Exercise knowledge, barriers and motivators among LRRK2 G2019S mutation carriers

INTRODUCTION

People with a Gly2019Ser mutation in the leucine-rich repeat kinase 2 (LRRK2 G2019S) are at increased risk of developing Parkinson's disease (PD). Recent evidence suggests that exercise may delay or prevent the development of clinically overt symptoms of PD in people at risk of PD. We determined whether LRRK2 G2019S mutation carriers with and without manifest PD are aware of the relationship between exercise and PD and how they differ in awareness, barriers and motivators to exercise.

METHODS

We deployed a survey among 4422 LRRK2 G2019S mutation carriers. In total, 505 (11.4%) of them completed the survey, of whom 105 had self-reported manifest PD.

RESULTS

Ninety-two percent of the LRRK2 G2019S mutation carriers with manifest PD and 63% of those with non-manifest PD were aware of the relationship between exercise and PD. Lack of motivation was the top barrier for those without manifest PD, while having an injury/disability was the most common barrier for those with manifest PD. Improvement of body functioning was the top motivator for both.

CONCLUSION

The fact that many at-risk individuals are not aware of the importance of exercise and would exercise more with fewer barriers creates opportunities for trials using exercise as a possible prevention strategy for PD.

Good vibrations: tactile cueing for freezing of gait in Parkinson's disease

BACKGROUND

Cueing strategies can alleviate freezing of gait (FOG) in people with Parkinson's disease (PD). We evaluated tactile cueing delivered via vibrating socks, which has the benefit of not being noticeable to bystanders.

OBJECTIVE

To evaluate the effect of tactile cueing compared to auditory cueing on FOG.

METHODS

Thirty-one persons with PD with FOG performed gait tasks during both ON and OFF state. The effect of open loop and closed loop tactile cueing, as delivered by vibrating socks, was compared to an active control group (auditory cueing) and to a baseline condition (uncued gait). These four conditions were balanced between subjects. Gait tasks were videotaped and annotated for FOG by two experienced raters. Motion data were collected to analyze spatiotemporal gait parameters. Responders were defined as manifesting a relative reduction of > 10% in the percent time frozen compared to uncued gait.

RESULTS

The average percent time frozen during uncued gait was 11.2% in ON and 21.5% in OFF state. None of the three tested cueing modalities affected the percentage of time frozen in either the ON (p = 0.20) or OFF state (p = 0.12). The number of FOG episodes and spatiotemporal gait parameters were also not affected. We found that 22 out of 31 subjects responded to cueing, the response to the three types of cueing was highly individual.

CONCLUSIONS

Cueing did not improve FOG at the group level; however, tactile as well as auditory cueing improved FOG in many individuals. This highlights the need for a personalized approach when using cueing to treat FOG.

Design of the PERSPECTIVE study: PERsonalized SPEeCh Therapy for actIVE conversation in Parkinson's disease (randomized controlled trial)

Objective

To evaluate the effectiveness of personalized and home-based speech therapy on quality of life, intelligibility, and social participation for people with Parkinson’s disease (PD) who have a reduced intelligibility of speech.

Background

Speech problems in PD have a profound negative impact on social interaction and quality of life. Evidence for speech therapy in PD is growing, but more work remains needed to explore its full potential. Efficacy exists for highly intensive standardized speech treatment programs, but not all patients can comply with this rather intense intervention, especially the more severely affected ones. Here, we aim to study the effectiveness of personalized and home-based (remote) speech therapy in PD on quality of life and speech. The intervention will be supported by a dedicated speech training app. We expect that this approach will improve speech intelligibility and quality of life in patients irrespective of disease stage.

Methods

We will perform a single blind, randomized controlled trial, comparing 8 weeks of speech therapy to no intervention using a waiting list design. A total of 215 PD patients with problems in intelligibility will be recruited by 12 highly experienced speech therapists. All patients will be measured at baseline and after 8 weeks (primary endpoint). Additionally, the experimental group will be re-assessed one more time, after a wash-out period of 24 weeks. The control group will receive deferred treatment after 8 weeks, but without additional follow-up assessments. Our primary outcome is quality of life (as measured with PDQ-39). Secondary outcomes include speech and voice quality, intelligibility, severity of voice and speech complaints, and caregiver burden.

Results

The inclusion of participants has started on March 1, 2019, and is expected to be finalized on April 1, 2021. We expect to have the first results in January 2022.

Conclusions

We will investigate the effectiveness of speech therapy in PD. Particular strengths of our study include a randomized and single-blinded design, the personalized treatment approach, the inclusion of PD patients irrespective of disease stage or severity of the speech complaint, the long-term follow-up, the adequate power, and the use of a patient-relevant primary endpoint. This will allow us to draw firm conclusions about the effectiveness of personalized and remote speech therapy for PD patients in all disease stages.

Trial registration

ClinicalTrials.govNCT03963388. Registered on May 24, 2019

Aerobic exercise alters brain function and structure in Parkinson's disease a randomized controlled trial

Objective

Randomized clinical trials have shown that aerobic exercise attenuates motor symptom progression in Parkinson's disease, but the underlying neural mechanisms are unclear. Here, we investigated how aerobic exercise influences disease‐related functional and structural changes in the corticostriatal sensorimotor network, which is involved in the emergence of motor deficits in Parkinson's disease. Additionally, we explored effects of aerobic exercise on tissue integrity of the substantia nigra, and on behavioral and cerebral indices of cognitive control.

Methods

The Park‐in‐Shape trial is a single‐center, double‐blind randomized controlled trial in 130 Parkinson's disease patients who were randomly assigned (1:1 ratio) to aerobic exercise (stationary home trainer) or stretching (active control) interventions (duration = 6 months). An unselected subset from this trial (exercise, n = 25; stretching, n = 31) underwent resting‐state functional and structural magnetic resonance imaging (MRI), and an oculomotor cognitive control task (pro‐ and antisaccades), at baseline and at 6‐month follow‐up.

Results

Aerobic exercise, but not stretching, led to increased functional connectivity of the anterior putamen with the sensorimotor cortex relative to the posterior putamen. Behaviorally, aerobic exercise also improved cognitive control. Furthermore, aerobic exercise increased functional connectivity in the right frontoparietal network, proportionally to fitness improvements, and it reduced global brain atrophy.

Interpretation

MRI, clinical, and behavioral results converge toward the conclusion that aerobic exercise stabilizes disease progression in the corticostriatal sensorimotor network and enhances cognitive performance. ANN NEUROL 2022;91:203–216

Mental health in people with Parkinson's disease during the COVID-19 pandemic: potential for targeted interventions?

