Parkinson's Disease Neuropathology Research Articles

LRRK2 phosphorylates novel tau epitopes and promotes tauopathy

Mutations in the gene encoding leucine-rich repeat kinase 2 (LRRK2) are the most frequent cause of familial Parkinson’s disease (PD). The neuropathology of LRRK2-related PD is heterogeneous and can include aberrant tau phosphorylation or neurofibrillary tau pathology. Recently, LRRK2 has been shown to phosphorylate tau in vitro; however, the major epitopes phosphorylated by LRRK2 and the physiological or pathogenic consequences of these modifications in vivo are unknown. Using mass spectrometry, we identified multiple sites on recombinant tau that are phosphorylated by LRRK2 in vitro, including pT149 and pT153, which are phospho-epitopes that to date have been largely unexplored. Importantly, we demonstrate that expression of transgenic LRRK2 in a mouse model of tauopathy increased the aggregation of insoluble tau and its phosphorylation at T149, T153, T205, and S199/S202/T205 epitopes. These findings indicate that tau can be a LRRK2 substrate and that this interaction can enhance salient features of human disease.Electronic supplementary materialThe online version of this article (doi:10.1007/s00401-013-1188-4) contains supplementary material, which is available to authorized users.

Selective and Brain‐Permeable Polo‐like Kinase‐2 (Plk‐2) Inhibitors That Reduce α‐Synuclein Phosphorylation in Rat Brain

Polo-like kinase-2 (Plk-2) has been implicated as the dominant kinase involved in the phosphorylation of α-synuclein in Lewy bodies, which are one of the hallmarks of Parkinson's disease neuropathology. Potent, selective, brain-penetrant inhibitors of Plk-2 were obtained from a structure-guided drug discovery approach driven by the first reported Plk-2-inhibitor complexes. The best of these compounds showed excellent isoform and kinome-wide selectivity, with physicochemical properties sufficient to interrogate the role of Plk-2 inhibition in vivo. One such compound significantly decreased phosphorylation of α-synuclein in rat brain upon oral administration and represents a useful probe for future studies of this therapeutic avenue toward the potential treatment of Parkinson's disease.

Mechanisms of neurotoxicity and implications for neurological disorders

Keywords: chemical contaminants, neurodegeneration, neurodevelopment, neuroinflammation, neurotoxicty.On 13 July 2012, in conjunction with the 8th FENSForum of Neuroscience in Barcelona, Dr. JordiLlorens and I organized a Satellite Event in theform of a 1-day symposium. The main focus of thesymposium was on the mechanisms of neurotox-icity potentially involved in neurodegenerative dis-eases or neurodevelopmental disorders. Aspectsincluding gene–environment interactions, specificcellular alterations and neurodevelopmental impli-cations were covered by internationally recognizedexperts in their respective field. Reviews based onsix of the oral presentations from invited speakersare included in this issue of the Journal of InternalMedicine.The review by Dr. Julie Andersen, Buck Institutefor Age Research, Novato CA, USA, discusses thepossible link between environmental stress,aging, glial cell senescence and Parkinson’s dis-ease [1]. Certain chronic environmental expo-sures have been linked to the age-relateddevelopment of Parkinson’s disease neuropathol-ogy. Neuronal damage is believed to involve theinduction of neuroinflammatory events mediatedby glial cell activation. Senescent cells accumu-late with age, and they express a senescence-associated secretory phenotype (SASP) connectedto the secretion of many inflammatory cytokines,growth factors and proteases. Andersen proposesthat senescent glia could contribute to age-related neurodegeneration by creating a chroni-cally inflamed milieu. If correct, this novelpotential link between glial senescence and Par-kinson’s disease could change the current under-standing on the role of glial cells in age-relatedneurodegenerative diseases. In particular envi-ronmental stressors associated with Parkinson’sdisease, such as paraquat and MPTP, may act inpart by eliciting senescence and SASP expressionby glial cells in the aging brain, thereby contrib-uting to the characteristic decline in neuronalintegrity that occurs in the disorder.Dr. Rosario Moratalla, Instituto Cajal, CSIC,Madrid,describesinherreviewtheroleofdopaminereceptors in the neurotoxicity of the synthetic drugmethamphetamine [2]. Despite its neurotoxiceffects including loss of dopaminergic fibres andcell bodies, methamphetamine is consumed bymillions of users. There is evidence from clinicalreports suggesting that methamphetamine abusersare predisposed to Parkinson’s disease. The mech-anism of methamphetamine neurotoxicity involvesdopamine receptors. In fact, genetic inactivation ofD1orD2receptorsubtypesprotectsagainstthelossof dopaminergic fibres in the striatum and loss ofdopaminergic neurons in the substantia nigrainduced by methamphetamine. The protectiongiven by D1 receptor inactivation is due to blockadeof hyperthermia, lower dopamine content and turn-over,andhigherlevelsofstoredvesiculardopaminein D1 receptor

