Quality of life and depression in Parkinson's disease

Behavioral and neurochemical effects of chronic L-DOPA treatment on nonmotor sequelae in the hemiparkinsonian rat

Depression and anxiety are the prevalent nonmotor symptoms that worsen quality of life for Parkinson's disease (PD) patients. Although dopamine (DA) cell loss is a commonly proposed mechanism, the reported efficacy of DA replacement therapy with L-DOPA on affective symptoms is inconsistent. To delineate the effects of DA denervation and chronic L-DOPA treatment on affective behaviors, male Sprague-Dawley rats received unilateral 6-hydroxydopamine or sham lesions and were treated daily with L-DOPA (12 mg/kg+benserazide, 15 mg/kg, subcutaneously) or vehicle (0.9% NaCl, 0.1% ascorbic acid) for 28 days before commencing investigations into anxiety (locomotor chambers, social interaction) and depression-like behaviors (forced swim test) during the OFF phase of L-DOPA. One hour after the final treatments, rats were killed and striatum, prefrontal cortex, hippocampus, and amygdala were analyzed through high-performance liquid chromatography for monoamine levels. In locomotor chambers and social interaction, DA lesions exerted mild anxiogenic effects. Surprisingly, chronic L-DOPA treatment did not improve these effects. Although DA lesion reduced climbing behaviors on day 2 of exposure to the forced swim test, chronic L-DOPA treatment did not reverse these effects. Neurochemically, L-DOPA treatment in hemiparkinsonian rats reduced norepinephrine levels in the prefrontal cortex, striatum, and hippocampus. Collectively, these data suggest that chronic L-DOPA therapy in severely DA-lesioned rats does not improve nonmotor symptoms and may impair nondopaminergic processes, indicating that long-term L-DOPA therapy does not exert necessary neuroplastic changes for improving affect.

Tryptophan hydroxylase 2 aggregates through disulfide cross-linking upon oxidation: possible link to serotonin deficits and non-motor symptoms in Parkinson's disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by the loss of dopamine neurons of the nigrostriatal system, resulting in severe motor disturbances. Although much less appreciated, non-motor symptoms are also very common in PD and many can be traced to serotonin neuronal deficits. Tryptophan hydroxylase (TPH) 2, the rate-limiting enzyme in the serotonin biosynthesis, is a phenotypic marker for serotonin neurons and is known to be extremely labile to oxidation. Therefore, the oxidative processes that prevail in PD could cause TPH2 misfolding and modify serotonin neuronal function much as is seen in dopamine neurons. Oxidation of TPH2 inhibits enzyme activity and leads to the formation of high molecular weight aggregates in a dithiothreitol-reversible manner. Cysteine-scanning mutagenesis shows that as long as a single cysteine residue (out of a total of 13 per monomer) remains in TPH2, it cross-links upon oxidation and only cysteine-less mutants are resistant to this effect. The effects of oxidants on TPH2 catalytic function and cross-linking are also observed in intact TPH2-expressing HEK293 cells. Oxidation shifts TPH2 from the soluble compartment into membrane fractions and large inclusion bodies. Sequential non-reducing/reducing 2-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting confirmed that TPH2 was one of a small number of cytosolic proteins that form disulfide-bonded aggregates. The propensity of TPH2 to misfold upon oxidation of its cysteine residues is responsible for its catalytic lability and may be related to loss of serotonin neuronal function in PD and the emergence of non-motor (psychiatric) symptoms.

Does the clinical practice guideline on Parkinson's disease change health outcomes? A cluster randomized controlled trial

The successful transfer of clinical practice guidelines (CPGs) into patient care depends on the appropriateness of the implementation method. This study strived for a better understanding of which intervention strategy is effective in implementing the CPG on Parkinson's disease (CPG-PD). In a cluster randomized controlled trial, we compared the impact of two different implementation strategies of the CPG-PD on health outcomes of PD patients. The primary outcome of health-related quality of life was measured by PDQ-39. The neurologists of the intervention group (IG) versus a control group (CG) received the CPG-PD with special instructions, a 4-h training and were offered personal feedback. Patients were followed over three assessment times: baseline, post-test (6 months) and follow-up (9 months). Lack of time and remuneration resulted in low study participation (32 out of 619 contacted neurologists). Multilevel modelling revealed that primary (PDQ-39) and secondary efficacy variables (EQ-5D, CGI, HADS-D, ZUF-8) of 386 patients were not affected significantly by the intervention and failed to show any significant difference between the two groups. The EQ-5D VAS scale (p = 0.0288) and the CGI-P severity scale (p = 0.0072) showed a significant worsening over time. A significant decrease of hours of dyskinesias in the IG (p = 0.007) was observed, whereas Parkinson symptoms did not change significantly between the groups. Lacking awareness of the CPG-PD seems to be no longer a barrier for its use, but it is still a major challenge to find effective implementation methods to optimise clinical outcome. Further studies are needed for a more comprehensive understanding of successful implementation strategies.

Occurrence of depression and anxiety prior to Parkinson's disease

OBJECTIVE

To assess the relationship between depression and anxiety and Parkinson's disease (PD).

BACKGROUND

Many people with PD suffer from depression and anxiety prior to the onset of motor symptoms. Studies suggest these psychiatric conditions may be risk factors for PD or prodromal non-motor symptoms.

METHODS

Using a population-based approach in three California counties, we recruited 371 incident PD cases, 402 population and 115 sibling controls. We recorded self-reports of lifetime depression/anxiety diagnoses and use of psychotropic medications. We adjusted for age, race, sex, pack-years of smoking, and education, and also conducted analyses after excluding (lagging) both diagnoses and medication use first occurring within 2, 5, 10, and 20 years of the index/diagnosis date.

RESULTS

Cases were more likely to have received a diagnosis of depression or anxiety at any time prior to index date (OR 1.42, 95% CI 1.01, 2.00), but were not more likely to have been both diagnosed and treated (OR 1.11, 95% CI 0.77, 1.60). Male PD patients received diagnoses combined with treatment more often than population controls within 5 years of PD diagnosis (OR 2.21, 95% CI 1.21, 4.04; 2 year lag: OR 2.44, 95% CI 1.29, 4.61; 5 year lag: OR 1.67, 95% CI 0.80, 3.49). We did not see any differences for females. Results for cases compared to sibling controls were similar to those for population controls.

CONCLUSION

These results suggest that depression and anxiety may be early symptoms during the prodromal phase of PD.