The COVID-19 pandemic has introduced a myriad of challenges to the social life and care of people with Parkinson’s disease (PD), which could potentially worsen mental health problems. We used baseline data of the PRIME-NL study (N = 844) to examine whether the association between COVID-19 stressors and mental health is disproportionately large in specific subgroups of people with PD and to explore effects of hypothetical reductions in COVID-19 stressors on mental health and quality of life. The mean (SD) age of the study population was 70.3 (7.8) years and 321 (38.0%) were women. The linear regression effect estimate of the association of COVID-19 stressors with mental health was most pronounced in women, highly educated people, people with advanced PD and people prone to distancing or seeking social support. Smaller effect estimates were found in people scoring high on confrontive coping or planful problem solving. The parametric G-formula method was used to calculate the effects of hypothetical interventions on COVID-19 stressors. An intervention reducing stressors with 50% in people with above median MDS-UPDRS-II decreased the Beck Depression Inventory in this group from 14.7 to 10.6, the State-Trait Anxiety Inventory from 81.6 to 73.1 and the Parkinson’s Disease Quality of Life Questionnaire from 35.0 to 24.3. Insights from this cross-sectional study help to inform tailored care interventions to subgroups of people with PD most vulnerable to the impact of COVID-19 on mental health and quality of life.

Visual cues added to a virtual environment paradigm do not improve motor arrests in Parkinson's disease

Objective. Elucidating how cueing alleviates freezing of gait (FOG) in Parkinson's disease (PD) would enable the development of more effective, personalized cueing strategies. Here, we aimed to validate a visual cueing virtual environment (VE) paradigm for future use in e.g. neuroimaging studies and behavioral studies on motor timing and scaling in PD patients with FOG.Approach. We included 20 PD patients with FOG and 16 age-matched healthy control subjects. Supine participants were confronted with a VE displaying either no cues, bars or staircases. They navigated forward using alternate suppression of foot pedals. Motor arrests (as proxy for FOG), and measures of motor timing and scaling were compared across the three VE conditions for both groups.Main results. VE cues (bars and staircases) did not reduce motor arrests in PD patients and healthy control subjects. The VE cues did reduce pedal amplitude in healthy control subjects, without effects on other motor parameters.Conclusion. We could not validate a visual cueing VE paradigm to study FOG. The VE cues possibly failed to convey the necessary spatial and temporal information to support motor timing and scaling. We discuss avenues for future research.

Validation of the Auditory Stroop Task to increase cognitive load in walking tasks in healthy elderly and persons with Parkinson's disease

Background

The development of treatments for freezing of gait (FOG) in Parkinson’s disease (PD) requires experimental study set-ups in which FOG is likely to occur, and is amenable to therapeutic interventions. We explore whether the ‘Auditory Stroop Task’ (AST) can be used to increase cognitive load (and thereby elicit FOG), simultaneously with visual cues (as a therapeutic intervention for FOG). We additionally examined how these two contrasting effects might interact in affecting gait and FOG parameters.

Objectives

We investigated whether: (1) the ‘Auditory Stroop Task’ (AST) influences gait in healthy elderly and persons with PD who experience FOG, and increases the frequency of FOG events among PD patients; (2) the AST and visual cues interact; and (3) different versions of the AST exert different cognitive loads.

Methods

In ‘Experiment 1’, 19 healthy elderly subjects performed a walking task while performing a high and low load version of the AST. Walking with a random numbers task, and walking without cognitive load served as control conditions. In ‘Experiment 2’, 20 PD patients with FOG and 18 healthy controls performed a walking task with the AST, and no additional cognitive load as control condition. Both experiments were performed with and without visual cues. Velocity, cadence, stride length, and stride time were measured in all subjects. FOG severity was measured in patients.

Results

Compared to the control conditions, the AST negatively affected all gait parameters in both patients and controls. The AST did not increase the occurrence of FOG in patients. Visual cues reduced the decline in stride length induced by cognitive load in both groups. Both versions of the AST exerted similar effects on gait parameters in controls.

Conclusions

The AST is well-suited to simulate the effects of cognitive load on gait parameters, but not FOG severity, in gait experiments in persons with PD and FOG.

The Personalized Parkinson Project: examining disease progression through broad biomarkers in early Parkinson's disease

BACKGROUND

Our understanding of the etiology, pathophysiology, phenotypic diversity, and progression of Parkinson's disease has stagnated. Consequently, patients do not receive the best care, leading to unnecessary disability, and to mounting costs for society. The Personalized Parkinson Project (PPP) proposes an unbiased approach to biomarker development with multiple biomarkers measured longitudinally. Our main aims are: (a) to perform a set of hypothesis-driven analyses on the comprehensive dataset, correlating established and novel biomarkers to the rate of disease progression and to treatment response; and (b) to create a widely accessible dataset for discovery of novel biomarkers and new targets for therapeutic interventions in Parkinson's disease.

METHODS/DESIGN

This is a prospective, longitudinal, single-center cohort study. The cohort will comprise 650 persons with Parkinson's disease. The inclusion criteria are purposely broad: age ≥ 18 years; and disease duration ≤5 years. Participants are followed for 2 years, with three annual assessments at the study center. Outcomes include a clinical assessment (including motor and neuro-psychological tests), collection of biospecimens (stool, whole blood, and cerebrospinal fluid), magnetic resonance imaging (both structural and functional), and ECG recordings (both 12-lead and Holter). Additionally, collection of physiological and environmental data in daily life over 2 years will be enabled through the Verily Study Watch. All data are stored with polymorphic encryptions and pseudonyms, to guarantee the participants' privacy on the one hand, and to enable data sharing on the other. The data and biospecimens will become available for scientists to address Parkinson's disease-related research questions.

DISCUSSION

The PPP has several distinguishing elements: all assessments are done in a single center; inclusion of "real life" subjects; deep and repeated multi-dimensional phenotyping; and continuous monitoring with a wearable device for 2 years. Also, the PPP is powered by privacy and security by design, allowing for data sharing with scientists worldwide respecting participants' privacy. The data are expected to open the way for important new insights, including identification of biomarkers to predict differences in prognosis and treatment response between patients. Our long-term aim is to improve existing treatments, develop new therapeutic approaches, and offer Parkinson's disease patients a more personalized disease management approach.

TRIAL REGISTRATION

Clinical Trials NCT03364894 . Registered December 6, 2017 (retrospectively registered).

Exploring the Parkinson patients' perspective on home-based video recording for movement analysis: a qualitative study

Background

Parkinson’s disease is a complex neurological disorder characterized by a variety of motor- as well as non-motor symptoms. Video-based technology (using continuous home monitoring) may bridge the gap between the fragmented in-clinic observations and the need for a comprehensive understanding of the progression and fluctuation of disease symptoms. However, continuous monitoring can be intrusive, raising questions about feasibility as well as potential privacy violation.

Methods

We used a grounded theory approach in which we performed semi-structured interviews to explore the opinion of Parkinson’s patients on home-based video recording used for vision-based movement analysis.

Results

Saturation was reached after sixteen interviews. Three first–level themes were identified that specify the conditions required to perform continuous video monitoring: Camera recording (e.g. being able to turn off the camera), privacy protection (e.g. patient’s behaviour, patient’s consent, camera location) and perceived motivation (e.g. contributing to science or clinical practice).

Conclusion

Our findings show that Parkinson patients’ perception of continuous, home-based video recording is positive, when a number of requirements are taken into account. This knowledge will enable us to start using this technology in future research and clinical practice in order to better understand the disease and to objectify outcomes in the patients’ own homes.