Deep brain stimulation of the subthalamic nucleus increases premature responding in a rat gambling task

Deep brain stimulation of the subthalamic nucleus (STN-DBS) is a treatment option for the motor symptoms of Parkinson's disease (PD). However, several recent studies have found an association between STN-DBS and increased impulsivity. Currently, it is not clear whether the observed increase in impulsivity results from STN-DBS per se, or whether it involves an interaction with the underlying PD neuropathology and/or intake of dopaminergic drugs. We investigated the effects of STN-DBS on performance of intact rats on two tasks measuring impulsive responding: a novel rat gambling task (rGT) and a differential reinforcement of low rate responding (DRL20s) schedule. Following initial behavioural training, animals received electrode implantation into the STN (n=24) or sham surgery (n=24), and were re-tested on their assigned behavioural task, with or without STN-DBS. Bilateral STN-DBS administered for two hours immediately prior to testing, had no effects on rGT choice behaviour or on DRL response inhibition (p>0.05). However, STN-DBS significantly increased premature responding in the rGT task (p=0.0004), an effect that took several sessions to develop and persisted in subsequent trials when no stimulation was given. Consistent with the notion of distinct facets of impulsivity with unique neurochemical underpinnings, we observed differential effects of STN-DBS in the two tasks employed. These results suggest that STN-DBS in the absence of parkinsonism may not lead to a general loss of inhibitory control, but may instead affect impulsivity under specific conditions.

Modeling early Parkinson's disease pathology with chronic low dose MPTP treatment

Parkinson's disease (PD) is a movement disorder mainly characterized by progressive neurodegeneration of dopaminergic (DAergic) neurons in the substantia nigra (SN). As yet, unknown molecular changes contribute to the development of PD leading to a great need for in vivo models that herald this disorder. Here we characterize an animal model presenting early PD pathology. Young, adult C57/BL6 mice were treated for five weeks twice a week with 15 mg/kg 1-methyl-4-phenyl1,2,3,6-tetrahydropyridine (MPTP) in combination with 250 mg/kg probenecid. During the treatment mice were tested on their dopamine dependent movement skills. The integrity of their nigrostriatal system was examined through immunohistochemical studies. During the treatment, mice developed dopamine-dependent movement deficits induced by loss of tyrosine hydroxylase (TH) positive nigrostriatal axon terminals. Immunohistochemical study identified astrogliosis and microgliosis in the SN but no decrease of TH immunostaining, demonstrating lack of DAergic neuron degeneration. We also observed formation of α-synuclein inclusion bodies in the SN. The combined features of this MPTP model appear to represent an early neurotoxic cellular stress to the SN neurons bearing a striking resemblance to the early stages of PD neuropathology. This model might prove very useful to investigate early neurodegenerative events in the nigrostriatal DAergic system and to study the effects of potential treatment strategies counteracting the early PD cellular changes.