Impact of psychiatric symptoms and sleep disorders on the quality of life of patients with Parkinson's disease

The objective of this study is to assess how the non-motor symptoms of Parkinson's disease (PD), such as depression, cognitive deterioration, neuropsychiatric and sleep disorders, affect the quality of life, and to compare them with the motor symptoms in order to determine their real impact. A cross-sectional study was designed including 99 patients (mean age 68.5 ± 9.9 years, duration of disease 8.7 ± 6.2 years). Demographic data, onset of PD, years on treatment with levodopa (LD), class of dopaminergic drug prescribed, and dosages were obtained. The following scales were used: quality of life (PDQ-39), Unified Parkinson's Disease Rating Scale (UPDRS I-IV), Parkinson Disease Sleep Scale (PDSS) and daytime sleepiness (Epworth), Mini-Mental State Examination, depression (HAM-D), and the neuropsychiatric inventory (NPI-10). The PDQ-39 summary index (PDQ-39 SI) was 24.7 ± 13.2. A linear regression model including all variables showed that four independent variables accounted for 67.2% of the variance in the PDQ-39 SI (F = 33,277; p < 0.001): NPI, PDSS, UPDRS IV, and UPDRS I. When sub-items of the NPI, PDSS and UPDRS IV scales are analyzed, significant correlations (p < 0.001) are found between the PDQ-39 SI and depression, agitation, apathy, anxiety, hallucinations, delusions, incontinence of urine, morning painful posturing, restlessness in bed, morning fatigue, duration of off periods, unpredictable and predictable off periods, early morning dystonia, and sudden off periods. Neuropsychiatric symptoms, especially depression, nighttime sleep disorders such as urinary incontinence, nighttime restlessness, morning fatigue and somnolence, off-period dystonia and motor fluctuations are the variables that most affect the quality of life of patients with PD.

Determinants of health-related quality of life in Parkinson's disease: a systematic review

This systematic review critically evaluates the literature to identify the demographic and clinical factors that predict the health-related quality of life (HRQOL) of people with Parkinson's disease (PD). Understanding how these factors relate to HRQOL in people with PD may assist clinicians minimise the functional and social impact of the disease by optimising their assessment and clinical decision making processes. A tailored search strategy in six databases identified 29 full-text reports that fulfilled the pre-defined inclusion and exclusion criteria. The quality of included studies was assessed by two independent reviewers using a customized assessment form. A best-evidence synthesis was used to summarise the demographic and clinical factors that were examined in relation to HRQOL. Depression was the most frequently identified determinant of HRQOL in people with idiopathic PD. Disease severity and disease disability were also found to be predictive of poor HRQOL outcomes in many studies. The motor symptoms that contributed most often to overall life quality were gait impairments and complications arising from medication therapy. To minimise the impact of PD on HRQOL, it may be necessary to consider the extent to which demographic factors and motor and non-motor symptoms contribute to life quality.

Health-related quality of life in Parkinson disease: correlation between Health Utilities Index III and Unified Parkinson's Disease Rating Scale (UPDRS) in U.S. male veterans

Objective

To apply a scaled, preference-based measure to the evaluation of health-related quality of life (HRQoL) in Parkinson's disease (PD); to evaluate the relationship between disease-specific rating scales and estimated HRQoL; and to identify predictors of diminished HRQoL.

Background

Scaled, preference-based measures of HRQoL ("utilities") serve as indices of impact of disease, and can be used to generate quality-adjusted estimates of survival for health-economic evaluations. Evaluation of utilities for PD and their correlation with standard rating scales have been limited.

Methods

Utilities were generated using the Health Utilities Index Mark III (HUI-III) on consecutive patients attending a PD Clinic between October 2003 and June 2006. Disease severity, medical, surgical (subthalamic nucleus deep brain stimulation (STN-DBS)), and demographic information were used as model covariates. Predictors of HUI-III utility scores were evaluated using the Wilxocon rank-sum test and linear regression models.

Results

68 men with a diagnosis of PD and a mean age of 74.0 (SD 7.4) were included in the data analysis. Mean HUI-III utility at first visit was 0.45 (SD 0.33). In multivariable models, UPDRS-II score (r² = 0.56, P < 0.001) was highly predictive of HRQoL. UPDRS-III was a weaker, but still significant, predictor of utility scores, even after adjustment for UPDRS-II (P = 0.01).

Conclusions

Poor self-care in PD reflected by worsening UPDRS-II scores is strongly correlated with low generic HRQoL. HUI-III-based health utilities display convergent validity with the UPDRS-II. These findings highlight the importance of measures of independence as determinants of HRQoL in PD, and will facilitate the utilization of existing UPDRS data into economic analyses of PD therapies.

[Behavioral disorders in Parkinson's disease: from pathophysiology to the mastery of dopaminergic treatment]

INTRODUCTION

Behavioral changes in Parkinson's disease are complex and their pathophysiology is not yet fully understood. The dopaminergic system seems to play a major role and most of the behavioral disorders in Parkinson's disease can be classified into either hypodopaminergic if related to the disease itself or hyperdopaminergic if related to dopaminergic treatment.

STATE OF THE ART

Subthalamic stimulation, which enables withdrawal of dopaminergic medication at an advanced stage in the disease, provides a model for the study of certain nonmotor, dopamine-sensitive symptoms. Such a study has shown that apathy, which is the most frequent behavioral problem in Parkinson's disease, is part of a much broader hypodopaminergic behavioral syndrome which also includes anxiety and depression. Nonmotor fluctuations--essential fluctuations in the patient's psychological state--are an expression of mesolimbic denervation, as shown in positron emission tomography. Drug-induced sensitization of the denervated mesolimbic system accounts for hyperdopaminergic behavioral problems that encompass impulse control disorders that can be alternatively classified as behavioral addictions. The association of impulse control disorders and addiction to the dopaminergic medication has been called dopamine dysregulation syndrome. While L-dopa is the most effective treatment for motor symptoms, dopamine agonists are more effective in improving the nonmotor levodopa-sensitive symptoms. On the other hand, L-dopa induces more motor complications and dopamine agonist more behavioral side effects. There is increasing data and awareness that patients' quality of life appears to be dictated by hypo- and hyperdopaminergic psychological symptoms stemming from mesolimbic denervation and dopaminergic treatment rather than by motor symptoms and motor complications related to nigrostriatal denervation and dopaminergic treatment.

