Utility of the NeuroTrax computerized battery for cognitive screening in Parkinson's disease: comparison with the MMSE and the MoCA

To determine the utility of a computerized assessment in Parkinson's disease (PD), we compared the cognitive performance of 50 PD patients on the NeuroTrax computerized battery relative to the mini-mental state examination (MMSE) and the Montreal Cognitive Assessment (MoCA). The results revealed fair agreement between impairment on the NeuroTrax and the MMSE (kappa=.291, p=.031) but only slight agreement between the NeuroTrax and the MoCA (kappa=.138, p = .054) and between the MoCA and the MMSE (kappa = .168, p = .069). The NeuroTrax identified 52% of the sample as average or above, 40% as below average, and 8% as impaired. The MoCA identified 54% of the sample as impaired (28% average or above and 18% below average), while the MMSE identified 66% as average or above (20% below average and 14% impaired). Several stepwise regressions revealed that executive and verbal functions were the best predictors of cognitive functioning on the NeuroTrax, while memory recall, serial sevens, naming, and abstraction were the best predictors on the MoCA. These results suggest that although the NeuroTrax may be useful in identifying executive cognitive deficits in PD, similar to the MMSE the NeuroTrax may lack optimal sensitivity. While the MoCA is sensitive, it may be too stringent in overclassifying PD patients as impaired.

Onset of dyskinesia with adjunct ropinirole prolonged-release or additional levodopa in early Parkinson's disease

Levodopa-induced dyskinesia can result in significant functional disability and reduced quality of life in patients with Parkinson's disease (PD). The goal of this study was to determine if the addition of once-daily ropinirole 24-hour prolonged-release (n = 104) in PD patients not optimally controlled with levodopa after up to 3 years of therapy with less than 600 mg/d delays the onset of dyskinesia compared with increasing doses of levodopa (n = 104). During the study, 3% of the ropinirole prolonged-release group (mean dose 10 mg/d) and 17% of the levodopa group (mean additional dose 284 mg/d) developed dyskinesia (P < 0.001). There were no significant differences in change in Unified Parkinson's Disease Rating Scale activities of daily living or motor scores, suggesting comparable efficacy between the two treatments. Adverse events were comparable in the two groups with nausea, dizziness, insomnia, back pain, arthralgia, somnolence, fatigue, and pain most commonly reported. Ropinirole prolonged-release delayed the onset of dyskinesia with comparable efficacy to increased doses of levodopa in early PD patients not optimally controlled with levodopa.

Subthalamic nucleus deep brain stimulation changes speech respiratory and laryngeal control in Parkinson's disease

Adequate respiratory and laryngeal motor control are essential for speech, but may be impaired in Parkinson's disease (PD). Bilateral subthalamic nucleus deep brain stimulation (STN DBS) improves limb function in PD, but the effects on respiratory and laryngeal control remain unknown. We tested whether STN DBS would change aerodynamic measures of respiratory and laryngeal control, and whether these changes were correlated with limb function and stimulation parameters. Eighteen PD participants with bilateral STN DBS were tested within a morning session after a minimum of 12 h since their most recent dose of anti-PD medication. Testing occurred when DBS was on, and again 1 h after DBS was turned off, and included aerodynamic measures during syllable production, and standard clinical ratings of limb function. We found that PD participants exhibited changes with DBS, consistent with increased respiratory driving pressure (n = 9) and increased vocal fold closure (n = 9). However, most participants exceeded a typical operating range for these respiratory and laryngeal control variables with DBS. Changes were uncorrelated with limb function, but showed some correlation with stimulation frequency and pulse width, suggesting that speech may benefit more from low-frequency stimulation and shorter pulse width. Therefore, high-frequency STN DBS may be less beneficial for speech-related respiratory and laryngeal control than for limb motor control. It is important to consider these distinctions and their underlying mechanisms when assessing the impact of STN DBS on PD.

