Mortality in patients with Parkinson's disease

Mechanisms of Swallowing, Speech and Voice Disorders in Parkinson's Disease: Literature Review with Our First Evidence for the Periperal Nervous System Involvement

The majority of patients with Parkinson's disease (PD) develop swallowing, speech, and voice (SSV) disorders. Importantly, swallowing difficulty or dysphagia and related aspiration are life-threatening conditions for PD patients. Although PD treatments have significant therapeutic effects on limb motor function, their effects on SSV disorders are less impressive. A large gap in our knowledge is that the mechanisms of SSV disorders in PD are poorly understood. PD was long considered to be a central nervous system disorder caused by the death of dopaminergic neurons in the basal ganglia. Aggregates of phosphorylated α-synuclein (PAS) underlie PD pathology. SSV disorders were thought to be caused by the same dopaminergic problem as those causing impaired limb movement; however, there is little evidence to support this. The pharynx, larynx, and tongue play a critical role in performing upper airway (UA) motor tasks and their dysfunction results in disordered SSV. This review aims to provide an overview on the neuromuscular organization patterns, functions of the UA structures, clinical features of SSV disorders, and gaps in knowledge regarding the pathophysiology underlying SSV disorders in PD, and evidence supporting the hypothesis that SSV disorders in PD could be associated, at least in part, with PAS damage to the peripheral nervous system controlling the UA structures. Determining the presence and distribution of PAS lesions in the pharynx, larynx, and tongue will facilitate the identification of peripheral therapeutic targets and set a foundation for the development of new therapies to treat SSV disorders in PD.

TNFR1-mediated neuroinflammation is necessary for respiratory deficits observed in 6-hydroxydopamine mouse model of Parkinsońs Disease

Parkinson's Disease (PD) is characterized by classic motor symptoms related to movement, but PD patients can experience symptoms associated with impaired autonomic function, such as respiratory disturbances. Functional respiratory deficits are known to be associated with brainstem neurodegeneration in the mice model of PD induced by 6-hydroxydopamine (6-OHDA). Understanding the causes of neuronal death is essential for identifying specific targets to prevent degeneration. Many mechanisms can explain why neurons die in PD, and neuroinflammation is one of them. To test the influence of inflammation, mediated by microglia and astrocytes cells, in the respiratory disturbances associated with brainstem neurons death, we submitted wild-type (WT) and TNF receptor 1 (TNFR1) knockout male mice to the 6-OHDA model of PD. Also, male C57BL/6 animals were induced using the same PD model and treated with minocycline (45 mg/kg), a tetracycline antibiotic with anti-inflammatory properties. We show that degeneration of brainstem areas such as the retrotrapezoid nucleus (RTN) and the pre-Botzinger Complex (preBotC) were prevented in both protocols. Notably, respiratory disturbances were no longer observed in the animals where inflammation was suppressed. Thus, the data demonstrate that inflammation is responsible for the breathing impairment in the 6-OHDA-induced PD mouse model.

Modelling the Cost Effectiveness of Treatments for Parkinson's Disease: An Updated Methodological Review

OBJECTIVE

This article systematically reviewed the methodological quality of modelling approaches for economic evaluations of the treatment of motor symptoms in Parkinson's disease in studies published after 2010.

METHODS

A systematic literature search was undertaken using PubMed, EconLit, the Cochrane Database of Systematic Reviews, National Health Service Economic Evaluation Database and Health Technology Assessment databases of the UK National Health Service Centre for Review and Dissemination (March 2010 to July 2022). Quality was assessed using a checklist from the German Scientific Working Group.

RESULTS

A total of 20 studies were evaluated, with the majority based on Markov models (n = 18). Studies assessed the cost effectiveness of medical (n = 12) or surgical (n = 8) treatment, and included costs from a payer or healthcare provider's perspective (n = 17). Furthermore, all studies included quality-adjusted life-years as an effect measure. In the quality assessment of the literature, a mean score of 42.1 points (out of 56 points) on the checklist of the German Scientific Working Group was achieved. Seventeen studies concluded the intervention under study was (likely) cost effective. No intervention was classified as cost ineffective.

CONCLUSIONS

The quality of economic evaluation models in Parkinson's disease has improved in terms of calculating cost and transition parameters, as well as carrying out probabilistic sensitivity analyses, compared with the published literature of previous systematic reviews up to 2010. However, there is still potential for further development in terms of the integration of non-motor complications and treatment changes, the transparent presentation of parameter estimates, as well as conducting sensitivity analyses and validations to support the interpretation of results.

Correlation Between EAT-10 and Aspiration Risk Differs by Dysphagia Etiology

Agreement between self-reported dysphagic symptoms and actual swallowing physiology can vary widely across individuals. The Eating Assessment Tool-10 (EAT-10) is a self-report questionnaire commonly used to identify individuals with oropharyngeal dysphagia, but its interpretation for highly prevalent populations is poorly defined. Our primary objective was to determine if correlation strength between EAT-10 and Penetration-Aspiration Scale (PAS) scores differed by dysphagia etiology. Our secondary objective was to identify clinical factors that were associated with a mismatch between EAT-10 scores and videofluoroscopic findings. Outpatients with Parkinson disease (PD), stroke, and/or head and neck cancer (HNC) who completed EAT-10 and underwent videofluoroscopy were included (n = 203). EAT-10/PAS correlations were calculated by dysphagia etiology. We found that across the sample, higher EAT-10 scores were significantly correlated to higher PAS scores (r_s = 0.31, p < 0.001). EAT-10 and PAS were moderately correlated in the HNC group (r_s = 0.41, p < 0.001, n = 87), but correlations were modest in the PD (r_s = 0.18, n = 41) and stroke groups (r_s = 0.12, n = 59). Clinical characteristics of individuals with a "matched" profile (normal EAT-10 score and normal swallow physiology) and a "mismatched" profile (normal EAT-10 score and abnormal swallow physiology) were also compared. Individuals with a "mismatched" EAT-10/PAS profile appeared to be significantly older and had a worse Charlson Comorbidity Index than individuals with a "matched" profile. Within the HNC subgroup, EAT-10/PAS correlations for specific tumor sites, treatment types, and time since treatment are reported. Clinicians may consider these aspiration risk profiles when making recommendations for instrumented swallowing assessment.

Accuracy of death certificates for recording parkinsonian syndromes and associated dementia

INTRODUCTION

Death certification is often used to identify patients with certain diseases in epidemiologic research. There have been few studies looking at the accuracy of recording of parkinsonian diagnoses, any associated dementia and the cause of death on death certificates in people with parkinsonian conditions. This study aimed to assess this.

METHODS

Data for these analyses were derived from a prospective incident cohort of degenerative/vascular parkinsonian syndromes with lifelong follow-up from Scotland, UK (the PINE study). In those who died, the available research and clinical care records were reviewed to establish the cause for each patient's death. The sensitivity of death certificates was calculated to detect any parkinsonian diagnosis mentioned on the death certificate, the correct specific diagnosis and the presence of dementia. The causes of death were compared between clinical records and death certificates.

RESULTS

Two hundred and seventy-seven patients had died (180 men), mean age at diagnosis and death 76.9 years and 81.9 years respectively. 66.8% of death certificates mentioned any parkinsonian syndrome but only 49.5% had the correct diagnosis. Sensitivity was highest for Parkinson's disease, those who had parkinsonian-related deaths, had longer disease durations and died out of hospital. Death certificates detected 51.2% of those with dementia. The commonest causes of death were pneumonia, end-stage Parkinsonism and vascular disease with moderate agreement between case-note review and death certification.

CONCLUSION

Deaths certificates often do not mention underlying Parkinsonism or associated dementia and so epidemiological studies should not rely on this as a sole method of identifying cases or studying mortality.

