Risk of dementia in Parkinson's disease: a community-based, prospective study

Cognitive impairment in patients with Parkinson's disease: A 30-month follow-up study

OBJECTIVE

A longitudinal (30-month) study of the cognitive changes in Parkinson's disease patients and analysis of influencing factors.

METHODS

The cognitive function and related symptoms of 102 patients with idiopathic Parkinson's disease were assessed using the Montreal Cognitive Assessment (MoCA), Mini-Mental State Examination (MMSE), and relevant scales, at baseline and 30-month follow-up. The t-test, nonparametric tests, and regression analyses were used to evaluate cognitive decline and investigate risk factors for cognitive impairment.

RESULTS

From baseline to follow-up, the MMSE and MoCA scores significantly decreased, respectively, from 28.16±2.29 to 26.18±3.64, and from 24.60±4.23 to 21.94±5.47 (both P<0.001). Impairment was observed in multiple cognitive areas, significantly in naming, delayed recall, and orientation (P<0.01). Patients at baseline with postural instability and gait disturbance (PIGD), lower MoCA scores, or depression had a higher risk of cognitive impairment at follow-up (P<0.01).

CONCLUSION

Cognitive impairment is highly prevalent in Parkinson's disease patients, especially for those with lower MoCA scores, PIGD, and depression.

Cognitive Training in Parkinson's Disease: A Review of Studies from 2000 to 2014

Cognitive deficits are prevalent among patients with Parkinson's disease (PD), in both early and late stages of the disease. These deficits are associated with lower quality of life, loss of independence, and institutionalization. To date, there is no effective pharmacological treatment for the range of cognitive impairments presented in PD. Cognitive training (CT) has been explored as an alternative approach to remediating cognition in PD. In this review we present a detailed summary of 13 studies of CT that have been conducted between 2000 and 2014 and a critical examination of the evidence for the effectiveness and applicability of CT in PD. Although the evidence shows that CT leads to short-term, moderate improvements in some cognitive functions, methodological inconsistencies weaken these results. We discuss several key limitations of the literature to date, propose methods of addressing these questions, and outline the future directions that studies of CT in PD should pursue. Studies need to provide more detail about the cognitive profile of participants, include larger sample sizes, be hypothesis driven, and be clearer about the training interventions and the outcome measures.

Aldehyde dehydrogenase 2 is associated with cognitive functions in patients with Parkinson's disease

Neurotransmitter degradation has been proposed to cause the accumulation of neurotoxic metabolites. The metabolism of these metabolites involves aldehyde dehydrogenase 2 (ALDH2). The Asian-specific single nucleotide polymorphism rs671 causes reduced enzyme activity. This study aims to explore whether Parkinson's disease (PD) patients with reduced ALDH2 activity owing to the rs671 polymorphism are at risk for neuropsychological impairments. A total of 139 PD patients were recruited. Each participant was assessed for medical characteristics and their ALDH2 genotype. The Mini-Mental State Examination (MMSE), the Clinical Dementia Rating Scale and the Frontal Behavioral Inventory were used to measure neuropsychological functions. We found that the MMSE scores were significantly lower in patients with inactive ALDH2 (U = 1873.5, p = 0.02). The presence of cognitive impairments was significantly more frequent in the inactive ALDH2 group (46.0%) than in the active ALDH2 group (26.3%) (χ(2) = 5.886, p = 0.01). The inactive group showed significant deterioration in hobbies and exhibited more severe "disorganization" and "hyper-sexuality" behaviours. The additive effects of the allele on the development of cognitive impairments in PD patients may be an important finding that provides further insight into the pathogenic mechanism of cognitive dysfunction in PD.

Structural Magnetic Resonance Imaging Markers of Alzheimer's Disease and Its Retranslation to Rodent Models

The importance of imaging biomarkers has been acknowledged in the diagnosis and in the follow-up of Alzheimer's disease (AD), one of the major causes of dementia. Next to the molecular biomarkers and PET imaging investigations, structural MRI approaches provide important information about the disease progression and about the pathomechanism. Furthermore,a growing body of literature retranslates these imaging biomarkers to various rodent models of the disease. The goal of this review is to provide an overview of the macro- and microstructural imaging biomarkers of AD, concentrating on atrophy measures and diffusion MRI alterations. A survey is also given of the imaging approaches used in rodent models of dementias that can promote drug development.

Long-Term Efficacy of Memantine in Parkinson' Disease Dementia: An 18-Month Prospective Perfusion Single Photon Emission Computed Tomography Preliminary Study

Background and Purpose

Although the treatment efficacy of memantine in Parkinson's disease dementia (PDD) has been reported after several weeks of administration, the long-term effects on brain perfusion and clinical symptoms remain unclear. The current study aimed to follow-up PDD patients after 18 months of memantine treatment using ^99mTc hexamethylpropylene amine oxime single photon emission computed tomography (SPECT).

Methods

A total of 15 patients with PDD and 11 healthy participants were recruited into this study and they were assessed with brain SPECT, Mini-Mental State Examination (MMSE), Clinical Dementia Rating (CDR), Global Deterioration Scale (GDS), and Neuropsychiatric Inventory (NPI). Differences in regional cerebral blood flow (rCBF) between the two groups were evaluated at baseline. After 18 months of memantine administration, changes in brain perfusion, severity of dementia, cognition, and neuropsychiatric disturbances were examined in the patients with PDD.

Results

The PDD group showed hypoperfusion in most of the cortical, subcortical, and cerebellar areas compared to healthy controls at baseline. At the follow-up, changes in rCBF, CDR (p=0.32), sum of box of CDR (p=0.49), MMSE (p=0.61), GDS (p=0.79), and NPI (p=0.23) were not significant in the PDD patients.

Conclusions

Our findings implicate that memantine may delay the progression of brain perfusion deficits and clinical symptoms of PDD in the long term.

Validation of Neuropsychological Tests to Screen for Dementia in Chinese Patients With Parkinson's Disease

To compare the accuracy of different neuropsychological tests and their combinations for deriving reliable cognitive indices for dementia diagnosis in Parkinson's disease (PD). One hundred forty consecutive patients with PD were recruited and administrated an extensive battery of neuropsychological tests. Discriminant analysis and receiver-operator characteristic curve were used to evaluate their correct classifications and validity. Patients with PD having dementia (PDD; 23.5%) performed significantly worse in all tests than patients without dementia. Age of onset, disease duration, Hoehn-Yahr grade, Unified Parkinson's Disease Rating Scale part III scores, and education were associated with dementia in patients with PD. Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment, and Block Design (BD) showed better specificity and sensitivity when used alone, and combined use of MMSE and BD further increased the validity. Our results indicated that the accuracy of MMSE was better in dementia diagnosis of Chinese patients with PD, and combined use of MMSE and BD could further increase the validity of dementia diagnosis.