PERSPECTIVES

Better management requires knowledge of the clinical syndromes of hyper- and hypodopaminergic behaviors and nonmotor fluctuations, a better understanding of their underlying mechanisms and the development of new evaluation tools for these nonmotor symptoms.

CONCLUSIONS

The neurologist who strives to gain mastery of dopaminergic treatment needs to fine tune the dosage of levodopa and dopamine agonists on an individual basis, depending on the presence of motor and nonmotor signs respectively.

Double-blind study of pardoprunox, a new partial dopamine agonist, in early Parkinson's disease

This study examined the efficacy and safety of the partial dopamine agonist, pardoprunox (SLV308), in the treatment of patients with early Parkinson's disease (PD). Patients were randomized to receive pardoprunox (n = 69) or placebo (n = 70). Pardoprunox was titrated to each patient's optimal dose (9-45 mg/d) over 2 to 6 weeks and then maintained at this dose for a further 3 weeks. Concomitant anti-Parkinson treatment was not permitted. In the primary analysis, Unified PD Rating Scale (UPDRS)-Motor score was improved in pardoprunox-treated patients (overall mean dose 23.8 mg/d; -7.3 points), as compared with placebo (-3.0 points; P = 0.0001), from baseline to end point. At end point, there were more responders (> or = 30% reduction in UPDRS-Motor score) in the pardoprunox group (50.7%) than in the placebo group (15.7%; P < 0.0001). In other secondary analyses, UPDRS-activities of daily living (ADL) and -ADL+Motor scores were also significantly more improved in the pardoprunox group. Nausea was reported by 32 of 68 (47.1%) pardoprunox-treated patients (vs. 3/70, 4.3%, placebo-treated patients), with dizziness, somnolence, headache, and asthenia also reported by > or = 10 patients. In this exploratory proof-of-concept study, pardoprunox significantly improved motor function in patients with early PD. The efficacy and safety profile of pardoprunox justifies its further investigation in PD.

Potential mechanisms underlying anxiety and depression in Parkinson's disease: consequences of l-DOPA treatment

Though the most recognizable symptoms of Parkinson's disease (PD) are motor-related, many patients also suffer from debilitating affective symptoms that deleteriously influence quality of life. Dopamine (DA) loss is likely involved in the onset of depression and anxiety in PD. However, these symptoms are not reliably improved by DA replacement therapy with l-3,4-dihydroxyphenylalanine (l-DOPA). In fact, preclinical and clinical evidence suggests that l-DOPA treatment may worsen affect. Though the neurobiological mechanisms remain unclear, recent research contends that l-DOPA further perturbs the function of the norepinephrine and serotonin systems, already affected by PD pathology, which have been intimately linked to the development and expression of anxiety and depression. As such, this review provides an overview of the clinical characteristics of affective disorders in PD, examines the utility of animal models for the study of anxiety and depression in PD, and finally, discusses potential mechanisms by which DA loss and subsequent l-DOPA therapy influence monoamine function and concomitant affective symptoms.

Efficacy and acceptability of selective serotonin reuptake inhibitors for the treatment of depression in Parkinson's disease: a systematic review and meta-analysis of randomized controlled trials

Background

Selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed antidepressants for the treatment of depression in patients with Parkinson's Disease (PD) but data on their efficacy are controversial.

Methods

We conducted a systematic review and meta-analysis of randomized controlled trials to investigate the efficacy and acceptability of SSRIs in the treatment of depression in PD.

Results

Ten studies were included. In the comparison between SSRIs and Placebo (n = 6 studies), the combined risk ratio (random effects) was 1.08 (95% confidence interval: 0.77 - 1.55, p = 0.67). In the comparison between SSRIs and Tricyclic Antidepressants (TCAs) (n = 3 studies) the combined risk ratio was 0.75 (0.39 - 1.42, p = 0.37). An acceptability analysis showed that SSRIs were generally well tolerated.

Conclusions

These results suggest that there is insufficient evidence to reject the null hypothesis of no differences in efficacy between SSRIs and placebo in the treatment of depression in PD. Due to the limited number of studies and the small sample sizes a type II error (false negative) cannot be excluded. The comparison between SSRIs and TCAs is based on only three studies and further trials with more pragmatic design are needed.

New developments in depression, anxiety, compulsiveness, and hallucinations in Parkinson's disease

Increasing research efforts are focused on nonmotor aspects of Parkinson's disease (PD). Depression, anxiety, compulsivity (dopamine dysregulation symptoms), and hallucinations/psychosis are among these disorders, and all complicate the management of PD with negative influences on quality of life. There is a strong overlap between depression and apathy and likewise, depression and anxiety can coexist and require careful pharmacologic management. Dopamine dysregulation syndrome is linked to medication use and most clearly associated with dopamine agonists. In contrast, although hallucinations and psychosis do not occur unless patients with PD are treated with dopaminergic drugs, medication doses do not directly relate to this problem. Functional neuroimaging provides an excellent resource for investigating these behaviors as well as their anatomical and neurochemical bases. New treatments are being developed, but there have been very few large-scale randomized clinical trials to test the relative roles of new or available agents for abating these problematic behaviors.

The impact of levodopa on quality of life in patients with Parkinson disease

BACKGROUND

Parkinson disease (PD) is associated with a progressive decline in patient quality of life (QoL), because of motor and nonmotor manifestations of PD and treatment-related side effects.

REVIEW SUMMARY

Treatment with carbidopa/levodopa-the current gold standard therapy-improves QoL in the short term, but gains are not maintained over a long term. Long-term treatment is associated with symptom re-emergence (end-of-dose "wearing off") and development of dyskinesia, which may have an adverse impact on QoL.

CONCLUSIONS

Levodopa (LD; combined with carbidopa) remains the gold standard for symptomatic treatment of PD, but long-term treatment is associated with complications that may adversely affect QoL. Recent studies have suggested that the addition of a catechol-O-methyltransferase inhibitor may improve QoL through the reduction of some of the motor complications of LD therapy. Further studies are required to determine the full effects of this as well as other treatments that are used to manage LD-associated complications on QoL.

Risk of sleep-disordered breathing in Parkinson's disease

OBJECTIVE

The objective of this study is to assess the risk of sleep-disordered breathing (SDB) in patients with Parkinson's disease (PD) in a cross-sectional survey of PD subjects and controls in a university-based movement disorders clinic.