Dysphagia is associated with presynaptic dopaminergic dysfunction and greater non-motor symptom burden in early drug-naïve Parkinson's patients

BACKGROUND

The underlying pathophysiology of dysphagia is multifactorial and evidence clarifying the precise mechanisms are scarce. Dysfunction in dopamine-related and non-dopamine-related pathways, changes in cortical networks related with swallowing and peripheral mechanisms have been implicated in the pathogenesis of dysphagia. We aimed at investigating whether dysphagia is associated with presynaptic dopaminergic deficits, faster motor symptom progression and cognitive decline in a population of early drug-naïve patients with Parkinson's disease.

METHODS

By exploring the database of Parkinson's Progression Markers Initiative we identified forty-nine early drug-naïve Parkinson's disease patients with dysphagia. Dysphagia was identified with SCOPA-AUT question 1 (answer regularly) and was assessed with MDS-UPDRS Part-II, Item 2.3 (Chewing and Swallowing). We compared Parkinson's disease patients with dysphagia to Parkinson's disease patients without dysphagia, and investigated differences in striatal [123I]FP-CIT single photon emission computed tomography levels. Using Cox proportional hazards analyses, we also evaluated whether dysphagia can predict motor deterioration and cognitive dysfunction.

RESULTS

Parkinson's disease patients with dysphagia, harbored a greater deterioration regarding motor and non-motor symptoms and decreased [123I]FP-CIT binding when compared with patients without dysphagia. Higher burden of dysphagia (MDS-UPDRS-II, item 2.3) was correlated with lower [123I]FP-CIT uptakes within the striatum (rs = -0.157; P = 0.002) and the caudate (rs = -0.156; P = 0.002). The presence of dysphagia was not a predictor of motor progression (Hazard ratio [HR]: 1.143, 95% confidence interval [CI]: 0.848-1.541; P = 0.379) or cognitive decline (HR: 1.294, 95% CI: 0.616-2.719; P = 0.496).

CONCLUSIONS

Dysphagia is associated with decreased presynaptic dopaminergic integrity within caudate and greater motor and non-motor symptoms burden in early drug-naïve PD.

Increased risk of all-cause mortality associated with domperidone use in Parkinson's patients: a population-based cohort study in the UK

AIMS

Domperidone is used to treat gastrointestinal symptoms in patients with Parkinson's disease (PD) and is linked to an increased risk of mortality. We sought to examine the risk of all-cause mortality associated with domperidone exposure in PD.

METHODS

We conducted a cohort study using data from the Clinical Practice Research Datalink database (1987-2011). The first recorded PD diagnosis defined index date. Time-dependent Cox proportional hazards models estimated hazard ratios (HRs) of all-cause mortality associated with domperidone use. PD patients were stratified by domperidone use (current/recent/past), with never used as the referent. Current domperidone users were stratified by daily dose, domperidone duration and other anti-Parkinson's medications. A secondary analysis compared PD patients to matched (1:1) non-PD patients.

RESULTS

A total of 5114 PD patients were identified. Current use of domperidone among PD patients was associated with a two-fold increase in all-cause mortality (HR_adj  = 2.00, 95% confidence interval [CI]: 1.64-2.45), as compared to patients never exposed to domperidone. All-cause mortality risk was highest in those starting domperidone in the previous month [HR_adj  = 2.97, 95% CI: 2.06-4.27]. When compared to matched non-PD patients, PD was associated with a 43% increased risk of all-cause mortality, yet this increased to a 2.4-fold increased risk among PD patients currently using domperidone.

CONCLUSION

Current use of domperidone was associated with a two-fold increased mortality risk in PD patients, as compared to PD patients that never used domperidone. The risk is highest in the first month of use and does not appear to be attributable to PD alone.

Cost-effectiveness of neurostimulation in Parkinson's disease with early motor complications

BACKGROUND

Recent research efforts have focused on the effects of deep brain stimulation of the subthalamic nucleus (STN DBS) for selected patients with mild-to-moderate PD experiencing motor complications.

OBJECTIVES

We assessed the cost utility of subthalamic DBS compared with the best medical treatment for German patients below the age of 61 with early motor complications of PD.

METHODS

We applied a previously published Markov model that integrated health utilities based on EuroQoL and direct costs over patients' lifetime adjusted to the German health care payer perspective (year of costing: 2013). Effectiveness was evaluated using the Parkinson's Disease Questionnaire 39 summary index. We performed sensitivity analyses to assess uncertainty.

RESULTS

In the base-case analysis, the incremental cost-utility ratio for STN DBS compared to best medical treatment was 22,700 Euros per quality-adjusted life year gained. The time to, and costs for, battery exchange had a major effect on the incremental cost-utility ratios, but never exceeded a threshold of 50,000 Euros per quality-adjusted life year.

CONCLUSIONS

Our decision analysis supports the fact that STN DBS at earlier stages of the disease is cost-effective in patients below the age of 61 when compared with the best medical treatment in the German health care system. This finding was supported by detailed sensitivity analyses reporting robust results. Whereas the EARLYSTIM study has shown STN DBS to be superior to medical therapy with respect to quality of life for patients with early motor complications, this further analysis has shown its cost-effectiveness. © 2016 International Parkinson and Movement Disorder Society.

Survival and Causes of Death Among People With Clinically Diagnosed Synucleinopathies With Parkinsonism: A Population-Based Study

Importance

To our knowledge, a comprehensive study of the survival and causes of death of persons with synucleinopathies compared with the general population has not been conducted. Understanding the long-term outcomes of these conditions may inform patients and caregivers of the expected disease duration and may help with care planning.

Objective

To compare survival rates and causes of death among patients with incident, clinically diagnosed synucleinopathies and age- and sex-matched referent participants.

Design, Setting, and Participants

This population-based study used the Rochester Epidemiology Project medical records-linkage system to identify all residents in Olmsted County, Minnesota, who received a diagnostic code of parkinsonism from 1991 through 2010. A movement-disorders specialist reviewed the medical records of each individual to confirm the presence of parkinsonism and determine the type of synucleinopathy. For each confirmed patient, an age- and sex-matched Olmsted County resident without parkinsonism was also identified.

Main Outcomes and Measures

We determined the age- and sex-adjusted risk of death for each type of synucleinopathy, the median time from diagnosis to death, and the causes of death.

Results

Of the 461 patients with synucleinopathies, 279 (60.5%) were men, and of the 452 referent participants, 272 (60.2%) were men. From 1991 through 2010, 461 individuals received a diagnosis of a synucleinopathy (309 [67%] of Parkinson disease, 81 [17.6%] of dementia with Lewy bodies, 55 [11.9%] of Parkinson disease dementia, and 16 [3.5%] of multiple system atrophy with parkinsonism). During follow-up, 68.6% (n = 316) of the patients with synucleinopathies and 48.7% (n = 220) of the referent participants died. Patients with any synucleinopathy died a median of 2 years earlier than referent participants. Patients with multiple system atrophy with parkinsonism (hazard ratio, 10.51; 95% CI, 2.92-37.82) had the highest risk of death compared with referent participants, followed by those with dementia with Lewy bodies (hazard ratio, 3.94; 95% CI, 2.61-5.94), Parkinson disease with dementia (hazard ratio, 3.86; 95% CI, 2.36-6.30), and Parkinson disease (hazard ratio, 1.75; 95% CI, 1.39-2.21). Neurodegenerative disease was the most frequent cause of death listed on the death certificate for patients, and cardiovascular disease was the most frequent cause of death among referent participants.

Conclusions and Relevance

Individuals with multiple system atrophy with parkinsonism, dementia with Lewy bodies, and Parkinson disease dementia have increased mortality compared with the general population. The mortality among persons with Parkinson disease is only moderately increased compared with the general population.

Phrenic and hypoglossal nerve activity during respiratory response to hypoxia in 6-OHDA unilateral model of Parkinson's disease

AIMS

Parkinson's disease (PD) patients apart from motor dysfunctions exhibit respiratory disturbances. Their mechanism is still unknown and requires investigation. Our research was designed to examine the activity of phrenic (PHR) and hypoglossal (HG) nerves activity during a hypoxic respiratory response in the 6-hydroxydopamine (6-OHDA) model of PD.