Early diagnosis of Parkinson's disease: recommendations from diagnostic clinical guidelines

Therapeutic options for Parkinson's disease (PD) are currently limited to symptomatic agents. Levodopa is the most efficacious treatment; however, higher doses and long-term use are associated with adverse effects such as motor fluctuations and dyskinesia. Early treatment of PD with other agents such as dopamine agonists and monoamine oxidase type B inhibitors can provide symptomatic benefit and delay initiation of levodopa therapy. Early treatment of PD is contingent upon early and accurate diagnosis of the disease, which can be challenging because there are no biomarkers or neuroimaging or other clinical tests available to confirm the diagnosis. PD diagnosis is currently based on the presence or absence of various clinical features and the experience of the treating physician. A definitive diagnosis can be made only after autopsy. Moreover, the signs and symptoms present in early PD can resemble those of a number of other movement disorders, particularly other forms of parkinsonism, such as multiple system atrophy, drug-induced parkinsonism, and vascular parkinsonism, as well as diffuse Lewy body disease and essential tremor. Nevertheless, diagnosis of PD based on clinical features and response to antiparkinsonian medication can be achieved with a fairly high level of accuracy, particularly when made by a physician specializing in movement disorders. This article reviews and summarizes published recommendations for the clinical diagnosis of PD.

Mitochondrial respiration and respiration-associated proteins in cell lines created through Parkinson's subject mitochondrial transfer

Parkinson's disease (PD) is associated with perturbed mitochondrial function. Studies of cytoplasmic hybrid (cybrid) cell lines containing mitochondria from PD subjects suggest complex I dysfunction in particular is a relatively upstream biochemical defect. To evaluate potential downstream consequences of PD mitochondrial dysfunction, we used a cybrid approach to model PD mitochondrial dysfunction; our cybrid cell lines were generated via transfer of PD or control subject platelet mitochondria to mtDNA-depleted NT2 cells. To confirm our PD cybrid mitochondria did indeed differ from control cybrid mitochondria we measured complex I V(max) activities. Consistent with other PD cybrid reports, relative to control cybrid cell lines the PD cybrid cell line mean complex I V(max) activity was reduced. In this validated model, we used an oxygen electrode to characterize PD cybrid mitochondrial respiration. Although whole cell basal oxygen consumption was comparable between the PD and control cybrid groups, the proton leak was increased and maximum respiratory capacity was decreased in the PD cybrids. PD cybrids also had reduced SIRT1 phosphorylation, reduced peroxisome proliferator-activated receptor-gamma coactivator-1alpha levels, and increased NF-kB activation. We conclude mitochondrial respiration and pathways influenced by aerobic metabolism are altered in NT2 cybrid cell lines generated through transfer of PD subject platelet mitochondria.

Older onset essential tremor: More rapid progression and more degenerative pathology

There are few data on rate of progression in essential tremor (ET). To quantify the rate of tremor progression in a cross-sectional sample of 348 ET cases in an epidemiological study; characterize the relationship between age of tremor onset and rate of tremor progression in that sample; and characterize the relationship between age of tremor onset, rate of tremor progression, and severity of underlying brain changes in 9 cases from a brain repository. Rate of tremor progression was defined as tremor severity / duration. The degeneration index = number of torpedoes per section / Purkinje cell linear density. In the epidemiological study, older age of tremor onset was associated with faster rate of tremor progression (P < 0.001). In the brain repository, older age of tremor onset was associated with higher degeneration index (P = 0.037), and higher degeneration index was associated with faster rate of tremor progression (P = 0.018). In a large clinical sample, older age of onset was associated with more rapid tremor progression. In a brain bank, older age of onset was associated with more degenerative pathology in the cerebellum. As in several neurodegenerative disorders, in older onset cases, it is possible that the disease advances more rapidly.