METHODS

One hundred thirty-four consecutive PD subjects and 94 control subjects without prior diagnosis of SDB were assessed. Participants were assessed with clinical history, Unified Parkinson's Disease Rating Scale, Geriatric Depression Scale, Berlin Questionnaire to classify SDB risk, Epworth Sleepiness Scale, Parkinson's Disease Sleep Scale, and SF-36 to examine quality of life. The presence of risk for SDB was assessed by the Berlin Questionnaire.

RESULTS

High risk for SDB was apparent in 66 (49.3%) of the PD patients and 32 (34.8%) of the controls. After adjustment for age, gender, and body mass index (BMI), PD subjects in comparison to controls showed higher risk for SBD (odds ratio = 2.81; 95% confidence interval, 1.36-5.82). Quality of life (physical component score) was significantly diminished in PD patients at high risk for SDB. PD severity did not correlate well with SDB risk. PD patients at high risk for SDB had higher BMIs and Epworth scores.

CONCLUSIONS

PD patients have features suggesting increased risk for SDB. This frequently undiagnosed sleep disorder may have a substantial impact on quality of life of PD patients.

Pramipexole for the treatment of depressive symptoms in patients with Parkinson's disease: a randomised, double-blind, placebo-controlled trial

BACKGROUND

Depression is common in patients with Parkinson's disease, but evidence on the efficacy of antidepressants in this population is lacking. Because depression in patients with Parkinson's disease might be related to dopaminergic dysfunction, we aimed to assess the efficacy of the dopamine agonist pramipexole for treatment of depressive symptoms in patients with Parkinson's disease.

METHODS

We did a 12-week randomised, double-blind, placebo-controlled (1:1 ratio) trial of pramipexole (0.125-1.0 mg three times per day) compared with placebo in patients with mild-to-moderate Parkinson's disease. Patients from 76 centres in 12 European countries and South Africa were included if they were on stable antiparkinsonian therapy without motor fluctuations and had depressive symptoms (15-item geriatric depression scale score > or =5 and unified Parkinson's disease rating scale [UPDRS] part 1 depression item score > or =2). Patients were randomly assigned by centre in blocks of four by use of a randomisation number generating system. Clinical monitors, the principal investigator, and patients were masked to treatment allocation. The primary endpoint was change in Beck depression inventory (BDI) score and all treated patients who had at least one post-baseline efficacy assessment were included in the primary analysis. We also did a pre-specified path analysis with regression models to assess the relation between BDI and UPDRS part 3 (motor score) changes. This trial is registered with ClinicalTrials.gov, number NCT00297778, and EudraCT, number 2005-003788-22.

FINDINGS

Between March, 2006, and February, 2008, we enrolled 323 patients. Of 296 patients randomly assigned to pramipexole or placebo, 287 were included in the primary analysis: 139 in the pramipexole group and 148 in the placebo group. BDI scores decreased by an adjusted mean 5.9 (SE 0.5) points in the pramipexole group and 4.0 (0.5) points in the placebo group (difference 1.9, 95% CI 0.5-3.4; p=0.01, ANCOVA). The UPDRS motor score decreased by an adjusted mean 4.4 (0.6) points in the pramipexole group and 2.2 (0.5) points in the placebo group (difference 2.2, 95% CI 0.7-3.7; p=0.003, ANCOVA). Path analysis showed the direct effect of pramipexole on depressive symptoms accounted for 80% of total treatment effect (p=0.04). Adverse events were reported in 105 of 144 patients in the pramipexole group and 101 of 152 in the placebo group. Adverse events in the pramipexole group were consistent with the known safety profile of the drug.

INTERPRETATION

Pramipexole improved depressive symptoms in patients with Parkinson's disease, mainly through a direct antidepressant effect. This effect should be considered in the clinical management of patients with Parkinson's disease.

Rasch analysis of the Beck Depression Inventory-II in a neurological rehabilitation sample

PURPOSE

To apply Rasch analysis to the Beck Depression Inventory-II (BDI-II) responses of a mixed neurorehabilitation sample to determine its suitability for assessing depression among this group.

METHOD

Three hundred and fifteen in-patients undergoing post-acute specialist in-patient rehabilitation at the Regional Rehabilitation Unit (RRU) of Northwick Park Hospital in North London were administered the Beck Depression Inventory. All patients were administered the BDI-II by a clinical psychologist using a large print version and taking as much time as patients required. Rasch analysis was completed using the RUMM2020 software. Where disordered thresholds were identified item rescoring was undertaken. Each item was also examined for Differential Item Functioning. Where misfit to model expectations was identified items were removed in an iterative fashion. The effect of any deletion upon person estimates was examined. Specific tests of unidimensionality were undertaken at each iterative phase.

RESULTS

Rescoring was necessary before Items 1-4, 6, 8-12, 20 and 21 showed ordered thresholds. Three items failed to satisfy model expectations - items 16 (changes in sleeping pattern), 18 (changes in appetite) and 21 (loss of interest in sex) and were deleted - after which good overall fit to the Rasch model was observed. The three items deleted affected person estimates in a significant way such that the 21 item version in this group of patients may be biased because of multidimensionality.

CONCLUSIONS

The BDI-II in a sample of patients undergoing neurorehabilitation satisfies unidimensional Rasch model expectations in an 18-item format. Some disordering of response categories was evident, but this evidence requires replication before any common rescoring option should be considered.

Parkinson's disease: Impact of clinical and cognitive aspects on quality of life

Parkinson's disease (PD) is a chronic disease manifested principally by motor signs and symptoms, but with frequent neuropsychological alterations.

OBJECTIVES

To study the relationship between clinical and cognitive aspects and the perception of quality of life (QOL) in PD patients.

METHODS

Twenty consecutive patients (13 men) with idiopathic PD (mean age: 64.5y), mean disease time of 7.8 years and at stages 1-3 according to the modified Hoehn and Yahr staging scale (HYS), all outpatients from the Neurology Department of the Celso Pierro General and Maternity Hospital (PUC-Campinas), were analyzed. The following were applied: a clinical-neurological assessment, the Mini-Mental State Examination (MMSE), standard neuropsychological battery of the CERAD (Consortium to Establish a Registry for Alzheimer's Disease), Hamilton Depression Rating Scale (HAM-D) and a QOL questionnaire (Parkinson's Disease Questionnaire - PDQ-39). Statistical analysis was carried out at a significance level of p<0.05.

RESULTS

On the PDQ-39 under the sections total, mobility and activities of daily living, and the items motor compromise (HYS) and language of the MMSE were predictors of worse QOL. Verbal fluency was a factor for emotional well-being on the PDQ-39, whereas higher scores for HAM-D and worse performance on the item attention and calculation of the MMSE were associated with worse QOL in the social support section. Total score on the MMSE and educational level were QOL factors in cognition.