Design and effects of outcome-based payment models in healthcare: a systematic review

INTRODUCTION

Outcome-based payment models (OBPMs) might solve the shortcomings of fee-for-service or diagnostic-related group (DRG) models using financial incentives based on outcome indicators of the provided care. This review provides an analysis of the characteristics and effectiveness of OBPMs, to determine which models lead to favourable effects.

METHODS

We first developed a definition for OBPMs. Next, we searched four data sources to identify the models: (1) scientific literature databases; (2) websites of relevant governmental and scientific agencies; (3) the reference lists of included articles; (4) experts in the field. We only selected studies that examined the impact of the payment model on quality and/or costs. A narrative evidence synthesis was used to link specific design features to effects on quality of care or healthcare costs.

RESULTS

We included 88 articles, describing 12 OBPMs. We identified two groups of models based on differences in design features: narrow OBPMs (financial incentives based on quality indicators) and broad OBPMs (combination of global budgets, risk sharing, and financial incentives based on quality indicators). Most (5 out of 9) of the narrow OBPMs showed positive effects on quality; the others had mixed (2) or negative (2) effects. The effects of narrow OBPMs on healthcare utilization or costs, however, were unfavourable (3) or unknown (6). All broad OBPMs (3) showed positive effects on quality of care, while reducing healthcare cost growth.

DISCUSSION

Although strong empirical evidence on the effects of OBPMs on healthcare quality, utilization, and costs is limited, our findings suggest that broad OBPMs may be preferred over narrow OBPMs.

Balancing between the two: Are freezing of gait and postural instability in Parkinson's disease connected?

Postural instability and freezing of gait (FoG) are key features of Parkinson's disease (PD) closely related to falls. Growing evidence suggests that co-existing postural deficits could influence the occurrence and severity of FoG. To date, the exact nature of this interrelationship remains largely unknown. We analyzed the complex interaction between postural instability and gait disturbance by comparing the findings available in the posturographic literature between patients with and without FoG. Results showed that FoG and postural instability are intertwined, can influence each other behaviorally and may coincide neurologically. The most common FoG-related postural deficits included weight-shifting impairments, and inadequate scaling and timing of postural responses most apparent at forthcoming postural changes under time constraints. Most likely, a negative cycle of combined and more severe postural deficits in people with FoG will enhance postural stability breakdown. As such, the wide brain network deficiencies involved in FoG may also concurrently influence postural stability. Future work needs to examine whether training interventions targeting both symptoms will have extra clinical benefits on fall frequency.

Professional occupation and the risk of Parkinson's disease

BACKGROUND AND PURPOSE

Creativity in Parkinson's disease (PD) is strongly related to dopaminergic activity and medication. We hypothesized that patients with PD, including those who are in the pre-diagnostic phase of PD, are prone to choose highly structured 'conventional' professional occupations and avoid highly creative 'artistic' occupations.

METHODS

At baseline of the population-based Rotterdam Study, we asked 12 147 individuals aged ≥45 years about their latest occupation and categorized occupations according to the RIASEC model. Participants underwent baseline and follow-up (median 11 years) examinations for PD. We determined associations of artistic (versus any other occupation) and conventional (versus any other occupation) occupations with PD. Additionally, we pooled our results with a recently published case-control study (Radboud Study).

RESULTS

At baseline, conventional occupations were common [n = 4356 (36%)], whereas artistic occupations were rare [n = 137 (1%)]. There were 217 patients with PD, including 91 with prevalent PD and 126 with incident PD. The risk of PD varied substantially across occupational categories (chi-square, 14.61; P = 0.01). The penalized odds ratio (OR) of artistic occupations for PD was 0.19 [95% confidence interval (CI), 0.00-1.31; P = 0.11], whereas the OR of conventional occupations for PD was 1.23 (95% CI, 0.95-1.66; P = 0.10). The direction and magnitude of ORs were similar in cross-sectional and longitudinal subsamples. Pooled ORs across the Rotterdam and Radboud Studies were 0.20 (95% CI, 0.08-0.52; P < 0.001) for artistic and 1.23 (95% CI, 0.92-1.67; P = 0.08) for conventional occupations.

CONCLUSIONS

The risk of PD varies substantially by choice of professional occupation. Our findings suggest that dopaminergic degeneration affects choice of occupation, which may start in the pre-diagnostic phase of PD.

[Shared decision-making: dilemmas in daily practice]

Shared decision-making is an essential - but often neglected - component of evidence-based medicine. In practice, doctors, nurses and patients encounter dilemmas which are understandable, but not insurmountable. We illustrate this by means of a complex decision concerning therapy in the advanced stage of Parkinson's disease. Evidence of effectiveness differs with each individual therapy, and, in practice, the experiences of neurologists also vary widely. In addition, the various treatment strategies all require a different sort of daily care, and have differing impacts on people's lives. It is time that we worked towards a realistic view of shared decision-making. Shared decision-making cannot be generalised to a 'one size fits all' strategy that we can choose to apply or not to apply at will. It should be a flexible instrument which, depending on the individual and the specific situation, can be put to use to deliver the best tailored care.

The wrong end of the telescope: neuromuscular mimics of movement disorders (and vice versa)

The rapid advances in modern neurology have led to increased specialisation in clinical practice. Being an expert in a neurology subspecialty offers advantages for diagnosing and managing specific disorders. However, specialisation also risks tunnel vision: interpreting symptoms and signs within one's own framework of reference, while ignoring differential diagnostic options from other subspecialties. This is particularly relevant when the patient's presentation potentially belongs to different neurological subspecialties. We illustrate this challenge by highlighting a series of clinical features that partially overlap between two common subspecialties: movement disorders and neuromuscular disorders. An overlap in clinical presentation is not rare, and includes, for example, involuntary eyelid closure (which could be active eye closure due to blepharospasm, or ptosis due to weakness). Other overlapping features include abnormal postures, involuntary movements and gait changes. We describe two of these overlapping features in more detail and emphasise the possible consequences of 'looking through the wrong end of the telescope' in such patients, as this may lead to a wrong differential diagnosis, unnecessary investigations and a delayed treatment start.

Center of mass trajectories during turning in patients with Parkinson's disease with and without freezing of gait

BACKGROUND

Despite the strong relationship between freezing of gait (FOG) and turning in Parkinson's disease (PD), few studies have addressed specific postural characteristics during turning that might contribute to freezing.

METHODS

Thirty participants with PD (16 freezers, 14 non-freezers) (all tested OFF medication) and 14 healthy controls walked 5 meters and turned 180° in a 3D gait laboratory. COM behavior was analyzed during four turning quadrants of 40° between 10° and 170° pelvic rotation and during 40° before actual FOG episodes. These pre-FOG segments were compared with similar turning sections in turns of freezers without FOG. Outcome parameters were turn time, COM distance, COM velocity, step width and the medial- and anterior COM position.

RESULTS

Turn time was increased in freezers compared to non-freezers (p=.000). No differences were found regarding COM distance and velocity during turning quadrants between groups and between freezers' pre-FOG segments and similar turning segments without FOG. Medial COM deviation was reduced in PD patients compared to controls (p=.004), but no differences were found between freezers and non-freezers. In turns with freezing, turn time increased (p=.005) and step width decreased (p=.025) pre-FOG. Freezers also showed a less medial (p=.020) and more anterior (p=.016) COM position pre-FOG compared to turning sections without FOG.

