Parkinson's disease dementia

Psychiatric and cognitive symptoms of Parkinson's disease: A life's tale

INTRODUCTION

Neuropsychiatric symptoms are highly prevalent in Parkinson's disease (PD) and significantly affect the quality of life of patients and their significant others. The aim of this work is to describe typical neuropsychiatric symptoms and their treatment.

METHODS

This is a narrative opinion paper, illustrated by a fictional case report. The most common neuropsychiatric symptoms such as depressive symptoms, anxiety, apathy, psychotic symptoms, impulse control disorders, as well as cognitive impairment are discussed in the context of prodromal stage, early stage, fluctuations stage, post-surgical intervention, and late stage of PD.

RESULTS

Multiple factors such as pathophysiology, dopaminergic medication, deep brain stimulation, personality traits and individual life circumstances influence neuropsychiatric symptoms. Since the complexity and causes of neuropsychiatric symptoms can change, management strategies have to be adapted and individualised throughout the disease trajectory.

DISCUSSION

Recognising neuropsychiatric symptoms within the framework of the disease stage and identifying their potential causes is pivotal to provide adequate interventions.

Hippocampal CA2 Lewy pathology is associated with cholinergic degeneration in Parkinson's disease with cognitive decline

Although the precise neuropathological substrates of cognitive decline in Parkinson's disease (PD) remain elusive, it has long been regarded that pathology in the CA2 hippocampal subfield is characteristic of Lewy body dementias, including dementia in PD (PDD). Early non-human primate tracer studies demonstrated connections from the nucleus of the vertical limb of the diagonal band of Broca (nvlDBB, Ch2) to the hippocampus. However, the relationship between Lewy pathology of the CA2 subfield and cholinergic fibres has not been explored. Therefore, in this study, we investigated the burden of pathology in the CA2 subsector of PD cases with varying degrees of cognitive impairment and correlated this with the extent of septohippocampal cholinergic deficit. Hippocampal sections from 67 PD, 34 PD with mild cognitive impairment and 96 PDD cases were immunostained for tau and alpha-synuclein, and the respective pathology burden was assessed semi-quantitatively. In a subset of cases, the degree of CA2 cholinergic depletion was quantified using confocal microscopy and correlated with cholinergic neuronal loss in Ch2. We found that only cases with dementia have a significantly greater Lewy pathology, whereas cholinergic fibre depletion was evident in cases with mild cognitive impairment and this was significantly correlated with loss of cholinergic neurons in Ch2. In addition, multiple antigen immunofluorescence demonstrated colocalisation between cholinergic fibres and alpha-synuclein but not tau pathology. Such specific Lewy pathology targeting the cholinergic system within the CA2 subfield may contribute to the unique memory retrieval deficit seen in patients with Lewy body disorders, as distinct from the memory storage deficit seen in Alzheimer's disease.

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.

Neural Stem Cells Rescue Cognitive and Motor Dysfunction in a Transgenic Model of Dementia with Lewy Bodies through a BDNF-Dependent Mechanism

Accumulation of α-synuclein (α-syn) into insoluble aggregates occurs in several related disorders collectively referred to as synucleinopathies. To date, studies have used neural stem cells (NSCs) to examine questions about α-syn propagation, but have overlooked the therapeutic potential of NSC transplantation to modulate cognition in disorders such as dementia with Lewy bodies or Parkinson’s disease dementia. Here, we show that striatal transplantation of NSCs into aged α-syn transgenic mice significantly improves performance in multiple cognitive and motor domains. This recovery is associated with NSC expression of brain-derived neurotrophic factor (BDNF), which restores depleted levels and modulates dopaminergic and glutamatergic systems. Most importantly, transplantation of BDNF-depleted NSCs fails to improve behavior, whereas AAV-mediated BDNF delivery mimics the benefits of NSC transplantation, supporting a critical role for this neurotrophin in functional improvement. Thus, NSC transplantation could offer a promising approach to treat the understudied yet devastating cognitive components of many synucleinopathies.