Association between polychlorinated biphenyls and Parkinson's disease neuropathology

Polychlorinated biphenyls (PCBs) are synthetic chemicals primarily used as coolants and insulators in electrical equipment. Although banned for several decades, PCBs continue to exist in the environment because of their long half-life, continued presence in items produced before the ban, and poor disposal practices. Epidemiological and experimental studies have identified exposure to PCBs as a potential risk factor for Parkinson's disease, perhaps more so in females. The objective of this work was to examine the association between PCB levels in post-mortem human brain tissue and the diagnosis of Parkinson's disease, as well as the degree of nigral depigmentation. We also sought to determine if this association was more significant when patients were stratified by sex. Post-mortem brain samples from control patients and those diagnosed with Parkinson's disease were obtained from the Emory University Brain Bank and from the Nun Study. Concentrations of eight prevalent PCB congeners were extracted from post-mortem brain tissue and analyzed using gas chromatography-mass spectrometry. PCB congeners 153 and 180 were significantly elevated in the brains of Parkinson's disease patients. When stratified by sex, the female Parkinson's disease group demonstrated significantly elevated concentrations of total PCBs and specifically congeners 138, 153, and 180 compared to controls, whereas PCB concentrations in males were not significantly different between control and Parkinson's disease groups. In a separate population of women (Nun Study) who had no clinical signs or symptoms of PD, elevated concentrations total PCB and congeners 138, 153 and 180 were also observed in post-mortem brain tissue exhibiting moderate nigral depigmentation compared to subjects with mild or no depigmentation. These quantitative data demonstrate an association between brain PCB levels and Parkinson's disease-related pathology. Furthermore, these data support epidemiological and laboratory studies reporting a link between PCB exposure and an increased risk for Parkinson's disease, including greater susceptibility of females.

Inflammation and α-synuclein's prion-like behavior in Parkinson's disease--is there a link?

Parkinson’s disease patients exhibit progressive spreading of aggregated α-synuclein in the nervous system. This slow process follows a specific pattern in an inflamed tissue environment. Recent research suggests that prion-like mechanisms contribute to the propagation of α-synuclein pathology. Little is known about factors that might affect the prion-like behavior of misfolded α-synuclein. In this review, we suggest that neuroinflammation plays an important role. We discuss causes of inflammation in the olfactory bulb and gastrointestinal tract and how this may promote the initial misfolding and aggregation of α-synuclein, which might set in motion events that lead to Parkinson's disease neuropathology. We propose that neuroinflammation promotes the prion-like behavior of α-synuclein and that novel anti-inflammatory therapies targeting this mechanism could slow disease progression.

Genetic mouse models for understanding LRRK2 biology, pathology and pre-clinical application

Missense mutations in Leucine-Rich Repeat kinase 2 (LRRK2) are the most common cause of inherited Parkinson's disease (PD). Elucidation of LRRK2 biology and pathophysiology is central to the development of therapeutic intervention. Our group and others have developed a number of genetic mouse models of LRRK2 utilizing different genetic approaches. These models exhibit certain PD-related pathologies (e.g. impaired dopamine transmission and tauopathies) and abnormal motor functions, providing valuable insight into potential LRRK2-mediated pathogenesis of PD. However, not surprisingly they lack of substantial neuropathology and clinical syndromes of PD. Ongoing investigation of these models has begun to shed light on LRRK2 cellular functions and pathogenic pathways and is expected to assist the identification and validation of PD drug targets. This report summarizes the recent findings in our genetic LRRK2 models and discusses their utility in understanding much needed knowledge regarding early stage (pre-symptomatic) disease progression, drug target identification, and potential application in chemical screening focused on inhibitors of kinase activity of LRRK2.