An open-label conversion study of pramipexole to ropinirole prolonged release in Parkinson's disease

Ropinirole prolonged release (PR) is a once daily oral dopamine agonist approved for the treatment of Parkinson's disease (PD). The goal of this 4 week, open-label study was to determine the most effective conversion ratio with the fewest adverse effects (AEs) when switching from pramipexole to ropinirole PR. Sixty patients with PD taking pramipexole were converted overnight to ropinirole PR at ratios of 1:3, 1:4, or 1:5 such that 20 consecutive subjects were enrolled in each group. Ropinirole PR dose adjustments were allowed to maintain efficacy or to reduce AEs. An overnight switch from pramipexole to ropinirole PR was found to be well tolerated and AEs were typical for a dopamine agonist. The most common AEs were worsening of PD symptoms, dizziness, somnolence, and nausea, the majority of which resolved after dose adjustments. Thirteen subjects discontinued ropinirole PR before 4 weeks. These subjects were taking a significantly greater dose of pramipexole, the majority greater than 4 mg/day, and tended to have longer disease durations. A conversion ratio of 1 mg of pramipexole to 4 mg of ropinirole PR resulted in the fewest discontinuations of ropinirole PR, the fewest dose adjustments and the largest percentage of subjects that preferred ropinirole PR.

Assessment of the effects of subthalamic stimulation in Parkinson disease patients by artificial neural network

This study aims at using a probabilistic neural network (PNN) for discriminating between normal and Parkinson disease (PD) subjects using as input the principal components (PCs) derived from vertical component of the ground reaction force (vGRF). The trained PNN was further used for evaluating the effects of deep brain stimulation of the subthalamic nucleus (STN DBS) on PD, with and without medication. A sample of 45 subjects (30 normal and 15 PD subjects who underwent STN DBS) was evaluated by gait analysis. PD subjects were assessed under four test conditions: without treatment (mof-sof), only with stimulation (mof-son) or medication (mon-sof), and with combined treatments (mon-son). PC analysis was applied on vGRF, where six PC scores were chosen by the broken stick test. Using a bootstrap approach for the PNN model, and the area under the receiver operating characteristic curve (AUC) as performance measurement, the first three and fifth PCs were selected as input variables. The PNN presented AUC = 0.995 for classifying controls and PD subjects in the mof-sof condition. When applied to classify the PD subjects under treatment, the PNN indicated that STN DBS alone is more effective than medication, and further vGRF enhancement is obtained with combined therapies.

Early biomechanical markers of postural instability in Parkinson's disease

Current clinical assessments do not adequately detect the onset of postural instability in the early stages of Parkinson's disease (PD). The aim of this study was to identify biomechanical variables that are sensitive to the effects of early Parkinson's disease on the ability to recovery from a balance disturbance. Ten adults diagnosed with idiopathic PD and no clinically detectable postural instability, and ten healthy age-range matched controls (HC) completed the study. The first step in the response to a backwards waist pull was quantified in terms of strategy, temporal, kinematic, kinetic, and center of pressure (COP) variables. People with PD, compared to HC, tended to be less consistent in the choice of stepping limb, utilized more time for weight shift, used a modified ankle joint motion prior to liftoff, and the COP was further posterior at landing. The study results demonstrate that PD changes the response to a balance disturbance which can be quantified using biomechanical variables even before the presence of clinically detectable postural instability. Further studies are required to determine if these variables are sensitive and specific to postural instability.

Occupation and risk of parkinsonism: a multicenter case-control study

BACKGROUND

We examined risk of parkinsonism in occupations (agriculture, education, health care, welding, and mining) and toxicant exposures (solvents and pesticides) putatively associated with parkinsonism.

OBJECTIVE

To investigate occupations, specific job tasks, or exposures and risk of parkinsonism and clinical subtypes.

DESIGN

Case-control.

SETTING

Eight movement disorders centers in North America.

PARTICIPANTS

Inclusion criteria were parkinsonism (>or=2 cardinal signs), diagnosis within 8 years of recruitment (to minimize survival bias), and ability to participate in detailed telephone interviews. Control subjects were primarily nonblood relatives or acquaintances of patients.

MAIN OUTCOME MEASURES

This multicenter case-control study compared lifelong occupational and job task histories to determine associations with parkinsonism and certain clinical subtypes (postural instability and gait difficulty and age at diagnosis <or=50 years).

