Depression in Parkinson disease--epidemiology, mechanisms and management

[Coexistent depressive and anxiety disorders in neurological diseases: from a perspective of multimorbidity]

The high rate of coexistent emotional disorders in neurological diseases is challenging. As a rule this coexistence comprises a more dramatic subjective suffering, reduced psychological coping, possible negative interferences with somatic treatments and rehabilitation, an impaired quality of life and higher grades of psychosocial disability. It may also lead to an overall increased risk of somatic morbidity and even mortality in the further course of illness. The complex interrelations may be favorably integrated within a biopsychosocial model. Psychological and psychosocial stressors can be appreciated on their own discrete levels but have to be reflected in their neurobiological correlates. Both neurological and emotional disorders frequently share decisive pathogenetic mechanisms, i.e. the underlying process of neurological disease may contribute to major affective problems also in a somatopsychic direction. From a perspective of multimorbidity the prevalence and clinical relevance of coexistent depressive and anxiety disorders, common pathogenetic mechanisms and implications for treatment will be described for stroke and Parkinson's disease, as selected neurological disorders.

Paroxetine ameliorates lipopolysaccharide-induced microglia activation via differential regulation of MAPK signaling

BACKGROUND

Paroxetine, a selective serotonin reuptake inhibitor for counteracting depression, has been recently suggested as having a role in prevention of dopaminergic neuronal degeneration in substantia nigra, a hallmark of Parkinson's disease (PD). The pathogenesis of this type of neurological disorders often involves the activation of microglia and associated inflammatory processes. Thus in this study we aimed to understand the role of paroxetine in microglia activation and to elucidate the underlying mechanism(s).

METHODS

BV2 and primary microglial cells were pretreated with paroxetine and stimulated with lipopolysaccharide (LPS). Cells were assessed for the responses of pro-inflammatory mediator and cytokines, and the related signaling pathways were evaluated and analyzed in BV2 cells.

RESULTS

Paroxetine significantly inhibited LPS-induced production of nitric oxide (NO) and pro-inflammatory cytokines such as TNF-α and IL-1β. Further analysis showed inducible nitric oxide synthase (iNOS) and mRNA expression of TNF-α and IL-1β were attenuated by paroxetine pretreatment. Analyses in signaling pathways demonstrated that paroxetine led to suppression of LPS-induced JNK1/2 activation and baseline ERK1/2 activity, but had little effect on the activation of p38 and p65/NF-κB. Interference with specific inhibitors revealed that paroxetine-mediated suppression of NO production was via JNK1/2 pathway while the cytokine suppression was via both JNK1/2 and ERK1/2 pathways. Furthermore, conditioned media culture showed that paroxetine suppressed the microglia-mediated neurotoxicity.

CONCLUSIONS

Paroxetine inhibits LPS-stimulated microglia activation through collective regulation of JNK1/2 and ERK1/2 signaling. Our results indicate a potential role of paroxetine in neuroprotection via its anti-neuroinflammatory effect besides targeting for depression.

Effects of the Lee Silverman Voice Treatment (LSVT® LOUD) on hypomimia in Parkinson's disease

Given associations between facial movement and voice, the potential of the Lee Silverman Voice Treatment (LSVT) to alleviate decreased facial expressivity, termed hypomimia, in Parkinson's disease (PD) was examined. Fifty-six participants--16 PD participants who underwent LSVT, 12 PD participants who underwent articulation treatment (ARTIC), 17 untreated PD participants, and 11 controls without PD--produced monologues about happy emotional experiences at pre- and post-treatment timepoints ("T1" and "T2," respectively), 1 month apart. The groups of LSVT, ARTIC, and untreated PD participants were matched on demographic and health status variables. The frequency and variability of facial expressions (Frequency and Variability) observable on 1-min monologue videorecordings were measured using the Facial Action Coding System (FACS). At T1, the Frequency and Variability of participants with PD were significantly lower than those of controls. Frequency and Variability increases of LSVT participants from T1 to T2 were significantly greater than those of ARTIC or untreated participants. Whereas the Frequency and Variability of ARTIC participants at T2 were significantly lower than those of controls, LSVT participants did not significantly differ from controls on these variables at T2. The implications of these findings, which suggest that LSVT reduces parkinsonian hypomimia, for PD-related psychosocial problems are considered.

Loss of dopaminergic nigrostriatal neurons accounts for the motivational and affective deficits in Parkinson's disease

Parkinson's disease (PD) involves the degeneration of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNc) that is thought to cause the classical motor symptoms of this disease. However, motivational and affective impairments are also often observed in PD patients. These are usually attributed to a psychological reaction to the general motor impairment and to a loss of some of the neurons within the ventral tegmental area (VTA). We induced selective lesions of the VTA and SNc DA neurons that did not provoke motor deficits, and showed that bilateral dopamine loss within the SNc, but not within the VTA, induces motivational deficits and affective impairments that mimicked the symptoms of PD patients. Thus, motivational and affective deficits are a core impairment of PD, as they stem from the loss of the major group of neurons that degenerates in this disease (DA SNc neurons) and are independent of motor deficits.

