Intellectual impairment in Parkinson's disease: clinical, pathologic, and biochemical correlates

Modeling of age-related neurological disease: utility of zebrafish

Many age-related neurological diseases still lack effective treatments, making their understanding a critical and urgent issue in the globally aging society. To overcome this challenge, an animal model that accurately mimics these diseases is essential. To date, many mouse models have been developed to induce age-related neurological diseases through genetic manipulation or drug administration. These models help in understanding disease mechanisms and finding potential therapeutic targets. However, some age-related neurological diseases cannot be fully replicated in human pathology due to the different aspects between humans and mice. Although zebrafish has recently come into focus as a promising model for studying aging, there are few genetic zebrafish models of the age-related neurological disease. This review compares the aging phenotypes of humans, mice, and zebrafish, and provides an overview of age-related neurological diseases that can be mimicked in mouse models and those that cannot. We presented the possibility that reproducing human cerebral small vessel diseases during aging might be difficult in mice, and zebrafish has potential to be another animal model of such diseases due to their similarity of aging phenotype to humans.

Effects of deep brain stimulation on cognitive functioning in treatment-resistant depression: a systematic review and meta-analysis

Deep brain stimulation (DBS) is a promising intervention for treatment-resistant depression (TRD). Effects on cognitive functioning are unclear since they have been studied in small samples. We aim to estimate the impact of DBS on cognitive functioning in TRD with a systematic review and meta-analyses. After systematically searching PubMed we included 10 studies which compared standardized neuropsychological tests before and after DBS or between active and sham DBS in TRD. Different random-effects meta-analyses were done for different cognitive (sub-)domains and for different follow-up time windows (<6 months, 6-18 months, and >18 months). We found no significant differences in cognitive functioning up to 6 months of DBS. After 6-18 months of DBS small to moderate improvements were found in verbal memory (Hedge's g = 0.22, 95% CI = [0.01-0.43], p = 0.04), visual memory (Hedge's g = 0.37, 95% CI = [0.03-0.71], p = 0.04), attention/psychomotor speed (Hedge's g = 0.26, 95% CI = [0.02-0.50], p = 0.04) and executive functioning (Hedge's g = 0.37, 95% CI = [0.15-0.59], p = 0.001). Not enough studies could be retrieved for a meta-analysis of effects after >18 months of DBS or for the comparison of active and sham DBS. Qualitatively, generally no differences in cognitive functioning between active and sham DBS were found. No cognitive decline was found in this meta-analysis up to 18 months of DBS in patients with TRD. Results even suggest small positive effects of DBS on cognitive functioning in TRD, although this should be interpreted with caution due to lack of controlled data.

Frequency, pattern and predictors of cognitive impairments in patients with Parkinson's disease using the Community Screening Instrument for Dementia

Background

Parkinson's disease (PD) is a chronic neurodegenerative disorder complicated by cognitive dysfunctions which are associated with increased caregiver burden, pressure on community health facilities, and mortality in affected patients. Most of the data concerning cognitive dysfunctions in PD are from studies conducted in Europe and North America, but there is paucity of data from Sub-Saharan Africa.

Objective

The objective of this study is to determine the frequency, pattern and predictors of cognitive impairments amongst patients with Parkinson's disease.

Materials and methods

This was a cross sectional case control study carried out at a tertiary health facility in South-south Nigeria. Participants with PD were consecutively recruited from the neurology outpatient clinics. Demographic and disease-specific data were obtained with the use of a pre-tested questionnaire. Cognitive performance of thirty patients with PD were compared with thirty demographically matched controls using the Community Screening Instrument for Dementia (CSID). CSID was already validated among Nigerians.

