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Biomarkers have the potential to improve diagnosis and prognosis, and guide clinical treatment decisions. In research, biomarkers can be used for patient selection and as outcome measures in clinical trials. A range of biochemical and imaging biomarkers are relevant to patients with Lewy body disorders, including PD, PD dementia, and dementia with Lewy bodies. Dopaminergic imaging is used for differential diagnosis of parkinsonian disorders versus tremor disorders without dopamingeric deficits, and also to differentiate dementia with Lewy bodies from Alzheimer's disease. Markers of underlying Alzheimer's disease pathology have been applied to PD patients experiencing cognitive decline to determine the extent of mixed pathology in these cases. Assessment of alpha-synuclein species in spinal fluid is possible, and more specific assays attempt to identify alpha-synuclein aggregates or phosphorylated alpha-synuclein. While alpha-synuclein markers are intended to measure the pathology most central to PD dementia and dementia with Lewy bodies, convincing evidence of robust reliability and validity from multiple laboratories is lacking. Similarly, alpha-synuclein imaging by PET or single-photon emission computed tomography, while an important research goal, is not yet available. In addition to their uses in the clinic, biomarkers have natural uses in therapeutic trials that target cognitive and neuropsychiatric features of Lewy body disorders. The biomarkers most likely to be incorporated into trials are dopaminergic and amyloid imaging for the purpose of accurate patient selection, and possibly to demonstrate the utility of antiamyloid treatments in Lewy body disorders patients with mixed pathology. © 2018 International Parkinson and Movement Disorder Society.

Treatments to slow the progression of cognitive dysfunction to dementia and improve the quality of life of persons with Parkinson's disease (PD) are desperately needed. Because PD mild cognitive impairment is considered a transitional stage before dementia, it opens a window to timely intervention. This article critically reviews the strengths and challenges of pharmacologic and nonpharmacologic clinical therapeutic trials in PD mild cognitive impairment conducted during the past 5 years, including ongoing trials. Relatively few high-quality trials have been conducted, and some important factors in designing future clinical trials are discussed. © 2018 International Parkinson and Movement Disorder Society.

Little is known about the underlying mechanisms of clinical symptoms in dementia with Lewy bodies. The aim of this study was to explore the association between loss of striatal dopamine transporter binding and symptoms in dementia with Lewy bodies.Thirty-five patients with dementia with Lewy bodies underwent single-photon emission computerized tomography brain imaging with N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane ([(123) I]FP-CIT). Associations between striatal binding ratios and motor (UPDRS), psychiatric (Neuropsychiatric Inventory; [NPI]), and cognitive (Mini-Mental State Examination [MMSE] and neuropsychological tests) symptoms were assessed by linear regression analysis.The explorative analysis showed that the motor UPDRS was negatively associated with putamen dopamine transporter binding, whereas no association with striatal dopamine transporter binding was found for total NPI, hallucinations, apathy, depression, anxiety, and MMSE scores. However, in post-hoc analysis, executive impairment was positively associated with dopamine transporter loss after adjustment of age and gender.Dopamine deficiency in patients with dementia with Lewy bodies was associated with severity of motor symptoms, but did not correlate significantly with ratings of neurobehavioral disturbances or overall cognition.

Cognitive impairment in Parkinson's disease (PD) is common and does directly impact patients' everyday functioning. However, the underlying mechanisms of early cognitive decline are not known. This study explored the association between striatal dopaminergic deficits and cognitive impairment within a large cohort of early, drug-naïve PD patients and tested the hypothesis that executive dysfunction in PD is associated with striatal dopaminergic depletion. A cross-sectional multicenter cohort of 339 PD patients and 158 healthy controls from the Parkinson's Progression Markers Initiative study was analyzed. Each individual underwent cerebral single-photon emission CT (SPECT) and a standardized neuropsychological assessment with tests of memory as well as visuospatial and executive function. SPECT imaging was performed with [(123) I]FP-CIT, and specific binding ratios in left and right putamen and caudate nucleus were calculated. The association between specific binding ratios, cognitive domain scores, and age was analyzed using Pearson's correlations, partial correlation, and conditional process analysis. A small, but significant, positive association between total striatal dopamine transporter binding and the attention/executive domain was found (r = 0.141; P = 0.009) in PD, but this was not significant after adjusting for age. However, in a moderated mediation model, we found that cognitive executive differences between controls and patients with PD were mediated by an age-moderated striatal dopaminergic deficit. Our findings support the hypothesis that nigrostriatal dopaminergic deficit is associated with executive impairment, but not to memory or visuospatial impairment, in early PD.