Anxiety and depression in Parkinson's disease

OPINION STATEMENT

Anxiety and depression, while very common problems in Parkinson's disease (PD), have not been subject to adequate treatment trials. While a handful of double blind placebo-controlled trials of depression have been published, only a small number of subjects have been enrolled in most of these. There have been no adequate treatment trials of anxiety. Thus, most practitioners base their treatments on what has been published in the general population and their own personal experience. The data suggest that depression is probably treatable in some cases, but there are no data to support any drug treatment of anxiety. Much of the rationale for treating these disorders is based primarily on side effect profiles rather than efficacy and is almost entirely based on anecdotal experience. Although we lack convincing data, we do believe in the pharmacologic treatment of depression and anxiety and choose medications based on side effect profiles, some of which may be useful. We favor the selective serotonin reuptake inhibitors (SSRIs) in general for both depression and anxiety because of their relative freedom from side effects but will often choose mirtazapine if insomnia or weight loss is a problem, clonazepam for anxiety without depression if an SSRI is insufficient or if REM sleep behavior disorder is a problem, or a tricyclic antidepressant if drooling is troubling and the patient is not demented. Alternatively, we use the serotonin and noradrenaline reuptake inhibitor venlafaxine in those who do not tolerate an SSRI. SSRIs cannot be used for anxiety on an as needed basis, whereas short-acting benzodiazepines may be useful for this purpose. Psychosocial treatments of both depression and anxiety have also been under-studied, with probable benefits and a benign adverse effect profile.

Parkinson's disease and risk of mortality: meta-analysis and systematic review

To evaluate the existing prospective observational studies on the morality risk among Parkinson's disease (PD) patients and determine the overall risk ratio (RR) of mortality by conducting a meta-analysis and systematic review. Original articles published in English were searched in PubMed and Embase databases prior to March 2013. Only prospective observational studies providing adjusted risk estimates related to PD and future mortality were considered eligible. Pooled adjusted RR and 95% confidence interval (CI) were computed either by fixed-effects models or by random-effects models. Eight studies with 72,833 participants were identified and analysed. In the pooled analyses, patients with PD had a greater risk of all-cause mortality (RR = 2.22; 95% CI: 1.78-2.77). Subgroup analyses based on the design, gender, follow-up duration and sample size showed that a consistent positive association between PD and the mortality risk in each subgroup. However, no statistical significance was found for the baseline age <65 years (RR = 1.42; 95% CI: 0.72-2.77). PD patients with dementia had particularly high mortality risks (RR = 3.78; 95% CI: 2.06-6.92). This meta-analysis indicated that among patients with PD, the all-cause mortality increased by 2.22-fold compared with the general population. PD patients with dementia particularly had higher risks of mortality.

Depressive symptoms in Parkinson's disease are related to reduced [123I]FP-CIT binding in the caudate nucleus

BACKGROUND

Depression is a common neuropsychiatric symptom in Parkinson's disease (PD). In previous research, PD-related depression was associated with striatal dopaminergic deficits, presumably due to degeneration of brainstem dopaminergic projections. Segregated areas of the striatum are crucially involved in various parallelly arranged cortical-striatal-thalamocortical circuits and serve functions in, among others, motor control or emotion. This suggests regional specificity of dopaminergic deficits in the striatum in motor and depressive symptoms in PD.

METHODS

In this cross-sectional retrospective study, we correlated severity scores of depressive and motor symptoms in 100 non-demented PD patients (median Hoehn & Yahr stage: 2) with dopamine loss in specific regions of the striatum as measured by [(123)I]FP-CIT SPECT tracer binding to the dopamine transporter (DaT).

RESULTS

Depressive symptoms were related to lower DaT binding in the right caudate nucleus, while motor symptoms were associated with decreased DaT binding in the right putamen. This double dissociation was most pronounced in early-stage PD patients.

CONCLUSIONS

These results suggest that depressive symptoms in PD are associated with dopamine loss in the caudate nucleus, possibly related to degeneration of dopaminergic projections from the ventral tegmental area, while motor symptoms are associated with low dopamine signalling to the putamen and loss of nigrostriatal projections. This is consistent with the neuroanatomy of partially segregated cortical-striatal-thalamocortical circuits and supports the role of dysfunctional associative and motivational circuits in PD-related depression.

Prevalence of neurological conditions across the continuum of care based on interRAI assessments

Background

Although multiple studies have estimated the prevalence of neurological conditions in the general Canadian population, limited research exists regarding the proportion affected with these conditions in non-acute health care settings in Canada. Data from standardized clinical assessments based on the interRAI suite of instruments were used to estimate the prevalence of eight neurological conditions across the continuum of care including Alzheimer’s disease, Parkinson’s disease, epilepsy, traumatic brain injury, multiple sclerosis, cerebral palsy, Huntington’s disease, and amyotrophic lateral sclerosis.

Methods

Cohorts of individuals receiving care in nursing homes (N=103,820), home care (N=91,021), complex continuing care (N=10,581), and psychiatric hospitals (N=23,119) in Canada were drawn based on their most recent interRAI assessment within each sector for a six-month period in 2010. These data were linked to the Discharge Abstract Database and National Ambulatory Care Reporting System data sets to develop five different case definition scenarios for estimating prevalence.

Results

The conditions with the highest estimated prevalences in these care settings in Canada were Alzheimer’s disease and related dementias, Parkinson’s disease, epilepsy, and traumatic brain injury. However, there were notable cross-sector differences in the prevalence of each condition, and regional variations. Prevalence estimates based on acute hospital administrative data alone were substantially lower for all conditions evaluated.

Conclusions

The proportion of persons with neurological conditions in non-acute health care settings in Canada is substantially higher than is generally reported for the general population. It is essential for these care settings to have the expertise and resources to respond effectively to the strengths, preferences, and needs of the growing population of persons with neurological conditions. The use of hospital or emergency department records alone is likely to substantially underestimate the true prevalence of neurological conditions across the continuum of care. However, interRAI assessment records provide a helpful source of information for obtaining these estimates in nursing home, home care, and mental health settings.