MAIN METHODS

Male adult Wistar rats were injected unilaterally with 6-OHDA (20μg) or the vehicle into the right medial forebrain bundle (MFB). Two weeks after the surgery the activity of the phrenic and hypoglossal nerve was registered in anesthetized, vagotomized, paralyzed, and mechanically ventilated rats under normoxic and hypoxic conditions. Lesion effectiveness was confirmed by the cylinder test, performed before the MFB injection and 14days after, before the respiratory experiment.

KEY FINDINGS

6-OHDA lesioned animals showed a significant increase in normoxic inspiratory time. Expiratory time and total time of the respiratory cycle were prolonged in PD rats after hypoxia. The amplitude of the PHR activity and its minute activity were increased in comparison to the sham group at recovery time and during 30s of hypoxia. The amplitude of the HG activity was increased in response to hypoxia in 6-OHDA lesioned animals. The degeneration of dopaminergic neurons decreased the pre-inspiratory/inspiratory ratio of the hypoglossal burst amplitude during and after hypoxia.

SIGNIFICANCE

Unilateral MFB lesion changed the activity of the phrenic and hypoglossal nerves. The altered pre-inspiratory hypoglossal nerve activity indicates modifications to the central mechanisms controlling the activity of the HG nerve and may explain respiratory disorders seen in PD, i.e. apnea.

Increase in Parkinson's disease-related mortality among males in Northern Italy

BACKGROUND

According to standard mortality statistics based on the underlying cause of death (UCOD), mortality from Parkinson's disease (PD) is increasing in most European countries. However, mortality trends are better investigated taking into account all the diseases reported in the death certificate (multiple causes of death approach, MCOD).

METHODS

All deaths of residents in the Veneto Region (Northern Italy) aged≥45 years with any mention of PD were extracted from 2008 to 2015. The Annual Percent Change (APC) in age-standardized mortality rates was computed both for PD as the UCOD, and by MCOD. The association with common chronic comorbidities and acute complications was investigated by log-binomial regression. The frequency of the mention of PD in death certificates was investigated through linkage with an archive of patients with a previous clinical diagnosis of the disease.

RESULTS

PD was reported in 2.1% of all deaths, rising from 1.9% in 2008 to 2.4% in 2015. Among males, age-standardized rates increased over time both in analyses based on the UCOD (APC +4.1%; Confidence Interval +1.5%,+6.7%), and on MCOD (APC +2.2%; +0.2,+4.2%). Among females time trends were not significant. Mention of PD was associated with that of dementia/Alzheimer and acute infectious diseases. Among known PD patients, the disease was reported only in 60.2% of death certificates.

CONCLUSIONS

Mortality associated to PD is steeply increasing among males in Northern Italy; further investigations on time trends for PD, both through all available electronic health archives and clinical studies, should be set as a priority for epidemiological research.

Parkinson's disease and intensive exercise therapy--a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate and compare the effect of 3 intensive exercise therapy modalities - Resistance Training (RT), Endurance Training (ET) and Other Intensive Training Modalities (OITM) - in Parkinson's Disease (PD). Design A systematic review and meta-analysis of randomized controlled trials.

METHODS

A systematic literature search was conducted (Embase, Pubmed, Cinahl, SPORTDiscus, Cochrane, PEDro), which identified 15 studies that were categorized as RT, ET or OITM. The different exercise modalities were reviewed and a meta-analysis evaluating the effect of RT on muscle strength was made.

RESULTS

In PD intensive exercise therapy (RT, ET and OITM) is feasible and safe. There is strong evidence that RT can improve muscle strength in PD, which is underlined by the meta-analysis (g'=0.54 [95%CI 0.22;0.86]). There is moderate evidence that ET can improve cardio-respiratory fitness in PD. RT, ET and OITM may have beneficial effects on balance, walking performance, Unified Parkinson's Disease Rating Scale-III (UPDRS-III) score and quality of life in PD, but findings are inconsistent. No studies find deterioration in any outcomes following exercise therapy.

CONCLUSION

RT, ET and OITM all represent feasible, safe and beneficial adjunct rehabilitation therapies in PD.

Mortality in Parkinson's disease: a 38-year follow-up study

BACKGROUND

In this study we report on the outcome including overall and cause-specific mortality of Parkinson's disease (PD) patients subsequent to 38 years of surveillance. This is an extension study of our previous report on mortality.

METHODS

Two hundred thirty-seven patients with a symptom onset between 1974 and 1984 were followed until the date of December 31, 2012 or death, representing a follow-up period of up to 38 years. Overall and cause-specific standardized mortality ratios (SMRs) were calculated, and predictors for survival at disease onset were estimated.

RESULTS AND CONCLUSION

Two hundred thirty patients had died by December 31, 2012; a total of 3,489 person-years were available for observation. The SMR at 38 years of follow-up was 2.02 (1.76-2.29). Employing Cox's proportional hazard modeling, male sex, gait disorder, absence of classical rest tremor, and absence of asymmetry predicted poor survival in this cohort. Increased cause-specific SMRs were found for pneumonia and cerebrovascular and cardiovascular diseases.

Sudden death in Parkinson's disease: a retrospective autopsy study

The aim of this paper is to reveal the causes of death and to verify sudden death of Parkinson's disease (PD) in an autopsy study. We reviewed the clinical data and the causes of death in 16 PD patients who had postmortem examinations. Prior to autopsy, nine patients died of known causes: five patients died of aspiration pneumonia, two of myocardial infarction, one of asphyxia, and one of dilated cardiomyopathy. Autopsy confirmed that the putative causes of death were compatible with the pathological ones. The remaining seven patients died suddenly of unknown causes. Autopsy revealed that the causes of death were asphyxia in two patients and perforation of a duodenal ulcer in one patient. Autopsy did not determine the causes of unknown death in the remaining four patients. Consequently, autopsy revealed that eight patients died of swallowing problems such as aspiration pneumonia and asphyxia, four of sudden death, three of cardiac problems, and one of a gastrointestinal problem. Although there was a bias that all patients had a postmortem examination, our study revealed that several PD patients died of sudden death without any satisfactory causes of death determined even by autopsy. Therefore, we propose that a non-negligible number of PD patients die of sudden death.

Mortality in levodopa-treated Parkinson's disease

Parkinson's disease (PD) is associated with increased mortality despite many advances in treatment. Following the introduction of levodopa in the late 1960's, many studies reported improved or normalized mortality rates in PD. Despite the remarkable symptomatic benefits provided by levodopa, multiple recent studies have demonstrated that PD patients continue to die at a rate in excess of their peers. We undertook this retrospective study of 211 deceased PD patients to determine the factors associated with mortality in levodopa-treated PD. Our findings confirm that PD is associated with increased mortality in both men and women. Unlike the majority of other mortality studies, we found that women have a greater reduction in lifespan compared to men. We also found that patients with early onset PD (onset at the age of 50 or before) have reduced survival relative to PD patients with later ages of onset. A final important finding is that survival is equal in PD patients treated with levodopa early (within 2 years or less of PD onset) versus later.