Results

The frequency of cognitive impairment using the CSID was 50% for PD patients (3.3% for controls). Poor cognitive performance was observed across several cognitive domains including language, executive dysfunction, psychomotor speed, and constructional apraxia among PD patients. The independent predictors of the overall cognitive impairment in patients with PD determined by logistic regression analysis include recall deficiency (p = 0.007), impairment with naming (p = 0.044), apraxia (p = 0.003), Hoen&Yahr staging (p = 0.046), UPDRS score (p = 0.015) and age at presentation (p = 0.014).

Conclusion

Cognitive impairments occur more frequently in patients with PD compared to controls. This study also demonstrated the predictive role of severity of disease based on Hoehn &Yahr staging and UPDRS score, and presence of recall deficiency, poor naming ability and apraxia.

Real-World Testing of a Machine Learning-Derived Visual Scale for Tc99m TRODAT-1 for Diagnosing Lewy Body Disease: Comparison with a Traditional Approach Using Semiquantification

Objectives: Abnormal dopamine transporter (DAT) uptake is an important biomarker for diagnosing Lewy body disease (LBD), including Parkinson’s disease (PD) and dementia with Lewy bodies (DLB). We evaluated a machine learning-derived visual scale (ML-VS) for Tc99m TRODAT-1 from one center and compared it with the striatal/background ratio (SBR) using semiquantification for diagnosing LBD in two other centers. Patients and Methods: This was a retrospective analysis of data from a history-based computerized dementia diagnostic system. MT-VS and SBR among normal controls (NCs) and patients with PD, PD with dementia (PDD), DLB, or Alzheimer’s disease (AD) were compared. Results: We included 715 individuals, including 122 NCs, 286 patients with PD, 40 with AD, 179 with DLB, and 88 with PDD. Compared with NCs, patients with PD exhibited a significantly higher prevalence of abnormal DAT uptake using all methods. Compared with the AD group, PDD and DLB groups exhibited a significantly higher prevalence of abnormal DAT uptake using all methods. The distribution of ML-VS was significantly different between PD and NC, DLB and AD, and PDD and AD groups (all p < 0.001). The correlation coefficient of ML-VS/SBR in all participants was 0.679. Conclusions: The ML-VS designed in one center is useful for differentiating PD from NC, DLB from AD, and PDD from AD in other centers. Its correlation with traditional approaches using different scanning machines is also acceptable. Future studies should develop models using data pools from multiple centers for increasing diagnostic accuracy.

Assessing and treating conversations with partners in Parkinson's disease: A scoping review of the evidence

Purpose: This is a scoping review of the methods used in published research to assess conversations and the interventions used to treat conversations between people with Parkinson's disease and their partners. Communication partners were defined as significant others or next-of-kin. The aims were to describe the assessment methods and interventions used, and to identify gaps in the literature.Method: Four online databases were used to identify peer reviewed journal articles in English, which assess and/or treat conversations in this population. The titles and abstracts of the obtained articles were screened and irrelevant articles were excluded. The full texts of the remaining articles were read to determine which studies met the inclusion/exclusion criteria of this review. The methods used, conversational aspects assessed, the treatments conducted and outcome measures used, and the speech and language domains targeted were charted in order to examine the extent of the evidence to inform future research directions.Result: Eight studies met inclusion criteria. "Conversation analysis" was the most widely used method to assess conversations. These studies assessed conversational aspects relating to the domains of pragmatics, fluency, prosody and semantics. They highlighted the role of communication partners to support conversational interactions by using repair strategies during a communication breakdown. Only one study treated conversations by implementing communication partner training.Conclusion: The findings of this review emphasise gaps in the literature. It highlights the need for future research implementing communication partner training. There is also a need to assess conversation skills of partners in order to determine which strategies would be most effective to support their interaction. It highlights the importance of incorporating a participation-based approach to assessment and intervention involving all communication partners. This may lead to enhanced support for people with Parkinson's disease and their families, thus improving their quality of life.