RESULTS

Findings in 519 cases and 511 controls were analyzed. Work in agriculture, education, health care, or welding was not associated with increased risk of parkinsonism. Unexpected increased risks associated with legal, construction and extraction, or religious occupations were not maintained after adjustment for duration. Risk of parkinsonism increased with pesticide use (odds ratio, 1.90; 95% confidence interval, 1.12-3.21), use of any of 8 pesticides mechanistically associated with experimental parkinsonism (2.20; 1.02-4.75), and use of 2,4-dichlorophenoxyacetic acid (2.59; 1.03-6.48). None of the specific occupations, job tasks, or task-related exposures were associated with younger age at diagnosis (<or=50 years). Ever working in business and finance, legal occupations, construction and extraction, or transportation and material moving was associated with postural instability and gait difficulty subtype of parkinsonism. Tobacco use was inversely associated with parkinsonism risk.

CONCLUSION

The association of disease risk with pesticides support a toxicant-induced cause of parkinsonism.

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

As no comprehensive assessment instrument for impulse control disorders (ICDs) in Parkinson's 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 Parkinson's 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.

Randomized, double-blind, pilot evaluation of intravenous glutathione in Parkinson's disease

The objective of this study was to evaluate the safety, tolerability, and preliminary efficacy of intravenous glutathione in Parkinson's disease (PD) patients. This was a randomized, placebo-controlled, double-blind, pilot trial in subjects with PD whose motor symptoms were not adequately controlled with their current medication regimen. Subjects were randomly assigned to receive intravenous glutathione 1,400 mg or placebo administered three times a week for 4 weeks. Twenty-one subjects were randomly assigned, 11 to glutathione and 10 to placebo. One subject who was assigned to glutathione withdrew from the study for personal reasons prior to undergoing any postrandomization efficacy assessments. Glutathione was well tolerated and there were no withdrawals because of adverse events in either group. Reported adverse events were similar in the two groups. There were no significant differences in changes in Unified Parkinson's Disease Rating Scale (UPDRS) scores. Over the 4 weeks of study medication administration, UPDRS ADL + motor scores improved by a mean of 2.8 units more in the glutathione group (P = 0.32), and over the subsequent 8 weeks worsened by a mean of 3.5 units more in the glutathione group (P = 0.54). Glutathione was well tolerated and no safety concerns were identified. Preliminary efficacy data suggest the possibility of a mild symptomatic effect, but this remains to be evaluated in a larger study.

Torpedoes in Parkinson's disease, Alzheimer's disease, essential tremor, and control brains

Purkinje cell axonal swellings ("torpedoes"), described in several cerebellar disorders as well as essential tremor (ET), have not been quantified in common neurodegenerative conditions. The aim of this study was to quantify torpedoes Parkinson's disease (PD) and Alzheimer's disease (AD) compared with ET and control brains. Brains included 40 ET cases (34 cerebellar ET, 6 Lewy body variant of ET) and age-matched comparison brains (21 AD, 14 PD/diffuse Lewy body disease, 25 controls). Torpedoes were counted in 20 x 25 mm cerebellar cortical sections stained with Luxol Fast Blue/Hematoxylin and Eosin. The median number of torpedoes in cerebellar ET (12) was 12x higher than that of controls (1) and nearly 2.5x higher than in AD (5) or PD/DLBD (5) (all P < or = 0.005). Furthermore, in a logistic regression model that adjusted for age and Alzheimer's-type changes, each torpedo more than doubled the odds of having cerebellar ET (Odds ratio(cerebellar ET vs. control) = 2.57, P = 0.006), indicating that the association between increased torpedoes and cerebellar ET was independent of these Alzheimer's-type changes. Although torpedoes are increased in AD and PD, as well as cerebellar ET, the magnitude of increase in cerebellar ET is greater, and cannot be accounted for by concomitant AD or PD pathology.

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

As no comprehensive assessment instrument for impulse control disorders (ICDs) in Parkinson's 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 Parkinson's 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.

