Neuropsychiatric aspects of Parkinson's disease

Online cognitive testing in Parkinson's disease: advantages and challenges

Parkinson's disease (PD) is primarily characterized by motor symptoms. Yet, many people with PD experience cognitive decline, which is often unnoticed by clinicians, although it may have a significant impact on quality of life. For over half a century, traditional in-person PD cognitive assessment lacked accessibility, scalability, and specificity due to its inherent limitations. In this review, we propose that novel methods of online cognitive assessment could potentially address these limitations. We first outline the challenges of traditional in-person cognitive testing in PD. We then summarize the existing literature on online cognitive testing in PD. Finally, we explore the advantages, but also the limitations, of three major processes involved in online PD cognitive testing: recruitment and sampling methods, measurement and participation, and disease monitoring and management. Taking the limitations into account, we aim to highlight the potential of online cognitive testing as a more accessible and efficient approach to cognitive testing in PD.

Integrating virtual reality and exergaming in cognitive rehabilitation of patients with Parkinson disease: a systematic review of randomized controlled trials

INTRODUCTION

In recent years, growing attention is rising to virtual reality (VR) tools and exergaming in rehabilitation management of patients with Parkinson disease (PD). However, no strong evidence supports the effectiveness of these cutting-edge technologies on cognitive function and the integration of these promising tool in the rehabilitation framework of PD patients is still challenging. Therefore, the present systematic review of randomized controlled trials (RCTs) aimed at assessing the effects of VR and exergames/telerehabilitation in the cognitive rehabilitation management of patients with PD.

EVIDENCE ACQUISITION

PubMed, Scopus and Web of Science databases were systematically searched up to February 14^th, 2022, to identify RCTs assessing patients with PD undergoing cognitive rehabilitation including VR or exergames/telerehabilitation. The intervention was compared to conventional rehabilitation protocols. The primary outcome was cognitive function. The quality assessment was performed following the Version 2 of the Cochrane risk-of-bias tool for randomized trials (RoB 2). PROSPERO registration code: CRD42022319788.

EVIDENCE SYNTHESIS

Out of 1419 identified studies, 66 articles were assessed for eligibility, and, at the end of the screening process, 10 studies were included in the present systematic review. Five RCTs (50%) assessed the exergaming devices, reporting significant positive results on cognitive outcomes scales (Trail Making test scale, Digit Span backward, MoCA, and MyCQ score). The other 5 RTCs (50%) assessed VR approaches, reporting significant improvement in executive functions. The RoB 2 showed an overall high risk of bias for the 40% of studies included.

CONCLUSIONS

Exergaming and VR might be considered promising rehabilitation interventions in the cognitive rehabilitation framework of PD patients. Further high-quality studies are needed to define the role of exergames and VR in a comprehensive rehabilitation approach aiming at improving the multilevel cognitive impairment characterizing patients with PD.

Neuropsychiatric Symptoms in Parkinson’s Disease Patients Are Associated with Reduced Health-Related Quality of Life and Increased Caregiver Burden

Parkinson’s disease (PD) is a progressive neurodegenerative disorder resulting in reduced health-related quality of life (HR-QoL) of people with PD (PwP) and their caregivers. Furthermore, there is an accumulating burden on caregivers of patients in advanced stages of the disease. In previous studies, motor- and non-motor-symptoms of PwP have been identified to contribute to reduced HR-QoL and an increased caregiver burden. This cross-sectional observational study aimed to study the influence of neuropsychiatric symptoms measured with the Scale for Evaluation of Neuropsychiatric Disorders in Parkinson’s Disease (SEND-PD) questionnaire on the HR-QoL of PwP, as well as the caregiver burden. Analyses revealed a significant association between SEND-PD subscale mood/apathy and reduced HR-QoL in PwP, measured by the Parkinson’s disease quality of life questionnaire (PDQ-8) (p < 0.001). Furthermore, mood/apathy was significantly correlated with caregiver burden (p = 0.001) in the multiple linear regression analysis. Hence, neuropsychiatric symptoms were found to have a profound impact on the HR-QoL of PwP, as well as on caregiver burden. Since neuropsychiatric symptoms were one of the main predictors for caregiver burden, physicians of PwP should treat these symptoms to stabilize caregiver burden, as well as HR-QoL in PwP and their caregivers.