Operational Determination of Subjective Cognitive Decline, Mild Cognitive Impairment, and Dementia Using Sum of Boxes of the Clinical Dementia Rating Scale

Objectives: The Clinical Dementia Rating (CDR) Scale is the gold standard for the staging of dementia due to Alzheimer's disease (AD). However, the application of CDR for the staging of subjective cognitive decline (SCD) and mild cognitive impairment (MCI) in AD remains controversial. This study aimed to use the sum of boxes of the CDR (CDR-SB) plus an SCD single questionnaire to operationally determine the different stages of cognitive impairment (CI) due to AD and non-AD. Methods: This was a two-phase study, and we retrospectively analyzed the Show Chwan Dementia registry database using the data selected from 2015 to 2020. Individuals with normal cognition (NC), SCD, MCI, and mild dementia (MD) due to AD or non-AD with a CDR < 2 were included in the analysis. Results: A total of 6,946 individuals were studied, including 875, 1,009, 1,585, and 3,447 with NC, SCD, MCI, and MD, respectively. The cutoff scores of CDR-SB for NC/SCD, SCD/MCI, and MCI/dementia were 0/0.5, 0.5/1.0, and 2.5/3.0, respectively. The receiver operating characteristic (ROC) analysis showed that the area under the curve (AUC) values of the test groups were 0.85, 0.90, and 0.92 for discriminating NC from SCD, SCD from MCI, and MCI from dementia, respectively. Compared with the Cognitive Abilities Screening Instrument or the Montreal Cognitive Assessment, the use of CDR-SB is less influenced by age and education. Conclusion: Our study showed that the operational determination of SCD, MCI, and dementia using the CDR-SB is practical and can be applied in clinical settings and research on CI or dementia.

The Effect of a Secondary Task on Kinematics during Turning in Parkinson’s Disease with Mild to Moderate Impairment

Patients with Parkinson’s disease (PD) show typical gait asymmetries. These peculiar motor impairments are exacerbated by added cognitive and/or mechanical loading. However, there is scarce literature that chains these two stimuli. The aim of this study was to investigate the combined effects of a dual task (cognitive task) and turning (mechanical task) on the spatiotemporal parameters in mild to moderate PD. Participants (nine patients with PD and nine controls (CRs)) were evaluated while walking at their self-selected pace without a secondary task (single task), and while repeating the days of the week backwards (dual task) along a straight direction and a 60° and 120° turn. As speculated, in single tasking, PD patients preferred to walk with a shorter stride length (p < 0.05) but similar timing parameters, compared to the CR group; in dual tasking, both groups walked slower with shorter strides. As the turn angle increased, the speed will be reduced (p < 0.001), whereas the ground–foot contact will become greater (p < 0.001) in all the participants. We showed that the combination of a simple cognitive task and a mechanical task (especially at larger angles) could represent an important training stimulus in PD at the early stages of the pathology.

Tremor in Vascular Cognitive Impairment Raises the Possibility of Mixed Pathology With Lewy Body Disease

Objectives

Tremor is common in patients with Lewy body disease (LBD) and not rare in normal individuals. Prevalence of tremor in patients with vascular cognitive impairment (VCI) and its association with other comorbidities are seldom studied. The aim of this study was to investigate the patient characteristics of VCI associated with tremor and to evaluate the possibility of mixed pathology with LBD in these patients.

Methods

Retrospective analysis of a large population with VCI registered in the database of a regional healthcare system was performed. VCI patients were divided into tremor and non-tremor groups. The associated characteristics including demographics, clinical features in motor and non-motor domains, vascular risk factors, and neuroimaging features were compared between the tremor group and the non-tremor group.

Results

Among 1337 patients with VCI, 292 (21.8%) had tremor, while 1045 (78.2%) did not have tremor. The tremor group had significantly higher prevalence of all motor and non-motor LBD clinical features than the non-tremor group. The tremor group also demonstrated more severe neuropsychiatric symptoms. Among patients with tremor, patients having tremor onset earlier than stroke onset showed significantly higher prevalence of rapid eye movement sleep behavior disorder. All comparisons were adjusted for age and severity of dementia.