CONCLUSIONS

Our results revealed no subgroup differences in COM behavior during uninterrupted turning. However, we found a reduced medial deviation, a forward COM shift and a decreased step width in freezers just before FOG episodes. These abnormalities may play a causal role, as they could hamper stability and fluent weight shifting necessary for continued stepping during turning.

Protocol of a randomised delayed-start double-blind placebo-controlled multi-centre trial for Levodopa in EArly Parkinson's disease: the LEAP-study

Background

The aim of this study is to investigate if early treatment with levodopa has a beneficial disease modifying effect on Parkinson’s disease (PD) symptoms and functional health, improves the ability to (maintain) work, and reduces the use of (informal) care, caregiver burden, and costs. Additionally, cost-effectiveness and cost-utility of early levodopa treatment will be assessed.

Methods

To differentiate between the direct symptomatic effects and possible disease modifying effects of levodopa, we use a randomised delayed-start double-blind placebo-controlled multi-centre trial design. Patients with early stage PD whose functional health does not yet necessitate initiation of PD-medication will be randomised to either 40 weeks of treatment with levodopa/carbidopa 100/25 mg TID including 2 weeks of dose escalation or to 40 weeks placebo TID. Subsequently, all patients receive levodopa/carbidopa 100/25 mg TID for 40 weeks. There are 8 assessments: at baseline and at 4, 22, 40, 44, 56, 68, and 80 weeks. The primary outcome measure is the difference in the mean total Unified Parkinson’s Disease Rating Scale scores between the early- and delayed-start groups at 80 weeks. Secondary outcome measures are rate of progression, the AMC Linear Disability Score, side effects, perceived quality of life with the Parkinson’s Disease Questionnaire-39, the European Quality of Life-5 Dimensions (EQ-5D), ability to (maintain) work, the use of (informal) care, caregiver burden, and costs. 446 newly diagnosed PD patients without impaired functional health need to be recruited in order to detect a minimal clinical relevant difference of 4 points on the total UPDRS at 80 weeks.

Discussion

The LEAP-study will provide insights into the possible disease modifying effects of early levodopa.

Trial registration

ISRCTN30518857, EudraCT number 2011-000678-72

Parkinson's disease patients compensate for balance control asymmetry

In Parkinson's disease (PD) subtle balance abnormalities can already be detected in early-stage patients. One feature of impaired balance control in PD is asymmetry: one leg produces more corrective joint torque than the other. We hypothesize that in mild to moderately affected PD patients, the least impaired leg compensates for the more impaired leg. Twenty PD patients and eleven healthy matched control subjects participated. Clinical asymmetry was determined by the difference between the left and right body side scores on the Unified Parkinson's Disease Rating Scale. Balance was perturbed with two independent continuous multisine perturbations in the forward-backward direction. Subsequently, we applied closed-loop system identification, which determined the spectral estimate of the stabilizing mechanisms, for each leg. Balance control behavior was similar in PD patients and control subjects at the ankle, but at the hip stiffness was increased. Control subjects exhibited symmetric balance control, but in PD patients the balance contribution of the leg of the clinically least affected body side was higher whereas the leg of the clinically most affected body side contributed less. The ratio between the legs helped to preserve a normal motor output at the ankle. Our results suggest that PD patients compensate for balance control asymmetries by increasing the relative contribution of the leg of their least affected body side. This compensation appears to be successful at the ankle but is accompanied by an increased stiffness at the hip. We discuss the possible implications of these findings for postural stability and fall risk in PD patients.

Susceptibility-weighted imaging improves the diagnostic accuracy of 3T brain MRI in the work-up of parkinsonism

BACKGROUND AND PURPOSE

The differentiation between Parkinson disease and atypical parkinsonian syndromes can be challenging in clinical practice, especially in early disease stages. Brain MR imaging can help to increase certainty about the diagnosis. Our goal was to evaluate the added value of SWI in relation to conventional 3T brain MR imaging for the diagnostic work-up of early-stage parkinsonism.

MATERIALS AND METHODS

This was a prospective observational cohort study of 65 patients presenting with parkinsonism but with an uncertain initial clinical diagnosis. At baseline, 3T brain MR imaging with conventional and SWI sequences was performed. After clinical follow-up, probable diagnoses could be made in 56 patients, 38 patients diagnosed with Parkinson disease and 18 patients diagnosed with atypical parkinsonian syndromes, including 12 patients diagnosed with multiple system atrophy-parkinsonian form. In addition, 13 healthy controls were evaluated with SWI. Abnormal findings on conventional brain MR imaging were grouped into disease-specific scores. SWI was analyzed by a region-of-interest method of different brain structures. One-way ANOVA was performed to analyze group differences. Receiver operating characteristic analyses were performed to evaluate the diagnostic accuracy of conventional brain MR imaging separately and combined with SWI.

RESULTS

Disease-specific scores of conventional brain MR imaging had a high specificity for atypical parkinsonian syndromes (80%-90%), but sensitivity was limited (50%-80%). The mean SWI signal intensity of the putamen was significantly lower for multiple system atrophy-parkinsonian form than for Parkinson disease and controls (P < .001). The presence of severe dorsal putaminal hypointensity improved the accuracy of brain MR imaging: The area under the curve was increased from 0.75 to 0.83 for identifying multiple system atrophy-parkinsonian form, and it was increased from 0.76 to 0.82 for identifying atypical parkinsonian syndromes as a group.

CONCLUSIONS

SWI improves the diagnostic accuracy of 3T brain MR imaging in the work-up of parkinsonism by identifying severe putaminal hypointensity as a sign indicative of multiple system atrophy-parkinsonian form.

Move for Change Part III: a European survey evaluating the impact of the EPDA Charter for People with Parkinson's Disease

BACKGROUND AND PURPOSE

Move for Change is an online pan-European patient survey based on the European Parkinson's Disease Association (EPDA) Charter for People with Parkinson's Disease (PD), which states that all PD patients have the right to: be referred to a doctor with a specialist interest in PD; receive an accurate diagnosis; have access to support services; receive continuous care; and take part in managing their illness.

METHODS

This part of the survey focuses on the final two elements of the Charter. It was administered online through the EPDA website and through affiliated patient associations' websites. A total of 1591 questionnaires were received and 1546 were analysed (97.2%).

RESULTS

Approximately half of the patients (53.0%) consulted a neurologist regularly (every 4-6 months). Consultations were usually arranged as part of a follow-up process (65.5%) and lasted for 15-30 min (63.2%), with 16.1% lasting <10 min and 17.9% lasting >30 min. Patients were largely satisfied with the attention they received (63.2%) but just 11.6% of patients were involved in treatment decisions, and 39.1% prepared a list of symptom changes for discussion. Two hundred caregivers also took part in the survey, and 71.4% felt included in the treatment plan by the doctor.

CONCLUSIONS

These results highlight that PD disease-management is driven by the clinician; he/she arranges consultations and makes the majority of management decisions, rather than patients being included in the process. This survey can be used to raise awareness for PD patients, encouraging greater involvement in the management of PD.