Altered spontaneous brain activity in patients with Parkinson's disease accompanied by depressive symptoms, as revealed by regional homogeneity and functional connectivity in the prefrontal-limbic system

As patients with Parkinson’s disease (PD) are at high risk for comorbid depression, it is hypothesized that these two diseases are sharing common pathogenic pathways. Using regional homogeneity (ReHo) and functional connectivity approaches, we characterized human regional brain activity at resting state to examine specific brain networks in patients with PD and those with PD and depression (PDD). This study comprised 41 PD human patients and 25 normal human subjects. The patients completed the Hamilton Depression Rating Scale and were further divided into two groups: patients with depressive symptoms and non-depressed PD patients (nD-PD). Compared with the non-depressed patients, those with depressive symptoms exhibited significantly increased regional activity in the left middle frontal gyrus and right inferior frontal gyrus, and decreased ReHo in the left amygdala and bilateral lingual gyrus. Brain network connectivity analysis revealed decreased functional connectivity within the prefrontal-limbic system and increased functional connectivity in the prefrontal cortex and lingual gyrus in PDD compared with the nD-PD group. In summary, the findings showed regional brain activity alterations and disruption of the mood regulation network in PDD patients. The pathogenesis of PDD may be attributed to abnormal neural activity in multiple brain regions.

Treatment of cognitive, psychiatric, and affective disorders associated with Parkinson's disease

Neuropsychiatric symptoms are common in Parkinson's disease (PD) and add significantly to the burden of disease. These symptoms are most commonly part of the disease spectrum owing to pathological changes within relevant brain regions. Neuropsychiatric problems include disorders of cognition, ranging from mild cognitive impairment to dementia, psychotic symptoms, including, most commonly, well-formed visual hallucinations and paranoid delusions, and mood disorders, such as depression and anxiety. The other common cause of neuropsychiatric problem is secondary to use of dopaminergic drugs. Some PD patients may develop behavioral disorders, including impulse control disorders (ICDs) and addictive symptoms. Psychosis can be due to a mixture of underlying pathology, with triggering or worsening of symptoms with changes to PD medications. Currently, management of these disorders primarily uses therapies developed for general psychiatry and cognitive neurology, rather than specifically for PD. However, significant adverse effects, such as worsening of the motor symptoms of PD, can limit use of some drug therapies. Identification of drug-induced symptoms, such as ICDs, enables withdrawal of the offending drug as the principal management strategy. Research is ongoing in an effort to develop more specific therapies for PD-related neuropsychiatric symptoms.

Deep brain stimulation improves survival in severe Parkinson's disease

OBJECTIVES

Levodopa and other dopaminergic treatments have not had the expected effect on survival in Parkinson's disease (PD). Bilateral subthalamic nucleus deep brain stimulation (STN-DBS) has been shown to improve motor function, motor fluctuations, health-related quality of life, and to reduce medication usage and drug-induced dyskinesia in patients with severe PD refractory to medical therapy. Little however, has been described on the impact of STN-DBS on the survival of these patients. We aim in this study to examine the impact of STN-DBS on the survival of patients with severe PD.

METHODS

Patients who were eligible for STN-DBS were given the choice of undergoing surgery or continuing on medical treatment. Those who exercised patient choice and preferred to continue with medical treatment formed a control population. All eligible patients seen in a 10-year period are included in this study. Our primary outcome measure is a difference in mortality between the two groups with a secondary measure of admission rates to residential (nursing home) care.

RESULTS

106 patients underwent STN-DBS, and 41 patients exercised patient choice and declined the procedure. The two groups were matched for age, gender, ethnicity, duration of disease, rates of pre-existing depression and Levodopa equivalent doses of anti-Parkinson's medications taken. Patients undergoing STN-DBS had significantly longer survival and were significantly less likely to be admitted to a residential care home than those managed purely medically. The statistical significance of these findings persisted after adjusting for potential confounding factors (survival: p=0.002, HR 0.29 (0.13 to 0.64) (residential care home admission: OR: 0.1 (95% CI 0.0 to 0.3; p<0.001).

INTERPRETATION

We show for the first time that there is a survival advantage of DBS surgery in advanced PD. The effect of potential bias factors is examined. The survival advantage may arise for several postulated reasons, ranging from improvement in axial functions, such as swallowing, to some as yet unrecognised benefit of reduction in dopaminergic medication. These findings are of great interest to both patients with PD and the health professionals considering the treatment options for patients with severe PD.

Clinical and pathological features of Parkinson's disease

Parkinson's disease (PD) is, after Alzheimer's disease, the second most common neurodegenerative disorder with an approximate prevalence of 0.5-1% among persons 65-69 years of age, rising to 1-3% among persons 80 years of age and older. Pathologically, PD is characterized by the loss of neurons in the substantia nigra pars compacta (SNpc), and by the presence of eosinophilic protein deposits (Lewy bodies) in this region, in other aminergic nuclei and in cortical and limbic structures. Moreover, it has now been shown that pathology also involves the peripheral nervous system. Braak and colleagues suggested a thread of pathology starting from the vagal nerve to progress to the brainstem, and eventually to limbic and neocortical brain regions. This progression of pathology may account for the clinical evolution of PD toward a composite symptomatology. However, this hypothesis has been criticized by others. In this chapter, we review the clinical features of PD (motor and nonmotor) and their pathological correlates.

Neural and behavioral substrates of subtypes of Parkinson's disease

Parkinson’s disease (PD) is a neurological disorder, associated with rigidity, bradykinesia, and resting tremor, among other motor symptoms. In addition, patients with PD also show cognitive and psychiatric dysfunction, including dementia, mild cognitive impairment (MCI), depression, hallucinations, among others. Interestingly, the occurrence of these symptoms—motor, cognitive, and psychiatric—vary among individuals, such that a subgroup of PD patients might show some of the symptoms, but another subgroup does not. This has prompted neurologists and scientists to subtype PD patients depending on the severity of symptoms they show. Neural studies have also mapped different motor, cognitive, and psychiatric symptoms in PD to different brain networks. In this review, we discuss the neural and behavioral substrates of most common subtypes of PD patients, that are related to the occurrence of: (a) resting tremor (vs. nontremor-dominant); (b) MCI; (c) dementia; (d) impulse control disorders (ICD); (e) depression; and/or (f) hallucinations. We end by discussing the relationship among subtypes of PD subgroups, and the relationship among motor, cognitive, psychiatric factors in PD.