Parkinson disease affects peripheral sensory nerves in the pharynx

Dysphagia is very common in patients with Parkinson disease (PD) and often leads to aspiration pneumonia, the most common cause of death in PD. Current therapies are largely ineffective for dysphagia. Because pharyngeal sensation normally triggers the swallowing reflex, we examined pharyngeal sensory nerves in PD patients for Lewy pathology.Sensory nerves supplying the pharynx were excised from autopsied pharynges obtained from patients with clinically diagnosed and neuropathologically confirmed PD (n = 10) and healthy age-matched controls (n = 4). We examined the glossopharyngeal nerve (cranial nerve IX), the pharyngeal sensory branch of the vagus nerve (PSB-X), and the internal superior laryngeal nerve (ISLN) innervating the laryngopharynx. Immunohistochemistry for phosphorylated α-synuclein was used to detect Lewy pathology. Axonal α-synuclein aggregates in the pharyngeal sensory nerves were identified in all of the PD subjects but not in the controls. The density of α-synuclein-positive lesions was greater in PD patients with dysphagia versus those without dysphagia. In addition, α-synuclein-immunoreactive nerve fibers in the ISLN were much more abundant than those in cranial nerve IX and PSB-X. These findings suggest that pharyngeal sensory nerves are directly affected by pathologic processes in PD. These abnormalities may decrease pharyngeal sensation, thereby impairing swallowing and airway protective reflexes and contributing to dysphagia and aspiration.

Evidence for adaptive cortical changes in swallowing in Parkinson's disease

Dysphagia is a relevant symptom in Parkinson's disease, whose pathophysiology is poorly understood. It is mainly attributed to degeneration of brainstem nuclei. However, alterations in the cortical contribution to deglutition control in the course of Parkinson's disease have not been investigated. Here, we sought to determine the patterns of cortical swallowing processing in patients with Parkinson's disease with and without dysphagia. Swallowing function in patients was objectively assessed with fiberoptic endoscopic evaluation. Swallow-related cortical activation was measured using whole-head magnetoencephalography in 10 dysphagic and 10 non-dysphagic patients with Parkinson's disease and a healthy control group during self-paced swallowing. Data were analysed applying synthetic aperture magnetometry, and group analyses were done using a permutation test. Compared with healthy subjects, a strong decrease of cortical swallowing activation was found in all patients. It was most prominent in participants with manifest dysphagia. Non-dysphagic patients with Parkinson's disease showed a pronounced shift of peak activation towards lateral parts of the premotor, motor and inferolateral parietal cortex with reduced activation of the supplementary motor area. This pattern was not found in dysphagic patients with Parkinson's disease. We conclude that in Parkinson's disease, not only brainstem and basal ganglia circuits, but also cortical areas modulate swallowing function in a clinically relevant way. Our results point towards adaptive cerebral changes in swallowing to compensate for deficient motor pathways. Recruitment of better preserved parallel motor loops driven by sensory afferent input seems to maintain swallowing function until progressing neurodegeneration exceeds beyond the means of this adaptive strategy, resulting in manifestation of dysphagia.

Recovery of hypothalamic tuberoinfundibular dopamine neurons from acute toxicant exposure is dependent upon protein synthesis and associated with an increase in parkin and ubiquitin carboxy-terminal hydrolase-L1 expression

Hypothalamic tuberoinfundibular dopamine (TIDA) neurons remain unaffected in Parkinson disease (PD) while there is significant degeneration of midbrain nigrostriatal dopamine (NSDA) neurons. A similar pattern of susceptibility is observed in acute and chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse and rotenone rat models of degeneration. It is not known if the resistance of TIDA neurons is a constitutive or induced cell-autonomous phenotype for this unique subset of DA neurons. In the present study, treatment with a single injection of MPTP (20 mg/kg; s.c.) was employed to examine the response of TIDA versus NSDA neurons to acute injury. An acute single dose of MPTP caused an initial loss of DA from axon terminals of both TIDA and NSDA neurons, with recovery occurring solely in TIDA neurons by 16 h post-treatment. Initial loss of DA from axon terminals was dependent on a functional dopamine transporter (DAT) in NSDA neurons but DAT-independent in TIDA neurons. The active metabolite of MPTP, 1-methyl, 4-phenylpyradinium (MPP+), reached higher concentration and was eliminated slower in TIDA compared to NSDA neurons, which indicates that impaired toxicant bioactivation or distribution is an unlikely explanation for the observed resistance of TIDA neurons to MPTP exposure. Inhibition of protein synthesis prevented TIDA neuron recovery, suggesting that the ability to recover from injury was dependent on an induced, rather than a constitutive cellular mechanism. Further, there were no changes in total tyrosine hydroxylase (TH) expression following MPTP, indicating that up-regulation of the rate-limiting enzyme in DA synthesis does not account for TIDA neuronal recovery. Differential candidate gene expression analysis revealed a time-dependent increase in parkin and ubiquitin carboxyl-terminal hydrolase-L1 (UCH-L1) expression (mRNA and protein) in TIDA neurons during recovery from injury. Parkin expression was also found to increase with incremental doses of MPTP. The increase in parkin expression occurred specifically within TIDA neurons, suggesting that these neurons have an intrinsic ability to up-regulate parkin in response to MPTP-induced injury. These data suggest that TIDA neurons have a compensatory mechanism to deal with toxicant exposure and increased oxidative stress, and this unique TIDA neuron phenotype provides a platform for dissecting the mechanisms involved in the natural resistance of central DA neurons following toxic insult.

Telepractice Supported Delivery of LSVT®LOUD

This article outlines the essential features and underlying principles of Lee Silverman Voice Treatment (LSVT®LOUD) and explores the delivery of this treatment via telepractice. A detailed summary of the core features of LSVT®LOUD and the principles underpinning this treatment are presented. Current evidence to support the feasibility and validity of synchronous and asynchronous delivery of LSVT®LOUD to people with Parkinson disease (PD) is reviewed. Technology specifications, cost-benefit analyses, and patient satisfaction are discussed. The challenges involved in delivery of LSVT®LOUD via telepractice, such as inconsistent audio and video quality during videoconferencing, accurate measurement of vocal parameters, technical skill level of the clinician, and patient candidacy, are highlighted. LSVT®LOUD can be effectively and reliably delivered via telepractice. Improvements in telecommunications are required to overcome some of the technology challenges encountered in this mode of delivery. Positive benefits of online treatment in relation to savings in time and money and reduced carer burden are emerging. Patient satisfaction with telepractice in the management of the speech disorder associated with PD is high. The uptake of LSVT®LOUD into telepractice is likely to steadily increase with advances in mobile technologies and web-based applications designed to deliver this treatment.

Epidemiology and etiology of Parkinson's disease: a review of the evidence

The etiology of Parkinson's disease (PD) is not well understood but likely to involve both genetic and environmental factors. Incidence and prevalence estimates vary to a large extent-at least partly due to methodological differences between studies-but are consistently higher in men than in women. Several genes that cause familial as well as sporadic PD have been identified and familial aggregation studies support a genetic component. Despite a vast literature on lifestyle and environmental possible risk or protection factors, consistent findings are few. There is compelling evidence for protective effects of smoking and coffee, but the biologic mechanisms for these possibly causal relations are poorly understood. Uric acid also seems to be associated with lower PD risk. Evidence that one or several pesticides increase PD risk is suggestive but further research is needed to identify specific compounds that may play a causal role. Evidence is limited on the role of metals, other chemicals and magnetic fields. Important methodological limitations include crude classification of exposure, low frequency and intensity of exposure, inadequate sample size, potential for confounding, retrospective study designs and lack of consistent diagnostic criteria for PD. Studies that assessed possible shared etiological components between PD and other diseases show that REM sleep behavior disorder and mental illness increase PD risk and that PD patients have lower cancer risk, but methodological concerns exist. Future epidemiologic studies of PD should be large, include detailed quantifications of exposure, and collect information on environmental exposures as well as genetic polymorphisms.