Diagnostic accuracy of Parkinson's disease and atypical parkinsonism in nursing homes

INTRODUCTION

Management of Parkinson's disease (PD) and atypical parkinsonism in nursing homes depends on a timely and accurate diagnosis. However, little is known about the diagnostic accuracy of these parkinsonian syndromes in nursing homes. We examined this issue in a large group of Dutch nursing home residents.

METHODS

Twelve large nursing home organizations in the Netherlands accounting for 100 nursing homes with a total population of 5480 residents participated. Residents with PD or atypical parkinsonism were identified according to their nursing home medical chart diagnosis. Additionally, local pharmacists provided a list of all residents using antiparkinson medication. We compared the admission diagnosis to a clinical diagnosis made in the study, based upon interview and detailed neurological examination by movement disorders experts. Diagnoses were based on accepted clinical criteria for PD and atypical parkinsonism.

RESULTS

In the total population of 5480 residents, 258 had previously been diagnosed with a form of parkinsonism according to their medical record. In 53 of these residents (20.5%) we changed or rejected the diagnosis. Specifically, we found no parkinsonism in 22 of these 53 residents (8.5% of all patients with suspected parkinsonism). In the remaining 31 residents (12%), we established a new diagnosis within the parkinsonian spectrum.

CONCLUSIONS

In a large population of Dutch nursing home residents, 20% of diagnoses within the parkinsonian spectrum were inaccurate. Almost 9% of residents had inadvertently received a diagnosis of parkinsonism. Better recognition of parkinsonism in nursing homes is important, because of the consequences for management and prognosis.

Benign paroxysmal positional vertigo in Parkinson's disease

BACKGROUND

Dizziness is a frequent complaint of patients with Parkinson's disease (PD), and orthostatic hypotension (OH) is often thought to be the cause. We studied whether benign paroxysmal positional vertigo (BPPV) could also be an explanation.

AIM

To assess the prevalence of benign paroxysmal positional vertigo in patients with Parkinson's disease, with and without dizziness.

METHODS

305 consecutive outpatients with PD completed the Movement Disorders Society-sponsored revision of the Unified Parkinsons' Disease Rating Scale-motor score, the Dizziness Handicap Inventory, the Dix-Hallpike maneuver and a test for orthostatic hypotension. When positive for benign paroxysmal positional vertigo, a repositioning maneuver was performed. Patients were followed for three months to determine the clinical response.

RESULTS

305 patients responded (186 men (61%), mean age 70.5 years (Standard Deviation 9.5 years)), of whom 151 (49%) complained of dizziness. 57 (38%) of the dizzy patients appeared to have orthostatic hypotension; 12 patients (8%) had a classical but previously unrecognized benign paroxysmal positional vertigo. A further four patients (3%) had a more atypical presentation of benign paroxysmal positional vertigo. Three months after treatment, 11 (92%) of patients with classical benign paroxysmal positional vertigo were almost or completely without complaints. We found no 'hidden' benign paroxysmal positional vertigo among patients without dizziness. The prevalence of benign paroxysmal positional vertigo among all patients with PD was 5.3%.

CONCLUSION

Among Parkinson patients with symptoms of dizziness, up to 11% may have benign paroxysmal positional vertigo, which can be treated easily and successfully.

Summary of the recommendations of the EFNS/MDS-ES review on therapeutic management of Parkinson's disease

OBJECTIVE

To summarize the 2010 EFNS/MDS-ES evidence-based treatment recommendations for the management of Parkinson's disease (PD). This summary includes the treatment recommendations for early and late PD.

METHODS

For the 2010 publication, a literature search was undertaken for articles published up to September 2009. For this summary, an additional literature search was undertaken up to December 2010. Classification of scientific evidence and the rating of recommendations were made according to the EFNS guidance. In cases where there was insufficient scientific evidence, a consensus statement ('good practice point') is made.

RESULTS AND CONCLUSIONS

For each clinical indication, a list of therapeutic interventions is provided, including classification of evidence.

EFNS/MDS-ES/ENS [corrected] recommendations for the diagnosis of Parkinson's disease

BACKGROUND

A Task Force was convened by the EFNS/MDS-ES Scientist Panel on Parkinson's disease (PD) and other movement disorders to systemically review relevant publications on the diagnosis of PD.

METHODS

Following the EFNS instruction for the preparation of neurological diagnostic guidelines, recommendation levels have been generated for diagnostic criteria and investigations.

RESULTS

For the clinical diagnosis, we recommend the use of the Queen Square Brain Bank criteria (Level B). Genetic testing for specific mutations is recommended on an individual basis (Level B), taking into account specific features (i.e. family history and age of onset). We recommend olfactory testing to differentiate PD from other parkinsonian disorders including recessive forms (Level A). Screening for pre-motor PD with olfactory testing requires additional tests due to limited specificity. Drug challenge tests are not recommended for the diagnosis in de novo parkinsonian patients. There is an insufficient evidence to support their role in the differential diagnosis between PD and other parkinsonian syndromes. We recommend an assessment of cognition and a screening for REM sleep behaviour disorder, psychotic manifestations and severe depression in the initial evaluation of suspected PD cases (Level A). Transcranial sonography is recommended for the differentiation of PD from atypical and secondary parkinsonian disorders (Level A), for the early diagnosis of PD and in the detection of subjects at risk for PD (Level A), although the technique is so far not universally used and requires some expertise. Because specificity of TCS for the development of PD is limited, TCS should be used in conjunction with other screening tests. Conventional magnetic resonance imaging and diffusion-weighted imaging at 1.5 T are recommended as neuroimaging tools that can support a diagnosis of multiple system atrophy (MSA) or progressive supranuclear palsy versus PD on the basis of regional atrophy and signal change as well as diffusivity patterns (Level A). DaTscan SPECT is registered in Europe and the United States for the differential diagnosis between degenerative parkinsonisms and essential tremor (Level A). More specifically, DaTscan is indicated in the presence of significant diagnostic uncertainty such as parkinsonism associated with neuroleptic exposure and atypical tremor manifestations such as isolated unilateral postural tremor. Studies of [(123) I]MIBG/SPECT cardiac uptake may be used to identify patients with PD versus controls and MSA patients (Level A). All other SPECT imaging studies do not fulfil registration standards and cannot be recommended for routine clinical use. At the moment, no conclusion can be drawn as to diagnostic efficacy of autonomic function tests, neurophysiological tests and positron emission tomography imaging in PD.

CONCLUSIONS

The diagnosis of PD is still largely based on the correct identification of its clinical features. Selected investigations (genetic, olfactory, and neuroimaging studies) have an ancillary role in confirming the diagnosis, and some of them could be possibly used in the near future to identify subjects in a pre-symptomatic phase of the disease.

Quantifying daily physical activity and determinants in sedentary patients with Parkinson's disease

BACKGROUND

Although physical activity is beneficial for Parkinson's disease (PD) patients, many do not meet the recommended levels. The range of physical activity among sedentary PD patients is unknown, as are factors that determine this variability. Hence, we aimed to (1) assess daily physical activity in self-identified sedentary PD patients; (2) compare this with criteria of a daily physical activity guideline; and (3) identify determinants of daily physical activity.