Increasing recognition that Parkinson's disease (PD) may start outside of the substantia nigra has led to a rapidly expanding effort to define prodromal stages of PD, before motor signs permit classical diagnosis. Many of these efforts center around the identification of clinical non-motor symptoms and signs of disease. There is now direct evidence that olfaction, rapid eye movement (REM) sleep behavior disorder (RBD), constipation, and depression can be present in prodromal PD. In addition, there is suggestive evidence that visual changes, other autonomic symptoms, and subtle cognitive changes may also be present at prodromal stages. A critical issue in utility of these prodromal markers will be assessment of sensitivity, specificity, and positive and negative predictive values. Although these have yet to be fully defined, olfactory deficits, some visual changes, and autonomic symptoms occur in the majority of PD patients at diagnosis, suggesting good potential sensitivity. However, with the exception of RBD and perhaps some specific autonomic measures, specificity, and positive predictive value of these markers may be insufficient to be used alone as identifiers of prodromal disease. The evidence for the utility of olfaction, RBD, autonomic markers, visual changes, mood disorders, and cognitive loss as markers of prodromal PD and the potential sensitivity and specificity of these markers are summarized.

Mild cognitive impairment is common in nondemented Parkinson's disease (PD) patients and may be a harbinger of dementia. In view of its importance, the Movement Disorder Society commissioned a task force to delineate diagnostic criteria for mild cognitive impairment in PD. The proposed diagnostic criteria are based on a literature review and expert consensus. This article provides guidelines to characterize the clinical syndrome and methods for its diagnosis. The criteria will require validation, and possibly refinement, as additional research improves our understanding of the epidemiology, presentation, neurobiology, assessment, and long-term course of this clinical syndrome. These diagnostic criteria will support future research efforts to identify at the earliest stage those PD patients at increased risk of progressive cognitive decline and dementia who may benefit from clinical interventions at a predementia stage.

Background: We investigated to what extent cognitive impairment and dementia were related to the direct medical and nonmedical costs in Parkinson's disease. Methods: Sixty-one patients with Parkinson's disease from a population-based cohort were assessed for motor and cognitive symptoms in 1993, 1997, and 2001. Data on use of health care and social services were collected. Results: The costs of patients with dementia were 3.3 times higher (€34,980) than those of nondemented patients (€10,626) per year of survival. Institutional care was the largest cost factor, representing 67% of the costs. Cognitive functioning predicted direct costs by 29.4%. Cognitive decline was associated with increased costs, even in nondemented subjects. Conclusions: Our findings suggest that dementia has a substantial impact on direct costs in Parkinson's disease, mainly due to high costs for institutional care. In addition, there were indications that even patients with mild cognitive impairment have higher nonmedical costs. © 2011 Movement Disorder Society

The trajectory of cognitive functioning in patients with Parkinson's disease (PD) is not known. We used a random change point model to study the individual cognitive trajectory for up to 15 years in a prevalence sample of 238 PD patients, and used the mini-mental state examination (MMSE) to assess the longitudinal cognitive course. We observed that the rate of global cognitive decline was nonlinear. Following a relatively stable period, an inflection point was identified, after which the rate of decline gained momentum with an annual decline of 2.8 points on the MMSE. The course was similar in men and women. This inflection point was estimated to occur 13.3 years (95% credible interval 11.8, 13.6) after the diagnosis of PD; however, there were wide interindividual variations in the time from onset of PD to the inflection point.