Therapeutic strategies for nonmotor symptoms in early Parkinson's disease: the case for a higher priority and stronger evidence

It is now recognized that the neuropathology of early Parkinson's disease (PD) is not limited to the nigrostriatal dopaminergic system, but also involves various brainstem nuclei, the hypothalamus, the olfactory system, and the peripheral autonomic nervous system. Given the disseminated neuropathology of early PD, the earliest clinical signs include a myriad of non-motor manifestations including sleep-wake cycle regulation, cognition, mood and motivation, olfactory and gustatory functions, autonomic functions, and sensory and pain processing. Despite this realization, there is clearly a paucity of trials that have systematically evaluated the treatment of non-motor symptoms of PD in the early stages. For example, only one large-scale, placebo-controlled randomized trial has been conducted on the treatment of depression in PD patients. There are no reports of randomized controlled trials of therapeutic agents looking at the frequently reported anxiety and fatigue in early PD patients. Based on this lack of evidence, therapy for early non-motor manifestations is often ignored and the focus remains on dopamine replacement strategies with main outcomes being restricted to motor measurements, such as the Unified Parkinson's Disease Rating Scale. This article presents the case for prioritizing well-designed, controlled clinical trials of therapeutic interventions focusing on non-motor symptoms in early PD patients.

Assessing the role of dopamine in limb and cranial-oromotor control in a rat model of Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder primarily characterized by sensorimotor dysfunction. The neuropathology of PD includes a loss of dopamine (DA) neurons of the nigrostriatal pathway. Classic signs of the disease include rigidity, bradykinesia, and postural instability. However, as many as 90% of patients also experience significant deficits in speech, swallowing (including mastication), and respiratory control. Oromotor deficits such as these are underappreciated, frequently emerging during the early, often hemi-Parkinson, stage of the disease. In this paper, we review tests commonly used in our labs to model early and hemi-Parkinson deficits in rodents. We have recently expanded our tests to include sensitive models of oromotor deficits. This paper discusses the most commonly used tests in our lab to model both limb and oromotor deficits, including tests of forelimb-use asymmetry, postural instability, vibrissae-evoked forelimb placing, single limb akinesia, dry pasta handling, sunflower seed shelling, and acoustic analyses of ultrasonic vocalizations and pasta biting strength. In particular, we lay new groundwork for developing methods for measuring abnormalities in the acoustic patterns during eating that indicate decreased biting strength and irregular intervals between bites in the hemi-Parkinson rat. Similar to limb motor deficits, oromotor deficits, at least to some degree, appear to be modulated by nigrostriatal DA. Finally, we briefly review the literature on targeted motor rehabilitation effects in PD models. Learning outcomes: Readers will: (a) understand how a unilateral lesion to the nigrostriatal pathway affects limb use, (b) understand how a unilateral lesion to the nigrostriatal pathway affects oromotor function, and (c) gain an understanding of how limb motor deficits and oromotor deficits appear to involve dopamine and are modulated by training.

Animal Models of Gastrointestinal Problems in Parkinson's Disease

Gastrointestinal (GI) symptoms are being increasingly recognized as early, common, and severe features of Parkinson's disease (PD), and they are important determinants of quality of life and disability throughout the disease course. In addition, the concept that GI symptoms could represent "pre-motor" PD has been hotly debated and has recently become a driving force for investigations into the pathophysiology and neuropathology of PD. Clinical data has been supported by many pathological studies demonstrating α-synuclein neuritic pathology and neuronal loss in central and peripheral areas relevant to GI function. As understanding has matured concerning the impact of GI dysmotility on patients and its potential relationship to incipient PD, behavioral and neuropathological examination of the GI tract has become a critical aspect of evaluation and validation of PD animal models. This review will briefly summarize GI symptoms and neuropathology in PD important to model in animals, behavioral and neuropathological examination of the GI tract in animals, and the current state of modeling parkinsonian GI dysfunction in animal model systems.

Colonic Neuropathology is Independent of Olfactory Dysfunction in Parkinson's Disease

Olfactory dysfunction (OD) and constipation are two frequent and early non-motor features of Parkinson's disease (PD). Colonic PD neuropathology, the putative cause of constipation, can be analyzed and quantified using routine colonic biopsies and parallels disease severity. The present study was aimed at investigating whether the severity of neuropathology in the colon in PD is related to OD. Twenty-six PD patients were included. Colonic neuropathology, i.e., the density of Lewy pathology and the number of submucosal neurons, was unrelated to OD as assessed using the University of Pennsylvania Smell Identification. This suggests that unlike colonic Lewy pathology, OD is unrelated to disease severity.