Conclusion

Tremor is a common comorbidity of VCI. VCI patients with tremor had a higher prevalence of motor and non-motor LBD features. These findings raised the possibility of VCI patients with tremor having high possibility of mixed pathology with LBD.

Freezing of Speech Single Questionnaire as a Screening Tool for Cognitive Dysfunction in Patients With Dementia With Lewy Bodies

Introduction

Freezing phenomenon is a striking feature of Parkinson's disease. However, it has never been studied in people with dementia with Lewy bodies (DLB). We designed a freezing of speech single questionnaire (FOSSQ) and investigated the frequency and association of freezing of speech (FOS) in patients with DLB and other types of dementia.

Methods

This is a retrospective analysis of data from the project of history-based artificial intelligent computerized dementia diagnostic system. We compared the frequencies of FOS among non-demented (ND) participants, patients with Alzheimer's disease (AD), vascular dementia (VaD), and DLB. Further, we explored the association factors of FOS in all the participants.

Results

We enrolled 666 individuals with the following disease distribution: 190, ND; 230, AD; 183, VaD; and 63, DLB. Compared to individuals with ND (2.1%), patients with AD (6.1%), or VaD (18.0%), DLB (54.0%) showed a significantly higher frequency of positive FOS (all p < 0.001). The association factors of FOS were older age, more severe dementia, more severe motor dysfunction, fluctuating cognition, visual hallucinations, parkinsonism, rapid eye movement sleep behavior disorder, attention, mental manipulation, and language.

Conclusion

Our study showed that the informant-based FOSSQ may be a practical screening tool for discriminating DLB from individuals with ND or other forms of dementia. The FOSSQ can be applied in clinical practice as well as on the artificial intelligent platform.

Frequency of non-motor symptoms and their impact on the quality of life in patients with Parkinson's disease: a prospective descriptive case series

AIM

In this study, we aimed to show non-motor symptoms (NMS), in addition to motor symptoms, in the foreground of idiopathic Parkinson's disease (IPD). We also examined the prevalence of dopamine dysregulation syndrome, which can be evaluated based on NMS, its risk factors, and its effects on quality of life (QOL) by using various scales and questionnaires.

METHODS

In total, 75 patients with IPD (46 men, 29 women) who attend the outpatient neurology clinic of our hospital were included in the study. The motor symptoms and NMS of IPD were examined. The severity of parkinsonism was evaluated with the Unified Parkinson's Disease Rating Scale and the Hoehn and Yahr scale. Cognitive tests, the NMS questionnaire, the Parkinson's Disease Sleep Scale, and the Dopamine Dysregulation Syndrome-Patient and Caregiver Inventory were used to identify NMS. The 39-item Parkinson's Disease Questionnaire evaluated QOL.

RESULTS

We observed a significant increase in scores on the tests assessing NMS, specifically the Parkinson's Disease Questionnaire, NMS questionnaire, Parkinson's Disease Sleep Scale, and Geriatric Depression Scale (P < 0.05). These increases correlated with an increase in the Unified Parkinson's Disease Rating Scale score and a stage increase on the Hoehn and Yahr scale. Based on the scores, motor severity most affected QOL.

CONCLUSION

Ignoring NMS while focusing primary on motor symptoms in IPD can cause serious insufficiencies in treatment plans. Assessing NMS and dopamine dysregulation syndrome with structured scales that employ an integrated approach can improve QOL in IPD.

An Informant-Based Simple Questionnaire for Visuospatial Dysfunction Assessment in Dementia

Objectives

Visuospatial dysfunction (VSD) is one of the most important symptoms for the diagnosis of dementia with Lewy bodies (DLB). The aim of this study was to validate a novel VSD questionnaire and determine the cutoff score for the screening for VSD in DLB.