Neuropsychiatric Symptoms in Parkinson's Disease Dementia Are More Similar to Alzheimer's Disease than Dementia with Lewy Bodies: A Case-Control Study

Background and purpose

Previous studies on the clinical and pathological manifestations of Parkinson’s disease dementia (PDD) have reported findings more similar to dementia with Lewy bodies (DLB) than to Alzheimer’s disease (AD). The aim of this study was to investigate the neuropsychiatric symptoms of PDD compared to DLB and AD.

Methods

We conducted a retrospective case-control study on 125 newly diagnosed consecutive PDD patients and age- and dementia stage-matched controls with either DLB (N = 250) or AD (N = 500) who visited the same hospital over the same period. For each case and control, neuropsychiatric symptoms were assessed using the Neuropsychiatric Inventory (NPI).

Results

Overall, 513 (58.6%) patients were female and 362 (41.4%) were male. Comparisons of clinical data revealed that the PDD group, similar to the AD group, had a lower NPI total score, NPI caregiver burden score, and rate of antipsychotic use (all p < 0.001) than the DLB group. One or more psychiatric symptoms were reported in 95.2% of the PDD, 99.2% of the DLB, and 96.8% of the AD patients. The PDD group had lower subscores in the items of delusions, hallucinations, agitation, anxiety, irritation, aberrant motor behavior compared to the DLB group. Severe neuropsychiatric symptoms among all dementia patients were associated with younger age, more advanced stage, and a diagnosis of DLB.

Conclusion

Neuropsychiatric symptoms in PDD were more like those in AD than in DLB. Severe neuropsychiatric symptoms in degenerative dementia were associated with younger age, more advanced stage of dementia, and a diagnosis of DLB.

Use of the Montreal Cognitive Assessment and Alzheimer's Disease-8 as cognitive screening measures in Parkinson's disease

OBJECTIVE

To examine the sensitivity and specificity of the Montreal Cognitive Assessment (MoCA), a brief cognitive screening measure previously validated for use in Parkinson's disease (PD), and Alzheimer's Disease-8 (AD8), an eight-item informant report used to screen for dementia, but not yet validated for use in PD, to identify cognitive impairment in a sample of 111 patients with PD.

METHODS

Cognitive impairment was determined based on a battery of neuropsychological measures, excluding the MoCA and AD8. Classification rates of both the MoCA and AD8 in identifying cognitive impairment were examined using logistic regression and receiver operator characteristic (ROC) analysis. Optimal cutoff scores were determined to maximize sensitivity and specificity.

RESULTS

The MoCA correctly classified 78.4% of participants (p < 0.001), and ROC analysis yielded an area under the curve (AUC) of 0.82. A MoCA cutoff score of <25 yielded optimal sensitivity (0.77) and specificity (0.79) for identifying PD patients with cognitive impairment. Similar analyses for the AD8 were statistically nonsignificant, although the classification rate was 70.5%, with an AUC of 0.50.

CONCLUSIONS

These results provide additional support for the MoCA, but not the AD8, in identifying cognitive impairment in patients with PD.

An Alzheimer's Disease-Derived Biomarker Signature Identifies Parkinson's Disease Patients with Dementia

Biomarkers from multiple modalities have been shown to correlate with cognition in Parkinson's disease (PD) and in Alzheimer's disease (AD). However, the relationships of these markers with each other, and the use of multiple markers in concert to predict an outcome of interest, are areas that are much less explored. Our objectives in this study were (1) to evaluate relationships among 17 biomarkers previously reported to associate with cognition in PD or AD and (2) to test performance of a five-biomarker classifier trained to recognize AD in identifying PD with dementia (PDD). To do this, we evaluated a cross-sectional cohort of PD patients (n = 75) across a spectrum of cognitive abilities. All PD participants had 17 baseline biomarkers from clinical, genetic, biochemical, and imaging modalities measured, and correlations among biomarkers were assessed by Spearman's rho and by hierarchical clustering. We found that internal correlation among all 17 candidate biomarkers was modest, showing a maximum pairwise correlation coefficient of 0.51. However, a five-marker subset panel derived from AD (CSF total tau, CSF phosphorylated tau, CSF amyloid beta 42, APOE genotype, and SPARE-AD imaging score) discriminated cognitively normal PD patients vs. PDD patients with 80% accuracy, when employed in a classifier originally trained to recognize AD. Thus, an AD-derived biomarker signature may identify PDD patients with moderately high accuracy, suggesting mechanisms shared with AD in some PDD patients. Based on five measures readily obtained during life, this AD-derived signature may prove useful in identifying PDD patients most likely to respond to AD-based crossover therapies.

Role of G-protein coupled receptor kinase 5 gene in cognitive impairment in Parkinson's disease

The objective of our study was to investigate the association of two single nucleotide polymorphisms (SNPs) with genetic risk of dementia. In 212 patients with Parkinson's disease (PD), we investigated two polymorphisms within the G-protein coupled receptor kinase 5 (GRK5) gene (rs2420616, rs4752293) to determine a possible risk factor for dementia. We identified two alleles most significantly present in PD patients with dementia: G and T alleles. We also identified risk haplotypes: GC, and AT. We demonstrated that the SNPs and the related haplotypes could play a central role in predisposing PD patients to cognitive impairment.

Targeted case finding for dementia in primary care: Surrey Downs dementia diagnosis project

Currently less than half of the estimated number of people with dementia in England receive a formal diagnosis of dementia or have contact with specialist dementia services. Case finding focused on high risk groups may be an effective way to identify the undiagnosed. This joint Surrey Downs Clinical Commissioning Group and Surrey and Borders NHS Foundation Trust quality improvement project aimed to increase the rate of dementia diagnosis across Surrey Downs using specialist link nurses (SLNs).

Thirty three GP surgeries covering the entire Surrey Downs area took part in the project. Individuals at high risk of developing dementia were identified from GP electronic disease registers, and were offered screening at their GP practices by SLNs, using a combination of mini cognitive test (Mini-Cog) and functional assessment questionnaire (FAQ). Suitable individuals who screened positive were seen by their GP and where appropriate referred to secondary care services for further evaluation.

Based on the presence of risk factors, 6657 (11.9%) people were identified from a total population of 55 845 over 65s, and 1980 (29.7%) completed the screening assessment. Three hundred and fifty eight (18.1%) individuals screened positive and were referred to their GP, who referred 205 (57.2%) of them to the memory services for further assessment. Of those referred, 164 (80%) had a comprehensive specialist assessment. Forty one (20%) declined further assessment, and their GPs were informed.

The mean age of the cohort who completed the comprehensive assessment was 82.3 years (SD=4.26), and were predominantly white and male. Fifty four (32.9%) had mild cognitive disorder (MCD), and 101 (61.6%) patients were diagnosed with dementia. The most common dementia was mixed type (43; 42.6%), followed by Alzheimer's dementia (32; 31.7%). The most common risk factor among patients with cognitive impairment (MCD or dementia) was hypertension (69; 44.5 %), followed by ischemic heart disease (64, 41.3%).