Clinical characteristics with an impact on ADL functions of PD patients with cognitive impairment indicative of dementia

BACKGROUND

Dementia in Parkinson's disease (PD) is defined as cognitive decline severe enough to affect activities of daily living function (ADL). The aim of our exploratory study was to compare two groups of PD patients. Both groups had cognitive deficits severe enough to justify diagnosis of dementia, but they differed according to caregivers' rating on ADL dysfunction. Parameters which differed between the two groups were interpreted to affect the caregivers' perception of ADL dysfunction in PD patients with cognitive impairment indicative of Parkinson's disease dementia.

METHODOLOGY/PRINCIPAL FINDINGS

Thirty of 131 Parkinson's disease patients fulfilled the Movement Disorders Society Task Force - recommended, cognitive Level-I-criteria for dementia. According to standardized caregiver ratings, volunteers were grouped into 18 patients with (ADL-) and 12 without instrumental activities of daily living dysfunction (ADL+). Caregiver activities of daily living function ratings closely correlated with self-estimates of patients and those of physician (p<0.001). ADL- patients performed worse on tests assessing visual-construction (p<0.05) and attention (p=0.03) than ADL+ patients. Moreover, the postural instability and gait disorder subtype was more frequent in ADL- patients (p=0.009). ADL- patients tended to have more communication problems (p=0.05), more anxiety (p=0.05) and showed a tendency to be treated more often with neuroleptics (p=0.049) than ADL+.

CONCLUSIONS/SIGNIFICANCE

Results indicate that worse attention, visual-construction abilities, the postural instability and gait disorder subtype, communication problems, medication and presence of anxiety are related to activities of daily living dysfunctions in Parkinson's disease patients with cognitive decline indicative of dementia. Our data suggests that not only cognitive factors but also non-cognitive factors seem to be linked to the diagnosis of Parkinson's disease dementia associated with significant impact on instrumental activities of daily living function. Further studies with larger sample sizes are needed to verify our results.

Plasma levels of soluble tumor necrosis factor receptors are associated with cognitive performance in Parkinson's disease

Inflammatory mechanisms have been implicated in a series of neuropsychiatric conditions, including behavioral disturbances, cognitive dysfunction, and affective disorders. Accumulating evidence also strongly suggests their involvement in the pathophysiology of Parkinson's disease (PD). This study aimed to evaluate plasma levels of inflammatory biomarkers, and their association with cognitive performance and other non-motor symptoms of PD. PD patients and control individuals were subjected to various psychometric tests, including the Mini-Mental State Examination (MMSE), Frontal Assessment Battery (FAB), and Beck's Depression Inventory (BDI). Biomarker plasma levels were measured by enzyme-linked immunosorbent assay (ELISA). PD patients exhibited worse performance on MMSE and the programming task of FAB, and presented higher soluble tumor necrosis factor receptor (sTNFR) plasma levels than control individuals. Among PD patients, increased sTNFR1 and sTNFR2 concentrations were associated with poorer cognitive test scores. After multiple linear regression, sTNFR1 and education remained a significant predictor for FAB scores. Our data suggest that PD is associated with a proinflammatory profile, and sTNFRs are putative biomarkers of cognitive performance, with elevated sTNFR1 levels predicting poorer executive functioning in PD patients.

Brainstem aminergic nuclei and late-life depressive symptoms

IMPORTANCE

The neurobiologic basis of late-life depressive symptoms is not well understood.

OBJECTIVE

To test the hypothesis that neurodegeneration and neuronal density in brainstem aminergic nuclei are related to late-life depressive symptoms. DESIGN, SETTING, PARTICIPANTS, AND EXPOSURE: Longitudinal clinicopathological cohort study at residences of participants in the Chicago, Illinois, metropolitan area. Participants included 124 older persons without dementia in the Rush Memory and Aging Project who had annual evaluations for a mean (SD) of 5.7 (2.8) years, died, and underwent a postmortem neuropathological examination that provided estimates of the densities of Lewy bodies, neurofibrillary tangles, and aminergic neurons in the locus ceruleus, dorsal raphe nucleus, substantia nigra, and ventral tegmental area.

MAIN OUTCOMES AND MEASURES

The number of depressive symptoms (mean [SD], 1.61 [1.48]; range, 0-6; skewness, 0.94) on the Center for Epidemiological Studies Depression Scale averaged across annual evaluations.

RESULTS

Brainstem Lewy bodies were associated with depressive symptoms, and the association was attenuated in those taking antidepressant medication. Brainstem tangles were associated with more depressive symptoms in those without cognitive impairment but with fewer symptoms in those with mild cognitive impairment. Lower density of tyrosine hydroxylase-immunoreactive neurons in the ventral tegmental area was robustly associated with a higher level of depressive symptoms (mean [SE] estimate, -0.014 [0.003]; P < .001; 16.3% increase in adjusted R2). The association was not modified by medication use or cognitive impairment. Neither tyrosine hydroxlyase-immunoreactive neurons in the locus ceruleus nor tryptophan hydroxlyase-immunoreactive neurons in the dorsal raphe nucleus were related to depressive symptoms.

CONCLUSIONS AND RELEVANCE

The results suggest that the mesolimbic dopamine system, especially the ventral tegmental area, has an important role in late-life depressive symptoms.