Methods

This is a retrospective analysis of data from a project of the History-based Artificial Intelligent Clinical Dementia Diagnostic System (HAICDDS). VSD of non-demented control (NDC), Alzheimer’s disease (AD), and DLB participants were analyzed and compared using the visuospatial questionnaire in the HAICDDS (HAI-VSQ), the Draw subscale in the Cognitive Abilities Screening Instrument (CASI-Draw), and the visuospatial subscale in Montreal Cognitive Assessment (MoCA-VS).

Results

A total of 440 individuals were studied, including 154 NDC, 229 AD, and 57 DLB participants. Compared to NDC or AD participants, DLB participants showed a higher total score on HAI-VSQ after adjustment for age. Using HAI-VSQ, a cutoff score ≥ 2 was useful for the screening for VSD in DLB with a sensitivity of 0.77 and a specificity of 0.94. Compared with CASI-Draw or MoCA-VS, HAI-VSQ was least influenced by gender, age, and education and had the highest correlation with the sum of boxes of the Clinical Dementia Rating scale. After adjustment for age, education, gender, and global cognitive function, HAI-VSQ significantly discriminated DLB from AD and NDC whereas MoCA-VS or CASI-Draw did not.

Conclusion

Our study showed that the newly designed simple questionnaire was a practical screening tool for VSD in DLB that can be applied in clinical practice as well as on a registration platform.

L-3-n-butylphthalide soft capsules in the treatment of Parkinson disease dementia: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

In recent years, L-3-n-butylphthalide (L-NBP) has been used for Parkinson disease dementia (PDD) to attenuate cognitive impairments in China. Therefore, we selected published and qualified clinical trials to conduct a systematic review and meta-analysis with the aim of assessing the effectiveness and safety of L-NBP in the treatment of PDD.

OBJECTIVE

This systematic review and meta-analysis aimed to assess the effectiveness and safety of L-NBP in the treatment of PDD.

METHODS

We searched PubMed, EMBASE, China National Knowledge Infrastructure, Chinese Scientific Journal Database (VIP database), and Wan-Fang Database to collect eligible articles. We calculated pooled estimates of odds ratios or the standard mean deviation with 95% confidence intervals.

RESULTS

Eight randomized controlled trials were included in our meta-analysis. Our meta-analysis showed that L-NBP combined with Western medicine (WM) had a better effect on improving cognitive dysfunction, the total effective rate, symptoms of Parkinson disease (PD), and activities of daily living function than WM alone. Regarding safety, no serious adverse events were observed in the experimental group.

CONCLUSION

We found that L-NBP as a complementary therapy may have a positive therapeutic effect for improving cognitive dysfunction, the total effective rate, symptoms of PD, quality of life, and the related serum factors in the treatment of PDD. Furthermore, L-NBP was a safe treatment for PDD. However, the findings of our meta-analysis may be influenced by the low quality of the included studies. We highlight the need to conduct trials with higher methodological quality.

Association of visual hallucinations with very mild degenerative dementia due to dementia with Lewy bodies

BACKGROUND AND PURPOSE

Complex, well-formed, and detailed visual hallucinations (VHs) are among the core clinical features of dementia with Lewy bodies (DLB). We investigated the diagnostic value of VHs in different types of very mild degenerative dementia.

METHODS

Participants were required to complete a structured interview form recording their basic data, clinical history, neuropsychological tests, and neuropsychiatric symptoms. Basic demographic characteristics of the participants were summarized and compared. The frequency and association factors of VHs were compared among three major degenerative dementia groups, namely, Alzheimer's disease (AD), Parkinson's disease dementia (PDD), and DLB.

RESULTS

A total of 197 patients with dementia and a clinical dementia rating of 0.5 were investigated, comprising 124 with AD, 35 with PDD, and 38 with DLB. A significantly higher frequency of VHs was found in the DLB group compared with the other groups (DLB, PDD, and AD = 31.6%, 11.4%, and 4.0%; p < 0.001). A multivariable logistic regression test for associations of positive VHs revealed that DLB was the only independently predictive factor (odds ratio: 13.62; p < 0.001).