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α-Synuclein mice exhibit significant DLB/PDD-associated cognitive and motor deficits

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Striatal NSC transplantation dramatically improves cognitive and motor function

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BDNF is necessary for NSC-mediated behavioral improvements

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NSC-BDNF promotes recovery by regulating dopaminergic and glutamatergic systems

Combined therapy of Di-Huang-Yi-Zhi with Donepezil in patients with Parkinson's disease dementia

Here we conducted a randomized and double-blind study attempting to explore the safety and efficacy of combined therapy of Di-Huang-Yi-Zhi (DHYZ) with donepezil in treating Parkinson's disease dementia (PDD). Sixty PDD patients were included and randomly divided into control group and DHYZ group. All patients were given donepezil (5 mg last for a month, then 10 mg for the rest months, once daily), while patients in DHYZ group were additionally administrated with DHYZ (150 ml, twice daily). The measurement subjects included mini-mental state examination (MMSE), Montreal cognitive assessment (MoCA), Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog), the Barthel Index for activities of daily living (ADL) and Traditional Chinese medical (TCM) symptoms before and after treatment in this study. The whole study lasted for six months. Significant differences were observed on MMSE, MoCA, ADAS-Cog, ADL and TCM in both control and DHYZ group (P<0.05 or P<0.01) before and after drug treatment. Furthermore, there were more obvious changes of MMSE, MoCA, ADAS-Cog, ADL and TCM scores compared the DHYZ group with the control group (P<0.01) which suggested the DHYZ group showed a more effective improvement on cognition, behavior as well global function. In conclusion, the combined therapy of DHYZ with donepezil showed a more effective improvement in PDD and the underlying mechanism may be related to the synergic amelioration of cholinergic system between them.

[Severe olfactory dysfunction is a predictor of dementia with Parkinson's disease]

Recently, we identified that hyposmia, one of the most typical non-motor features in Parkinson's disease (PD), was a predictive feature of PDD (Parkinson's disease dementia). The multivariate logistic analysis identified severe hyposmia and visuoperceptual impairment as independent risk factors for subsequent dementia within 3 years. The patients with severe hyposmia had an 18.7-fold increase in their risk of dementia for each 1 SD (2.8) decrease in the score of odor stick identification test for Japanese (OSIT-J). We also found an association between severe hyposmia and a characteristic distribution of cerebral metabolic decline, which was identical to the findings observed in PDD. Furthermore, volumetric magnetic resonance imaging analyses demonstrated close relationships between olfactory dysfunction and the atrophy of focal brain structures, including the amygdala and other limbic structures. Dementia is one of the most debilitating symptoms of PD. Despite its clinical importance, the development of dementia is still difficult to predict at early stages. As cognitive impairments are known to be associated with poor prognoses in PD, olfactory tests may be a useful tool for the management of PD cases especially in advanced stages.

Mattis Dementia Rating Scale cutoffs are inadequate for detecting dementia in Parkinson's disease

The Mattis Dementia Rating Scale (DRS) is widely used to assess cognition and screen for dementia in Parkinson's disease (PD). In 2008, Llebaria and colleagues reported excellent sensitivity and specificity detecting dementia in PD using a DRS total score cutoff of 123. However, this study used a sample with rather low mean educational achievement (8.9 years). The 123 cutoff score was cross-validated in a sample of 51 PD patients with a rather high mean educational achievement (14.84 years). A total score cutoff of 123 correctly classified 60.7% of the sample, with 20% sensitivity and 100% specificity. Use of age- and education-corrected scaled scores improved classification accuracy, but these cutoffs corresponded to the 25th percentile. Optimal classification of 82.4% accuracy was achieved using a raw total score cutoff of 133, corresponding roughly to the 16th percentile. Neither age nor education evinced a strong correlation to DRS total score in our sample. Results suggest caution in applying the DRS-2 total score cutoff of 123 and highlight the importance of comprehensive neuropsychological evaluations for clinical diagnosis of dementia in PD.

Severe olfactory dysfunction is a prodromal symptom of dementia associated with Parkinson's disease: a 3 year longitudinal study

Dementia is one of the most debilitating symptoms of Parkinson's disease. A recent longitudinal study suggests that up to 80% of patients with Parkinson's disease will eventually develop dementia. Despite its clinical importance, the development of dementia is still difficult to predict at early stages. We previously identified olfactory dysfunction as one of the most important indicators of cortical hypometabolism in Parkinson's disease. In this study, we investigated the possible associations between olfactory dysfunction and the risk of developing dementia within a 3-year observation period. Forty-four patients with Parkinson's disease without dementia underwent the odour stick identification test for Japanese, memory and visuoperceptual assessments, (18)F-fluorodeoxyglucose positron emission tomography scans and magnetic resonance imaging scans at baseline and 3 years later. A subgroup of patients with Parkinson's disease who exhibited severe hyposmia at baseline showed more pronounced cognitive decline at the follow-up survey. By the end of the study, 10 of 44 patients with Parkinson's disease had developed dementia, all of whom had severe hyposmia at baseline. The multivariate logistic analysis identified severe hyposmia and visuoperceptual impairment as independent risk factors for subsequent dementia within 3 years. The patients with severe hyposmia had an 18.7-fold increase in their risk of dementia for each 1 SD (2.8) decrease in the score of odour stick identification test for Japanese. We also found an association between severe hyposmia and a characteristic distribution of cerebral metabolic decline, which was identical to that of dementia associated with Parkinson's disease. Furthermore, volumetric magnetic resonance imaging analyses demonstrated close relationships between olfactory dysfunction and the atrophy of focal brain structures, including the amygdala and other limbic structures. Together, our findings suggest that brain regions related to olfactory function are closely associated with cognitive decline and that severe hyposmia is a prominent clinical feature that predicts the subsequent development of Parkinson's disease dementia.