METHODS

Daily physical activity of 586 self-identified sedentary PD patients was measured with a tri-axial accelerometer for seven consecutive days. Physical fitness and demographic, disease-specific, and psychological characteristics were assessed. Daily physical activity was compared with the 30-min activity guideline. A linear mixed-effects model was estimated to identify determinants of daily physical activity.

RESULTS

Accelerometer data of 467 patients who fulfilled all criteria revealed that >98% of their day was spent on sedentary to light-intensity activities. Eighty-two percent of the participants were 'physically inactive' (0 days/week of 30-min activity); 17% were 'semi-active' (1-4 days/week of 30-min activity). Age, gender, physical fitness, and scores on the Unified Parkinson's Disease Rating Scale explained 69% of the variability in daily physical activity.

CONCLUSIONS

Performance-based measurements confirmed that most self-identified sedentary PD patients are 'physically inactive'. However, the variance in daily physical activity across subjects was considerable. Higher age, being female, and lower physical capacity were the most important determinants of reduced daily physical activity. Future therapeutic interventions should aim to improve daily physical activity in these high-risk patients, focusing specifically on modifiable risk factors.

Are postural responses to backward and forward perturbations processed by different neural circuits?

Startle pathways may contribute to rapid accomplishment of postural stability. Here we investigate the possible influence of a startling auditory stimulus (SAS) on postural responses. We formulated four specific questions: (1) can a concurrent SAS shorten the onset of automatic postural responses?; and if so (2) is this effect different for forward versus backward perturbations?; (3) does this effect depend on prior knowledge of the perturbation direction?; and (4) is this effect different for low- and high-magnitude perturbations? Balance was perturbed in 11 healthy participants by a movable platform that suddenly translated forward or backward. Each participant received 160 perturbations, 25% of which were combined with a SAS. We varied the direction and magnitude of the perturbations, as well as the prior knowledge of perturbation direction. Perturbation trials were interspersed with SAS-only trials. The SAS accelerated and strengthened postural responses with clear functional benefits (better balance control), but this was only true for responses that protected against falling backwards (i.e. in tibialis anterior and rectus femoris). These muscles also demonstrated the most common SAS-triggered responses without perturbation. Increasing the perturbation magnitude accelerated postural responses, but again with a larger acceleration for backward perturbations. We conclude that postural responses to backward and forward perturbations may be processed by different neural circuits, with influence of startle pathways on postural responses to backward perturbations. These findings give directions for future studies investigating whether deficits in startle pathways may explain the prominent backward instability seen in patients with Parkinson's disease and progressive supranuclear palsy.

Decomposing effects of dopaminergic medication in Parkinson's disease on probabilistic action selection--learning or performance?

Dopamine has long been implicated in reward-based learning and the expression of such learned associations on performance. Robust evidence supports its effects on learning and performance, but teasing these apart has proved challenging. Here we have adapted a classic test of value-based learning, the probabilistic selection task, to disentangle effects of dopamine on value-based performance from effects on value-based learning. Valence-specific effects of dopamine on this specific task cannot be accounted for by modulation of learning, and therefore must reflect modulation of performance. We found that dopaminergic medication, consisting of levodopa and/or dopamine agonists taken at own dose, in 18 patients with mild Parkinson's disease (Hoehn and Yahr < 2.5) potentiated reward-based approach in terms of both accuracy and reaction times, while leaving punishment-based avoidance unaffected. These data demonstrate that the effects of dopamine on probabilistic action selection are at least partly mediated by effects on the expression of learned associations rather than on learning itself, and help refine current models of dopamine's role in reward.

Prospective analysis of falls in dominant ataxias

In a previous retrospective study, we demonstrated that falls are common and often injurious in dominant spinocerebellar ataxias (SCAs) and that nonataxia features play an important role in these falls. Retrospective surveys are plagued by recall bias for the presence and details of prior falls. We therefore sought to corroborate and extend these retrospective findings by means of a prospective extension of this fall study. 113 patients with SCA1, SCA2, SCA3 or SCA6, recruited from the EuroSCA natural history study, were asked to keep a fall diary in between their annual visits to the participating centres. Additionally, patients completed a detailed questionnaire about the first three falls, to identify specific fall circumstances. Relevant disease characteristics were retrieved from the EuroSCA registry. 84.1% of patients reported at least one fall during a time period of 12 months. Fall-related injuries were common and their frequency increased with that of falls. The presence of nonataxia symptoms was associated with a higher fall frequency. This study confirms that falls are a frequent and serious complication of SCA, and that the presence of nonataxia symptoms is an important etiological factor in its occurrence.

Move for Change Part II: a European survey evaluating the impact of the EPDA Charter for people with Parkinson's disease

BACKGROUND AND PURPOSE

The Move for Change campaign is a three-part series of pan-European surveys designed by the European Parkinson's Disease Association (EPDA) to assess the impact that the EPDA Charter for People with Parkinson's disease (PD) has had since its launch in 1997. Here, we report results from the second survey, focusing on the third right of the Charter; that is, 'all patients have the right to have access to support services'. Although the level of evidence for different support services varies, it is important to ensure that patients can access services with clinically proven benefits.

METHODS

This survey comprised nine questions administered online via the EPDA and PD organization Web sites. Accessibility of support services was defined as 'services/medication/multidisciplinary healthcare professionals, etc. being available and on hand to patients when required'.

RESULTS

Neurologists and general practitioners (GPs) received highest accessibility results (90.0 and 87.0% of respondents, respectively), with moderate results for physiotherapists (68.0%) and PD organizations (72.0%) and lower results for PD specialist nurses (26.0%), occupational therapists (23.0%), and counselors (27.0%). Support provided by neurologists and PD specialists was considered to be 'very helpful' by 59.0 and 55.7%, respectively, whilst only 31.8% of respondents gave such favorable ratings to GPs. Funding of services was variable across Europe.

CONCLUSIONS

These data demonstrate the challenges faced by PD patients in accessing the adequate care and support required throughout the course of their disease. These findings can assist healthcare professionals and policymakers in improving access to support services for patients and their families across Europe.

Sleep matters in Parkinson's disease: use of a priority list to assess the presence of sleep disturbances

BACKGROUND AND PURPOSE

Despite their high prevalence and clinical impact, sleep disorders in Parkinson's disease appear to receive insufficient attention in clinical practice. We compared the importance of sleep disorders relative to other symptoms and daily issues. Furthermore, we determined whether relevance as perceived by patients correlated with the subjective presence of sleep disruption scored with a rating scale.

METHODS

We studied a cohort of 153 consecutive patients (95 men) who were referred for problems other than sleep to our referral center. Prior to their visit, patients ranked their individual top five clinical priorities (of 23 items), indicating the most problematic domains for which they requested medical attention. Additionally, nocturnal sleep quality and excessive daytime sleepiness (EDS) were assessed with validated questionnaires.