Study on the Regulation Effect of Optogenetic Technology on LFP of the Basal Ganglia Nucleus in Rotenone-Treated Rats

Background

Parkinson's disease (PD) is a common neurological degenerative disease that cannot be completely cured, although drugs can improve or alleviate its symptoms. Optogenetic technology, which stimulates or inhibits neurons with excellent spatial and temporal resolution, provides a new idea and approach for the precise treatment of Parkinson's disease. However, the neural mechanism of photogenetic regulation remains unclear.

Objective

In this paper, we want to study the nonlinear features of EEG signals in the striatum and globus pallidus through optogenetic stimulation of the substantia nigra compact part.

Methods

Rotenone was injected stereotactically into the substantia nigra compact area and ventral tegmental area of SD rats to construct rotenone-treated rats. Then, for the optogenetic manipulation, we injected adeno-associated virus expressing channelrhodopsin to stimulate the globus pallidus and the striatum with a 1 mW blue light and collected LFP signals before, during, and after light stimulation. Finally, the collected LFP signals were analyzed by using nonlinear dynamic algorithms.

Results

After observing the behavior and brain morphology, 16 models were finally determined to be successful. LFP results showed that approximate entropy and fractal dimension of rats in the control group were significantly greater than those in the experimental group after light treatment (p < 0.05). The LFP nonlinear features in the globus pallidus and striatum of rotenone-treated rats showed significant statistical differences before and after light stimulation (p < 0.05).

Conclusion

Optogenetic technology can regulate the characteristic value of LFP signals in rotenone-treated rats to a certain extent. Approximate entropy and fractal dimension algorithm can be used as an effective index to study LFP changes in rotenone-treated rats.

Presence phenomena in parkinsonian disorders: Phenomenology and neuropsychological correlates

INTRODUCTION

The feeling of a presence that occurs in the absence of objectively identifiable stimuli is common in parkinsonian disorders. Although previously considered benign and insignificant, recent evidence suggests that presence phenomena may act as the gateway to more severe hallucinations and dementia. Despite this, we still know relatively little about these phenomena.

OBJECTIVE

To examine parkinsonian disorder patients' subjective experience of presence phenomena, and retrospectively analyse their cognitive correlates, in order to elucidate the emergence of information processing deficits in parkinsonian disorders.

METHODS/DESIGN

25 patients who endorsed presence phenomena were asked to complete a semi-structured interview about their experiences. The cognitive profiles of these patients were then compared to those of age- and education-matched patients who denied presence phenomena.

RESULTS

Patients described the presence as mostly that of an unknown human with neutral valence. Patients who described it as unpleasant were noted to also demonstrate elevated anxiety. Patients who identified the presence as a known person, described it as touching them, or interacted with the presence emotionally or physically demonstrated reduced insight. Patients with presence phenomena demonstrated more frequent impairments in visual processing, executive function and speed of processing.

CONCLUSIONS

Presence phenomena occur in the company of advancing cognitive impairment and involvement of the posterior cortical functions. Initially encountered as a neutral spatial skeleton, the experience is then shaped by the patient's affective state and level of insight.

MPP+-Lesioned Mice: an Experimental Model of Motor, Emotional, Memory/Learning, and Striatal Neurochemical Dysfunctions

The neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induces motor and nonmotor dysfunctions resembling Parkinson's disease (PD); however, studies investigating the effects of 1-methyl-4-phenylpyridinium (MPP⁺), an active oxidative product of MPTP, are scarce. This study investigated the behavioral and striatal neurochemical changes (related to oxidative damage, glial markers, and neurotrophic factors) 24 h after intracerebroventricular administration of MPP⁺ (1.8-18 μg/mouse) in C57BL6 mice. MPP⁺ administration at high dose (18 μg/mouse) altered motor parameters, since it increased the latency to leave the first quadrant and reduced crossing, rearing, and grooming responses in the open-field test and decreased rotarod latency time. MPP⁺ administration at low dose (1.8 μg/mouse) caused specific nonmotor dysfunctions as it produced a depressive-like effect in the forced swim test and tail suspension test, loss of motivational and self-care behavior in the splash test, anxiety-like effect in the elevated plus maze test, and short-term memory deficit in the step-down inhibitory avoidance task, without altering ambulation. MPP⁺ at doses of 1.8-18 μg/mouse increased tyrosine hydroxylase (TH) immunocontent and at 18 μg/mouse increased α-synuclein and decreased parkin immunocontent. The astrocytic calcium-binding protein S100B and glial fibrillary acidic protein (GFAP)/S100B ratio was decreased following MPP⁺ administration (18 μg/mouse). At this highest dose, MPP⁺ increased the ionized calcium-binding adapter molecule 1 (Iba-1) immunocontent, suggesting microglial activation. Also, MPP⁺ at a dose of 18 μg/mouse increased thiobarbituric acid reactive substances (TBARS) and glutathione (GSH) levels and increased glutathione peroxidase (GPx) and hemeoxygenase-1 (HO-1) immunocontent, suggesting a significant role for oxidative stress in the MPP⁺-induced striatal damage. MPP⁺ (18 μg/mouse) also increased striatal fibroblast growth factor 2 (FGF-2) and brain-derived neurotrophic factor (BDNF) levels. Moreover, MPP⁺ decreased tropomyosin receptor kinase B (TrkB) immunocontent. Finally, MPP⁺ (1.8-18 μg/mouse) increased serum corticosterone levels and did not alter acetylcholinesterase (AChE) activity in the striatum but increased it in cerebral cortex and hippocampus. Collectively, these results indicate that MPP⁺ administration at low doses may be used as a model of emotional and memory/learning behavioral deficit related to PD and that MPP⁺ administration at high dose could be useful for analysis of striatal dysfunctions associated with motor deficits in PD.