The prevalence and patterns of pharyngoesophageal dysmotility in patients with early stage Parkinson's disease

Dysphagia occurs in the majority of patients with Parkinson's disease (PD) and is known to correlate with abnormalities of oropharyngeal function. The aim of this study was to evaluate pharyngoesophageal activity in patients with early-stage PD. Newly diagnosed PD patients with a symptom duration not exceeding 3 years were included. All PD patients were questioned about symptoms of dysphagia and underwent combined multichannel intraluminal impedance manometry and multiple rapid swallow tests. Fifty-four patients (22 men and 32 women, 67.1 ± 10.3 years) were enrolled. The duration of Parkinsonian motor symptoms was 11.5 ± 8.8 months, the Hoehn and Yahr stage was 1.6 ± 0.4, and the total Unified Parkinson's Disease Rating Scale was 25.1 ± 18.6. Esophageal manometry in the liquid swallow and viscous swallow tests was abnormal in 22 (40.7%) and 31 (67.4%) patients, respectively. Although manometric abnormalities were more common in patients with more severe dysphagia symptoms, many patients with no or minimal symptoms also had manometric abnormalities. Repetitive deglutition significantly correlated with failed peristalsis and incomplete bolus transit. Abnormal responses to multiple rapid swallow tests were found in 33 out of 54 patients; 29 with incomplete inhibition (repetitive contraction) and 4 with failed peristalsis. These results suggest that the majority of patients with early-stage PD showed pharyngeal and esophageal dysfunction even before clinical manifestations of dysphagia, which may reflect selective involvement of either the brain stem or the esophageal myenteric plexus in early-stage PD.

Mortality from Parkinson's disease and other causes among a workforce manufacturing paraquat: a retrospective cohort study

Objective To assess the risk of Parkinson's disease (PD) and update information on mortality from major causes of death among a UK workforce who manufactured paraquat (PQ) between 1961 and 1995. There have been no previous studies of the incidence of PD among PQ production workers, although much epidemiological literature exists concerning the relationship between pesticides and PD, and interest has focused on PQ and its users. Methods The cohort included all employees who had ever worked on any of the four plants at Widnes where PQ was manufactured between 1961 and 1995, and 926 male and 42 female workers were followed through 30 June 2009. Mortalities for males were compared with national and local rates, including rates for PD as a mentioned cause of death. Results Overall, 307 workers had died by 30 June 2009. One male death was due to PD, and no other death certificate mentioned PD. At least 3.3 death certificates of male employees would have been expected to have mentioned PD (standardised mortality ratio=31; 95% CI 1 to 171). Personal monitoring results were indicative that the exposure of a PQ production worker on a daily basis was at least comparable with that of a PQ sprayer or mixer/loader. Reduced mortalities compared with local rates were found for major causes of death. Conclusions The study provided no evidence of an increased risk of PD, or increased mortalities from other causes.

Management of the hospitalized patient with Parkinson's disease: current state of the field and need for guidelines

OBJECTIVE

To review the literature and to identify practice gaps in the management of the hospitalized Parkinson's disease (PD) patient.

BACKGROUND

Patients with PD are admitted to hospitals at higher rates, and frequently have longer hospital stays than the general population. Little is known about outpatient interventions that might reduce the need for hospitalization and also reduce hospital-related complications.

METHODS

A literature review was performed on PubMed about hospitalization and PD between 1970 and 2010. In addition, in press peer-reviewed papers or published abstracts known to the authors were included. Information was reviewed by a National Parkinson Foundation workgroup and a narrative review article was generated.

RESULTS

Motor disturbances in PD are believed to be a causal factor in the higher rates of admissions and complications. However, other conditions are commonly recorded as the primary reason for hospitalization including motor complications, reduced mobility, lack of compliance, inappropriate use of neuroleptics, falls, fractures, pneumonia, and other important medical problems. There are many relevant issues related to hospitalization in PD. Medications, dosages and specific dosage schedules are critical. Staff training regarding medications and medication management may help to avoid complications, particularly those related to reduced mobility, and aspiration pneumonia. Treatment of infections and a return to early mobility is also critical to management.

CONCLUSIONS

Educational programs, recommendations, and guidelines are needed to better train interdisciplinary teams in the management of the PD patient. These initiatives have the potential for both cost savings and improved outcomes from a preventative and a hospital management standpoint.

Parkinson's disease and cancer risk: a systematic review and meta-analysis

OBJECTIVE

To appraise the existing literature on cancer risk among patients with Parkinson's disease (PD), determine the overall cancer risk ratio among patients with PD, explore reasons for variations in study results, and assess the potential for publication bias.

METHODS

Studies reporting cancer risk in patients with PD were identified by searching electronic databases through 18 November 2009 using the terms PARKINSON DISEASE, NEOPLASM, and CANCER. Reviewers individually performed data extraction and scored each study using a quality assessment instrument. Cancer risk in all patients with PD was calculated overall, and after excluding melanoma and other skin cancers. We tested for heterogeneity and publication bias, and stratified for gender, smoking-related versus non-smoking-related cancers, and study quality. We pooled effect sizes using fixed-effects and random-effects models.

RESULTS

We included 29 studies in the overall analysis for a total of 107,598 patients with PD. Compared to controls, the aggregate risk for cancer in patients with PD was 0.73 (95% confidence interval [CI], 0.63-0.83), and after excluding skin tumors, 0.69 (95% CI, 0.62-0.78). These risks varied by gender (males, RR = 0.71, 95% CI, 0.57-0.88; females, RR = 0.82; 95% CI, 0.68-0.98). After strictly excluding skin tumors, both smoking-related (RR = 0.61; 95% CI, 0.58-0.65) and non-smoking-related cancer rates (RR = 0.76; 95% CI, 0.65-0.89) were significantly lower among patients with PD .

CONCLUSIONS

Studies on cancer risk among patients with PD collectively show significantly reduced cancer risk ratios. Further research to explain the biological mechanisms, particularly for the association with non-smoking-related cancers, appears warranted.

Prevalence and incidence of Parkinson's disease in The Faroe Islands

OBJECTIVE

A study in The Faroe Islands in 1995 suggested a high prevalence of idiopathic Parkinson's disease (IPD) and total parkinsonism of 187.6 and 233.4 per 100,000 inhabitants respectively.

METHODS

Detailed case-finding methods 10 years later were used and a neurologist has verified the diagnosis.

RESULTS

The crude prevalence of IPD and total parkinsonism was 206.7 per 100,000 and 227.4 per 100,000 respectively. The age-adjusted prevalence is twice as high as data from Norway and Denmark. Age at initiation of treatment and the fatality rate did not explain the increased prevalence. During 1995-2005, the average annual incidence was 21.1 per 100,000 persons for Parkinson's disease, and 22.9 per 100,000 persons, if including atypical parkinsonism.

CONCLUSION

The high prevalence was verified and linked to a high incidence. The cause of the high prevalence is unknown, but neurotoxic contaminants in traditional food may play a role in the pathogenesis in this population, perhaps jointly with genetic predisposition.

Speech treatment for Parkinson's disease

Researchers estimate that 89% of people with Parkinson's disease (PD) have speech and voice disorders including disorders of laryngeal, respiratory and articulatory function. Despite the high incidence of speech and voice impairment, studies suggest that only 3-4% of people with PD receive speech treatment. Here, we review the literature on the characteristics and features of speech and voice disorders in people with PD and the types of treatment techniques available (medical, surgical and behavioral), with a focus on behavioral therapies. We provide a summary of the current status of the field of speech treatment in PD and recommendations for implementation of the current efficacy of treatment interventions. Directions for future research, including a speculative viewpoint on how the field will evolve in 5 years time, are discussed.

Estimated life expectancy of Parkinson's patients compared with the UK population

OBJECTIVE

To calculate the best possible estimates for age specific life expectancy (LE) and anticipated age at the time of death (AAD) in patients with Parkinson's disease (PD) compared with the general population in the UK. These may be of greater value to patients than standardised mortality ratios (SMRs), which are usually reported in studies on mortality in PD.

METHODS

A literature review identified articles with data on age stratified life expectancy or SMRs to calculate estimations of LE using the Gompertz function and data on mortality and LE in the UK from the Office of National Statistics and Actuarial Department for the year 2003.