Mild cognitive impairment (MCI) may predict future development of dementia in Parkinson's disease (PD). We aimed to examine the extent of subcortical brain atrophy in patients with early PD with and without MCI compared to normal controls (NC). Participating in a population-based study were 43 early, drug-naïve PD patients and 41 NC. Eleven patients were classified with MCI (MCI PD) and 32 patients without (non-MCI PD). Volumetric segmentation of 3D-T1 weighted brain MRI was performed using FreeSurfer. Groups were compared applying MANCOVA corrected for total intracranial volume, age, and sex. Results showed that left inferior lateral ventricle and third ventricle volumes were significantly larger in MCI PD than in non-MCI PD and NC. Fourth ventricular size in MCI PD was significantly different from NC and highly correlated with memory performance in MCI PD patients. This suggests that cognitive dysfunction in early PD may be associated with ventricular enlargement.

We aimed to investigate whether mild cognitive impairment (MCI) in Parkinson's disease (PD) is characterized by region-specific gray matter (GM) atrophy and to explore correlations between GM and cognition in PD. Magnetic resonance images of 42 newly diagnosed PD patients (of which 11 had MCI) and 37 normal controls were analyzed using voxel-based morphometry. Analyses comparing groups showed no regional atrophy, and in patients there were no significant correlations between cognitive domain test performance and GM loss. In conclusion, GM atrophy does not seem to be a major feature of cognitive dysfunction in incident PD.

Neuropsychiatric symptoms are common in Parkinson's disease, even at the earliest stages, and have important consequences for quality of life and daily functioning, are associated with increased carer burden and increased risk for nursing home admission. In addition to cognitive impairment, a wide range of neuropsychiatric symptoms have been reported. In this article, the epidemiology, clinical course, diagnosis, and management of some of the most common neuropsychiatric symptoms in PD are discussed: depression, anxiety, apathy, fatigue, and psychotic symptoms. Although much is known regarding the prevalence and course of these symptoms, the empirical evidence for how to manage these symptoms is limited at best. There is thus an urgent need for systematic studies for the pharmacological and non-pharmacological management of these symptoms.

Psychotic symptoms are a frequent occurrence in Parkinson's disease (PD), affecting up to 50% of patients. The Movement Disorder Society established a Task Force on Rating Scales in PD, and this critique applies to published, peer-reviewed rating psychosis scales used in PD psychosis studies. Twelve psychosis scales/questionnaires were reviewed. None of the reviewed scales adequately captured the entire phenomenology of PD psychosis. While the Task Force has labeled some scales as "recommended" or "suggested" based on the fulfilling-defined criteria, none of the current scales contained all the basic content, mechanistic and psychometric properties needed to capture PD psychotic phenomena and to measure clinical response over time. Different scales may be better for some settings versus others. Since one scale may not be able to serve all needs, a scale used to measure clinical response and change over time [such as the Clinical Global Impression Scale (CGIS)] may need to be combined with another scale better at cataloging specific features [such as the Neuropsychiatric Inventory (NPI) or Schedule for Assessment of Positive Symptoms (SAPS)]. At the present time, for clinical trials on PD psychosis assessing new treatments, the following are recommended primary outcome scales: NPI (for the cognitively impaired PD population or when a caregiver is required), SAPS, Positive and Negative Syndrome Scale (PANSS), or Brief Psychiatric Rating Scale (BPRS) (for the cognitively intact PD population or when the patient is the sole informant). The CGIS is suggested as a secondary outcome scale to measure change and response to treatment over time.