Psychiatric aspects of Parkinson's disease

Parkinson's disease (PD) is essentially characterized by the motor symptoms in the form of resting tremor, rigidity and bradykinesia. However, over the years it has been recognized that motor symptoms are just the "tip of the iceberg" of clinical manifestations of PD. Besides motor symptoms, PD characterized by many non-motor symptoms, which include cognitive decline, psychiatric disturbances (depression, psychosis and impulse control), sleep difficulties, autonomic failures (gastrointestinal, cardiovascular, urinary, thermoregulation) and pain syndrome. This review evaluates the various aspects of psychiatric disorders including cognitive decline and sleep disturbances in patients with PD. The prevalence rate of various psychiatric disorders is high in patients with PD. In terms of risk factors, various demographic, clinical and treatment-related variables have been shown to be associated with higher risk of development of psychiatric morbidity. Evidence also suggests that the presence of psychiatric morbidity is associated with poorer outcome. Randomized controlled trials, evaluating the various pharmacological and non-pharmacological treatments for management of psychiatric morbidity in patients with PD are meager. Available evidence suggests that tricyclic antidepressants like desipramine and nortriptyline are efficacious for management of depression. Among the antipsychotics, clozapine is considered to be the best choice for management of psychosis in patients with PD. Among the various cognitive enhancers, evidence suggest efficacy of rivastigmine in management of dementia in patients with PD. To conclude, this review suggests that psychiatric morbidity is highly prevalent in patients with PD. Hence, a multidisciplinary approach must be followed to improve the overall outcome of PD. Further studies are required to evaluate the efficacy of various other measures for management of psychiatric morbidity in patients with PD.

Cognitive impairment in multiple sclerosis: clinical, radiologic and pathologic insights

Cognitive impairment is a common and debilitating feature of multiple sclerosis (MS) that has only recent gained considerable attention. Clinical neuropsychological studies have made apparent the multifaceted nature of cognitive troubles often encountered in MS and continue to broaden our understanding of its complexity. Radiographic studies have started to decipher the neuroanatomic substrate of MS-related cognitive impairment and have shed light onto its pathogenesis. Where radiographic studies have been limited by inadequate resolution or non-specificity, pathological studies have come to the fore. This review aims to provide an overview of the nature of cognitive impairment typically seen in MS and to explore the literature on imaging and pathological studies relevant to its evolution. In particular, the relative contributions of gray (i.e., cerebral cortex, hippocampus, thalamus and basal ganglia) and white matter to MS-related cognitive impairment will be discussed and the importance of interconnectivity between structures highlighted. The pressing need for longitudinal studies combining standardized neuropsychometric, paraclinical and radiographic outcomes obtained during life with post-mortem tissue analysis after death is presented.

Mianserin, an antidepressant kills Leishmania donovani by depleting ergosterol levels