Nurse led case finding for cognitive impairment in a high risk population identifies people with dementia who are not yet formally diagnosed. The combined use of brief instruments to assess cognitive functioning and functional capabilities is helpful in identifying individuals with possible dementia.

Differentiated Cells Derived from Fetal Neural Stem Cells Improve Motor Deficits in a Rat Model of Parkinson's Disease

Objective

Parkinson's disease (PD), which is one of the most common neurodegenerative disorders, is characterized by the loss of dopamine (DA) neurons in the substantia nigra in the midbrain. Experimental and clinical studies have shown that fetal neural stem cells (NSCs) have therapeutic effects in neurological disorders. The aim of this study was to examine whether cells that were differentiated from NSCs had therapeutic effects in a rat model of PD.

Methods

NSCs were isolated from 14-week-old embryos and induced to differentiate into neurons, DA neurons, and glial cells, and these cells were characterized by their expression of the following markers: βIII-tubulin and microtubule-associated protein 2 (neurons), tyrosine hydroxylase (DA neurons), and glial fibrillary acidic protein (glial cells). After a 6-hydroxydopamine (6-OHDA)-lesioned rat model of PD was generated, the differentiated cells were transplanted into the striata of the 6-OHDA-lesioned PD rats.

Results

The motor behaviors of the PD rats were assessed by the number of apomorphine-induced rotation turns. The results showed that the NSCs differentiated in vitro into neurons and DA neurons with high efficiencies. After transplantation into the striata of the PD rats, the differentiated cells significantly improved the motor deficits of the transplanted PD rats compared to those of the control nontransplanted PD rats by decreasing the apomorphine-induced turn cycles as early as 4 weeks after transplantation. Immunofluorescence analyses showed that the differentiated DA neurons survived more than 16 weeks.

Conclusions

Our results showed that cells that were differentiated from NSCs had therapeutic effects in a rat PD model, which suggests that differentiated cells may be an effective treatment for patients with PD.

Interactions of visual hallucinations, rapid eye movement sleep behavior disorder and cognitive impairment in Parkinson's disease: A review

Patients with Parkinson's disease may develop various non-motor symptoms during the course of the illness. Visual hallucinations (VH) and cognitive impairment (CI) are two common non-motor symptoms of Parkinson's disease. Studies have reported association of both VH and CI with presence of rapid eye movement sleep behavior disorder (RBD). Presence of visual hallucinations and cognitive impairment has been described as risk factors for emergence of each other. There is marked overlap in the risk factors for development of RBD, VH and CI in patients with PD. Results of clinical and epidemiological studies as well as studies based on neuroimaging, electrophysiology especially transcranial magnetic stimulation and neuropsycholgical evaluations in PD patients have suggested presence of certain common neurobiological process leading to emergence of RBD, VH and CI. Structural neuroimaging studies using voxel-based morphometry have often reported grey matter atrophy of hippocampus and parahippocampal cortices in PD patients with RBD, VH and CI. Cholinergic dysfunction is common in PD patients with RBD, VH and CI. This review explores the complex interactions of RBD, VH and CI in patients with PD and their potential implications.

Alteration of Brain Functional Networks in Early-Stage Parkinson's Disease: A Resting-State fMRI Study

Although alterations of topological organization have previously been reported in the brain functional network of Parkinson's disease (PD) patients, the topological properties of the brain network in early-stage PD patients who received antiparkinson treatment are largely unknown. This study sought to determine the topological characteristics of the large-scale functional network in early-stage PD patients. First, 26early-stage PD patients (Hoehn and Yahr stage:1-2) and 30 age-matched normal controls were scanned using resting-state functional MRI. Subsequently, graph theoretical analysis was employed to investigate the abnormal topological configuration of the brain network in early-stage PD patients. We found that both the PD patient and control groups showed small-world properties in their functional brain networks. However, compared with the controls, the early-stage PD patients exhibited abnormal global properties, characterized by lower global efficiency. Moreover, the modular structure and the hub distribution were markedly altered in early-stage PD patients. Furthermore, PD patients exhibited increased nodal centrality, primarily in the bilateral pallidum, the inferior parietal lobule, and the medial superior frontal gyrus, and decreased nodal centrality in the caudate nucleus, the supplementary motor areas, the precentral gyrus, and the middle frontal gyrus. There were significant negative correlations between the Unified Parkinson Disease Rating Scale motor scores and nodal centralities of superior parietal gyrus. These results suggest that the topological organization of the brain functional network was altered in early-stage PD patients who received antiparkinson treatment, and we speculated that the antiparkinson treatment may affect the efficiency of the brain network to effectively relieve clinical symptoms of PD.

Mild cognitive impairment in Parkinson's disease and its progression onto dementia: a 16-year outcome evaluation of the Denbighshire cohort

OBJECTIVE

Mild cognitive impairment in Parkinson's disease (PD-MCI) has been suggested to be a predictor for the development of PD dementia (PDD). This study explored the incidence and possible neuropsychological domain differences between PD patients with PD-MCI and without cognitive impairment (normal cognitive function with PD), on the basis of the Movement Disorders Task Force Guidelines for PD-MCI.

METHODS

At baseline (T1), 4 years (T2) and 6 years (T3), 166 patients with PD were administered global neuropsychological assessments. At 16 years, case note and neuropsychological assessment review was employed to calculate the number of patients who had progressed to PDD.

RESULTS

At baseline, 68 patients were classified as normal cognitive function with PD, 18 with PD-MCI and 80 with PDD. At T2, 12 of the PD-MCI cohort at T1 had progressed to PDD, and there were 15 incident cases of PD-MCI. At T3, nine PD-MCI cases at T2 had progressed to PDD. There were 10 incident cases of PD-MCI at T3. The incidence of progression from PD-MCI to PDD was 98.0 per 1000 person-years, with an annual conversion rate to PDD of 11%. Neuropsychological predictors for conversion from PD-MCI to PDD were semantic language, praxis (figure drawing/copying) and visuospatial deficits. At 16 years, 91% of the PD-MCI cohort had progressed to PDD.

CONCLUSIONS

Mild cognitive impairment in Parkinson's disease is an important predictor for the progression to PDD. This investigation also confirmed that if PD patients live long enough, they will develop cognitive impairment or dementia. Early detection of cognitive impairment in these individuals is possible with existing standardised global cognitive assessments, which include semantic language assessment.

The long-term development of non-motor problems after STN-DBS

OBJECTIVES

Stimulation of the subthalamic nucleus (STN-DBS) is an established treatment with long-term beneficial effects on motor symptoms in patients with Parkinson's disease (PD). The long-term development of non-motor problems after STN-DBS is not fully understood. In this study, we have studied how non-motor problems develop in patients with and without STN-DBS.

MATERIALS AND METHODS

We collected data from a prospectively followed cohort of patients that had been operated with STN-DBS 6-9 years before final examination and compared our findings to the longitudinal development of non-motor problems in a non-operated, comparable reference population.