Decreased glutamic acid decarboxylase mRNA expression in prefrontal cortex in Parkinson's disease

Parkinson's disease (PD) patients typically suffer from motor disorders but mild to severe cognitive deficits can also be present. Neuropathology of PD primarily involves loss of dopaminergic neurons in the substantia nigra, pars compacta, although more widespread pathology from the brainstem to the cerebral cortex occurs at different stages of the disease. Cognitive deficits in PD are thought to involve the cerebral cortex, and imaging studies have identified the dorsolateral prefrontal cortex (DLPFC) as a possible site for some of the symptoms. GABAergic neurons in the cerebral cortex play a key role in the modulation of pyramidal neurons and alterations in muscimol binding to GABA A receptors have been reported in Brodmann area 9 (BA9) of the prefrontal cortex in PD patients (Nishino et al., 1988). In order to further assess the likelihood that GABAergic activity is altered in the prefrontal cortex in PD, gene expression of the 67 kilodalton isoform of the GABA-synthesizing enzyme, glutamic acid decarboxylase (GAD67 encoded by the GAD1 gene), was examined in BA9 of post-mortem brains from 19 patients and 20 controls using isotopic in situ hybridization histochemistry. GAD67 mRNA labeling was examined and quantified on X-ray films and emulsion radioautographs. We show that GAD67 mRNA labeling is significantly lower in PD compared to control cases. Analysis of emulsion radioautographs indicates that GAD67 mRNA labeling is decreased in individual neurons and is not paralleled by a decrease in the number of GAD67 mRNA-labeled neurons. Analysis of expression data from a microarray study performed in 29 control and 33 PD samples from BA9 confirms that GAD67 expression is decreased in PD. Another finding from the microarray study is a negative relationship between GAD67 mRNA expression and age at death. Altogether, the results support the possibility that GABAergic neurotransmission is impaired in the DLPFC in PD, an effect that may be involved in some of the behavioral deficits associated with the disease.

Leucine-Rich Repeat Kinase 2 Is Associated With the Endoplasmic Reticulum in Dopaminergic Neurons and Accumulates in the Core of Lewy Bodies in Parkinson Disease

Mutation of the leucine-rich repeat kinase 2 (LRRK2) gene is the most frequent genetic cause of Parkinson disease (PD). To understand the role of LRRK2 in the neuropathology of PD, we investigated the protein expression in a healthy brain and brains from patients with PD and its subcellular localization in dopaminergic neurons. LRRK2 was found to be widely expressed in healthy adult brain, including areas involved in PD. By double fluorescent staining, we found that endogenous LRRK2 is colocalized with the endoplasmic reticulum (ER) markers Neurotrace and KDEL in human dopaminergic neurons. Labeling of brain sections with anti-LRRK2 and anti-α-synuclein antibodies revealed localization of LRRK2 in the core of 24% of Lewy bodies (LBs) in the substantia nigra and 11% of LBs in the locus coeruleus in idiopathic PD patients. The percentage was increased to 50% in both areas in a patient with the G2019S LRRK2 mutation. The finding of ER localization suggests the possibility that LRRK2 is involved in the ER stress response and could account for the susceptibility to neuronal degeneration of LRRK2 mutation carriers. The localization of LRRK2 protein in the core of a subset of LBs demonstrates the contribution of LRRK2 to LB formation and disease pathogenesis.

Are dysautonomic and sensory symptoms present in early Parkinson’s disease?