In the present study, we have investigated the antileishmanial potential of mianserin, an antidepressant. Mianserin was found to inhibit both the promastigote and amastigote forms of the parasite in a dose dependant manner. The IC50 values for promastigotes and amastigotes were 21 μM and 46 μM respectively. Interestingly, mianserin failed to inhibit THP-1 differentiated macrophages up to 100 μM concentration thus, exhibiting parasite selectivity. When mianserin was incubated with recombinant Leishmania donovani 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) enzyme, it exhibited an IC50 value of 19.8 μM. Inhibition kinetics revealed competitive mode of enzyme inhibition as the Km increased with no change in Vmax. Further structural investigation of enzyme-inhibitor interaction revealed quenching of HMGR tryptophan intrinsic fluorescence with a K(sv) value of 3.025±0.37 M(-1) and an apparent binding constant of 0.0954 mM. We further estimated ergosterol levels which is a major component of Leishmania cell membrane. It is synthesized by HMGR enzyme, the first rate limiting enzyme of the sterol biosynthetic pathway. Analysis of ergosterol levels by HPLC revealed ∼2.5-fold depletion in mianserin treated promastigotes with respect to untreated parasites. This data was further validated by exogenous supplementation of mianserin treated cells with ergosterol and cholesterol. Reversal of growth inhibition was observed only upon ergosterol addition though it was refractory to cholesterol supplementation. Overall, our results demonstrate the possibility of repositioning of an antidepressant for the treatment of Visceral Leishmaniasis.

Neuropsychiatric symptoms in mild dementia with lewy bodies and Alzheimer's disease

BACKGROUND/AIMS

To compare neuropsychiatric symptoms in patients with Alzheimer's disease (AD) and dementia with Lewy bodies(DLB).

METHODS

Neuropsychiatric symptoms and caregiver distress were assessed using the Neuropsychiatric Inventory (NPI) in mild DLB (n = 57) and AD (n = 126), and compared across the two groups using non-parametric tests.

RESULTS

The DLB patients had a higher NPI totalscore (median 24 vs. 11.5, p < 0.005), more numerous symptoms (median 5 vs. 4, p = 0.001) and more clinically significant symptoms (3 vs. 1, p = 0.001). They also had higher item hallucinations (6 vs. 2, p < 0.005) and apathy (7 vs. 5, p = 0.002) subscores. Caregivers scored higher on the NPI total caregiver distress scale (12.5 vs. 6, p = 0.003).

CONCLUSIONS

In mild dementia, DLB patients have more neuropsychiatric symptoms and more associated caregiver distress compared with AD.

Clinicopathological correlates of behavioral and psychological symptoms of dementia

Behavioral and psychological symptoms are commonly observed in a majority of demented patients at some time during the course of their illness. Many of these psychiatric manifestations, especially those related to mood, may be early expressions of dementia and/or mild cognitive impairment. The literature suggests that behavioral and psychological symptoms of dementia (BPSD) are an integral part of the disease process. The dissociation, in many cases, between BPSD and the rather linear decline in cognitive functions suggests that independent pathophysiological mechanisms give rise to these symptoms. A review of the neuroimaging and neuropathology literature indicates that BPSD are the expression of regional rather than diffuse brain pathology. Psychotic symptoms in demented patients usually demonstrate preferential involvement of the frontal lobe and/or limbic regions. Visual hallucinations differentiate themselves from other psychotic symptoms by their tendency to involve the occipital lobes. There is a significant association between apathy and structural changes of the anterior cingulate gyrus. White matter hyperintensities occur in a significant number of depressed patients; otherwise, there is lack of association between depression and either specific brain changes or affected regions. Strictly neuropathological explanations are likely to be insufficient to explain BPSD. Environmental changes, neurochemical abnormalities, past psychiatric history (including premorbid personality), social history (e.g., intellectual achievement and life-long learning), family history, and genetic susceptibility are factors, among others, that influence BPSD.

The contribution of neuroimaging for the study of cognitive deficits in Parkinson's disease

The last few years have seen an increase in the number of studies using functional Magnetic Resonance Imaging (fMRI) along with receptor imaging and regional cerebral blood flow Positron Emission Tomography (PET) to understand the neurobiological underpinnings of cognitive deficits in Parkinson's disease (PD). These studies have shown evidence that the nigrostriatal degeneration solely cannot account for these deficits and that involvement of other neural systems such as the mesocortical dopamine may also play an important role. In this article, we provide a review of neuroimaging results regarding the role of possible compensatory activity, L-Dopa medication, and difference in genotypes on the cognitive deficits observed in PD. Finally, some future avenues for research are proposed.

Neuropsychiatric problems in Parkinson's disease: comparisons between self and caregiver report

INTRODUCTION

This study examined the level of agreement between caregiver and Parkinson's disease (PD) patient reports of neuropsychiatric problems.

METHOD

Forty-three patients and 43 informants who knew the patient well (caregivers) participated in the study. Caregivers rated patients' behaviour, as well as their own stress, using the Neuropsychiatric Inventory (NPI). Information from patients was obtained using commonly used scales (Beck Depression Inventory, Apathy Scale, Unified Parkinson's Disease Rating Scale and the Hamilton Anxiety Depression Scale). Both the patients and the caregivers also completed the Frontal Systems Behavior Scale, which assesses behaviours associated with apathy, disinhibition and executive dysfunction.