RESULTS

In general, the non-motor problems of advanced PD seem to develop independently of treatment with STN-DBS. We found that depressions do not worsen after STN-DBS, and the Montgomery and Aasberg Depression Rating Scale score in operated patients was substantially reduced from pre-operatively to post-operatively. Further, fatigue may represent an important unrecognized side effect of long-term stimulation, as fatigue was found to increase rapidly in operated patients already a year after surgery and continued to increase trough the 6- to 9-year follow-up.

CONCLUSIONS

The non-motor problems of advanced PD seem to develop independently of treatment with STN-DBS. This may influence the strategy for choice of when to perform this therapy for eligible patients.

The Neuropsychiatric and Motor Profile of GBA-Associated Parkinson's Disease: A Review

Background

Cognitive and motor decline, along with psychiatric symptoms, have a major impact on independence, nursing home admission, caregiver burden, and mortality in Parkinson's disease (PD). The single most common genetic risk factor for developing PD is a mutation in the glucocerebrosidase (GBA) gene.

Methods

This work is a literature review regarding "GBA" and "Parkinson's disease" as conducted by PubMed search.

Results

There is a higher prevalence of cognitive decline and more rapid trajectory of disease progression in PD-GBA carriers, compared to noncarriers. PD-GBA carriers also have domain-specific cognitive impairment, particularly in visual memory tasks. PD-GBA carriers may also have a more aggressive motor phenotype than noncarriers.

Conclusions

Early identification of PD-GBA carriers may lead to targeted therapies and development of new treatments.

Development of stem cell-based therapy for Parkinson's disease

Parkinson’s disease (PD) is one of the most common neurodegenerative disorders of aging, characterized by the degeneration of dopamine neurons (DA neurons) in the substantial nigra, leading to the advent of both motor symptoms and non-motor symptoms. Current treatments include electrical stimulation of the affected brain areas and dopamine replacement therapy. Even though both categories are effective in treating PD patients, the disease progression cannot be stopped. The research advance into cell therapies provides exciting potential for the treatment of PD. Current cell sources include neural stem cells (NSCs) from fetal brain tissues, human embryonic stem cells (hESCs), induced pluripotent stem cells (iPSCs) and directly induced dopamine neurons (iDA neurons). Here, we evaluate the research progress in different cell sources with a focus on using iPSCs as a valuable source and propose key challenges for developing cells suitable for large-scale clinical applications in the treatment of PD.

Recognition and treatment of neuropsychiatric disturbances in Parkinson's disease

The non-motor symptoms of Parkinson's disease (PD) have been attracting increasing attention due to their ubiquitous nature and their often devastating effects on the quality of life. Behavioral problems in PD include dementia, depression, apathy, fatigue, anxiety, psychosis, akathisia, personality change, sleep disorders and impulse control disorders. Some of these are intrinsic to the neuropathology while others occur as an interplay between pathology, psychology and pharmacology. While few data exist for guiding therapy, enough is known to guide therapy in a rational manner.

Clinical phenotype of drug-naïve Parkinson's disease based on nonmotor symptoms

BACKGROUND

Nonmotor symptoms in Parkinson's disease (PD) are heterogeneous and can result in a variety of symptoms at various disease stages. The objective of the present study was to identify clinically meaningful nonmotor symptoms and to assess the relationship between changes in nonmotor symptoms and cognition and motor symptoms.

METHODS

A total of 159 patients who had drug-naïve PD participated in this study. Nonmotor symptoms (Nonmotor Symptoms Scale), PD status (Unified Parkinson's Disease Rating Scale), depression (Geriatric Depression Scale or Montgomery-Asberg Depression Scale) and health-related quality of life (39-item Parkinson's Disease Questionnaire) were assessed. An exploratory factor analysis was performed to establish a nonmotor symptom factor, which was analyzed to evaluate whether the results were associated with the clinical severity measures.

RESULTS

Exploratory factor analysis revealed one factor comprised of sleep/fatigue, attention/memory and mood/cognition. The modified Hoehn and Yahr Stage, Unified Parkinson's Disease Rating Scale Part III, Montgomery-Asberg Depression Scale and the 39-item Parkinson's Disease Questionnaire Summary Index were independently associated with the sleep/fatigue, attention/memory and mood/cognition domains. The presence of these domains was associated with advanced Parkinson's disease or depressed mood.

CONCLUSIONS

This study shows that motor impairment and depressed mood in PD are related to sleep/fatigue, attention/memory and mood/cognition. Sleep/fatigue, attention/memory and mood/cognition also had a major impact on health-related quality of life. It is appropriate to identify patients with severe motor symptoms and depressed mood in order to signify the need to consider more detailed care and further assessment.

Cognitive performance and neuropsychiatric symptoms in early, untreated Parkinson's disease

This study was undertaken to determine the prevalence and correlates of cognitive impairment (CI) and neuropsychiatric symptoms (NPS) in early, untreated patients with Parkinson's disease (PD).

BACKGROUND

Both CI and NPS are common in PD and impact disease course and quality of life. However, limited knowledge is available about cognitive abilities and NPS.

METHODS

Parkinson's Progression Markers Initiative (PPMI) is a multi-site study of early, untreated PD patients and healthy controls (HCs), the latter with normal cognition. At baseline, participants were assessed with a neuropsychological battery and for symptoms of depression, anxiety, impulse control disorders (ICDs), psychosis, and apathy.

RESULTS

Baseline data of 423 PD patients and 196 HCs yielded no between-group differences in demographic characteristics. Twenty-two percent of PD patients met the PD-recommended screening cutoff for CI on the Montral Cognitive Assessment (MoCA), but only 9% met detailed neuropsychological testing criteria for mild cognitive impairment (MCI)-level impairment. The PD patients were more depressed than HCs (P < 0.001), with twice as many (14% vs. 7%) meeting criteria for clinically significant depressive symptoms. The PD patients also experienced more anxiety (P < 0.001) and apathy (P < 0.001) than HCs. Psychosis was uncommon in PD (3%), and no between-group difference was seen in ICD symptoms (P = 0.51).

CONCLUSIONS

Approximately 10% of PD patients in the early, untreated disease state met traditional criteria of CI, which is a lower frequency compared with previous studies. Multiple dopaminergic-dependent NPS are also more common in these patients compared with the general population, but others associated with dopamine replacement therapy are not or are rare. Future analyses of this cohort will examine biological predictors and the course of CI and NPS. © 2015 International Parkinson and Movement Disorder Society.

Intraventricular cerebrospinal fluid temperature analysis using MR diffusion-weighted imaging thermometry in Parkinson's disease patients, multiple system atrophy patients, and healthy subjects

PURPOSE

We examined the temperature of the intraventricular cerebrospinal fluid (Tv) in patients with Parkinson's disease (PD) and those with multiple system atrophy (MSA) in comparison with healthy subjects, and we examined normal changes in this temperature with aging.