CONCLUSIONS

The findings of the present study suggest that clinical, cognitive, motor or other depression-related factors contribute differently to the domains of QOL.

Destruction of dopaminergic neurons in the midbrain by 6-hydroxydopamine decreases hippocampal cell proliferation in rats: reversal by fluoxetine

Background

Non-motor symptoms (e.g., depression, anxiety, and cognitive deficits) in patients with Parkinson disease (PD) precede the onset of the motor symptoms. Although these symptoms do not respond to pharmacological dopamine replacement therapy, their precise pathological mechanisms are currently unclear. The present study was undertaken to examine whether the unilateral 6-hydroxydopamine (6-OHDA) lesion to the substantia nigra pars compacta (SNc), which represents a model of long-term dopaminergic neurotoxicity, could affect cell proliferation in the adult rat brain. Furthermore, we examined the effects of the selective serotonin reuptake inhibitor (SSRI) fluoxetine and the selective noradrenaline reuptake inhibitor maprotiline on the reduction in cell proliferation in the subgranular zone (SGZ) by the unilateral 6-OHDA lesion.

Methodology/Principal Findings

A single unilateral injection of 6-OHDA into the rat SNc resulted in an almost complete loss of tyrosine hydroxylase (TH) immunoreactivity in the striatum and SNc, as well as in reductions of TH-positive cells and fibers in the ventral tegmental area (VTA). On the other hand, an injection of vehicle alone showed no overt change in TH immunoreactivity. A unilateral 6-OHDA lesion to SNc significantly decreased cell proliferation in the SGZ ipsilateral to the 6-OHDA lesion, but not in the contralateral SGZ or the subventricular zone (SVZ), of rats. Furthermore, subchronic (14 days) administration of fluoxetine (5 mg/kg/day), but not maprotiline significantly attenuated the reduction in cell proliferation in the SGZ by unilateral 6-OHDA lesion.

Conclusions/Significance

The present study suggests that cell proliferation in the SGZ of the dentate gyrus might be, in part, under dopaminergic control by SNc and VTA, and that subchronic administration of fluoxetine reversed the reduction in cell proliferation in the SGZ by 6-OHDA. Therefore, SSRIs such as fluoxetine might be potential therapeutic drugs for non-motor symptoms as well as motor symptoms in patients with PD, which might be associated with the reduction in cell proliferation in the SGZ.

The impact of antidepressant treatment on cognitive functioning in depressed patients with Parkinson's disease

Depression is associated with more rapid cognitive decline in Parkinson's disease. The goal of this study was to examine the impact of the acute (8-week) and longer-term (24-week) antidepressant treatment on cognition in Parkinson's disease and to detail cognitive predictors of treatment response. Fifty-two depressed Parkinson's disease patients were enrolled in an NIH-funded randomized, controlled trial of nortriptyline, paroxetine, and placebo. Neuropsychological testing was performed at baseline and weeks 8 and 24. Higher baseline scores on measures of executive functioning, speed of processing, and verbal memory were associated with antidepressant response. Treatment responders did not exhibit larger gains in cognition than nonresponders. Findings warrant replication.

The impact of treatment of depression on quality of life, disability and relapse in patients with Parkinson's disease

Parkinson's disease (PD) is a common neurodegenerative disease affecting up to one million individuals in the United States. Depression is found in 40 to 50% of these patients and is associated with a variety of poor outcomes for both patients and their families. Despite this, there are few evidence-based data to guide clinical care. This was an NIH-funded, randomized, controlled trial of paroxetine, nortriptyline, and placebo. It included an 8 week acute phase and a 16 week blind extension phase. This report details the impact of depression treatment on quality of life (QoL) and disability in the acute and extension phase of this study. Secondary outcomes included relapse, tolerability, safety, and the impact of depression treatment on PD physical functioning. Patients who had improvement in depression, compared with those who did not, had significant gains in measures of QoL and disability (PDQ-8, P = 0.0001; SF-36, P = 0.0001) at 8 weeks and maintained their gains in the extension phase. Patients who were on active drug were significantly less likely to relapse in the extension phase than those on placebo (P = 0.041). Though relatively modest in size, this trial provides the first controlled data on the impact of treatment of depression on QoL and disability in PD. It suggests that successfully treating depression in PD leads to important, sustained improvements in these outcomes and that patients who improve on antidepressants are less likely to relapse than are patients who initially improve on placebo.

Depressive symptoms impacting on health-related quality of life in early Parkinson's disease: results from Chinese L-dopa exposed cohort

OBJECTIVE

To investigate the impact of depressive symptoms on health-related quality of life (HR-QOL) in a group of patients with early Parkinson's disease (PD).

METHODS

A 20-item scale, the Center for Epidemiologic Studies Depression Scale (CESD) and a 36-item questionnaire, the medical outcomes study short form (SF-36) were administered as part of baseline assessment of a clinical trial in PD, enrolling 391 early-stage, L-dopa exposed PD patients in China. We used multiple regression models to examine the relationship of depressive symptoms, measured by the CESD with HR-QOL, as measured by the SF-36. The SF-36 score of the depressed patients was compared with those non-depressed, as well.

RESULTS

A total of 146 (37.3%) patients screened positive for depression. Compared with those non-depressed, depressed patients had lower scores in all dimensions of SF-36 profile (p<0.001). Multiple regression analysis revealed that depressive symptoms, measured by CESD, increased our ability to explain the variance of SF-36 total score by 34.5%. Additionally, depressive symptom is the only variable which has the predictive value not only for total SF-36 total score, but also for each subdimension score of SF-36 profile.

CONCLUSION

Depressive symptoms are common early in the disease, having a substantial impact on patients' HR-QOL, affecting many areas other than the obvious mental health dimension of the HR-QOL profile. Our results highlight the broad importance of treating depression in this population.