RESULTS

The level of agreement between these self and caregiver reports was low, with only 45.8% agreement for depression, 45.0% for apathy, 28.6% for hallucinations, 26.9% for sleep problems and 6.7% for anxiety.

CONCLUSIONS

Given this low level of agreement between self and other report, these two methods of assessment cannot be considered interchangeable.

Single-photon emission computed tomography and positron emission tomography evaluations of patients with central motor disorders

Neuroimaging biomarkers in movement disorders during the past decade have served as diagnostic agents (Europe), tools for evaluation of novel therapeutics, and a powerful means for describing pathophysiology by revealing in vivo changes at different stages of disease and within the course of an individual patient's illness. As imaging with agents tracking dopaminergic function become more available, the next decade promises to enhance our clinical sophistication in the optimal use of dopaminergic imaging biomarkers for differential diagnosis, characterization of at-risk populations, guiding selection and management of appropriate treatments. The clinical role of these agents as clinical tools goes hand in hand with the development and availability of disease-modifying drugs, which carry the additional requirement for early and accurate diagnosis and improved clinical monitoring once treatment is initiated. Challenges remain in the ideal application of neuroimaging in the clinical algorithms for patient assessment and management. Further, the application of imaging to other targets, both monamineric and nonmonoaminergic, could serve a function beyond the important delineation of pathologic change occurring in patients with Parkinson's disease to suggest some role in improved phenotyping and classification of patients with Parkinson's disease presenting with different symptom clusters. New areas of focus based on the elucidation of mechanisms at the cellular and molecular level, including intense interest in alpha-synuclein and other protein inclusions in neurons and glia, have piqued interest in their in vivo assessment using scinitigraphic methods. Perhaps ultimately, treatment that is targeted to a better delineated pathophysiology-based characterization of movement disorder patients will emerge. The application of neuroimaging biomarkers to multiple ends in movement disorders provides an important model for the multiple roles diagnostic imaging agents can serve in neurodegenerative disorders; for diagnosis, for elaborating pathophysiology in patient populations, for developing new drugs, ultimately for improving clinical management.

The relationship between impulsivity and impulse control disorders in Parkinson's disease

A range of behaviors presumed to be related to dopaminergic medications have been recently recognized in Parkinson's disease (PD). We evaluated 50 consecutive cognitively intact PD patients on stable dopamine agonist and levodopa therapy and 100 healthy controls for compulsive sexual behavior, compulsive buying, or intermittent explosive disorders assessed by the Minnesota Impulsive Disorders Interview (MIDI), pathological gambling (South Oaks Gambling Screen, SOGS), impulsivity (Barratt Impulsiveness Scale), compulsivity (Maudsley obsessional-compulsive inventory), and depression scores (Geriatric Depression Scale). Overall 28% PD (14/50) and 20% healthy controls (20/100) reported at least one abnormal behavior at MIDI or pathological SOGS score. PD patients had higher scores than controls for impulsivity (P = 0.006), compulsivity (P < 0.001), and depression (P < 0.001). There was no correlation between impulsivity, compulsivity, and depression scores in PD. Male gender and higher impulsivity score, but not dose and kind of dopaminergic medications, were associated in PD with increased probability of impulsive disorders at MIDI. Impulse control disorders are also common in the control population. Individual susceptibility factors, such as high impulsivity and depression, underline abnormal behaviors in PD patients treated with stable dopaminergic therapy.

Striatal beta-amyloid deposition in Parkinson disease with dementia

Dementia is common in Parkinson disease (PD), although its anatomic and pathologic substrates remain undefined. Recently, striatal abnormalities in Lewy body diseases have been described, but their clinical relevance is not clear. Thirty PD cases from the United Kingdom Parkinson's Disease Society Tissue Bank were grouped as demented (PDD; n = 16) and nondemented (PD; n = 14) based on a review of clinical records. The extent of alpha-synuclein, tau, and amyloid beta peptide (Abeta) deposition in the caudate nucleus, putamen, and nucleus accumbens was assessed. All cases showed severe dopaminergic striatal terminal denervation based on tyrosine hydroxylase immunohistochemistry. Alpha-synuclein and tau deposition in the striatum were rare in both groups, but the Abeta burden was significantly greater in the striatum of PD cases with dementia than present in the nondemented PD group. Striatal Abeta deposition was type-independent of Alzheimer disease changes in the cortex and was minimal in nondemented PD cases. We conclude that Abeta deposition in the striatum strongly correlates with dementia in PD.