RESULTS

Two UK studies and four from Western Europe were used to estimate LE and AAD for patients with PD from SMRs. The mean LEs of patients with PD compared with the general population were: 38 (SD 5) years for onset between 25 and 39 years compared with 49 (SD 5) years; 21 (SD 5) years for onset between 40 and 64 years compared with 31 (SD 7) years; and 5 (SD 4) years for onset age > or = 65 years compared with 9 (SD 5) years. The average AAD of patients with PD with onset between 25 and 39 years was 71 (SD 3) years and considerably lower than that of the general population (82 (SD 2) years). The difference between average AAD for older individuals with PD (onset > or = 65 years) and the general population was smaller, with an AAD of approximately 88 (SD 7) years compared with 91 (SD 5) years.

CONCLUSIONS

The calculations showed that LE and AAD in PD are reduced for all onset ages but this reduction is greatest in individuals with a young onset. While the results are average estimates, these can provide useful indications of LE and AAD.

Evaluation of the Dutch version of the Parkinson's Disease Questionnaire 39

The psychometric properties of the Dutch version of the Parkinson's disease questionnaire 39 (PDQ39-DV) were tested in 177 patients with Parkinson's disease (PD). Internal consistency of 7 of the 8 scales was adequate (>or=0.70), but was insufficient for 'bodily discomfort' (0.59). Correlation between the PDQ39 and other instruments in this study, the SCOPA-psychosocial questionnaire, Euroqol-5D, hospital anxiety and depression scale, and a visual analogue scale for quality of life, were 0.82, 0.74, 0.63 and -0.54, respectively. The factor analysis yielded 8 factors, which accounted for 65% of the variance and revealed only small differences with the original UK version. We conclude that the PDQ39-DV displays satisfactory psychometric properties and is an appropriate instrument to assess quality of life in Dutch patients with PD.

Effects of subthalamic nucleus deep brain stimulation and levodopa on energy production rate and substrate oxidation in Parkinson's disease

Patients with Parkinson's disease (PD) often lose weight, but after subthalamic nucleus deep brain stimulation (STN-DBS), they gain weight. We compared daily energy intake (DEI), resting energy expenditure (REE) and substrate oxidation rates (measured by indirect calorimetry) in nineteen STN-DBS-treated patients (Group S), thirteen others on pharmacologic treatment by levodopa (Group L) and eight control subjects. We also determined the acute effects of STN-DBS and levodopa on REE and substrate oxidation rates. STN-DBS treated patients gained 9·7 (sem 7·1) kg after surgery, whereas patients on pharmacologic treatment lost 3·8 (sem 10·0) kg since diagnosis. In STN-DBS-treated patients, REE (−16·5 %;P<0·001), lipid oxidation (−27 %;P<0·05) and protein oxidation (−46 %;P<0·05) were decreased, whereas glucose oxidation was elevated (+81 %;P<0·05) as compared to patients on pharmacologic treatment. Levodopa acutely reduced REE (−8·3 %;P<0·05) and glucose oxidation (−37 %;P<0·01) with a slight hyperglycaemic effect (after levodopa challenge: 5·6 (sem 0·8)v.before levodopa challenge: 5·3 (sem 0·6) mmol/l;P<0·01). Switching ‘on’ STN-DBS acutely reduced REE (−17·5 %;P<0·01) and lipid oxidation (−24 %;P<0·001) 30 min after starting stimulation. Fasting glycaemia was slightly but significantly reduced (5·4 (sem 1·4)v.5·5 (sem 1·3) mmol/l;P<0·01). After STN-DBS, the normalization of REE and the reduction in lipid and protein oxidation contribute to the restoration of weight. As levodopa decreases glucose oxidation, the reduction in daily dose of levodopa in STN-DBS-treated patients helps prevent the effect of weight gain on glycaemia.

Survival of Parkinson's disease patients in a large prospective cohort of male health professionals

Parkinson's disease (PD) patients have higher mortality than individuals without PD. However, most of the previous studies were based on prevalent cases and few examined the potential effects of duration and smoking on the survival of PD patients. We compared the survival experience of 288 men with incident PD diagnosed between 1986 and 2000 with that of 51,012 men free of PD in the Health Professionals Follow-up Study. As of January 2002, 92 deaths occurred among PD cases and 8,485 among men without PD. After controlling for age, men with PD had 60% higher mortality than those without PD (95% CI: 1.3-2.0). PD mortality was strongly related to disease duration: compared with men without PD, the age-adjusted relative risk for PD patients was 1.1 during the first 5 years from diagnosis, 2.3 from 5 to 10 years, and 3.5 after 10 years (P < 0.0001 for trend). As expected, cigarette smoking was strongly and positively associated with total mortality among men free of PD (comparing >30 pack-years vs. never smokers, relative risk, 2.0; P < 0.0001 for trend), but this association was not observed among PD patients (RR: 1.0; P = 0.95 for trend). This study confirms that PD patients have a higher mortality than individuals without PD and that the excess mortality increases with disease duration. However, smoking seems to impose little additional risk among PD patients in this large cohort of health professionals.

Polychlorinated biphenyls and neurodegenerative disease mortality in an occupational cohort

BACKGROUND

Production of polychlorinated biphenyls (PCBs) ended in the United States in the 1970s, but PCBs persist in the environment and are detectable in the blood of approximately 80% of Americans over age 50. PCBs decrease dopamine levels in rats and monkeys. Loss of dopamine is the hallmark of Parkinson disease, a neurodegenerative disease. There are no epidemiologic studies of PCBs and neurodegenerative disease.

METHODS

We conducted a retrospective mortality study of 17,321 PCB-exposed workers to determine whether mortality from Parkinson disease, dementia, and amyotrophic lateral sclerosis was elevated compared with the U.S. population. All workers had a least 90 days employment in 1 of 3 electrical capacitor plants using PCBs from the 1940s to the 1970s. PCB serum levels from a sample of these workers in the 1970s were approximately 10 times the level of community controls.

RESULTS

We found no overall excess of Parkinson disease, amyotrophic lateral sclerosis, or dementia in the PCB-exposed cohort (standardized mortality ratios [SMRs]-1.40, 1.11, and 1.26, respectively, and number of deaths-14, 10, and 28 respectively). However, sex-specific analyses revealed that women had an excess of amyotrophic lateral sclerosis (SMR-2.26; 95% confidence interval [CI] = 1.08-4.15; 10 deaths). Furthermore, among highly exposed women (defined by a job-exposure matrix), we found an excess of Parkinson disease (SMR-2.95; 95% CI = 1.08-6.42; 6 deaths) and dementia (SMR-2.04; 95% CI = 1.12-3.43; 14 deaths).

CONCLUSIONS

Our data are limited due to small numbers and reliance on mortality rather than incidence data, but are suggestive of an effect of PCBs on neurodegenerative disease for women. The literature does not offer an explanation for why women would be more affected than men by PCB exposure for these outcomes.

Prognosis of Parkinson's disease: Time to stage III, IV, V, and to motor fluctuations

We report a long-term outcome on a large cohort of Japanese patients with Parkinson's disease (PD). A total of 1,768 (793 men, 975 women) consecutive patients visited our clinic from 1 January 1989 to 31 December 2002. Among them, 1,183 patients (531 men, 652 women) came to our clinic within 5 years from the onset of disease and at the Hoehn & Yahr Stage III or less at the first visit. Long-term outcome was evaluated in this subcohort of the patients. We examined the duration to reach Stage III, IV, and V, and the duration to develop wearing off and dyskinesia. Time to reach Stage III was slightly but significantly shorter in women, in that 23.8% of men and 35.3% of women reached Stage III by the end of the 5th year; 49.7% of men and 63.3% of women reached Stage III by the end of the 10th year, and 88.9% of men and 79.9% of women by the end of the 15th year (P < 0.001). Also, durations to develop wearing off and dyskinesia were shorter in women compared to men. These data suggest that the disease progression may be slightly faster for women. Young-onset patients showed significantly longer duration to reach Stage III, IV, and V but shorter duration to develop wearing off and dyskinesia. Not many studies are available in the literature on the long-term outcome of PD, and our data would be useful as a reference.