CONCLUSION

Our findings revealed a high diagnostic value of VHs in very mild degenerative dementia. VHs in this stage of dementia were significantly associated with DLB, and more than 30% of patients with very mild dementia caused by DLB presented with VHs.

Experiences of Persons With Parkinson's Disease Engaged in Group Therapeutic Singing

Background

Parkinson's disease (PD) is a progressive neurodegenerative disorder that leads to altered neural control of movement, including the control of voice, respiration, and swallowing. There is a prevalent need to provide therapy for voice, respiration, and swallowing difficulties because current pharmacological and surgical treatments do not effectively treat these impairments. Previous research has demonstrated that singing may be a treatment option to target voice, respiratory, and swallowing impairments, as well as quality of life. However, participants' perspectives related to reasons for enrolling and engaging in programs as well as evaluation of singing programs have been neglected.

Objective

The purpose of this descriptive study was thus to solicit participants' views of their involvement in a group singing intervention (GSI) led by credentialed music therapists.

Methods

Twenty persons with PD were interviewed 4 to 6 months after completing the singing intervention. Participants were asked about 1) why they chose to participate, 2) what were the beneficial and non-beneficial aspects of participating, and 3) how to improve overall design and delivery of the GSI.

Results

Using content analysis procedures, we learned that participants regarded their involvement in the study as mutually beneficial, fun, and engaging. Participants appreciated the fellowship with other persons with PD and offered minimal constructive criticism.

Conclusions

This study provided greater insight into how a therapeutic singing program may benefit participants and positively impact their lives.

Altered microRNA profiles in cerebrospinal fluid exosome in Parkinson disease and Alzheimer disease

The differential diagnosis of Parkinson's diseases (PD) is challenging, especially in the early stages of the disease. We developed a microRNA profiling strategy for exosomal miRNAs isolated from cerebrospinal fluid (CSF) in PD and AD. Sixteen exosomal miRNAs were up regulated and 11 miRNAs were under regulated significantly in PD CSF when compared with those in healthy controls (relative fold > 2, p < 0.05). MiR-1 and miR-19b-3p were validated and significantly reduced in independent samples. While miR-153, miR-409-3p, miR-10a-5p, and let-7g-3p were significantly over expressed in PD CSF exosome. Bioinformatic analysis by DIANA-mirPath demonstrated that Neurotrophin signaling, mTOR signaling, Ubiquitin mediated proteolysis, Dopaminergic synapse, and Glutamatergic synapse were the most prominent pathways enriched in quantiles with PD miRNA patterns. Messenger RNA (mRNA) transcripts [amyloid precursor protein, APP), α-synuclein (α-syn), Tau, neurofilament, light gene (NF-L), DJ-1/PARK7, Fractalkine and Neurosin] and long non-coding RNAs (RP11-462G22.1 and PCA3) were differentially expressed in CSF exosomes in PD and AD patients. These data demonstrated that CSF exosomal RNA molecules are reliable biomarkers with fair robustness in regard to specificity and sensitivity in differentiating PD from healthy and diseased (AD) controls.

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.

Aspectos comunicativos e enfrentamento da disfonia em pacientes com doença de Parkinson