Relationship between self-reported apathy and executive dysfunction in nondemented patients with Parkinson disease

OBJECTIVE

The prevalence of apathy was assessed across select cognitive and psychiatric variables in 32 nondemented patients with Parkinson disease (PD) and 29 demographically matched healthy control participants.

BACKGROUND

Apathy is common in PD, although differentiating apathy from motor, cognitive, and/or other neuropsychiatric symptoms can be challenging. Previous studies have reported a positive relationship between apathy and cognitive impairment, particularly executive dysfunction.

METHOD

Patients were categorized according to apathy symptom severity. Stringent criteria were used to exclude patients with dementia.

RESULTS

Approximately 44% of patients endorsed significant levels of apathy. Those patients performed worse than patients with nonsignificant levels of apathy on select measures of verbal fluency and on a measure of verbal and nonverbal conceptualization. Further, they reported a greater number of symptoms related to depression and behavioral disturbance than did those patients with nonsignificant levels of apathy. Apathy was significantly related to self-report of depression and executive dysfunction. Performance on cognitive tasks assessing verbal fluency, working memory, and verbal abstraction and also on a self-report measure of executive dysfunction was shown to significantly predict increasing levels of apathy.

CONCLUSIONS

Our findings suggest that apathy in nondemented patients with PD seems to be strongly associated with executive dysfunction.

A profile of neuropsychiatric problems and their relationship to quality of life for Parkinson's disease patients without dementia

Neuropsychiatric problems are common in Parkinson's disease (PD) but there is little information regarding how they impact on quality of life. PD patients without dementia (49) were assessed for low mood/depression, fatigue, apathy, sleep problems and hallucinations. Measures of quality of life and motor function were also obtained. Over 77% of the patients reported symptoms consistent with one or more neuropsychiatric problems. Low mood/depression, anxiety and the presence of hallucinations predicted poorer quality of life after controlling for motor symptoms. Additional to the motor symptoms, we found that specific neuropsychiatric problems may impact on quality of life for PD patients.

Assessment of psychiatric complications in Parkinson's disease: The SCOPA-PC

The objective of this study was to develop a clinimetric sound scale that addresses both psychotic and compulsive complications in Parkinson's disease (PD). The SCales for Outcomes in PArkinson's disease-Psychiatric Complications (SCOPA-PC) was developed by modifying the items of the Parkinson Psychosis Rating Scale (PPRS) and including an item on compulsive behavior in PD. To evaluate the validity of the SCOPA-PC, 106 PD patients were assessed. A subsample of 43 patients was assessed for interrater and test-retest reliability. Construct validity was evaluated using the Neuropsychiatric Inventory (NPI) and the South Oaks Gambling Scale (SOGS). Interrater and test-retest reliability for the total score was 0.95 and 0.91 (intraclass correlation coefficient), respectively. For the items, the interrater reliability ranged from 0.62 to 0.96 (weighted kappa) and the test-retest reliability ranged from 0.54 to 0.88 (weighted kappa). Cronbach's alpha was 0.68. The correlation between the SCOPA-PC total score and the NPI was 0.41. The correlation between SCOPA-PC items and NPI items that addressed similar constructs ranged from 0.34 to 0.68, whereas the correlation between the item on compulsive behavior and the SOGS was 0.49. In conclusion, the SCOPA-PC is a reliable, valid, and easily-administered semistructured questionnaire for both psychotic and compulsive complications in PD.

Beta-amlyoid 1-42 and tau-protein in cerebrospinal fluid of patients with Parkinson's disease dementia

Measurement of tau-protein and beta-amyloid(1-42 )(Abeta42) in cerebrospinal fluid (CSF) has gained increasing acceptance in the differential diagnosis of Alzheimer's disease. We investigated CSF tau-protein and Abeta42 concentrations in 73 patients with advanced idiopathic Parkinson's disease with dementia (PDD) and 23 patients with idiopathic Parkinson's disease without dementia (PD) and in a comparison group of 41 non-demented neurological patients (CG) using commercially available enzyme-linked-immunoabsorbant-assay (ELISA). tau-Protein levels were statistically significantly higher and Abeta42 lower in the PDD patients compared to PD patients and the CG. This observation was most marked (p < 0.05) in a subgroup of patients with PDD carrying the apolipoprotein genotype epsilon3/epsilon3. The distribution of the apolipoprotein genotypes in PDD and PD patients was similar to that of the CG. Although a significant difference in tau-protein values was observed between PDD and CG, no diagnostic cut-off value was established. These findings suggest that such protein CSF changes may help to support the clinical diagnosis of cognitive decline in PD and that there may be apolipoprotein-E-isoform-specific differences in CSF protein regulation in advanced PDD.