A preceding article described the clinical features of Parkinson's disease dementia (PD-D) and proposed clinical diagnostic criteria for "probable" and "possible" PD-D. The main focus of this article is to operationalize the diagnosis of PD-D and to propose practical guidelines based on a two level process depending upon the clinical scenario and the expertise of the evaluator involved in the assessment. Level I is aimed primarily at the clinician with no particular expertise in neuropsychological methods, but who requires a simple, pragmatic set of tests that are not excessively time-consuming. Level I can be used alone or in concert with Level II, which is more suitable when there is the need to specify the pattern and the severity on the dementia of PD-D for clinical monitoring, research studies or pharmacological trials. Level II tests can also be proposed when the diagnosis of PD-D remains uncertain or equivocal at the end of a Level I evaluation. Given the lack of evidence-based standards for some tests when applied in this clinical context, we have tried to make practical and unambiguous recommendations, based upon the available literature and the collective experience of the Task Force. We accept, however, that further validation of certain tests and modifications in the recommended cut off values will be required through future studies.

Prevalence rates of depressive disorders in Parkinson's disease (PD) vary widely across studies, ranging from 2.7% to more than 90%. The aim of this systematic review was to calculate average prevalences of depressive disorders taking into account the different settings and different diagnostic approaches of studies. Using Medline on Pubmed, a systematic literature search was carried out for studies of depression in Parkinson's disease. A total of 104 articles were included and assessed for quality; 51 articles fulfilled the quality criteria. Multiple publications from the same database were not included in the meta-analysis. In the remaining 36 articles, the weighted prevalence of major depressive disorder was 17% of PD patients, that of minor depression 22% and dysthymia 13%. Clinically significant depressive symptoms, irrespective of the presence of a DSM defined depressive disorder, were present in 35%. In studies using a (semi) structured interview to establish DSM criteria, the reported prevalence of major depressive disorder was 19%, while in studies using DSM criteria without a structured interview, the reported prevalence of major depressive disorder was 7%. Population studies report lower prevalence rates for both major depressive disorder and the clinically significant depressive symptoms than studies in other settings. This systematic review suggests that the average prevalence of major depressive disorder in PD is substantial, but lower than generally assumed.

Dementia has been increasingly more recognized to be a common feature in patients with Parkinson's disease (PD), especially in old age. Specific criteria for the clinical diagnosis of dementia associated with PD (PD-D), however, have been lacking. A Task Force, organized by the Movement Disorder Study, was charged with the development of clinical diagnostic criteria for PD-D. The Task Force members were assigned to sub-committees and performed a systematic review of the literature, based on pre-defined selection criteria, in order to identify the epidemiological, clinical, auxillary, and pathological features of PD-D. Clinical diagnostic criteria were then developed based on these findings and group consensus. The incidence of dementia in PD is increased up to six times, point-prevelance is close to 30%, older age and akinetic-rigid form are associated with higher risk. PD-D is characterized by impairment in attention, memory, executive and visuo-spatial functions, behavioral symptoms such as affective changes, hallucinations, and apathy are frequent. There are no specific ancillary investigations for the diagnosis; the main pathological correlate is Lewy body-type degeneration in cerebral cortex and limbic structures. Based on the characteristic features associated with this condition, clinical diagnostic criteria for probable and possible PD-D are proposed.

There are no standardized diagnostic criteria for psychosis associated with Parkinson's disease (PDPsy). As part of an NIH sponsored workshop, we reviewed the existing literature on PDPsy to provide criteria that distinguish PDPsy from other causes of psychosis. Based on these data, we propose provisional criteria for PDPsy in the style of the Diagnostic and Statistical Manual of Mental Disorders IV-TR. PDPsy has a well-characterized temporal and clinical profile of hallucinations and delusions, which is different than the pattern seen in other psychotic disorders such as substance induced psychosis or schizophrenia. PDPsy is associated with a poor prognosis of chronic psychosis, nursing home placement, and death. Medications used to treat Parkinson's disease (PD) contribute to PDPsy but may not be sufficient or necessary contributors to PDPsy. PDPsy is associated with Lewy bodies pathology, imbalances of monoaminergic neurotransmitters, and visuospatial processing deficits. These findings suggest that PDPsy may result from progression of the disease process underlying PD, rather than a comorbid psychiatric disorder or drug intoxication. PDPsy is not adequately described by existing criteria for psychotic disorders. We established provisional diagnostic criteria that define a constellation of clinical features not shared by other psychotic syndromes. The criteria are inclusive and contain descriptions of the full range of characteristic symptoms, chronology of onset, duration of symptoms, exclusionary diagnoses, and associated features such as dementia. These criteria require validation and may be refined, but form a starting point for studies of the epidemiology and pathophysiology of PDPsy, and are a potential indication for therapy development.