Parkinson's disease (PD) occurs with an annual incidence of 13/100.000, is slightly more frequent in men and is characterized by the motor symptoms tremor, rigidity, bradykinesia and postural instability. In addition, non-motor symptoms have been increasingly connected to the disease although already described in James Parkinson's 'Essay on the shaking palsy' from 1817. The motor symptoms in PD are related to the degeneration of dopaminergic cells in the substantia nigra (SN). These symptoms respond well to dopaminergic substitution. It is much more unclear whether non-motor symptoms like dysautonomia, insomnia, day-time sleepiness, fatigue, pain and neuropsychiatric symptoms respond to levodopa. Autonomic symptoms include dizziness because of orthostatic hypotension, constipation, nausea, voiding symptoms and increased sweating. Such symptoms as well as sensory symptoms like hyposmia and pain are very frequently reported in PD and seem to occur early in the disease process. Braak proposed a sequential model of neuropathology in PD starting with affection of the olfactory bulb and the autonomic innervation of the heart and gut. Affection of SN is seen from Braak stage 3, and limbic and cortical structures are affected in the later stages of the disease. Currently, the evidence for sensory and autonomic involvement in PD is reviewed with special focus on the early phase of the disease.

Diffusion Tensor Imaging in Idiopathic REM Sleep Behavior Disorder Reveals Microstructural Changes in the Brainstem, Substantia Nigra, Olfactory Region, and Other Brain Regions

Idiopathic rapid eye movement sleep behavior disorder (iRBD)--a parasomnia characterized by dream enactments--is a risk marker for the development of Parkinson disease (PD) and other alpha-synucleinopathies. The pathophysiology of iRBD is likely due to dysfunction of brainstem nuclei that regulate REM sleep. Diffusion tensor imaging (DTI) is a method for studying microstructural brain tissue integrity in vivo. We investigated whether DTI detects microstructural abnormalities in the brain of patients with iRBD--compared with age-matched control subjects--as an in vivo potential indicator for changes related to "preclinical (premotor)" neuropathology in PD. N/A. Patients with iRBD (n = 12) and age-matched healthy control subjects (n = 12) were studied. At a 1.5T MRI maschine, whole-head DTI scans of fractional anisotropy, axial diffusivity (a potential marker of neuronal loss), and radial diffusivity (a potential marker of glial pathology) were analyzed using track-based spatial statistics, and 2 types of group analysis tools (FreeSurfer and FSL). We found significant microstructural changes in the white matter of the brainstem (P < 0.0001), the right substantia nigra, the olfactory region, the left temporal lobe, the fornix, the internal capsule, the corona radiata, and the right visual stream of the patients with iRBD. Changes were identified in regions known to be involved in REM-sleep regulation and/or to exhibit neurodegenerative pathology in iRBD and/or early PD. The study findings suggest that iRBD-related microstructural abnormalities can be detected in vivo with DTI, a widely available MRI technique.

α-synuclein induced synapse damage is enhanced by amyloid-β1-42

BackgroundThe pathogenesis of Parkinson's disease (PD) and dementia with Lewy bodies (DLB) is associated with the accumulation of aggregated forms of the α-synuclein (αSN) protein. An early event in the neuropathology of PD and DLB is the loss of synapses and a corresponding reduction in the level of synaptic proteins. However, the molecular mechanisms involved in synapse damage in these diseases are poorly understood. In this study the process of synapse damage was investigated by measuring the amount of synaptophysin, a pre-synaptic membrane protein essential for neurotransmission, in cultured neurons incubated with αSN, or with amyloid-β (Aβ) peptides that are thought to trigger synapse degeneration in Alzheimer's disease.ResultsWe report that the addition of recombinant human αSN reduced the amount of synaptophysin in cultured cortical and hippocampal neurons indicative of synapse damage. αSN also reduced synaptic vesicle recycling, as measured by the uptake of the fluorescent dye FM1-43. These effects of αSN on synapses were modified by interactions with other proteins. Thus, the addition of βSN reduced the effects of αSN on synapses. In contrast, the addition of amyloid-β (Aβ)1-42 exacerbated the effects of αSN on synaptic vesicle recycling and synapse damage. Similarly, the addition of αSN increased synapse damage induced by Aβ1-42. However, this effect of αSN was selective as it did not affect synapse damage induced by the prion-derived peptide PrP82-146.ConclusionsThese results are consistent with the hypothesis that oligomers of αSN trigger synapse damage in the brains of Parkinson's disease patients. Moreover, they suggest that the effect of αSN on synapses may be influenced by interactions with other peptides produced within the brain.