METHODS

Tv was estimated by magnetic resonance (MR) diffusion-weighted imaging (DWI) thermometry in 36 PD patients (19 males, 17 females), 34 MSA patients (17 males, 17 females), 64 age-matched controls (27 men, 37 women), and 114 all-age adult controls (47 men, 67 women; 28-89 years old). The volume of lateral ventricles was also estimated using FreeSurfer in all subjects. Tv and ventricular volume data were compared among the PD and MSA patients and age-matched controls. We also evaluated the relationship between Tv and age in the 114 all-age controls, controlling for ventricular volume. Men and women were analyzed separately.

RESULTS

The male PD and MSA patients had significantly higher Tv values compared to the male controls, with no significant difference in ventricular volume among them. There was no significant difference in Tv between the female patients and controls. In the all-age male controls, there was a significant negative correlation between Tv and age controlling for ventricular volume, and this was not observed in the women.

CONCLUSION

DWI thermometry is a useful and easy method for demonstrating an altered intracranial environment in male patients and healthy controls, but not in females. DWI thermometry can thus be used to help to explore the pathophysiology of Parkinsonian syndromes and to differentiate individuals affected by neurodegenerative disease with autonomic dysfunction from those without it.

Cognitive profiles in Mild Cognitive Impairment (MCI) patients associated with Parkinson's disease and cognitive disorders

BACKGROUND

Mild cognitive impairment (MCI) is rapidly becoming one of the most common clinical manifestations affecting the elderly and represents an heterogeneous clinical syndrome that can be ascribed to different etiologies; the construct of MCI in Parkinson's disease (PD) (MCI-PD) is more recent but the range of deficits is still variable. Early recognition and accurate classification of MCI-PD could offer opportunities for novel therapeutic interventions to improve the natural pathologic course.

OBJECTIVE

To investigate the clinical phenotype of amnestic mild cognitive impairment (aMCI) and in patients with PD and MCI (MCI-PD).

MATERIALS AND METHODS

Seventy-three patients with aMCI and in 38 patients with MCI-PD were enrolled. They all underwent Mini-mental State Examination (MMSE), the Rey auditory-verbal learning test and the immediate visual memory (IVM) item of the Mental Deterioration Battery, the Rey auditory-verbal learning test included the Rey-immediate (Rey-I), and the delayed recall of the word list (Rey test deferred, Rey-D). The Geriatric Depression Scale (GDS) was used for mood assessment.

RESULTS

The results of the Rey-I and Rey-D and of the IVM item showed statistically significant differences between the aMCI and the MCI-PD group. The mean Rey-I and Rey-D score was significantly lower as well as the IVM score was higher in patients with aMCI than in those with MCI-PD, aMCI patients showed greater impairment in long-term memory, whereas more aMCI than MCI-PD patients had preserved attention, computation, praxis, and conceptualization.

CONCLUSIONS

Our findings demonstrate that the cognitive deficit profile is specific for each of the two disorders: Memory impairment was a typical feature in aMCI patients while MCI-PD patients suffered from executive functions and visuospatial attention deficits.

Clinical predictors of cognitive impairment and psychiatric complications in Parkinson’s disease

Objective To estimate the clinical and demographics aspects that may contribute to cognitive impairment and psychiatric symptoms in Parkinson’s disease (PD). Method All patients answered a structured standardized clinical questionnaire. Two movement disorders specialists performed the following scale: Unified Parkinson’s disease rating score (UPDRS), the modified Hoehn and Yahr staging, Schwab and England Scale, SCOPA cognition (SCOPA-COG), SCOPA-Psychiatric complications (SCOPA-PC) and Non-Motor Symptoms Scale (NMSS). We built a generalized linear model to assess predictors for the SCOPA-COG and SCOPA-PC scores. Results Almost 37% of our patients were demented as per SCOPA-COG scores. Level of education and the UPDRS-Subscale III were predictors of cognitive impairment. Higher scores in domain 3 of NMSS and male gender were associated with psychiatric complications as assessed per the SCOPA-PC. Conclusion Level of education and disease severity are predictors of dementia in PD. Psychiatric complications are more commonly observed in men.

Diffusion-MRI in neurodegenerative disorders

The ability to image the whole brain through ever more subtle and specific methods/contrasts has come to play a key role in understanding the basis of brain abnormalities in several diseases. In magnetic resonance imaging (MRI), "diffusion" (i.e. the random, thermally-induced displacements of water molecules over time) represents an extraordinarily sensitive contrast mechanism, and the exquisite structural detail it affords has proven useful in a vast number of clinical as well as research applications. Since diffusion-MRI is a truly quantitative imaging technique, the indices it provides can serve as potential imaging biomarkers which could allow early detection of pathological alterations as well as tracking and possibly predicting subtle changes in follow-up examinations and clinical trials. Accordingly, diffusion-MRI has proven useful in obtaining information to better understand the microstructural changes and neurophysiological mechanisms underlying various neurodegenerative disorders. In this review article, we summarize and explore the main applications, findings, perspectives as well as challenges and future research of diffusion-MRI in various neurodegenerative disorders including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease and degenerative ataxias.

Biomarkers of cognitive decline in Parkinson's disease

Cognitive impairment is a frequent and devastating non-motor symptom of Parkinson's disease (PD). Impaired cognition has a major impact on either quality of life or mortality in patients with PD. Notably, the rate of cognitive decline and pattern of early cognitive deficits in PD are highly variable between individuals. Given that the underlying mechanisms of cognitive decline or dementia associated with PD remain unclear, there is currently no mechanism-based treatment available. Identification of biological markers, including neuroimaging, biofluids and common genetic variants, that account for the heterogeneity of PD related cognitive decline could provide important insights into the pathological processes that underlie cognitive impairment in PD. These combined biomarker approaches will enable early diagnosis and provide indicators of cognitive progression in PD patients. This review summarizes recent advances in the development of biomarkers for cognitive impairments in PD.

Early diagnosis of Alzheimer's disease and Parkinson's disease associated with dementia using cerebral perfusion SPECT

BACKGROUND

Since patterns of cognitive dysfunction in mild Parkinson's disease associated with dementia (PDD) are similar to those in mild Alzheimer's disease (AD), it is difficult to accurately differentiate between these two types of dementia in their early phases using neuropsychological tests. The purpose of the current study was to investigate differences in cerebral perfusion patterns of patients with AD and PDD at the earliest stages using single photon emission computed tomography (SPECT).

METHODS

We consecutively recruited 31 patients with mild PDD, 32 patients with mild probable AD and 33 age-matched healthy subjects. All subjects underwent (99m)Tc-hexamethylpropyleneamine oxime perfusion SPECT and completed general neuropsychological tests.

RESULTS

We found that both mild PDD and AD patients showed distinct hypoperfusion in frontal, parietal and temporal regions, compared with healthy subjects. More importantly, hypoperfusion in occipital and cerebellar regions was observed only in mild PDD.

CONCLUSION

The observation of a significant decrease in cerebral perfusion in occipital and cerebellar regions in patients with mild PDD is likely useful to differentiate between PDD and AD at the earliest stages.