Dementia is common in patients with Parkinson's disease (PDD). The etiology of PDD is still unclear, but exciting advances have been made in discovering pathogenetic components in Parkinson's disease (PD), implicating the role of genetic factors. It is, however, still controversial whether genetic factors also contribute to the development of dementia in PD. Thus, we investigated the association between development of dementia and a positive family history of PD or dementia in a community-based study of PD in Rogaland County, Norway (n = 219). The patients were followed prospectively with neurological and neuropsychological assessments. Dementia was more common in patients with a strong family association of PD (first-degree relatives > second-degree relatives > no family history; P < 0.05). However, time to dementia did not differ between the two groups. No associations between dementia in PD and familial occurrence of dementia could be shown. Further studies with larger samples are needed to explore a possible relationship between a family history of PD and development of dementia in PD and its potential pathogenetic mechanisms.

The aim of this study was to establish the rate of progression from mild cognitive impairment (MCI) to dementia in patients with Parkinson's disease (PD). PD patients without dementia were recruited in 1997 from an ongoing prospective epidemiological study. The assessment included neurological and psychiatric examinations, a clinical interview based on the Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition (DSM-III-R) criteria for dementia, and a battery of neuropsychological tests. PD was diagnosed according to established criteria, dementia was diagnosed according to the DSM-III-R criteria, and subtypes of MCI were classified according to modified Petersen's criteria. Seventy-two nondemented PD patients were included. A total of 34 were cognitively intact, whereas 38 were diagnosed with MCI (amnestic, n = 6; single nonmemory domain, n = 17; multiple domains slightly impaired, n = 15). Fifty-nine patients (82%) completed follow-up examination 4 years later, and 18 (62%) of the patients with MCI and 6 (20%) of the cognitively intact PD patients were demented (P = 0.001). Single domain nonmemory MCI and multiple domains slightly impaired MCI were associated with later development of dementia (P = 0.003; P = 0.04), whereas amnestic MCI subtype was not (P = 0.76). We conclude that patients with PD and MCI had a higher risk of developing dementia than cognitively intact PD patients, suggesting that MCI in PD is an early manifestation of dementia. However, these findings should be interpreted with caution due to the relatively small number of subjects included in this study.

We describe the pattern of cognitive profiles within a community-based sample of patients with Parkinson's disease (PD) and dementia (PDD) using cluster analyses, and compare the results with data from patients with Alzheimer's disease (AD) and dementia with Lewy bodies (DLB). Fifty patients with PDD and 39 with AD from Stavanger, Norway, and 62 patients with DLB from San Diego, CA, USA were diagnosed by either standardized clinical procedures or criteria (all PDD and all AD cases) or necropsy (all DLB cases). Four subgroups were identified: two subgroups with a subcortical cognitive profile (one with mild and one with moderate dementia severity), one subgroup with global impairment and severe dementia, and one subgroup with a cortical cognitive profile and moderate dementia. Of the patients with PDD and with DLB, 56% and 55%, respectively, had a subcortical cognitive profile, compared with only 33% of the AD patients. Conversely, 30% of the patients with PDD and 26% of those with DLB had a cortical cognitive profile, compared with 67% of the patients with AD. These findings suggest that in some patients with PDD, frontosubcortical changes are the main contributing factor to dementia, whereas in other patients, cortical and hippocampal changes are more important.