RESUMO Objetivo: Investigar as estratégias de enfrentamento utilizadas por indivíduos com doença de Parkinson (DP), os sintomas vocais mais relatados, os problemas de comunicação mais presentes e a relação entre o tipo de enfrentamento, os sintomas vocais e os aspectos comunicativos. Métodos: Participaram 73 indivíduos, 33 do grupo experimental, com diagnóstico de DP e apresentando desvio vocal, e 40 do grupo controle (GC), saudáveis, sem desvio vocal. Eles foram submetidos aos seguintes procedimentos: aplicação do Protocolo de Estratégias de Enfrentamento das Disfonias (PEEDBR), da Escala de Sintomas Vocais (ESV) e do Questionário Vivendo com Disartria (VcD). Resultados: O grupo experimental (GE) apresentou desvios em todos os protocolos: PEEDBR, sendo a estratégia de enfrentamento mais utilizada a de "Autocontrole", ESV, com o domínio prevalente "Limitação", e VcD, com alteração em todas as seções. O PEEDBR apresentou correlação regular com a ESV e o VcD. Já entre o Questionário VcD e a ESV, verificouse relação direta entre o escore total do VcD e o escore total e o domínio emocional da ESV. Conclusão: Pacientes com DP usam todos os tipos de estratégias de enfrentamento, principalmente "Autocontrole". Eles possuem grande quantidade de sinais e sintomas vocais, e "Limitação" foi o domínio mais predominante. Há presença de dificuldades em todos os aspectos que abrangem sua comunicação. Quanto maior a ocorrência de sinais e sintomas vocais, mais o paciente refere ser difícil viver com a disartria, particularmente quando há desvios no domínio emocional.

Beneficial effects of nicotine, cotinine and its metabolites as potential agents for Parkinson's disease

Parkinson’s disease (PD) is a progressive neurodegenerative disorder, which is characterized by neuroinflammation, dopaminergic neuronal cell death and motor dysfunction, and for which there are no proven effective treatments. The negative correlation between tobacco consumption and PD suggests that tobacco-derived compounds can be beneficial against PD. Nicotine, the more studied alkaloid derived from tobacco, is considered to be responsible for the beneficial behavioral and neurological effects of tobacco use in PD. However, several metabolites of nicotine, such as cotinine, also increase in the brain after nicotine administration. The effect of nicotine and some of its derivatives on dopaminergic neurons viability, neuroinflammation, and motor and memory functions, have been investigated using cellular and rodent models of PD. Current evidence shows that nicotine, and some of its derivatives diminish oxidative stress and neuroinflammation in the brain and improve synaptic plasticity and neuronal survival of dopaminergic neurons. In vivo these effects resulted in improvements in mood, motor skills and memory in subjects suffering from PD pathology. In this review, we discuss the potential benefits of nicotine and its derivatives for treating PD.

Dysfunctional action control as a specific feature of Parkinson's disease

Parkinson's disease (PD) is characterised by motor deficits as well as cognitive alterations, particularly concerning frontal lobe control. Here, we were interested in whether executive function is abnormal already early in PD, as well as whether this dysfunction worsens as a part of the dementia in PD. The following groups engaged in tasks addressing action control: PD patients with mild and advanced motor symptoms (aPD) without dementia, PD patients with dementia (PDD), patients with Alzheimer's disease (AD) and healthy subjects (CON). Subjects either had to perform or inhibit button presses upon go and no-go cues, respectively. These cues were preceded by pre-cues, either randomly instructive of right or left hand preparation (switch condition), or repetitively instructive for one side only (non-switch condition). PDD and aPD omitted more go responses than CON. Furthermore, PDD disproportionally committed failures upon no-go cues compared to CON. In the non-switch condition, PDD performed worse than AD, whose deficits increased to the level of PDD in the switch condition. Over all PD patients, task performance correlated with disease severity. Under the switch condition, task performance was low in both PDD and AD. In the non-switch condition, this also held true for advanced PD patients (with and without dementia), but not for AD. Thus, the deficits evident in PDD appear to develop from imbalanced inhibitory-to-excitatory action control generally inherent to PD. These results specify the concept of dysexecution in PD and differentiate the cognitive profile of PDD from that of AD patients.

What is the Clinical Significance of Cerebrospinal Fluid Biomarkers in Parkinson's disease? Is the Significance Diagnostic or Prognostic?