Impact of pre-morbid depression on health-related quality of life in non-demented Parkinson's disease patients

The need to understand and improve health-related quality of life (Hr-QoL) in Parkinson's disease (PD) has been emphasized. In order to investigate contributions of depression that existed before the onset of typical motor symptoms ("pre-PD depression"), idiopathic non-demented non-psychotic patients with (n = 32) and without (n = 120) a history of pre-PD depression, free of relevant comorbidity, calliper-matched for age, education and disease duration were evaluated for motor and non-motor disease aspects and Hr-QoL (Parkinson's Disease Questionnaire 39, PDQ-39). History of pre-PD depression was independently associated with higher actual levels of depression and anxiety, poorer sleep quality and mental set shifting, which all contributed to poorer Hr-QoL. Mediation analysis demonstrated significant indirect effects (mediated through the effects on mood/emotion/sleep and/or cognition) of pre-PD depression on PDQ summary index and subscales, but also direct (non-mediated) effects on emotional well-being and body discomfort subscales independent of the sociodemographic, motor/non-motor disease or treatment-related characteristics. Data indicate that for a given level of motor/non-motor PD symptoms severity, history of pre-PD depression contributes to poorer Hr-QoL.

Application of depression criteria (DSM-IV) in patients with Parkinson's disease

INTRODUCTION

The aim of this study is to analyze the clinical differences between Parkinson's disease patients with major (MD) and minor depression (md) and to see how both affect the quality of life.

MATERIAL AND METHODS

118 patients diagnosed with Parkinson's disease. The mean age of onset was 60.4+/-11.2 years with a mean duration of 8.5+/-6.2 years. Depression was diagnosed according to DSM-IV-TR criteria. Scores on the Hamilton depression inventory, MMSE, PDQ-39, NPI-10, UPDRS III, and UPDRS IV were recorded.

RESULTS

Twenty-one patients (17.8%) met the criteria of major depression (MD) and 33 (28.0%) those of minor depression (md). The scores on the PDQ-39 and NPI-10 of patients with MD were higher than in patients with md, and control group. The MMSE scores were lower in patients with MD. In 52.2% of the patients with MD, the diagnosis of depression was made prior to that of PD, this occurred only in 24.2% of the patients with md (p<0.001). The presence of anhedonia was related to cognitive impairment and the presence of neuropsychiatric symptoms.

DISCUSSION

MD is probably a part of the disease process of PD; it is associated with cognitive impairment and may precede motor symptoms.

Major depression and health-related quality of life in Parkinson's disease

Depression is a common psychiatric condition in Parkinson's disease (PD), yet the burden of depression on health-related quality of life (HRQL) has not been clearly delineated in this patient population.

OBJECTIVE

To evaluate the impact of depression and life stress on HRQL in the Canadian community dwelling population with PD.

METHODS

A total of 259 respondents from the Canadian Community Health Survey (CCHS 1.1) with self-reported PD were interviewed. Measures included Health Utilities Index Mark 3 (HUI3), Composite International Diagnostic Interview Short Form for Major Depression and a single question regarding the amount of stress in their lives most days. Adjusted HUI3 scores were compared according to depression and life stress using ANCOVA models.

RESULTS

Respondents without depression had overall HUI3 scores that were 0.29 units higher than respondents with depression [adjusted mean (95% CI) 0.49 (0.39-0.59) vs. 0.20 (0.03-0.37)]. The difference in overall HUI3 scores between respondents who reported high levels of stress as those who did not was 0.19 [adjusted mean (95% CI) 0.42 (0.29-0.55) vs. 0.23 (0.10-0.36)].

CONCLUSIONS

Substantial impact of depression and life stress, two modifiable factors, on HRQL is seen in PD. HRQL may be improved by clinical management of these nonmotor symptoms in PD.

Neuropsychiatric aspects of treated Wilson's disease

The objective of the current cross-sectional study was to use standardized psychiatric interviews (the Structured Clinical Interview for DSM-IV Axis I Disorders and the Neuropsychiatric Inventory; NPI) in order to better characterize psychiatric symptoms in 50 consecutive, treated and clinically stable patients with Wilson's disease (WD). Nine patients (18%) had one, 7 patients (14%) had two, and 20 (40%) had >or= 3 neuropsychiatric symptoms present. The most often endosed symptoms were anxiety (62%), depression (36%), irritability (26%), as well as disinhibition and apathy (24% each). Twenty two patients (44%) had a score >or= 4 on at least one of the NPI items: again, most frequently anxiety (17 patients; 34%), depression (13 patients; 26%) and apathy (9 patients; 18%). Therefore, even among stable, long-term treated patients with WD approximately 70% experienced psychiatric symptoms.

Increased vulnerability to 6-hydroxydopamine lesion and reduced development of dyskinesias in mice lacking CB1 cannabinoid receptors

Motor impairment, dopamine (DA) neuronal activity and proenkephalin (PENK) gene expression in the caudate-putamen (CPu) were measured in 6-OHDA-lesioned and treated (L-DOPA+benserazide) CB1 KO and WT mice. A lesion induced by 6-OHDA produced more severe motor deterioration in CB1 KO mice accompanied by more loss of DA neurons and increased PENK gene expression in the CPu. Oxidative/nitrosative and neuroinflammatory parameters were estimated in the CPu and cingulate cortex (Cg). CB1 KO mice exhibited higher MDA levels and iNOS protein expression in the CPu and Cg compared to WT mice. Treatment with L-DOPA+benserazide (12 weeks) resulted in less severe dyskinesias in CB1 KO than in WT mice. The results revealed that the lack of cannabinoid CB1 receptors increased the severity of motor impairment and DA lesion, and reduced L-DOPA-induced dyskinesias. These results suggest that activation of CB1 receptors offers neuroprotection against dopaminergic lesion and the development of L-DOPA-induced dyskinesias.

A controlled trial of antidepressants in patients with Parkinson disease and depression

BACKGROUND

Parkinson disease (PD) is a common neurodegenerative disease affecting up to 1 million individuals in the United States. Depression affects up to 50% of these patients and is associated with a variety of poor outcomes for patients and their families. Despite this, there are few evidence-based data to guide clinical care.

METHODS

An NIH-funded, randomized, controlled trial of paroxetine CR, nortriptyline, and placebo in 52 patients with PD and depression. The primary outcomes were the change in the Hamilton Depression Rating Scale (HAM-D) and the percentage of depression responders at 8 weeks.

RESULTS

Nortriptyline was superior to placebo for the change in HAM-D (p < 0.002); paroxetine CR was not. There was a trend for superiority of nortriptyline over paroxetine CR at 8 weeks (p < 0.079). Response rates favored nortriptyline (p = 0.024): nortriptyline 53%, paroxetine CR 11%, placebo 24%. In planned contrasts of response rates, nortriptyline was superior to paroxetine CR (p = 0.034). Nortriptyline was also superior to placebo in many of the secondary outcomes, including sleep, anxiety, and social functioning, while paroxetine CR was not. Both active drug treatments were well tolerated.