A review of ropinirole prolonged release in Parkinson's disease

Ropinirole prolonged release is a once-daily, 24-hour formulation of ropinirole, a non-ergot dopamine agonist. It is approved as monotherapy and as an adjunct to levodopa in the treatment of Parkinson's disease (PD). Several potential advantages of ropinirole prolonged release compared to the immediate release formulation include maintaining more consistent dopaminergic activity with steadier plasma levels, increased tolerability, greater compliance from a simpler once-daily dosing regimen and ease in dose titration. In a randomized, double-blind, non-inferiority, crossover study, ropinirole prolonged release was shown to have comparable efficacy and tolerability to immediate release ropinirole in early PD patients, with significantly greater compliance. Subjects were converted overnight between ropinirole formulations without loss of efficacy and with good tolerability. In a randomized, double-blind, placebo-controlled study in advanced PD, daily "off" time was reduced by an average of 2.1 hours with ropinirole prolonged release compared to 0.4 hours with placebo. Patients on ropinirole prolonged release were also more likely to require less daily levodopa. Ropinirole prolonged release is well tolerated with a similar adverse effect profile to other non-ergot dopamine agonists. The most common adverse effects include dyskinesia, nausea, dizziness, hallucinations, somnolence, abdominal pain or discomfort and orthostatic hypotension. Ropinirole prolonged release is a safe and effective treatment option for both early and advanced PD. This manuscript briefly reviews the current pharmacological treatment options for PD and provides a more detailed review of the currently available data regarding ropinirole prolonged release as a treatment option for PD.

Levodopa-related wearing-off in Parkinson's disease: identification and management

BACKGROUND

Levodopa is currently the most effective treatment for Parkinson's disease (PD); however, long-term levodopa therapy often results in motor complications, such as motor fluctuations and dyskinesia. The initial complication is commonly wearing-off, which is the re-emergence of motor and non-motor symptoms before the next scheduled levodopa dose.

OBJECTIVE

The purpose of this article was to review published literature that discusses wearing-off, focusing on the role of the healthcare professional, including the primary care physician, in the effective management of wearing-off.

METHODS

An electronic literature search was conducted using MEDLINE and EMBASE to find articles discussing wearing-off and its management using the following keywords: 'Parkinson's disease'; 'wearing-off'; 'levodopa'; 'primary care'.

FINDINGS AND CONCLUSIONS

Current evidence indicates that a consistent delivery of levodopa should improve long-term symptomatic efficacy and may prevent or delay motor complications. A number of therapeutic options are available to optimize therapeutic outcome, including modification of the levodopa dose or dosing schedule,switching to another levodopa formulation and the use of adjunct therapies, such as catechol-O-methyl transferase inhibitors, dopamine agonists and monoamine oxidase-B inhibitors. The management of wearing-off is dependent upon the early identification of symptoms and the initiation of effective treatment. Key issues are the need to educate patients and to facilitate good communication with both primary and secondary healthcare professionals. In most cases, patients with PD initially present to primary healthcare professionals who may refer the patient to a neurologist once disease management becomes more complex. However, in many cases, especially in rural areas where neurologists may not be widely available, the primary healthcare professionals may manage the patient throughout the disease course. Limitations of this review include the restricted search criteria and selected search period.

Pharmacotherapy of essential tremor : an overview of existing and upcoming agents

Essential tremor is one of the most common movement disorders, yet the pharmacological treatments currently available have limited efficacy, being effective in only approximately 50% of patients with this disorder. The most commonly used, and generally most effective, medications for essential tremor are propranolol and primidone, administered either as monotherapy or in combination. If these medications do not provide satisfactory control of tremor, other beta-adrenoceptor antagonists, such as metoprolol or atenolol, and other antiepileptic drugs, such as topiramate or gabapentin, are often tried. In addition, benzodiazepines can be effective in some patients, particularly those with associated anxiety. There is a need for additional medications that result in greater tremor control in a larger number of patients with essential tremor. Several new drugs, including 1-octanol, sodium oxybate, dimethoxymethyl-diphenyl-barbituric acid (T-2000) and carisbamate, are currently under investigation for the treatment of essential tremor.