Efficacy and safety of cholinesterase inhibitors and memantine in cognitive impairment in Parkinson's disease, Parkinson's disease dementia, and dementia with Lewy bodies: systematic review with meta-analysis and trial sequential analysis

OBJECTIVE

Recently, several large randomised controlled trials about the treatments of cognitive impairment or dementia due to Parkinson's disease (CIND-PD or PDD) and dementia with Lewy bodies (DLB) were completed. Here, we systematically reviewed the studies (including the recent reports) to provide updated evidence for the treatments of CIND-PD, PDD and DLB.

METHODS

We searched Cochrane Dementia and Cognitive Improvement Group Specialised Register, Pubmed, Embase, and other sources for eligible trials. We selected global impression and cognitive function as primary efficacy outcomes, and dropouts and adverse events as safety outcomes. Furthermore, Meta-analysis and trial sequential analysis (TSA) were used here.

RESULTS

Ten trials were included in this study. Cholinesterase inhibitors and memantine produced small global efficacy on clinicians' global impression of change (CGIC), from a weighted mean difference of -0.40 (95% CI -0.77 to -0.03) to -0.65 (95% CI -1.28 to -0.01); however, cholinesterase inhibitors but not memantine significantly improved cognition on Mini-Mental State Examination (MMSE), from 1.04 (95% CI 0.43 to 1.65) to 2.57 (95% CI 0.90 to 4.23). Additionally, both of them had good safety outcomes, although rivastigmine showed an increased risk on adverse events than placebo (risk ratio, RR 1.19, TSA adjusted 95% CI 1.04 to 1.36), these events were usually mild or moderate, and the risk disappeared on serious adverse events.

CONCLUSIONS

Cholinesterase inhibitors and memantine slightly improve global impression; however, only cholinesterase inhibitors enhance cognitive function. Besides, all the drugs have good safety outcomes. But the limited trials precluded the generalisation of these outcomes.

Characteristics of language impairment in Parkinson's disease and its influencing factors

Background

Language impairment is relatively common in Parkinson’s disease (PD), but not all PD patients are susceptible to language problems. In this study, we identified among a sample of PD patients those pre-disposed to language impairment, describe their clinical profiles, and consider factors that may precipitate language disability in these patients.

Methods

A cross-sectional cohort of 31 PD patients and 20 controls were administered the Chinese version of the Western Aphasia Battery (WAB) to assess language abilities, and the Montreal Cognitive Assessment (MoCA) to determine cognitive status. PD patients were then apportioned to a language-impaired PD (LI-PD) group or a PD group with no language impairment (NLI-PD). Performance on the WAB and MoCA was investigated for correlation with the aphasia quotient deterioration rate (AQDR).

Results

The PD patients scored significantly lower on most of the WAB subtests than did the controls. The aphasia quotient, cortical quotient, and spontaneous speech and naming subtests of the WAB were significantly different between LI-PD and NLI-PD groups. The AQDR scores significantly and positively correlated with age at onset and motor function deterioration.

Conclusion

A subset group was susceptible to language dysfunction, a major deficit in spontaneous speech. Once established, dysphasia progression is closely associated with age at onset and motor disability progression.

Ceftriaxone prevents and reverses behavioral and neuronal deficits in an MPTP-induced animal model of Parkinson's disease dementia

Glutamatergic hyperactivity plays an important role in the pathophysiology of Parkinson's disease (PD). Ceftriaxone increases expression of glutamate transporter 1 (GLT-1) and affords neuroprotection. This study was aimed at clarifying whether ceftriaxone prevented, or reversed, behavioral and neuronal deficits in an 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD rat model. Male Wistar rats were injected daily with either ceftriaxone starting 5 days before or 3 days after MPTP lesioning (day 0) or saline and underwent a bar-test on days 1-7, a T-maze test on days 9-11, and an object recognition test on days 12-14, then the brains were taken for histological evaluation on day 15. Dopaminergic degeneration in the substantia nigra pars compacta and striatum was observed on days 3 and 15. Motor dysfunction in the bar test was observed on day 1, but disappeared by day 7. In addition, lesioning resulted in deficits in working memory in the T-maze test and in object recognition in the object recognition task, but these were not observed in rats treated pre- or post-lesioning with ceftriaxone. Lesioning also caused neurodegeneration in the hippocampal CA1 area and induced glutamatergic hyperactivity in the subthalamic nucleus, and both changes were suppressed by ceftriaxone. Increased GLT-1 expression and its co-localization with astrocytes were observed in the striatum and hippocampus in the ceftriaxone-treated animals. To our knowledge, this is the first study showing a relationship between ceftriaxone-induced GLT-1 expression, neuroprotection, and improved cognition in a PD rat model. Ceftriaxone may have clinical potential for the prevention and treatment of dementia associated with PD.

Dementia and cognitive impairment in patients with Parkinson's disease from India: a 7-year prospective study

Depression and cognitive impairment are frequent manifestations in Parkinson's disease (PD). Although a few longitudinal studies have reported on depression and dementia in PD, there is a yet a lack of such studies in India. This 7-year longitudinal study is a hospital-based prospective case (n = 250)-control (n = 280) study. In all, 36.8% had PD with no cognitive impairment (PD-Normal), 27.2% of the patients with PD were affected by dementia (PDD), and 36% of the remaining patients with PD had mild cognitive impairment (PD-MCI) at baseline. After 7 years of evaluation, 32 new patients, 12 patients from the PD-MCI group and 9 patients from the PD-Normal group, were diagnosed with dementia. The 7-year prevalence rate for dementia was estimated to be 49.28%. In the Indian population, an early onset of dementia is noted among patients with PD, with the age of onset being less than 55 years. Patients with early-onset PDD showed depression symptoms that differed significantly from the controls of the same age-group. There was a major difference in verbal fluency, word list recall, constructional praxis and recall, word list recognition, abridged Boston Naming Test, word list memory with repetition, and Mini-Mental State Examination between PD-MCI and PDD groups. Hallucinations before baseline (odds ratio [OR] = 4.427, 95% confidence interval [CI] = 2.122-9.373), akinetic/tremor dominancy (OR = 0.380, 95%CI = 0.149-0.953), and asymmetrical disease onset (OR = 0.3285, 95%CI = 0.1576-0.685) can be considered as risk factors for patients with dementia. Patients with early-onset PD might be more prone to complex depression and dementia. As the disease progresses, akinetic-dominant PD, early hallucinations, and asymmetrical disease onset are the potential risk factors for the development of dementia in patients with PD.