Orthostatic hypotension in Parkinson's disease: association with cognitive decline?

BACKGROUND

Orthostatic hypotension is common in Lewy body disorders and may be related to disease progression and the spread of Lewy body pathology. We therefore hypothesize that PD patients with orthostatic hypotension (OH) have a different cognitive profile compared to PD patients without OH.

METHODS

This cross-sectional study included 175 PD patients. Blood pressure (BP) was measured with a validated digital blood pressure monitor and patients with a systolic BP drop of > or =20 mmHg or a systolic pressure of <90 mm Hg after standing were considered to have OH. Cognition was assessed using MMSE extended by a selection of computerized cognitive tests focusing on reaction time, sustained attention, working memory and episodic verbal and visual memory.

RESULTS

Eighty-seven (49.7%) of the PD patients had OH. These patients were significantly more impaired in sustained attention and visual episodic memory compared to PD patients without OH.

CONCLUSION

We conclude that there are differences in the neuropsychological performance of patients with PD and OH, supporting the hypothesis that OH might be a marker for disease progression and cognitive decline in PD.

The basal ganglia: anatomy, physiology, and pharmacology

The basal ganglia are perceived as important nodes in cortico-subcortical networks involved in the transfer, convergence, and processing of information in motor, cognitive, and limbic domains. How this integration might occur remains a matter of some debate, particularly given the consistent finding in anatomic and physiologic studies of functional segregation in cortico-subcortical loops. More recent theories, however, have raised the notion that modality-specific information might be integrated not spatially, but rather temporally, by coincident processing in discrete neuronal populations. Basal ganglia neurotransmitters, given their diverse roles in motor performance, learning, working memory, and reward-related activity are also likely to play an important role in the integration of cerebral activity. Further work will elucidate this to a greater extent, but for now, it is clear that the basal ganglia form an important nexus in the binding of cognitive, limbic, and motor information into thought and action.

Dementia with Lewy Bodies

The neurobehavioral and pathologic features of Parkinson disease dementia (PDD) are virtually identical to those of dementia with Lewy bodies (DLB), suggesting that they represent different phenotypes of the same underlying disease. Both are characterized clinically by a "frontal-subcortical" dementia, fluctuating confusion, and, often, psychotic symptoms. Pathologically they are characterized by disseminated Lewy bodies and multiple transmitter deficits. These dementias with Lewy bodies constitute the second leading cause of dementia after Alzheimer disease (AD), and are thus an important treatment target. No drug has yet been approved for these indications, but treatment options are emerging. This paper addresses the conduct of clinical trials for this indication, including definition of target populations, screening metrics, outcome measures, and clinical trial designs. As the pathophysiology of these cognitive and behavioral changes becomes better understood, symptomatic as well as disease-modifying therapy may become possible, requiring an inclusive and consistent approach to clinical trials in this area.

A review of the cognitive and behavioral sequelae of Parkinson's disease: relationship to frontostriatal circuitry

BACKGROUND

Parkinson's disease is a neurodegenerative hypokinetic movement disorder presenting with subcortical pathology and characterized by motor deficits. However, as is frequently reported in the literature, patients with Parkinson's disease can also exhibit cognitive and behavioral impairments. These impairments may be attributed to dysfunction of multiple systems associated with the disease process in Parkinson's disease that are not necessarily related to motor symptoms. In recent years, considerable attention has addressed the circuits connecting the frontal cortical regions and the basal ganglia (i.e., frontostriatal circuits) and how they mediate cognition and behavior in humans. It has been suggested that these same circuits are disrupted in Parkinson's disease and may be responsible for the frontal/executive deficits predominantly reported in this patient population.

OBJECTIVE

The current survey of the literature provides a critique and analysis of the neuropsychological profile of Parkinson's disease, including cognitive impairments, behavioral alterations, and emotional processing deficits. A special feature of this paper is to ascertain how frontostriatal circuitry might provide the substrate for the neuropsychological impairments exhibited in Parkinson's disease. In so doing, studies involving nonhuman subjects, neurologically healthy adults, brain-lesioned individuals, and patients with Parkinson's disease are reviewed to provide a novel perspective in conceptualizing and categorizing the cognitive and behavioral sequelae concomitant to specific frontostriatal circuit dysfunction in Parkinson's disease.