Cause, seasonality of death and co-morbidities in progressive supranuclear palsy (PSP)

The aim of this study was to investigate the causes and seasonality of death and co-morbid conditions among progressive supranuclear palsy (PSP) patients. 22 consecutive clinicopathologically confirmed PSP patients were compared with 22 gender and age-matched Parkinson's disease (PD) patients and 26 non-neurological controls. All subjects consented during life to donate their brains to the University of Miami Brain Endowment Bank. Respiratory-related deaths were significantly more frequent in PSP when compared to PD patients. Recurrent respiratory infections were also very frequent in PSP patients and were commonly associated with respiratory-related deaths. Deaths that occurred during winter and spring months accounted for about 70% of deaths among PSP patients. The most common co-morbid condition in PSP was hypertension, present in 50% of cases.

Long–term survival of Parkinson's disease

In a set of a population- based study, long-term survival of 59 prevalent PD patients was compared with that of individuals free of neurological diseases matched 1:2 by sex and age of enrolment. PD individuals, compared with reference subjects, showed a two-fold increased risk of death (OR 2.1; 95 % CI 1.4, 3.1). Among causes of death, pneumonia and cachexia were significantly more frequent among PD patients than among individuals free of neurological diseases. We confirmed in a long-term follow-up study an increased mortality among PD individuals compared with that of the general population.

Burden of disease related to Parkinson's disease in Spain in the year 2000

We measured the burden caused by Parkinson's disease (PD) in Spain during the year 2000 and compared it against PD burden worldwide and in the European A subregion. Burden of disease (BoD) is an important factor in health policy. Disability-adjusted life years (DALY) as a measure of BoD is the result of adding years of life lost (YLL) and years lived with disability (YLD). The burden of PD (BPD) has not been studied in Spain. YLL were obtained from the Spanish death certificates and YLD from the estimated number of incident PD cases and the average PD duration. PD disability was calculated, using the Disability Weights for Diseases in the Netherlands. Prior PD DALY data for Europe and the world were obtained from the 2001 World Health Organization World Health Report. A discount rate of 3% and age-weighting modulation factor with K = 1 were used. In Spain, PD generated 67,582 DALY, comprising 6,351 (9.4%) YLL and 61,231 (90.6%) YLD. Most PD DALY (57.5%) occurred in the population 60 to 74 years of age. When PD DALY estimates were adjusted using the world population in 2000, Spain registered a PD DALY rate of 84 per 100,000 population, higher than both the world and European A subregion rates (24 and 35 per 100,000 population, respectively). PD burden in Spain in 2000 was high, with disability being the major contributing factor. Although BPD in Spain was greater than both world and European A subregion BPD, these differences should nevertheless be interpreted with caution.

Sydney multicenter study of Parkinson's disease: Non‐ L ‐dopa–responsive problems dominate at 15 years

One-third of the 149 people recruited 15 to 18 years ago in the Sydney Multicenter Study of Parkinson's disease have survived. The original study compared low-dose levodopa with low-dose bromocriptine. We now report the problems experienced by people who survive 15 years from diagnosis. The standardized mortality ratio is significantly elevated at 1.86 and is not significantly different between treatment arms. Falls occur in 81% of patients, and 23% sustained fractures. Cognitive decline is present in 84%, and 48% fulfill the criteria for dementia. Hallucinations and depression are experienced by 50%. Choking has occurred in 50%, symptomatic postural hypotension in 35%, and urinary incontinence in 41%. No patient is still employed, and 40% of patients live in aged care facilities. Although approximately 95% have experienced L-dopa-induced dyskinesia/dystonia and end of dose failure of medication, in the majority, these symptoms are not disabling. Dyskinesia and dystonia were delayed by early use of bromocriptine, but end-of-dose failure appeared at a similar time once L-dopa was added. The rate of disease progression is similar in both arms of the study. We conclude that the most disabling long-term problems of Parkinson's disease relate to the emergence of symptoms that are not improved by L-dopa. Neuroprotective interventions in Parkinson's disease should be judged by their ability to improve non-L-dopa-responsive aspects of the disease, rather than just by their capacity to delay the introduction of L-dopa or reduce its associated side effects.

Smoking and Parkinson's disease: systematic review of prospective studies

We estimated the pooled risk of tobacco smoking for Parkinson's disease (PD). Inclusion criteria included systematic searches of MedLine, PsycLIT, Embase, Current Contents, previously published reviews, examination of cited reference sources, and personal contact and discussion with several investigators expert in the field. Published prospective studies on PD and cigarette smoking. When two or more studies were based on an identical study, the study that principally investigated the relationship or the study that was published last was used. Seven prospective studies were carried out between 1959 and 1997, of which six reported risk estimates. Four cohorts were based on standardised mortality rates, which were exclusively of male. Only one study included risk estimates for both males and females separately. The risk of ever smoker was 0.51 (95% confidence interval, 0.43 to 0.61). There was an obvious protective effect of current smoking in the pooled estimate (relative risk, 0.35; 95% CI, 0.26-0.47). Former smokers had lower risk compared with never smokers (relative risk, 0.66; 95% CI, 0.49-0.88). Although our pooled estimates show that smoking is inversely associated with the risk of PD, the four prospective studies that were based on follow-up of mortality of smokers had many limitations. Further studies evaluating the association between smoking and PD in women are strongly needed.

Systematic assessment of decision models in Parkinson's disease

OBJECTIVE

To give an insight into the structural and methodological approaches used in published decision-analytic models evaluating interventions in Parkinson's disease (PD) and to derive recommendations for future comprehensive PD decision models.

METHODS

A systematic literature review was performed to identify studies that evaluated PD interventions using mathematical decision models. Using a standardized assessment form, information on the study design, methodological framework, and data sources was extracted from each publication and systematically reported. Strengths and limitations were assessed.

RESULTS

We identified eight studies that used mathematical models to evaluate different pharmaceutical (n=7) and surgical (n=1) treatment options in PD. All models included economic evaluations. Modeling approaches comprised mathematical equations, decision trees, and Markov models with a time horizon ranging from 5 years to lifetime. All based progression on the evolution of clinical surrogate endpoints. Treatment effects were either modeled via reduction of symptomatic progression and/or initial symptomatic improvement or via reduction of adverse effect rates. No model is currently available that encompasses both the underlying biologic disease progression and the spectrum of all relevant complications and also links them to patient preferences and economic outcomes.

CONCLUSIONS

Models have been successfully applied to evaluate PD treatments. However, currently available models have substantial limitations. We recommend that a comprehensive, generic, and flexible decision model for PD that can be applied to different treatment strategies should consider a large spectrum of clinically relevant outcomes and complications of the disease during a sufficiently long time horizon, include PD-specific mortality, systematically evaluate uncertainty including heterogeneity effects, and should be validated by independent data or other models. Approaches to model treatment effects included reduction of symptomatic progression, initial symptomatic improvement, or reduction of adverse effects. We believe that structural bias could be avoided if underlying disease progression and treatment effects on symptoms are modeled separately.

Survival time, mortality, and cause of death in elderly patients with Parkinson's disease. A 9-year follow-up

This community-based study of Parkinson's disease (PD) investigated age at death and cause of death in a cohort of 170 previously studied patients. The current study is a 9-year follow-up, and the results are compared to 510 sex- and age-matched controls from the same area. A total of 170 patients were diagnosed with PD on August 31, 1989, within a defined area of Sweden. A control group of 510 persons from the same area and with the same age and sex distribution was also examined regarding age at death and cause of death. After 9.4 years, 121 cases (71.1%) and 229 controls (44.9%) were no longer alive. Thus, the mortality rate ratio was 1.6 (95% confidence interval [CI], 1.3-1.8) when comparing PD patients with controls. The all-cause hazard ratio for cases compared to controls was 2.4 (95% CI, 1.9-3.0). The mean age at death for the cases was 81.9 (95% CI, 80.3-83.0) years and for the controls 82.9 (95% CI, 82.0-83.7) years. Survival analysis also showed a shorter survival time (P < 0.001) for PD patients. Only 53% of the death certificates for the deceased patients recorded PD as an underlying or contributory cause of death. Many PD patients reached a high age but had a shorter survival than the controls. There was a significant increase in deaths from pneumonia.