CONCLUSIONS

Though relatively modest in size, this is the largest placebo-controlled trial done to date in patients with Parkinson disease (PD) and depression. Nortriptyline was efficacious in the treatment of depression and paroxetine CR was not. When compared directly, nortriptyline produced significantly more responders than did paroxetine CR. The trial suggests that depression in patients with PD is responsive to treatment and raises questions about the relative efficacy of dual reuptake inhibitors and selective serotonin reuptake inhibitors.

Nonmotor manifestations of Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disease after Alzheimer's disease. Traditionally, attention has focused on the motor symptomatology of PD, but it is now appreciated that the nonmotor symptoms affecting neuropsychiatric, sleep, autonomic, and sensory domains occur in up to 88% of PD patients and can be an important source of disability. Nonmotor manifestations of PD play a significant role in the impairment of disease-related quality of life. The cause of nonmotor manifestations of PD is multifactorial, but to a large extent, these manifestations are related to the nature of the neurodegenerative process and the widespread nondopaminergic neuropathological changes associated with the disease. Recognition of nonmotor disability is essential not only for ascertaining the functional status of patients but also for better appreciating the nature of the neurodegenerative process in PD. In addition, a number of nonmotor manifestations can precede the onset of motor symptoms in PD and can be used as screening tools allowing for early disease identification and for trials of possible disease-modifying interventions. This article reviews depression, sleep, and autonomic dysfunction in PD.

Distribution of motor impairment influences quality of life in Parkinson's disease

We evaluated the relationship between upper extremity (UE) and lower extremity (LE) motor impairments in Parkinson's disease (PD) to overall disability and quality of life (QoL) measures. A total of 639 patients who were diagnosed with idiopathic PD were administered the Unified Parkinson's Disease Rating Scale (UPDRS), QoL, activities of daily living (ADL), and behavioral scales. Composite UE and LE scores from the motor section of the UPDRS were correlated with ADL, QoL, and behavioral measurement scores while controlling for disease duration. Patients with greater UE and LE motor impairments had lower QoL scores. However, LE impairments had a greater influence than UE impairments across all QoL measures.

Impact of newer pharmacological treatments on quality of life in patients with Parkinson's disease

Parkinson's disease is a common progressive neurodegenerative condition with multiple motor and nonmotor features contributing to impairment of health-related quality of life (HR-QOL). Pharmacological treatments have been directed primarily at dopamine replacement with levodopa and agents to improve its bioavailability, including DOPA decarboxylase inhibitors, catechol-O-methyltransferase (COMT) inhibitors and monoamine oxidase B (MAO-B) inhibitors, as well as synthetic dopamine agonists. These treatments to restore motor function are often very successful in early Parkinson's disease, with objective improvement and concomitant improvement in subjective HR-QOL scores. However, as the disease progresses, motor complications and nonmotor symptoms predominate and are often refractory to therapeutic interventions. Antiparkinsonian medications have been shown to improve motor severity and motor complications of advancing disease, and there is increasing evidence that this can be translated into subjective improvement of HR-QOL from a patient's point of view. However, the degree of improvement is less marked on HR-QOL scores than on motor scores, and some studies do not show improvement of HR-QOL in parallel to motor improvements. A number of explanations are possible, including limitations of the scales used, trial designs and lack of clinical improvement from the patients' point of view. This review concentrates on clinical trials with an index of HR-QOL as an outcome measure, with particular emphasis on well designed, randomized, double-blind, placebo-controlled or active comparator-controlled methodology. Drugs that have been more recently added to the armamentarium of Parkinson's disease, including the oral (pramipexole, ropinirole and piribedil) and transdermal (rotigotine) non-ergotamine-derived dopamine agonists, the novel MAO-B inhibitor rasagiline and the COMT inhibitors tolcapone and entacapone, were included. The effect of each of these agents on overall HR-QOL and depression, a factor that has been shown to significantly contribute to HR-QOL in several multivariate analyses, is discussed.Overall, the literature search revealed 14 double-blind, placebo- or active comparator-controlled trials with an index of HR-QOL as an outcome measure. Entacapone resulted in HR-QOL improvement in nonfluctuating patients (one study) but not clearly in those with motor fluctuations (two studies). Tolcapone was only tested in patients with motor fluctuations and resulted in significant improvement in two of four studies using HR-QOL as an outcome measure. Rasagiline improved HR-QOL as monotherapy in early Parkinson's disease (one study), but not clearly in more advanced disease (one study). Rotigotine improved HR-QOL in both early Parkinson's disease (one study) and more advanced disease with motor fluctuations (one study). The impact of ropinirole and pramipexole on HR-QOL as monotherapy in early Parkinson's disease versus placebo has not been assessed, but both agents have resulted in improved HR-QOL in patients with motor fluctuations (ropinirole one study, pramipexole one study). The evidence for antidepressant efficacy of antiparkinsonian medications is limited.

A comprehensive model of health-related quality of life in Parkinson's disease

BACKGROUND

Insight in how impairments and disabilities related to Parkinson's disease (PD) influence health-related quality of life (HRQoL) is required to review adequacy of current management strategies.

METHODS

The Scales for Outcomes in Parkinson's disease (SCOPA) evaluation was used to assess impairments and disabilities. HRQoL was assessed with the EuroQol-5D Visual Analogue Scale. 378 patients with PD who participated in the SCOPA/PROPARK cohort were assessed while on their usual treatment. Multiple linear regression analysis and structural equation modelling were used to construct a model of factors that influence HRQoL.

RESULTS

A model with good fit was constructed that identified various impairments and disabilities as important contributors to HRQoL in PD. Of the disabilities, psychosocial well-being had a larger impact on HRQoL than physical functioning. Of the impairments, depression had the largest contribution to HRQoL, followed by axial motor symptoms, gastrointestinal symptoms, and urinary symptoms. In addition, pain, psychiatric and motor complications, and daytime sleepiness had small but significant influences on HRQoL.

CONCLUSION

Multiple factors, including disabilities, nonmotor symptoms and axial motor symptoms, affect HRQoL in patients with PD. In patients who are on symptomatic treatment aiming to alleviate mainly motor symptoms, there is a large impact on HRQoL of nonmotor and nondopaminergic symptoms. Research is warranted to develop and evaluate management strategies for the aspects that currently impact on HRQoL as psychosocial well-being, depressive symptoms, axial motor symptoms, gastrointestinal symptoms, and urinary symptoms. These findings call for a multidisciplinary approach in the care of these features.