CONCLUSIONS

The current review suggests that the neuropsychological profile of Parkinson's disease, which predominantly reflects frontal/executive dysfunction, may be attributed to disruption of the frontostriatal circuitry. The information generated from this review can serve as a guide in the assessment of frontal/executive dysfunction in Parkinson's disease with suggestions for a clinical neuropsychological test battery.

Understanding and managing behavioural symptoms in Alzheimer's disease and related dementias: focus on rivastigmine

Behavioural and psychological symptoms of dementia (BPSD) are among the most distressing manifestations of dementia and result in considerable social and economic costs. Practical, non-pharmacological approaches such as environmental and behavioural changes may provide some benefit for patients in managing mild BPSD. In addition, various pharmacological approaches to treatment have been employed, such as neuroleptics and atypical antipsychotics, which differ in neurochemical target and clinical effectiveness. Growing evidence suggests that the neurobiological basis of BPSD in Alzheimer's disease (AD) and related dementias is a loss of cholinergic neurones and a resultant decline in acetylcholine (ACh) in brain regions which regulate behavioural and emotional responses, such as the limbic system. This cholinergic deficit can be partly corrected by inhibiting cholinesterase enzymes (ChEs). Studies of ChE inhibitors have shown positive effects to improve or stabilise existing BPSD and delay the emergence of new behavioural symptoms. In placebo-controlled studies, donepezil has reported efficacy in non-institutionalised moderate to moderately severe patients over a period of 24 weeks, but has failed to demonstrate efficacy in mild to moderate AD and in institutionalised patients with severe disease. Galantamine has been shown to delay the onset of BPSD in mild to moderate AD patients in one placebo-controlled study, and improve BPSD in a similar study of patients with cerebrovascular disease or probable vascular dementia. Studies with rivastigmine have shown efficacy in placebo-controlled studies of mild to moderately severe AD and in patients with Lewy body variant AD. Institutionalised patients with severe disease also show symptomatic benefits in BPSD with rivastigmine, resulting in a reduction in concomitant psychoactive medication use. Symptom complexes responding to ChE inhibitors appear to differ - all agents improve apathy, depression and anxiety, while rivastigmine additionally improves hallucinations and delusions, possibility as a result of dual inhibition of acetylcholinesterase and butyrylcholinesterase. The presence of hallucinations has been shown to predict response to rivastigmine. Accumulating data from studies of ChE inhibitors suggest that early intervention and long-term treatment, in addition to providing cognitive benefits, improves BPSD and offers potential to enhance quality of life. Differences seen between the agents in terms of efficacy in BPSD, tolerability and safety profiles may be the result of differences in neuropharmacological profiles.

Clinical Lewy body syndromes

Lewy bodies are spherical, intracytoplasmic, eosinophilic, neuronal inclusions comprising abnormally truncated and phosphorylated intermediate neurofilament proteins, alpha-synuclein, ubiquitin, and associated enzymes. The clinical presentation of LB disease varies according to the site of LB formation and associated neuronal loss. Three main clinicopathological syndromes have been described--movement disorder, autonomic failure, and dementia. Parkinsonism is the most common presentation of LB disease developing in middle life. In older patients, a mixture of cognitive, autonomic, and motor dysfunction is more common. Dementia with LB (DLB) is a relatively recently described clinicopathological syndrome that accounts for up to 20% of all cases of dementia in old age. Patients, typically in their seventh and eighth decades, have LB pathology in cortical neurons as well as in the brain stem. LB disease should be considered in the differential diagnosis of a wide range of clinical presentations including episodic disturbances of consciousness, syncope, sleep disorders, and unexplained delirium.

Spectrum of Parkinson's disease, Parkinson's dementia, and Lewy body dementia

Dementia occurs more commonly in individuals with Parkinson's disease (PD) than in the age-matched general population. Dementia in PD may result from a mixture of cortical and subcortical dementia syndromes caused by a variety of underlying pathologic processes and neurochemical deficits. A primary dementia syndrome has been described that shares several pathologic and clinical characteristics with PD. Dementia with Lewy bodies (DLB) accounts for 15% to 20% of all dementia syndromes in old age, which makes it second only to Alzheimer's disease in prevalence. The relationship between dementia in PD and DLB has not been fully resolved but may be considered useful in terms of neuropathologic substrate, clinical features, and response to treatment.