Rodent models of Parkinson's disease: beyond the motor symptomatology

Parkinson's disease (PD) is classically characterized by motor symptoms; however, non-motor symptoms (NMS) are increasingly recognized as relevant in disease-state, given the associated alterations in mood (depression and anxiety) and cognition. Here, particularly in regards to NMS, we aimed to compare the motor, emotional and cognitive behavior of three animal models of PD that trigger dopaminergic (DAergic) degeneration on both brain hemispheres: (i) the 6-hydroxydopamine (6-OHDA, 8 or 6 μg) lesion model; (ii) the paraquat (PQ) induced model, and (iii) a genetic model based on α-synuclein overexpression (α-syn). 6-OHDA and α-syn vector were injected bilaterally in the substantia nigra pars compacta (SNpc) of adult male Wistar rats; as for PQ delivery, micro-osmotic pumps were implanted in the interscapular region. Motor deficits were observed in all models, with histological analysis of tyrosine hydroxylase positive cells in the SNpc revealing a significant loss of DAergic neurons in all animal models. In addition, the α-syn animal model also presented a reduction in exploratory activity, and the 6-OHDA and PQ animals displayed a significant increase in both depressive- and anxiety-like behavior. Interestingly, cognitive impairment (working memory) was only observed in the 6-OHDA model. Overall, these PD models are suitable for mimicking the motor symptoms associated to PD, with each encompassing other relevant NMS components of the disorder that may prove beneficial for further studies in PD.

Depression and impulse control disorders in Parkinson's disease: two sides of the same coin?

Depression and impulse control disorders (ICD) are two common neuropsychiatric features in Parkinson's disease (PD). Studies have revealed that both phenomena are associated with aberrations in ventral striatal dopamine signaling and concomitant dysfunction of the reward-related (limbic) cortico-striatal-thalamocortical (CSTC) circuit. Depression in PD seems associated with decreased activity in the limbic CSTC circuit, whereas ICD seem associated with increased limbic CSTC circuit activity, usually after commencing dopamine replacement therapy (DRT). Not all DRT using PD patients, however, develop symptoms of ICD, suggesting an additional underlying neurobiological susceptibility. Furthermore, the symptoms of depression and ICD frequently coincide even though they are related to seemingly contrasting limbic CSTC circuit activation states. The aim of this review is to provide an overview of the currently available literature on the neurobiology of PD-related depression and ICD and discusses possible susceptibility factors. Finally, we propose a neurobiological model that identifies ventral striatal dopaminergic denervation as a common underlying neurobiological substrate of depression and ICD and subsequent dysfunction of reward and motivation-related brain areas.

Prevalence of headache in patients with Parkinson's disease and its association with the side of motor symptom onset

We compared the lifetime prevalence and the prevalence of headache during the previous year in patients with Parkinson's disease (PD) and control subjects. We also investigated the association between the side of PD symptom onset and the side of the headache. We interviewed 98 consecutive patients with an established diagnosis of PD between December 2010 and January 2012. The control group consisted of the 98 oldest sex-matched individuals from the nationwide Brazilian headache database. PD patients showed a significantly lower prevalence (40.8%) of headache in the previous year than controls (69.4%) (adjusted OR 0.5, CI 95% 0.2-0.9, p = 0.03). PD patients also showed a lower prevalence of headache throughout life (74.5%) than controls (93.9%) (adjusted OR 0.2, CI 95% 0.1-0.6, p = 0.01). Considering only patients who presented headache during the previous year, PD patients showed a higher association with occurrence of migraine than tension-type headache compared with controls (adjusted OR 3.3, CI 95% 1.2-8.9, p = 0.02). The headache side was ipsilateral to the side of PD onset in 21 patients (84%), with a concordance of 85.7% on the left side and 81.8% on the right side (p < 0.01). The prevalence of primary headache was significantly lower in patients with PD than controls. The predominant side of headache was ipsilateral to the side of initial motor signs of PD.

Building a new life: a chaplain's theory based case study of chronic illness

This article presents the case study of spiritual care for a patient suffering from Parkinson's disease who was referred to the chaplain in an out-patient depression research program. The chaplain's interventions were informed by an application of narrative theory, and the article demonstrates how this theory enabled the chaplain to help a patient develop new coping strategies for dealing with chronic disease. Using narrative theory, the chaplain assisted the patient to develop a new sense of identity as a spiritual, contingent self as the disease eroded his physical self and former life. The article includes a description of a patient's spiritual needs, chaplain interventions, and an outcomes measure of those interventions. The author argues that narrative theory provides chaplains with a language to identify and craft the unique intervention that spiritual care has in the life trajectory of this Parkinson's patient and other patients dealing with chronic illnesses.

Depressive syndromes in neurological disorders

Depressive syndromes represent a common and often characteristic feature in a number of neurological disorders. One prominent example is the development of post-stroke depression, which can be observed in more than one-third of stroke survivors in the aftermath of an ischemic stroke. Thus, post-stroke depression represents one of the most prevalent, disabling, and potentially devastating psychiatric post-stroke complications. On the other hand, depressive syndromes may also be considered as a risk factor for certain neurological disorders, as recently revealed by a meta-analysis of prospective cohort studies, which demonstrated an increased risk for ischemic events in depressed patients. Moreover, depressive syndromes represent common comorbidities in a number of other neurological disorders such as Parkinson's disease, multiple sclerosis, or epilepsy, in which depression has a strong impact on both quality of life and outcome of the primary neurological disorder.

Comparative efficacy and acceptability of antidepressants in Parkinson's disease: a network meta-analysis

Background

Depression is a common non-motor symptom in patients with Parkinson's disease (PD). There are many kinds of antidepressants being used, such as tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), and Dopamine agonists which are suggested as alternative antidepressants for the treatment of depression in PD. Which one should we choose first? Literatures have shown inconsistent results.

Methods

We conducted a network meta-analysis of randomized controlled trials to compare the efficacy and acceptability of therapeutic methods for the treatment of depression in Parkinson's disease.