Intracortical inhibition and facilitation of the response of the diaphragm to transcranial magnetic stimulation

Respiratory muscles respond to a subcortical automatic command and to a neocortical voluntary command. In diseases such as stroke or motor neurone disease, an abnormal diaphragmatic response to single transcranial magnetic stimuli can identify a central source for respiratory disorders, but this is not likely to be the case in disorders affecting intracortical inhibitory and facilitatory mechanisms. This study describes the response of the diaphragm to paired transcranial magnetic stimulation. Thirteen normal subjects were studied (age range, 22 to 43 years; 7 men; phrenic conduction, <6.8 msec; latency of diaphragmatic motor evoked potential, <20.5 msec). Motor evoked potentials in response to paired stimulation were obtained in eight subjects only, with the motor threshold in the remaining five subjects too high to absorb the loss of power inherent in the double-stimulation montage. Interstimulus intervals less than 5 msec resulted in a statistically significant inhibition (p < 0.01 for interstimulus intervals of 1 and 3 ms), whereas intervals longer than 6 msec were facilitatory (maximal, 15 msec). The diaphragmatic pattern matched that of the biceps brachii. The authors conclude that it is possible to study intracortical inhibition and facilitation of diaphragmatic control, although not in all subjects. Technical improvement should alleviate current limitations and make paired transcranial magnetic stimulation a tool to study respiratory muscle abnormalities in settings in which intracortical interactions are important, such as movement disorders.

Medical services utilization and prognosis in Parkinson disease: a population-based study

OBJECTIVES

To investigate prognostic outcomes and utilization of medical services by patients with Parkinson disease (PD) and to identify predictors of such use.

PATIENTS AND METHODS

Using the medical records linkage system of the Rochester Epidemiology Project, we identified an incidence cohort of 89 PD cases (Olmsted County, Minnesota, 1979-1988) and a reference group of 89 subjects without PD of the same age and sex and from the same population. Both patients with PD and reference subjects were followed up historically by medical record review from onset of PD (or index year) through death, last contact with the system, or end of study.

RESULTS

Patients with PD had significantly more physician consultations per year (median, 7.9 vs 5.9; P=.001) and more emergency department visits per year (median, 0.6 vs 0.4; P=.05) than did reference subjects. Response to dopaminergic medications and higher education predicted more physician consultations among patients. The PD patients used neuroleptics and antidepressants significantly more frequently than reference subjects. The risk of nursing home placement was significantly increased for PD patients compared with reference subjects (relative risk, 6.7; 95% confidence interval, 3.7-12.1; P<.001). Poor response to dopaminergic medications, lower education level, older age at onset of PD, and dementia predicted a shorter time between onset and nursing home placement among PD patients. Survival was significantly reduced in PD patients compared with reference subjects (relative risk, 2.2; 95% confidence interval, 1.4-3.4; P<.001). Good response to dopaminergic medications, higher education, younger age at onset of PD, and absence of dementia predicted better survival among PD patients.

CONCLUSIONS

Patients with PD used outpatient and nursing home services more often than subjects without PD. Patients with PD also experienced a reduced survival time. Demographic and clinical characteristics influenced utilization patterns and outcomes.

Causes of death in a community-based study of Parkinson's disease

INTRODUCTION

The aim of this community-based study of Parkinson's disease (PD) was to investigate the causes of death among PD patients over a 4-year period and to examine the quality of death certificates with regard to PD.

PATIENTS AND METHODS

A total of 245 patients were diagnosed with PD on Jan 1st 1993 in a defined geographical area in Norway. This patient cohort was followed from 1993 until Dec 31st 1996. Some 84 patients died in the 4-year period of follow-up. Their death certificates were collected, and causes of death were registered. A control group with the same age and sex distribution as the decedents, from the same geographical area, were also examined for causes of death.

RESULTS

We found that the deceased PD patients at baseline were older, had a higher Unified Parkinson's Disease Rating Scale (UPDRS) score and Hoehn and Yahr staging than those patients who did not die during the observation period. Twice as many PD patients (20%) as controls (9%) died from pneumonia, whereas more controls than patients died from ischemic heart disease. There was a trend towards more deaths from malignant neoplasms in the control group than among PD patients. Only 56% of the death certificates of the deceased patients had PD registered as either underlying or contributing cause of death.

CONCLUSION

We found that in an unselected group of PD patients there is a significant increase in deaths from pneumonia. The low frequency of PD on deceased patients' death certificates show that research based on these certificates should be evaluated with caution.

Breathing pattern in patients with Parkinson's disease

The improvement in motor performance resulting from levodopa administration in patients with Parkinson's disease (PD) provides the opportunity to investigate ventilatory changes brought about by the disease. The aim of this study has been to investigate these changes in order to specify the mechanisms of the impairment in breathing in PD. Breathing patterns at rest were investigated in 11 patients with idiopathic PD both before (OFF) and after (ON) administration of levodopa at a dose improving their motor performance by at least 30%. Airflow (Fleisch head mounted on a mask), rib cage and abdomen movements (inductance plethysmography) were recorded in the OFF condition 1 h after subjects woke up. Subjects then received levodopa and a new set of recordings was obtained 1 h later, in the ON condition. Breath-by-breath processing of recordings was carried out, and tidal volume (VT), inspiratory (TI) and expiratory (TE) durations were measured. The main finding was a lengthening of TI resulting in a decrease in ventilation and in VT/TI, and an increase in TI/TTOT in the ON compared to the OFF condition. In the ON condition abnormal rib cage-abdomen plots patterns were found in four out of six subjects. A hypothesis on the effect of PD on breathing is proposed on grounds of normal diaphragmatic activity but impaired activity of the other respiratory muscles and more specifically the intercostal muscles.

The sydney multicentre study of Parkinson's disease: progression and mortality at 10 years

OBJECTIVES

To report on a 10 year follow up of patients with idiopathic Parkinson's disease, particularly with respect to mortality and the effect of early treatment with bromocriptine.

METHODS

The patients are from the 149 new patients recruited for a double blind, randomised study of low dose levodopa-carbidopa versus low dose bromocriptine. Patients were examined neurologically at least yearly. Neuropsychological examinations were performed at 0, 3, 5, and 10 years. Mortality and cause of death in these patients were compared with the Australian population using standardised mortality ratios (SMRs). Mortality and disease progression were compared by sex and treatment group. Predictors of death within 10 years, nursing home admission, and progression in Columbia score of >/=20 points were examined by logistic regression analysis.

RESULTS

Thirteen patients were excluded as having atypical Parkinsonism and six were lost to follow up. All available patients have been followed up for 10 years. Fifty patients (38%) were dead by 10 years and 63 by the last follow up. The SMR was 1.58 for all patients (p<0. 001). There was no significant difference in SMRs between the sexes. The mean duration of disease until death was 9.1 years. Parkinson's disease was thought to have contributed substantially to the death of 30 patients. The most common cause of death was pneumonia. Women progressed at a similar rate to men until 8 years, when the severity of their disease as measured by Hoehn and Yahr stage became greater (p<0.05). Older age of onset correlated with increased risk of death but the SMR was increased even in those aged <70 years (SMR 1.80, p=0.03). Early use of bromocriptine did not reduce mortality or slow progression of disease. One quarter of all patients had been admitted to nursing homes by 10 years. Only four patients were still employed.

CONCLUSIONS

Mortality in Parkinson's disease remains increased despite low dose levodopa-carbidopa therapy and no additional benefit was gained from early use of bromocriptine. Duration of disease was similar to that in the era before levodopa.