RESULTS

The top three important domains according to the patient were movement (79.9%), medication (73.2%), and physical condition (63.4%). Sleep was the sixth most frequently reported item, marked by 37.9% of the patients. Amongst the patients who scored sleep as a priority, 47 (81%) had a poor sleep quality (Pittsburgh Sleep Quality Index > 5). Although EDS was present in almost 30% of patients, a minority of them put it on their priority list.

CONCLUSION

A priority list can be used to prioritize patient-centered quality of life issues. Our results show that sleep is a clinical priority for about one-third of patients. Surprisingly, EDS was usually not prioritized by patients during the consultation, underscoring the need to use ratings scales alongside subjective priorities.

The effects of vibrotactile biofeedback training on trunk sway in Parkinson's disease patients

BACKGROUND

Postural instability in Parkinson's disease (PD) can lead to falls, injuries and reduced quality of life. We investigated whether balance in PD can improve by offering patients feedback about their own trunk sway as a supplement to natural sensory inputs. Specifically, we investigated the effect of artificial vibrotactile biofeedback on trunk sway in PD.

METHODS

Twenty PD patients were assigned to a control group (n = 10) or biofeedback group (n = 10). First, all patients performed two sets of six gait tasks and six stance tasks (pre-training assessment). Subsequently, all subjects trained six selected tasks five times (balance training). During this training, the feedback group received vibrotactile feedback of trunk sway, via vibrations delivered at the head. After training, both groups repeated all twelve tasks (post-training assessment). During all tasks, trunk pitch and roll movements were measured with angular velocity sensors attached to the lower trunk. Outcomes included sway angle and sway angular velocity in the roll and pitch plane, and task duration.

RESULTS

Overall, patients in the feedback group had a significantly greater reduction in roll (P = 0.005) and pitch (P < 0.001) sway angular velocity. Moreover, roll sway angle increased more in controls after training, suggesting better training effects in the feedback group (P < 0.001).

CONCLUSIONS

One session of balance training in PD using a biofeedback system showed beneficial effects on trunk stability. Additional research should examine if these effects increase further after more intensive training, how long these persist after training has stopped, and if the observed effects carry over to non-trained tasks.

First trial reactions and habituation rates over successive balance perturbations in Parkinson's disease

BACKGROUND

Balance control in Parkinson's disease is often studied using dynamic posturography, typically with serial identical balance perturbations. Because subjects can learn from the first trial, the magnitude of balance reactions rapidly habituates during subsequent trials. Changes in this habituation rate might yield a clinically useful marker. We studied balance reactions in Parkinson's disease using posturography, specifically focusing on the responses to the first, fully unpractised balance disturbance, and on the subsequent habituation rates.

METHODS

Eight Parkinson patients and eight age- and gender-matched controls received eight consecutive toe-up rotations of a support-surface. Balance reactions were measured with a motion analysis system and converted to centre of mass displacements (primary outcome).

RESULTS

Mean centre of mass displacement during the first trial was 51% greater in patients than controls (P=0.019), due to excessive trunk flexion and greater ankle plantar-flexion. However, habituated trials were comparable in both groups. Patients also habituated slower: controls were fully habituated at trial 2, whereas habituation in patients required up to five trials (P=0.004). The number of near-falls during the first trial was significantly correlated with centre of mass displacement during the first trial and with habituation rate.

CONCLUSIONS

Higher first trial reactions and a slow habituation rate discriminated Parkinson's patients from controls, but habituated trials did not. Further work should demonstrate whether this also applies to clinical balance tests, such as the pull test, and whether repeated delivery of such tests offers better diagnostic value for evaluating fall risks in parkinsonian patients.

Move for change part I: a European survey evaluating the impact of the EPDA Charter for People with Parkinson's disease

BACKGROUND AND PURPOSE

The 1997 European Parkinson's Disease Association's (EPDA) Charter for People with Parkinson's disease (PD) outlines their rights in terms of standards of care. It states that all patients have the right to: be referred to a doctor with a special interest in PD; receive an accurate diagnosis; have access to support services; receive continuous care; and take part in managing their illness. Move for Change is a three-part series of pan-European patient surveys based on this Charter.

METHODS

This first survey, consisting of 23 questions, focusing on the initial two points of the Charter, was administered online through the EPDA and affiliated patient associations' Web sites. Of 2149 forms received from 35 European countries, 2068 (96.2%) were analyzed, with the remainder excluded, mainly due to incomplete responses.

RESULTS

The majority of patients were diagnosed within 2 years from the onset of first symptoms (82.7%; range, <1 year to ≥5 years). In relation to diagnosis delivery, 45.3% of patients stated that it was 'poor' or 'very poor'. During the 2 years following diagnosis, 43.8% of respondents had never seen a PD specialist. Care was usually overseen by generically active neurologists (92.5%) or family doctors (81.0%), with considerable overlap between the two.

CONCLUSIONS

  These data highlight challenges that patients with PD face during the period of diagnosis, despite introduction of the Charter. These findings can assist healthcare professionals and policy makers in improving the level of care for patients and their families across Europe, and we offer suggestions about how this can be achieved.

The effects of a novel histamine-3 receptor inverse agonist on essential tremor in comparison to stable levels of alcohol

Essential tremor (ET) is a common movement disorder. Animal studies show that histaminergic modulation may affect the pathological processes involved in the generation of ET. Histamine-3 receptor inverse agonists (H3RIA) have demonstrated attenuating effects on ET in the harmaline rat model. In this double-blind, three-way cross-over, single-dose, double-dummy study the effects of 25 mg of a novel H3RIA (MK-0249) and a stable alcohol level (0.6 g L(-1)) were compared with placebo, in 18 patients with ET. Tremor was evaluated using laboratory tremorography, portable tremorography and a clinical rating scale. The Leeds Sleep Evaluation Questionnaire (LSEQ) and a choice reaction time (CRT) test were performed to evaluate potential effects on sleep and attention, respectively. A steady state of alcohol significantly diminished tremor as assessed by laboratory tremorography, portable tremorography and clinical ratings compared with placebo. A high single MK-0249 dose was not effective in reducing tremor, but caused significant effects on the LSEQ and the CRT test. These results suggest that treatment with a single dose of MK-0249 does not improve tremor in alcohol-responsive patients with ET, whereas stable levels of alcohol as a positive control reproduced the commonly reported tremor-diminishing effects of alcohol.

"On" state freezing of gait in Parkinson disease: a paradoxical levodopa-induced complication

OBJECTIVE

To describe the phenotype of levodopa-induced "on" freezing of gait (FOG) in Parkinson disease (PD).

METHODS

We present a diagnostic approach to separate "on" FOG (deterioration during the "on state") from other FOG forms. Four patients with PD with suspected "on" FOG were examined in the "off state" (>12 hours after last medication intake), "on state" (peak effect of usual medication), and "supra-on" state (after intake of at least twice the usual dose).

RESULTS

Patients showed clear "on" FOG, which worsened in a dose-dependent fashion from the "on" to the "supra-on" state. Two patients also demonstrated FOG during the "off state," of lesser magnitude than during "on." In addition, levodopa produced motor blocks in hand and feet movements, while other parkinsonian features improved. None of the patients had cognitive impairment or a predating "off" FOG.