Results

We used the odds ratios (OR) as effect size firstly and the results indicated no statistical significance between each compared intervention. Then we used the logarithm of the individual odds ratios as effect size. With efficacy of TCAs as the standard of comparison, the degree of incoherence (a measure of how closely the entire network fits together) was small (ω =  4.824827e-05). The logor were: SSRIs −0.69 (95% CI −1.28– −0.10); Pramipexole −0.73 (−1.71– −0.26); Pergolide −1.97 (−3.67– 0.27); SNRIs −0.86 (−1.86– 0.15); Placebo −1.24 (−1.99– −0.50). With Placebo as the standard of comparison, the logor were: TCAs 1.24 (0.50– 1.99); SSRIs 0.55 (−0.03– 1.13); Pramipexole 0.51 (−0.12– 1.15); Pergolide −0.73 (−2.25– 0.80); SNRIs 0.38 (−0.42– 1.19); TCAs, pramipexole, pergolide and SNRIs showed better profile of acceptability, leading to significant fewer discontinuations than that of SSRIs.

Conclusions

There is insufficient evidence to support antidepressant efficacy for SSRIs, pramipexole, pergolide and SNRIs. TCAs might be the best choice when starting antidepressant treatment in patients of Parkinson's disease because it has the most favorable balance between benefits and acceptability, followed by pramipexole and SNRIs, SSRIs might be the last choice.

Nociceptin/orphanin FQ receptor antagonists as innovative antidepressant drugs

Nociceptin/orphanin FQ (N/OFQ) and its receptor (NOP) were identified in the mid 90s as a novel peptidergic system structurally related to opioids. A growing body of preclinical evidence suggests that blockade of NOP receptors evokes antidepressant-like actions. These have been explored using a range of compounds (peptide and non peptide antagonists), across different species (rat and mouse) and assays (behavioral despair and chronic mild stress) suggesting a robust and consistent antidepressant-like effect. Moreover, rats and mice knockout for the NOP receptor gene display an antidepressant-like phenotype in behavioral despair assays. Electrophysiological, immunohistochemical and neurochemical studies point to an important role played by monoaminergic systems, particularly 5-HTergic, in mediating the antidepressant-like properties of NOP antagonists. However other putative mechanisms of action, including modulation of the CRF system, circadian rhythm and a possible neuroendocrine-immune control might be involved. A close relationship between the N/OFQ-NOP receptor system and stress responses is well described in the literature. Stressful situations also alter endocrine, behavioral and neurochemical parameters in rats and chronic administration of a NOP antagonist restored these alterations. Interestingly, clinical findings showed that plasma N/OFQ levels were significantly altered in major and post-partum depression, and bipolar disease patients. Collectively, data in the literature support the notion that blockade of NOP receptor signaling could be a novel and interesting strategy for the development of innovative antidepressants.

Pesticide-induced gene mutations and Parkinson disease risk: a meta-analysis

AIMS

Increasing scientific evidence suggests that pesticide-induced gene mutations may contribute to increasing susceptibility to Parkinson disease (PD), but many existing studies have yielded inconclusive results. This meta-analysis aims at assessing the exact roles of pesticide-induced gene mutations in the development of PD.

METHODS

An extensive literature search for relevant studies was conducted on PubMed, Embase, Web of Science, Cochrane Library, and CBM databases from their inception through May 1st, 2013. This meta-analysis was performed using the STATA 12.0 software. The crude odds ratio with 95% confidence interval was calculated.

RESULTS

Ten case-control studies were included with a total of 1248 PD patients and 1831 healthy controls. Our meta-analysis revealed that PD patients with pesticide exposure had higher gene mutation rates than those of healthy controls. Subgroup analysis by gene type indicated that the mutation rates in the GSTP1, SLC6A3, and MDR1 genes of PD patients with pesticide exposure were higher than those of healthy controls. No publication bias was detected in this meta-analysis.

CONCLUSION

The current meta-analysis indicates that pesticide-induced gene mutations may contribute to increasing susceptibility to PD, especially in the GSTP1, SLC6A3, and MDR1 genes.

Nintendo Wii rehabilitation ("Wii-hab") provides benefits in Parkinson's disease

Parkinson's disease (PD) impairs both activities of daily living (ADLs) and motor function and has adverse effects on mood in many patients. While dopaminergic medications are quite helpful for motor and ADLs impairments in PD, complementary therapies are also important in helping patients achieve maximum benefits and quality of life. We hypothesized that the Nintendo Wii (Wii) is a useful tool in improving motor and non-motor aspects in patients with PD, given its ability to drive functional movements and interactive nature. We enrolled twenty subjects with early to mid-stage PD in an open-label within-subjects study design where each subject was evaluated at baseline and then re-evaluated after playing the Wii three times per week for four weeks. Subjects were then re-evaluated one month later after not playing the Wii for a month to see if effects carried over. Subjects demonstrated significant improvements in the primary outcome measure (Nottingham Extended Activities of Daily Living Test (NEADL)), quality of life (PDQ-39) and motor function (UPDRS), and a trend toward improved mood (HAM-D) after four weeks of Wii therapy. Follow-up assessments one month later showed continued improvement for quality of life and UPDRS scores. The results demonstrate that Wii therapy provides short-term motor, non-motor, and quality of life benefits in PD. Further studies are needed to determine if there are long-term benefits of Wii therapy in PD.

Advances in the pharmacological treatment of Parkinson's disease: targeting neurotransmitter systems

For several decades, the dopamine precursor levodopa has been the primary therapy for Parkinson's disease (PD). However, not all of the motor and non-motor features of PD can be attributed solely to dopaminergic dysfunction. Recent clinical and preclinical advances provide a basis for the identification of additional innovative therapeutic options to improve the management of the disease. Novel pharmacological strategies must be optimized for PD by: (i) targeting disturbances of the serotonergic, noradrenergic, glutamatergic, GABAergic, and cholinergic systems in addition to the dopaminergic system, and (ii) characterizing alterations in the levels of neurotransmitter receptors and transporters that are associated with the various manifestations of the disease.