Dystrophic serotonergic axons in neurodegenerative diseases

Neurodegenerative diseases such as Parkinson's disease (PD), frontal lobe dementia (FLD) and diffuse Lewy-body dementia (DLBD) have diverse neuropathologic features. Here we report that serotonin fibers are dystrophic in the brains of individuals with these three diseases. In neuropathologically normal (control) brains (n=3), serotonin axons immunoreactive (IR) with antibodies against the serotonin transporter (5-HTT) protein were widely distributed in cortex (entorhinal and dorsolateral prefrontal), hippocampus and rostral brainstem. 5-HTT-IR fibers-of-passage appeared thick, smooth, and unbranched in medial forebrain bundle, medial lemniscus and cortex white matter. The terminal branches were fine, highly branched and varicose in substantia nigra, hippocampus and cortical gray matter. In the diseased brains, however, 5-HTT-IR fibers in the forebrain were reduced in number and were frequently bulbous, splayed, tightly clustered and enlarged. Morphometric analysis revealed significant differences in the size distribution of the 5-HTT-IR profiles in dorsolateral prefrontal area between neurodegenerative diseases and controls. Our observations provide direct morphologic evidence for degeneration of human serotonergic axons in the brains of patients with neurodegenerative diseases despite the limited size (n=3 slices for each region (3) from each brain (4), total slices was n=36) and the lack of extensive clinical characterization of the analyzed cohort. This is the first report of dystrophic 5-HTT-IR axons in postmortem human tissue.

Is quality of life in non-demented Parkinson's disease patients related to cognitive performance? A clinic-based cross-sectional study

Whilst the association between dementia and poorer health-related quality of life (Hr-QoL) in Parkinson's disease (PD) has been well established, we aimed to explore the relationship between cognitive performance and Hr-QoL in PD without dementia. Consecutive PD patients (n = 124, 54% men, age 60.4 +/- 10.3 years) judged as non-demented based on DSM-IV criteria and Mini Mental State Examination, free of other neurodegenerative diseases or psychotic difficulties and antipsychotic/antidepressive/anxyolitic treatment were assessed in a battery of neuropsychological tests. We used Parkinson's disease questionnaire (PDQ-39) to asses Hr-QoL and Beck's Depression Inventory (BDI) to quantify depression. In the univariate analysis, better performance in each of the tests evaluating visual attention/memory or visuospatial and executive functions was associated with better Hr-QoL. In multivariate analysis [adjustment for BDI score, PD severity and duration, l-dopa dose, age, sex, education, employment status and early PD onset (<50 years of age)] in which these tests were either represented by a common variable identified in a principal components analysis or were considered individually, better cognitive performance was independently associated with better Hr-QoL. The association was conditional on the level of depression, i.e., apparent only in patients with low(er) BDI scores. Cognitive performance appears associated with Hr-QoL even in non-demented PD patients.

Depressive und Angststörungen bei somatischen Krankheiten

Depressiv-ängstliche Störungen sind bei den unterschiedlichen somatischen Erkrankungen häufig. Sie sind nicht nur als Reaktion auf die Situation der Erkrankung zu verstehen, sondern in ein komplexes Bedingungsgefüge eingebettet. Sie sind besonders häufig bei Erkrankungen, die das Zentralnervensystem oder endokrine Regulationssysteme direkt betreffen. Es besteht ein enger Zusammenhang zur Chronizität, Schwere und Prognose der Erkrankung. Eigenständige Effekte von diversen pharmakologischen Substanzgruppen sind wahrscheinlich.

Anxiety and depression: main determinants of health-related quality of life in Brazilian patients with Parkinson's disease

Determinants of health-related quality of life (HRQoL) were assessed in 115 Brazilian patients (56.5% males; mean age 62.5 years) with Parkinson's disease (PD). Hoehn and Yahr (H&Y) staging, Scales for Outcomes in Parkinson's Disease-Motor Scale (SCOPA-MS), Cumulative Illness Rating Scale-Geriatrics, Hospital Anxiety and Depression Scale (HADS), Parkinson's Disease Questionnaire (PDQ-39), and SCOPA-Psychosocial Questionnaire (SCOPA-PS) were applied. Median H&Y was 3 and the SCOPA-MS score was 25.6+/-13.1. The proportion of patients who scored > or =11 points in the HADS-Depression and HADS-Anxiety subscales were 47% and 30.4%, respectively. In the multivariate model, HADS-Anxiety or HADS-Depression (p<0.0001), disability (SCOPA-MS II) (p=0.0001) and comorbidity (p=0.0005) were independently associated to PDQ-39 and SCOPA-PS. Mood disturbances were the main determinants of HRQoL.

Depression and apathy in Parkinson’s disease

This article provides an update on depression and apathy in Parkinson's disease (PD), both of which are common but often misunderstood. The diagnosis of depression in PD can be challenging and we still do not have solid evidence on which to base our treatment decisions. Apathy is most commonly seen in the setting of dementia or depression but emerging evidence suggests that it may be a core feature of PD. There are conflicting reports about the effects of deep brain stimulation (DBS) on mood and apathy, but studies suggest that at least some patients may develop depression and apathy after the procedure. Although we are making strides toward a better understanding of depression and apathy in PD, it is clear that more research is needed about these non-motor features.

Quality of life and related concepts in Parkinson's disease: A systematic review

Several studies have investigated the quality of life (QOL) of patients with Parkinson's disease (PD). The purpose of this study was to review the conceptual and methodological quality of quality of life (QOL) studies among patients with PD and to identify factors associated with poor (HR)QOL. Computerized bibliographic databases were screened for publications from 1960 to January 2007. According to a list of predefined criteria, the methodological quality of the 61 studies, was moderate. The term 'QOL' was often used inappropriately. In fact, almost all studies in this review actually assessed health status (HS) instead of QOL. The functioning of patients with PD on physical, social, and emotional domains is affected by PD. Their HS seems to be lower when compared to healthy persons or patients with other chronic diseases. HS studies augment the insight in self-perceived functioning. Therefore, HS is conceived as a valuable construct. However, QOL is also an important factor in health care. Attention towards QOL is needed in order to draw valid conclusions regarding a person's subjective experience of well-being in a broad sense. In order to accomplish this, future studies should apply the QOL concept with more rigor, should use an adequate operational definition, and should employ sound measures.