White matter alteration of the cingulum in Parkinson disease with and without dementia: evaluation by diffusion tensor tract-specific analysis

BACKGROUND AND PURPOSE

In PD, the neurodegenerative process begins in the brain stem and extends to the limbic system and finally into the cerebral cortex. We used diffusion tensor tractography to investigate the FA of the cingulate fiber tracts in patients with PD with and without dementia.

MATERIALS AND METHODS

Fifteen patients with PD, 15 patients with PDD, and 15 age-matched healthy controls underwent diffusion tensor imaging with a 3T MR imager. Diffusion tensor tractography images of the anterior and posterior cingulate fiber tracts were generated. Mean diffusivity and FA were measured along the tractography of the anterior and posterior cingulate fiber tracts. One-way ANOVA with the Scheffé post hoc test was used to compare results among the groups.

RESULTS

FA was significantly lower in patients with PDD than in healthy controls in both the anterior and the posterior cingulate fiber tracts (P = .003, P = .015) and significantly lower in patients with PD than in healthy controls (P = .003) in the anterior cingulate fiber tract. There were no significant mean diffusivity differences among the groups. MMSE and FA values of the anterior cingulate fiber tracts in patients with PDD were significantly correlated (r = 0.633, P < .05).

CONCLUSIONS

The reduced FA in patients with PD and PDD might reflect neuropathologic changes such as Lewy body pathology in the cingulate fibers. This abnormality might contribute to the dementing process in PD.

Nondopaminergic treatments for Parkinson’s disease

SUMMARY The main treatment strategy for Parkinson’s disease (PD) is focused on dopamine replacement. However, PD is no longer seen purely as a disease of the dopaminergic system, as the pathological processes involve neurodegeneration and altered neurotransmission of several nondopaminergic systems that are involved in both motor and nonmotor features of the disease. This article reviews current and experimental nondopaminergic pharmacological approaches to treatments for PD with a focus on motor symptoms, treatments of L-dopa-induced motor complications and treatments of nonmotor symptoms including mood disorders, cognition, psychosis and autonomic problems.

Preoperative assessment and preparation of patients with neurologic disorders

Ageing of populataion world wide has significant contribution as one of the major risk factor for neurodegenerative disorders. The patients with neurodegenerative as well as other neuological diseases presented the population with possible great need either of small or big surgical intervention. There are several important issues in patients with neurological diseases: the nature, disease duration, therapy, the patient's ability to live without assistance. Neurological disease may become worst by general and regional anesthesia. Stopping therapy may lead to worsening of neurological diseases. One of the main common threat is the risk of significant cardiorespiratory complications, which is important in assessing operational risk, in preoperative preparation and in terms of postoperative recovery and outcomes of surgical treatment. This has resulted in greater preoperative care by detailed patient history evaluation and examination, patient information and informed consent. Besides the effect of the anaesthetic technique upon the course of the disease, there is also the interaction of drugs administered during anaesthesia and patient medication. Several undiagnosed diseases may be disclosed following a surgical/anaesthetic intervention.

Impulse control disorders following deep brain stimulation of the subthalamic nucleus in Parkinson's disease: clinical aspects

Parkinson's disease (PD) has been associated with the development of impulse control disorders (ICDs), possibly due to overstimulation of the mesolimbic system by dopaminergic medication. Preliminary reports have suggested that deep brain stimulation (DBS), a neurosurgical procedure offered to patients with treatment-resistant PD, affects ICD in a twofold way. Firstly, DBS allows a decrease in dopaminergic medication and hence causes an improvement in ICDs. Secondly, some studies have proposed that specific ICDs may develop after DBS. This paper addresses the effects of DBS on ICDs in patients with PD. A literature search identified four original studies examining a total of 182 patients for ICDs and nine case reports of 39 patients that underwent DBS and developed ICDs at some point. Data analysis from the original studies did not identify a significant difference in ICDs between patients receiving dopaminergic medication and patients on DBS, whilst the case reports showed that 56% of patients undergoing DBS had poor outcome with regards to ICDs. We discuss these ambivalent findings in the light of proposed pathogenetic mechanisms. Longitudinal, prospective studies with larger number of patients are required in order to fully understand the role of DBS on ICDs in patients with PD.