Intracerebroventricular administration of lipopolysaccharide induces indoleamine-2,3-dioxygenase-dependent depression-like behaviors

BACKGROUND

Activation of the tryptophan degrading enzyme indoleamine-2,3-dioxygenase 1 (IDO1) is associated with the development of behavioral signs of depression. Systemic immune challenge induces IDO1 in both the periphery and the brain, leading to increased circulating and brain concentrations of kynurenines. However, whether IDO1 activity within the brain is necessary for the manifestation of depression-like behavior of mice following a central immune challenge remains to be elucidated.

METHODS

We investigated the role of brain IDO1 in mediating depression-like behavior of mice in response to intracerebroventricular injection of saline or lipopolysaccharide (LPS, 10 ng).

RESULTS

LPS increased the duration of immobility in the tail suspension test and decreased preference for a sucrose solution. These effects were associated with an activation of central but not peripheral IDO1, as LPS increased brain kynurenine but had no effect on plasma concentrations of kynurenine. Interestingly, genetic deletion or pharmacological inhibition of IDO1, using 1-methyl-tryptophan, abrogated the reduction in sucrose preference induced by intracerebroventricular LPS. 1-Methyl-tryptophan also blocked the LPS-induced increase in duration of immobility during the tail suspension test.

CONCLUSIONS

These data indicate that activation of brain IDO1 is sufficient to induce depression-like behaviors of mice in response to central LPS.

[Depression and neurological diseases]

In many neurological diseases a depressive syndrome is a characteristic sign of the primary disease or is an important comorbidity. Post-stroke depression, for example, is a common and relevant complication following ischemic brain infarction. Approximately 4 out of every 10 stroke patients develop depressive disorders in the course of the disease which have a disadvantageous effect on the course and the prognosis. On the other hand depression is also a risk factor for certain neurological diseases as was recently demonstrated in a meta-analysis of prospective cohort studies which revealed a much higher stroke risk for depressive patients. Furthermore, depression plays an important role in other neurological diseases with respect to the course and quality of life, such as Parkinson's disease, multiple sclerosis and epilepsy. This article gives a review of the most important epidemiological, pathophysiological and therapeutic aspects of depressive disorders as a comorbidity of neurological diseases and as a risk factor for neurological diseases.

Attenuated neural response to gamble outcomes in drug-naive patients with Parkinson's disease

Parkinson's disease results from the degeneration of dopaminergic neurons in the substantia nigra, manifesting as a spectrum of motor, cognitive and affective deficits. Parkinson's disease also affects reward processing, but disease-related deficits in reinforcement learning are thought to emerge at a slower pace than motor symptoms as the degeneration progresses from dorsal to ventral striatum. Dysfunctions in reward processing are difficult to study in Parkinson's disease as most patients have been treated with dopaminergic drugs, which sensitize reward responses in the ventral striatum, commonly resulting in impulse control disorders. To circumvent this treatment confound, we assayed the neural basis of reward processing in a group of newly diagnosed patients with Parkinson's disease that had never been treated with dopaminergic drugs. Thirteen drug-naive patients with Parkinson's disease and 12 healthy age-matched control subjects underwent whole-brain functional magnetic resonance imaging while they performed a simple two-choice gambling task resulting in stochastic and parametrically variable monetary gains and losses. In patients with Parkinson's disease, the neural response to reward outcome (as reflected by the blood oxygen level-dependent signal) was attenuated in a large group of mesolimbic and mesocortical regions, comprising the ventral putamen, ventral tegmental area, thalamus and hippocampus. Although these regions showed a linear response to reward outcome in healthy individuals, this response was either markedly reduced or undetectable in drug-naive patients with Parkinson's disease. The results show that the core regions of the meso-cortico-limbic dopaminergic system, including the ventral tegmental area, ventral striatum, and medial orbitofrontal cortex, are already significantly compromised in the early stages of the disease and that these deficits cannot be attributed to the contaminating effect of dopaminergic treatment.

The pharmacologic management of depression in Parkinson's disease

Depression in Parkinson's disease (PD) is common, and it appears to worsen the motor and cognitive progression of the disease, and limits the patient's quality of life. In this paper, we review the pharmacotherapy of depression in people with PD. We find that evidence is sparse when it comes to this patient population. There is some evidence that older tricyclic antidepressants (nortriptyline and desipramine) may be effective in this population. There is also growing evidence that newer antidepressants like paroxetine and venlafaxine may be effective. We will also review a number of other promising medication treatments. What is apparent is the need for more research identifying the most effective medications for treating depression in this population. We provide recommendations that fall in line with current evidence-based practice for managing depression in the general population. Also, we suggest that collaborative models of depression care may be a promising approach to support the identification and effective treatment of those with PD also suffering from depressive disorders.

Bright light therapy in Parkinson's disease: an overview of the background and evidence

Sleep disorders are common in Parkinson's disease (PD) and seem to be strongly associated with depression. It has been suggested that sleep disorders as well as depression are caused by a disturbed circadian rhythm. Indeed, PD patients are prone to misalignment of their circadian rhythm due to various factors, and many patients with PD display a phase advance of their circadian rhythm. Current treatment options for sleep disorders and depression in patients with PD are limited and can have serious side effects; alternative treatments are therefore badly needed. Bright light therapy (BLT) restores circadian rhythmicity effectively in mood- and sleep-disturbed patients without PD. The few studies that focused on the efficacy of BLT in patients with PD demonstrated a positive effect of BLT not only on sleep and mood but also on motor function. More research on the neurobiology and efficacy of BLT in PD is warranted.

Cognitive dysfunction and depression in Parkinson's disease: what can be learned from rodent models?