CONCLUSIONS

True "on" FOG exists as a rare phenotype in PD, unassociated with cognitive impairment or a predating "off" FOG. Distinguishing the different FOG subtypes requires a comprehensive motor assessment in at least 3 medication states.

Prevalence of oropharyngeal dysphagia in Parkinson's disease: a meta-analysis

Dysphagia is a potentially harmful feature, also in Parkinson's disease (PD). As published prevalence rates vary widely, we aimed to estimate the prevalence of oropharyngeal dysphagia in PD in a meta-analysis. We conducted a systematic literature search in February 2011 and two independent reviewers selected the papers. We computed the estimates of the pooled prevalence weighted by sample size. Twelve studies were suitable for calculating prevalence rates. Ten studies provided an estimate based on subjective outcomes, which proved statistically heterogeneous (p < 0.001), with a pooled prevalence estimate with random effect analysis of 35% (95% CI 28-41). Four studies provided an estimate based on objective measurements, which were statistically homogeneous (p = 0.23), with a pooled prevalence estimate of 82% (95% CI 77-87). In controls the pooled subjective prevalence was 9% (95% CI 2-17), while the pooled objective prevalence was 23% (95% CI 13-32). The pooled relative risk was 3.2 for both subjective outcomes (95% CI 2.32-4.41) and objective outcomes (95% CI 2.08-4.98). Clinical heterogeneity between studies was chiefly explained by differences in disease severity. Subjective dysphagia occurs in one third of community-dwelling PD patients. Objectively measured dysphagia rates were much higher, with 4 out of 5 patients being affected. This suggests that dysphagia is common in PD, but patients do not always report swallowing difficulties unless asked. This underreporting calls for a proactive clinical approach to dysphagia, particularly in light of the serious clinical consequences.

Lower vascular tone and larger plasma volume in Parkinson's disease with orthostatic hypotension

The pathophysiology of orthostatic hypotension in Parkinson's disease (PD) is incompletely understood. The primary focus has thus far been on failure of the baroreflex, a central mediated vasoconstrictor mechanism. Here, we test the role of two other possible factors: 1) a reduced peripheral vasoconstriction (which may contribute because PD includes a generalized sympathetic denervation); and 2) an inadequate plasma volume (which may explain why plasma volume expansion can manage orthostatic hypotension in PD). We included 11 PD patients with orthostatic hypotension (PD + OH), 14 PD patients without orthostatic hypotension (PD − OH), and 15 age-matched healthy controls. Leg blood flow was examined using duplex ultrasound during 60° head-up tilt. Leg vascular resistance was calculated as the arterial-venous pressure gradient divided by blood flow. In a subset of 9 PD + OH, 9 PD − OH, and 8 controls, plasma volume was determined by indicator dilution method with radiolabeled albumin (125I-HSA). The basal leg vascular resistance was significantly lower in PD + OH (0.7 ± 0.3 mmHg·ml−1·min) compared with PD − OH (1.3 ± 0.6 mmHg·ml−1·min, P < 0.01) and controls (1.3 ± 0.5 mmHg·ml−1·min, P < 0.01). Leg vascular resistance increased significantly during 60° head-up tilt with no significant difference between the groups. Plasma volume was significantly larger in PD + OH (3,869 ± 265 ml) compared with PD − OH (3,123 ± 377 ml, P < 0.01) and controls (3,204 ± 537 ml, P < 0.01). These results indicate that PD + OH have a lower basal leg vascular resistance in combination with a larger plasma volume compared with PD − OH and controls. Despite the increase in leg vascular resistance during 60° head-up tilt, PD + OH are unable to maintain their blood pressure.

Walking patterns in Parkinson's disease with and without freezing of gait

The pathophysiology underlying freezing of gait (FOG) in Parkinson's disease remains incompletely understood. Patients with FOG ("freezers") have a higher temporal variability and asymmetry of strides compared to patients without FOG ("non-freezers"). We aimed to extend this view, by assessing spatial variability and asymmetry of steps and interlimb coordination between the upper and lower limbs during gait. Twelve freezers, 15 non-freezers, and 15 age-matched controls were instructed to walk overground and on a treadmill. Kinematic data were recorded with a motion analysis system. Both freezers and non-freezers showed an increased spatial variability of leg movements compared to controls. In addition, both patient groups had a deficit in interlimb coordination, not only between ipsilateral arms and legs, but also between diagonally positioned limbs. The only difference between freezers and non-freezers was a decreased step length during treadmill walking. We conclude that parkinsonian gait-regardless of FOG-is irregular, not only in the legs, but also with respect to interlimb coordination between the arms and legs. FOG is reflected by abnormal treadmill walking, presumably because this provides a greater challenge to the defective supraspinal control than overground walking, hampering the ability of freezers to increase their stride length when necessary.

Balance problems with Parkinson's disease: are they anxiety-dependent?

Non-motor symptoms, such as fear of falling and anxiety, are frequently reported in Parkinson's disease (PD). Recent evidence of anxiety and fear directly influencing balance control in healthy young and older adults, raises the question whether fear of falling and anxiety also directly contribute to the balance deficits observed in PD. The goal of the current study was to examine whether PD patients and controls responded similarly or differently to experimentally induced increases in anxiety. For this purpose, 14 PD patients (tested during a subjective optimal ON state) and 16 healthy age-matched control subjects stood in three conditions of different levels of postural threat: normal threat (quiet standing at ground level); medium threat (standing at the edge of a surface elevated to 80 cm); and high threat (same, but to 160 cm). Outcome measures included mean position, mean power of frequency (MPF) and root mean square (RMS) of centre of pressure (COP) displacements in the anterior-posterior (AP) and medial-lateral (ML) directions. Physiological and psychosocial measures of fear and anxiety were also recorded. Increased threat changed postural control similarly in PD patients and controls; MPF of AP and ML COP increased and the mean COP position was shifted backward in both groups. These results indicate that during the ON state, static balance in PD patients and controls is equally susceptible to the influence of anxiety. Significant correlations observed between COP changes and measures of fear and anxiety provide evidence to support the proposed neural links between structures controlling emotion and postural control. Future studies should further address this issue by including more severely affected patients, by testing the influence of dopaminergic medication, by including more anxious patients, and by using dynamic measures of balance.

Assessment of postural asymmetry in mild to moderate Parkinson's disease

Asymmetry of symptoms of Parkinson's disease is clinically most evident for appendicular impairments. For axial impairments such as freezing of gait, asymmetry is less obvious. To date, asymmetries in balance control in PD patients have seldom been studied. Therefore, in this study we investigated whether postural control can be asymmetrically affected in mild to moderate PD patients. Seventeen PD patients were instructed to stand as still and symmetrically as possible on a dual force-plate during two trials. Dynamic postural asymmetry was assessed by comparing the centre-of-pressure velocities between both legs. Results showed that four patients (24%) had dynamic postural asymmetry, even after correcting for weight-bearing asymmetry. Hence, this study suggests that postural control can be asymmetrical in early PD. However, future studies should investigate the prevalence of dynamic postural asymmetry, in a larger group of PD patients. It should also be further investigated whether this approach can be used as a tool to support the initial diagnosis or monitor disease progression, or as an outcome measure for interventions aimed at improving balance in PD.