Smartphone- and internet-assisted self-management and adherence tools to manage Parkinson's disease (SMART-PD): study protocol for a randomised controlled trial (v7; 15 August 2014)

BACKGROUND

Nonadherence to treatment leads to suboptimal treatment outcomes and enormous costs to the economy. This is especially important in Parkinson's disease (PD). The progressive nature of the degenerative process, the complex treatment regimens and the high rates of comorbid conditions make treatment adherence in PD a challenge. Clinicians have limited face-to-face consultation time with PD patients, making it difficult to comprehensively address non-adherence. The rapid growth of digital technologies provides an opportunity to improve adherence and the quality of decision-making during consultation. The aim of this randomised controlled trial (RCT) is to evaluate the impact of using a smartphone and web applications to promote patient self-management as a tool to increase treatment adherence and working with the data collected to enhance the quality of clinical consultation.

METHODS/DESIGN

A 4-month multicentre RCT with 222 patients will be conducted to compare use of a smartphone- and internet-enabled Parkinson's tracker smartphone app with treatment as usual for patients with PD and/or their carers. The study investigators will compare the two groups immediately after intervention. Seven centres across England (6) and Scotland (1) will be involved. The primary objective of this trial is to assess whether patients with PD who use the app show improved medication adherence compared to those receiving treatment as usual alone. The secondary objectives are to investigate whether patients who receive the app and those who receive treatment as usual differ in terms of quality of life, quality of clinical consultation, overall disease state and activities of daily living. We also aim to investigate the experience of those receiving the intervention by conducting qualitative interviews with a sample of participants and clinicians, which will be administered by independent researchers.

TRIAL REGISTRATION

ISRCTN45824264 (registered 5 November 2013).

Changes of brain gray matter structure in Parkinson's disease patients with dementia

Voxel-based morphometry is gaining considerable interest for studies examining Parkinson's disease dementia patients. In this study, 12 patients with clinically defined Parkinson's disease and dementia and 12 non-demented patients with Parkinson's disease were examined using a T1WI three-dimensional fast spoiled gradient echo sequence. Gray matter data were analyzed using a voxel-based morphometry method and independent sample t-test based on Statistical Parametric Mapping 5 software. Differences in gray matter volume were represented with statistical parametric mapping. Compared with Parkinson's disease patients without dementia, decreased gray matter volume in Parkinson's disease dementia patients was observed in the bilateral superior temporal gyrus, bilateral posterior cingulate and left cingulate gyrus, right parahippocampal gyrus and hippocampus, right precuneus and right cuneus, left inferior frontal gyrus and left insular lobe. No increased gray matter volume was apparent. These data indicate that gray matter atrophy in the limbic system and cerebral neocortex is related to the presence of dementia.

Introducing a multifaceted exercise intervention particular to older adults diagnosed with Parkinson's disease: a preliminary study

BACKGROUND AND AIM

With a substantial increase in diagnosed Parkinson's disease, it is of great importance to examine tolerance and physical measures of evolving exercise interventions. Of particular importance, a multifaceted exercise intervention combining active-assisted cycling and resistance training to older adults diagnosed with Parkinson's disease is being assessed.

METHODS

Fourteen older adults diagnosed with Parkinson's disease and ten healthy older adults (67.5 ± 7.9 years of age) engaged in an 8-week, 24-session, multifaceted exercise protocol. The protocol consisted of both active-assisted cycling and resistance training. Tolerance was measured, as well as multiple indicators of health-related physical fitness. These indicators examined improvements in cardiovascular performance, muscular strength, muscular endurance, and flexibility.

RESULTS

Twenty-two older adults and older adults diagnosed with Parkinson's disease tolerated the intervention by completing all 24 sessions. Repeated-measures analysis of variance demonstrated significant (P ≤ 0.003) improvements in cardiovascular performance, muscular strength, muscular endurance, and flexibility for both groups of individuals.

DISCUSSION AND CONCLUSION

The multifaceted intervention is the first to combine both active-assisted cycling and resistance training. The older adult and the older adult diagnosed with Parkinson's disease exhibited both tolerance and health-related improvements in physical fitness following the intervention.

Executive function and postural instability in people with Parkinson's disease

The specific aspects of cognition contributing to balance and gait have not been clarified in people with Parkinson's disease (PD). Twenty PD participants and twenty age- and gender-matched healthy controls were assessed on cognition and clinical mobility tests. General cognition was assessed with the Mini Mental State Exam and Addenbrooke's Cognitive Exam. Executive function was evaluated using the Trail Making Tests (TMT-A and TMT-B) and a computerized cognitive battery which included a series of choice reaction time (CRT) tests. Clinical gait and balance measures included the Tinetti, Timed Up & Go, Berg Balance, and Functional Reach tests. PD participants performed significantly worse than the controls on the tests of cognitive and executive function, balance, and gait. PD participants took longer on Trail Making Tests, CRT-Location, and CRT-Colour (inhibition response). Furthermore, executive function, particularly longer times on CRT-Distracter and greater errors on the TMT-B, was associated with worse balance and gait performance in the PD group. Measures of general cognition were not associated with balance and gait measures in either group. For PD participants, attention and executive function were impaired. Components of executive function, particularly those involving inhibition response and distracters, were associated with poorer balance and gait performance in PD.

Predictors of dementia in Parkinson's disease; findings from a 5-year prospective study using the SCOPA-COG

OBJECTIVE

Aim of this study was to identify risk factors for the development of dementia in patients with Parkinson's disease (PD).

METHODS

A broad range of motor and non-motor features was assessed at baseline and the following five years in 406 PD patients. Cross-sectional analyses of baseline data and longitudinal analyses of follow-up data were performed to identify risk factors for dementia.

RESULTS

Thirty-two percent of patients (n = 129) had dementia at baseline, while 26% of patients (n = 68) without dementia at baseline developed dementia during follow-up. Univariate survival analysis showed that higher age, fewer years of education, longer disease duration, higher age-at-onset, higher levodopa dose, higher Hoehn & Yahr stage, presence of dyskinesias, excessive daytime sleepiness (EDS), presence of hallucinations, and more severe autonomic and depressive symptoms were associated with an increased risk of dementia. Higher baseline Postural-Instability-and-Gait-Difficulty scores were also associated with an increased risk of dementia, whereas no effect of tremor severity was found. These findings largely corresponded with the variables that were associated with the presence of dementia at baseline. In a stepwise regression model, higher age at baseline, fewer years of education, higher daily levodopa dose and excessive daytime sleepiness (EDS) emerged as independent risk factors of future dementia.

CONCLUSIONS

In this large prospective cohort study, we identified a combination of potentially interacting risk factors for dementia in PD that are associated with higher age and more advanced disease.

Mapping cortical atrophy in Parkinson's disease patients with dementia

BACKGROUND

Cognitive impairment is very common in patients with Parkinson's disease (PD). Brain changes accompanying cognitive decline in PD are still not fully established.

METHODS

We applied cortical pattern matching and cortical thickness analyses to the three-dimensional T1-weighted brain MRI scans of 14 age-matched cognitively normal elderly (NC), 12 cognitively normal PD (PDC), and 11 PD dementia (PDD) subjects. We used linear regression models to investigate the effect of diagnosis on cortical thickness. All maps were adjusted for multiple comparisons using permutation testing with a threshold p < 0.01.