Parkinson's disease (PD) has for decades been considered a pure motor disorder and its cardinal motor symptoms have been attributed to the loss of dopaminergic (DAergic) neurons in the substantia nigra pars compacta and to nigral Lewy body pathology. However, there has more recently been a shift in the conceptualization of the disease, and its pathological features have now been recognized as involving several other areas of the brain and indeed even outside the central nervous system. There are a corresponding variety of intrinsic non-motor symptoms such as autonomic dysfunction, cognitive impairment, sleep disturbances and neuropsychiatric problems, which cannot be explained exclusively by nigral pathology. In this review, we will focus on cognitive impairment and affective symptoms in PD, and we will consider whether, and how, these deficits can best be modelled in rodent models of the disorder. As only a few of the non-motor symptoms respond to standard DA replacement therapies, the quest for a broader therapeutic approach remains a major research effort, and success in this area in particular will be strongly dependent on appropriate rodent models. In addition, better understanding of the different models, as well as the advantages and disadvantages of the available behavioural tasks, will result in better tools for evaluating new treatment strategies for PD patients suffering from these neuropsychological symptoms.

Neuroinflammation and non-motor symptoms: the dark passenger of Parkinson's disease?

Generally speaking, inflammation as a key piece to the Parkinson's disease (PD) puzzle is a relatively new concept. Acceptance of this concept has gained ground as studies by various researchers have demonstrated the potential of mitigating nigral cell death by curtailing inflammation in animal models of PD. We propose that the significance of inflammation in PD pathology may extend beyond the nigrostriatal region. In the current review, we present an argument for this based on the Braak staging and discuss how inflammation might contribute to the development of non-motor PD symptoms.

Major life events and development of major depression in Parkinson's disease patients

BACKGROUND AND PURPOSE

Non-motor symptoms including depression are important features of Parkinson's disease (PD). We aim to address the relationship between major life events and depression amongst PD patients free of depressive symptoms at baseline.

METHODS

New-onset PD patients from California were recruited in 2001-2007 and followed up for 3-4 years. The participants (n=221) were examined by neurologists and responded to comprehensive interviews that included major life events, social support, and coping measures from validated scales. Major depression was assessed using the Structured Clinical Interview for the DSM-IV depression module (SCID).

RESULTS

More than half of all patients had experienced major life events since diagnosed with PD, and 22 patients developed a major depression. The number of life events was associated with risk of depression in an exposure-dependent manner, with each additional event being associated with a 56% higher risk of depression (95% CI: 1.23-1.98). Most individual life events were associated with a two- to eight-fold higher risk of depression. Patients with low social support or coping capacities seemed to be particularly susceptible to developing depression after experiencing major life events.

CONCLUSIONS

Life events play an important role for onset of depression in patients with PD; an effect that seems to be modulated by social support and coping capacities and these factors may therefore be important to assess in order to identify patients with PD at high risk of depression and provide effective interventions.

Neuroprotective and neurotrophic actions of glucagon-like peptide-1: an emerging opportunity to treat neurodegenerative and cerebrovascular disorders

Like type-2 diabetes mellitus (T2DM), neurodegenerative disorders and stroke are an ever increasing, health, social and economic burden for developed Westernized countries. Age is an important risk factor in all of these; due to the rapidly increasing rise in the elderly population T2DM and neurodegenerative disorders, both represent a looming threat to healthcare systems. Whereas several efficacious drugs are currently available to ameliorate T2DM, effective treatments to counteract pathogenic processes of neurodegenerative disorders are lacking and represent a major scientific and pharmaceutical challenge. Epidemiological data indicate an association between T2DM and most major neurodegenerative disorders, including Alzheimer's and Parkinson's diseases. Likewise, there is an association between T2DM and stroke incidence. Studies have revealed that common pathophysiological features, including oxidative stress, insulin resistance, abnormal protein processing and cognitive decline, occur across these. Based on the presence of shared mechanisms and signalling pathways in these seemingly distinct diseases, one could hypothesize that an effective treatment for one disorder could prove beneficial in the others. Glucagon-like peptide-1 (GLP-1)-based anti-diabetic drugs have drawn particular attention as an effective new strategy to not only regulate blood glucose but also to reduce apoptotic cell death of pancreatic beta cells in T2DM. Evidence supports a neurotrophic and neuroprotective role of GLP-1 receptor (R) stimulation in an increasing array of cellular and animal neurodegeneration models as well as in neurogenesis. Herein, we review the physiological role of GLP-1 in the nervous system, focused towards the potential benefit of GLP-1R stimulation as an immediately translatable treatment strategy for acute and chronic neurological disorders.

Group III and subtype 4 metabotropic glutamate receptor agonists: discovery and pathophysiological applications in Parkinson's disease

Restoring the balance between excitatory and inhibitory circuits in the basal ganglia, following the loss of dopaminergic (DA) neurons of the substantia nigra pars compacta, represents a major challenge to treat patients affected by Parkinson's disease (PD). The imbalanced situation in favor of excitation in the disease state may also accelerate excitotoxic processes, thereby representing a potential target for neuroprotective therapies. Reducing the excitatory action of glutamate, the major excitatory neurotransmitter in the basal ganglia, should lead to symptomatic improvement for PD patients and may promote the survival of DA neurons. Recent studies have focused on the modulatory action of metabotropic glutamate (mGlu) receptors on neurodegenerative diseases including PD. Group III mGlu receptors, including subtypes 4, 7 and 8, are largely expressed in the basal ganglia. Recent studies highlight the use of selective mGlu4 receptor positive allosteric modulators (PAMs) for the treatment of PD. Here we review the effects of newly-designed group-III orthosteric agonists on neuroprotection, neurorestoration and reduction of l-DOPA induced dyskinesia in animal models of PD. The combination of orthosteric mGlu4 receptor selective agonists with PAMs may open new avenues for the symptomatic treatment of PD. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.