing clinical decline in PD between baseline and the 5‐year follow‐up visit against the background of dopaminergic therapy and best PD care.

Measuring Disease Progression in Early Parkinson Disease The National Institutes of Health Exploratory Trials in Parkinson Disease (NET-PD) Experience

IMPORTANCE Optimizing assessments of rate of progression in Parkinson disease (PD) is important in designing clinical trials, especially of potential disease-modifying agents. OBJECTIVE To examine the value of measures of impairment, disability, and quality of life in assessing progression in early PD. DESIGN, SETTING, AND PARTICIPANTS Inception cohort analysis of data from 413 patients with early, untreated PD who were enrolled in 2 multicenter, randomized, double-blind clinical trials. INTERVENTIONS Participants were randomly assigned to 1 of 5 treatments (67 received creatine, 66 received minocycline, 71 received coenzyme Q10, 71 received GPI-1485, and 138 received placebo). We assessed the association between the rates of change in measures of impairment, disability, and quality of life and time to initiation of symptomatic treatment. MAIN OUTCOMES AND MEASURES Time between baseline assessment and need for the initiation of symptomatic pharmaceutical treatment for PD was the primary indicator of disease progression. RESULTS After adjusting for baseline confounding variables with regard to the Unified Parkinsons Disease Rating Scale (UPDRS) Part II score, the UPDRS Part III score, the modified Rankin Scale score, level of education, and treatment group, we assessed the rate of change for the following measurements: the UPDRS Part II score; the UPDRS Part III score; the Schwab and England Independence Scale score (which measures activities of daily living); the Total Functional Capacity scale; the 39-item Parkinsons Disease Questionnaire, summary index, and activities of daily living subscale; and version 2 of the 12-item Short Form Health Survey Physical Summary and Mental Summary. Variables reaching the statistical threshold in univariate analysis were entered into a multivariable Cox proportional hazards model using time to symptomatic treatment as the dependent variable. More rapid change (ie, worsening) in the UPDRS Part II score (hazard ratio, 1.15 [95% CI, 1.08-1.22] for 1 scale unit change per 6 months), the UPDRS Part III score (hazard ratio, 1.09 [95% CI, 1.06-1.13] for 1 scale unit change per 6 months), and the Schwab and England Independence Scale score (hazard ratio, 1.29 [95% CI, 1.12-1.48] for 5 percentage point change per 6 months) was associated with earlier need for symptomatic therapy. CONCLUSIONS AND RELEVANCE In early PD, the UPDRS Part II score and Part III score and the Schwab and England Independence Scale score can be used to measure disease progression, whereas the 39-item Parkinsons Disease Questionnaire and summary index, Total Functional Capacity scale, and the 12-item Short Form Health Survey Physical Summary and Mental Summary are not sensitive to change. TRIAL REGISTRATION clinicaltrials.gov Identifiers: NCT00063193 and NCT00076492.

Determinants of the Timing of Symptomatic Treatment in Early Parkinson Disease: The National Institutes of Health Exploratory Trials in Parkinson Disease (NET-PD) Experience

OBJECTIVE To assess the predictive value of baseline measures of impairment, disability, and quality of life for the timing of initiation of symptomatic treatment in early Parkinson disease (PD). DESIGN Inception cohort analysis. SETTING Ambulatory population from multiple sites in the United States and Canada. PARTICIPANTS Four hundred thirteen patients with early, untreated PD who participated in 2 double-blind trials that assessed the potential of experimental drugs to serve as disease-modifying agents in PD. Intervention Participants were randomized into treatment groups: creatine (n = 67), minocycline (n = 66), coenzyme Q10 (n = 71), GPI-1485 (n = 71), and placebo (n = 138). Main Outcome Measure Time between baseline assessment and need for the initiation of symptomatic treatment for PD. The following baseline variables were assessed for their relation to the main outcome measure, while adjusting for possible treatment effect: sex; age; level of education; race/ethnicity; disease duration; occupational status; and Unified Parkinson Disease Rating Scale (UPDRS), Medical Outcomes Study Short Form Survey, Modified Rankin Scale, Schwab and England Activities of Daily Living Scale, Total Functional Capacity Scale, 39-item Parkinson Disease Questionnaire, and Geriatric Depression Scale scores. Variables reaching statistical threshold in univariate analyses (alpha = .15) were entered into a multivariable Cox proportional hazards regression model using time to symptomatic treatment as the dependent variable. RESULTS Approximately half (48.5%) of the participants reached end point within 12 months. Higher baseline impairment and disability, as determined by UPDRS III (motor section), UPDRS II (activities of daily living section, participant rating), and Modified Rankin Scale scores and level of education were independently associated with an earlier need for symptomatic treatment. CONCLUSIONS In early PD, greater impairment and disability and higher level of education are independently associated with an earlier need for symptomatic treatment.