RESULTS

PDD showed significantly thinner bilateral sensorimotor, perisylvian, lateral parietal, as well as right posterior cingulate, parieto-occipital, inferior temporal and lateral frontal cortices relative to NC (left p(corrected) = 0.06, right p(corrected) = 0.009). PDD showed significantly thinner bilateral sensorimotor, right frontal and right parietal-occipital cortices relative to PDC (right p(corrected) = 0.05). The absolute difference in cortical thickness between PDD and the other diagnostic groups ranged from 3% to 19%.

CONCLUSION

Our data shows that cognitive decline in PD is associated with cortical atrophy. PDD subjects have the most widespread gray matter atrophy suggesting more cortical involvement as PD patients progress to dementia.

Cerebral microbleeds in patients with Parkinson's disease

Cerebral microbleeds (CMBs) are known to be associated with cognitive impairments in the elderly and in patients with various diseases; however, the nature of this association has not yet been evaluated in Parkinson's disease (PD). In the present study, we analyzed the incidence of CMBs in PD according to cognitive status, and the impact of CMBs on cognitive performance was also evaluated. The CMBs in PD with dementia (n = 36), mild cognitive impairment (MCI, n = 46), or cognitively normal (n = 41) were analyzed using conventional T2*-weighted gradient-recalled echo images. Additionally, the relationship between the presence of CMBs and cognitive performance on individual tests of cognitive subdomains was analyzed using a detailed neuropsychological test. CMBs occurred more frequently in PD patients with dementia (36.1 %) compared to those with MCI (15.2 %), those who are cognitively normal (14.6 %), and normal controls (12.2 %, p = 0.025). However, the significant association of CMBs with PD dementia disappeared after adjusting white matter hyperintensities (WMHs) as a covariate. The frequencies of deep, lobar, and infratentorial CMBs did not differ among the four groups. After adjusting for age, sex, years of education, and WMHs, PD patients with CMBs had poorer performance in attention domain compared with those without CMBs (34.9 vs 42.6, p = 0.018). The present data demonstrate that even though CMBs were inseparably associated with the presence of WMHs, CMBs occur more commonly in PD patients with dementia than in those without dementia. Additionally, the burden of CMBs may contribute to further cognitive impairment in PD.

Correlation of sleep disturbance and cognitive impairment in patients with Parkinson's disease

OBJECTIVE

Cognitive impairment is a common nonmotor symptom of Parkinson's disease (PD) and is associated with high mortality, caregiver distress, and nursing home placement. The risk factors for cognitive decline in PD patients include advanced age, longer disease duration, rapid eye movement sleep behavior disorder, hallucinations, excessive daytime sleepiness, and nontremor symptoms including bradykinesia, rigidity, postural instability, and gait disturbance. We conducted a cross-sectional study to determine which types of sleep disturbances are related to cognitive function in PD patients.

METHODS

A total of 71 PD patients (29 males, mean age 66.46 ± 8.87 years) were recruited. All patients underwent the Mini- Mental State Examination (MMSE) and the Korean Version of the Montreal Cognitive Assessments (MoCA-K) to assess global cognitive function. Sleep disorders were evaluated with the Stanford Sleepiness Scale, Epworth Sleepiness Scale, Insomnia Severity Index (ISI), Pittsburg Sleep Quality Index, and Parkinson's Disease Sleep Scale in Korea (PDSS).

RESULTS

The ISI was correlated with the MMSE, and total PDSS scores were correlated with the MMSE and the MoCA-K. In each item of the PDSS, nocturnal restlessness, vivid dreams, hallucinations, and nocturnal motor symptoms were positively correlated with the MMSE, and nocturnal restlessness and vivid dreams were significantly related to the MoCA-K. Vivid dreams and nocturnal restlessness are considered the most powerful correlation factors with global cognitive function, because they commonly had significant correlation to cognition assessed with both the MMSE and the MoCA-K.

CONCLUSIONS

We found a correlation between global cognitive function and sleep disturbances, including vivid dreams and nocturnal restlessness, in PD patients.

Effects of ceftriaxone on the behavioral and neuronal changes in an MPTP-induced Parkinson's disease rat model

Hyperactivity of the glutamatergic system is involved in excitotoxicity and neurodegeneration in Parkinson's disease (PD) and treatment with drugs modulating glutamatergic activity may have beneficial effects. Ceftriaxone has been reported to increase glutamate uptake by increasing glutamate transporter expression. The aim of this study was to determine the effects of ceftriaxone on working memory, object recognition, and neurodegeneration in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD rat model. MPTP was stereotaxically injected into the substantia nigra pars compacta (SNc) of male Wistar rats. Then, starting the next day (day 1), the rats were injected daily with either ceftriaxone (200 mg/kg/day, i.p.) or saline for 14 days and underwent a T-maze test on days 8-10 and an object recognition test on days 12-14. MPTP-lesioned rats showed impairments of working memory in the T-maze test and of recognition function in the object recognition test. The treatment of ceftriaxone decreased the above MPTP-induced cognitive deficits. Furthermore, this study provides evidence that ceftriaxone inhibits MPTP lesion-induced dopaminergic degeneration in the nigrostriatal system, microglial activation in the SNc, and cell loss in the hippocampal CA1 area. In conclusion, these data support the idea that hyperactivity of the glutamatergic system is involved in the pathophysiology of PD and suggest that ceftriaxone may be a promising pharmacological tool for the development of new treatments for the dementia associated with PD.

Neuroprotective Potential of Peroxisome Proliferator Activated Receptor- α Agonist in Cognitive Impairment in Parkinson's Disease: Behavioral, Biochemical, and PBPK Profile

Parkinson's disease (PD) is a common neurodegenerative disorder affecting 1% of the population by the age of 65 years and 4-5% of the population by the age of 85 years. PD affects functional capabilities of the patient by producing motor symptoms and nonmotor symptoms. Apart from this, it is also associated with a higher risk of cognitive impairment that may lead to memory loss, confusion, and decreased attention span. In this study, we have investigated the effect of fenofibrate, a PPAR-α agonist in cognitive impairment model in PD. Bilateral intranigral administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) (100 µg/1 µL/side) produced significant cognitive dysfunctions. Fenofibrate treatment at 10, 30, and 100 mg/kg for twenty-five days was found to be neuroprotective and improved cognitive impairment in MPTP-induced PD model as evident from behavioral, biochemical (MDA, GSH, TNF-α, and IL-6), immunohistochemistry (TH), and DNA fragmentation (TUNEL positive cells) studies. Further, physiologically based pharmacokinetic (PBPK) modeling study was performed using GastroPlus to characterize the kinetics of fenofibric acid in the brain. A good agreement was found between pharmacokinetic parameters obtained from the actual and simulated plasma concentration-time profiles of fenofibric acid. Results of this study suggest that PPAR-α agonist (fenofibrate) is neuroprotective in PD-induced cognitive impairment.