Regional Brain Stem Atrophy in Idiopathic Parkinson's Disease Detected by Anatomical MRI

Idiopathic Parkinson's disease (PD) is a neurodegenerative disorder characterized by the dysfunction of dopaminergic dependent cortico-basal ganglia loops and diagnosed on the basis of motor symptoms (tremors and/or rigidity and bradykinesia). Post-mortem studies tend to show that the destruction of dopaminergic neurons in the substantia nigra constitutes an intermediate step in a broader neurodegenerative process rather than a unique feature of Parkinson's disease, as a consistent pattern of progression would exist, originating from the medulla oblongata/pontine tegmentum. To date, neuroimaging techniques have been unable to characterize the pre-symptomatic stages of PD. However, if such a regular neurodegenerative pattern were to exist, consistent damages would be found in the brain stem, even at early stages of the disease. We recruited 23 PD patients at Hoenn and Yahr stages I to II of the disease and 18 healthy controls (HC) matched for age. T1-weighted anatomical scans were acquired (MPRAGE, 1 mm3 resolution) and analyzed using an optimized VBM protocol to detect white and grey matter volume reduction without spatial a priori. When the HC group was compared to the PD group, a single cluster exhibited statistical difference (p<0.05 corrected for false detection rate, 4287 mm3) in the brain stem, between the pons and the medulla oblongata. The present study provides in-vivo evidence that brain stem damage may be the first identifiable stage of PD neuropathology, and that the identification of this consistent damage along with other factors could help with earlier diagnosis in the future. This damage could also explain some non-motor symptoms in PD that often precede diagnosis, such as autonomic dysfunction and sleep disorders.

Pattern of Depressive Symptoms in Parkinson's Disease

Depressive symptoms are common in Parkinson's disease (PD); however, it is unclear whether there are specific depressive symptom patterns in patients with PD and comorbid depression (dPD). The goal of this study is to examine the frequency and correlates of specific depressive symptoms in PD. A sample of 158 individuals with PD completed the self-rated Harvard Department of Psychiatry/National Depression Screening Day Scale (HANDS). By multiple-regression analysis, the authors examined the association between HANDS total and subscale scores and various demographic variables. The frequency of depression was 37% (N=58). Patients with a history of depression before PD had significantly more serious depression than those who had no such history. Of those who were more depressed, the most common symptoms of depression endorsed were low energy, difficulty with concentration/making decisions, feeling blue, feeling hopeless, and having poor sleep. There is a relatively high prevalence of dPD. Items on the HANDS that discriminated best between depressed and nondepressed subjects with PD included feeling blue, feeling hopeless, feeling worthless, lack of interest, and self-blame. It remains to be defined whether dPD should be understood primarily as a psychological reaction to a physical disability or perceived impending one, or as a direct expression of the neuropathology of PD.

Pattern of Depressive Symptoms in Parkinson's Disease

Background Depressive symptoms are common in Parkinson's disease (PD); however, it is unclear whether there are specific depressive symptom patterns in patients with PD and comorbid depression (dPD). Objective The goal of this study is to examine the frequency and correlates of specific depressive symptoms in PD. Method : A sample of 158 individuals with PD completed the self-rated Harvard Department of Psychiatry/National Depression Screening Day Scale (HANDS). By multiple-regression analysis, the authors examined the association between HANDS total and subscale scores and various demographic variables. Results The frequency of depression was 37% (N = 58). Patients with a history of depression before PD had significantly more serious depression than those who had no such history. Of those who were more depressed, the most common symptoms of depression endorsed were low energy, difficulty with concentration/making decisions, feeling blue, feeling hopeless, and having poor sleep. Conclusion There is a relatively high prevalence of dPD. Items on the HANDS that discriminated best between depressed and nondepressed subjects with PD included feeling blue, feeling hopeless, feeling worthless, lack of interest, and self-blame. It remains to be defined whether dPD should be understood primarily as a psychological reaction to a physical disability or perceived impending one, or as a direct expression of the neuropathology of PD.