The clinical diagnostic criteria of Parkinson's disease (PD) have limitations in detecting the disease at early stage and in differentiating heterogeneous clinical progression. The lack of reliable biomarker(s) for early diagnosis and prediction of prognosis is a major hurdle to achieve optimal clinical care of patients and efficient design of clinical trials for disease-modifying therapeutics. Numerous efforts to discover PD biomarkers in CSF were conducted. In this review, we describe the molecular pathogenesis of PD and discuss its implication to develop PD biomarkers in CSF. Next, we summarize the clinical utility of CSF biomarkers including alpha-synuclein for early and differential diagnosis, and prediction of PD progression. Given the heterogeneity in the clinical features of PD and none of the CSF biomarkers for an early diagnosis have been developed, research efforts to develop biomarkers to predict heterogeneous disease progression is on-going. Notably, a rapid cognitive decline followed by the development of dementia is a risk factor of poor prognosis in PD. In connection to this, CSF levels of Alzheimer's disease (AD) biomarkers have received considerable attention. However, we still need long-term longitudinal observational studies employing large cohorts to evaluate the clinical utility of CSF biomarkers reflecting Lewy body pathology and AD pathology in the brain. We believe that current research efforts including the Parkinson's Progression Markers Initiative will resolve the current needs of early diagnosis and/or prediction of disease progression using CSF biomarkers, and which will further accelerate the development of disease-modifying therapeutics and optimize the clinical management of PD patients.

A clinical profile of patients with Parkinson's disease and psychosis

AIMS

The aim of the study was to study the clinical profile of the patients with Parkinson's disease (PD) and psychosis.

SETTINGS AND DESIGN

This was a prospective, cross sectional, hospital-based study done at the Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India from September 2009 to January 2011. All patients with PD, diagnosed by United Kingdom PD Society Brain Bank criteria, having with features of psychosis as diagnosed by the neuropsychiatric inventory (NPI) were included. Patients without a caregiver who could validate the patient's symptoms were excluded.

RESULTS

A total of 40 patients (5 women, 35 men) with PD with psychosis (mean age: 54.2 ± 11.5 years, mean duration of illness: 6.5 ± 4.5 years, and mean duration of psychosis: 4.3 ± 4.3 years) were included in the study. The Global NPI score was 19.1 ± 11.5. Majority of the patients had pure hallucinations (85%), while the rest had either pure delusions (7.5%) or a combination of delusions and hallucinations (7.5%). In those with hallucinations, visual hallucinations were the commonest (60%) (pure only in 22.5%), followed by auditory (45%), minor hallucinations (45%), and tactile (20%). Only one person reported having olfactory hallucinations (2.5%). Loss of insight was most often observed during the visual hallucinations (52%), followed by tactile (44.4%), auditory (38.9 %), and minor hallucinations (33.3%).

CONCLUSIONS

In patients with PD and psychosis, pure hallucinations are common and visual hallucinations are the commonest among the hallucinations. A large proportion of patients have minor hallucinations, which need to be recognized early for effective and early management. The limitations of the study were small sample size, use of a single scale to assess psychosis and subjective assessment of insight.

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.

Associations between cognitive and gait performance during single- and dual-task walking in people with Parkinson disease

BACKGROUND

Cognitive impairments in Parkinson disease (PD) manifest as deficits in speed of processing, working memory, and executive function and attention abilities. The gait impairment in PD is well documented to include reduced speed, shortened step lengths, and increased step-to-step variability. However, there is a paucity of research examining the relationship between overground walking and cognitive performance in people with PD.

OBJECTIVE

This study sought to examine the relationship between both the mean and variability of gait spatiotemporal parameters and cognitive performance across a broad range of cognitive domains.

DESIGN

A cross-sectional design was used.

METHODS

Thirty-five participants with no dementia and diagnosed with idiopathic PD completed a battery of 12 cognitive tests that yielded 3 orthogonal factors: processing speed, working memory, and executive function and attention. Participants completed 10 trials of overground walking (single-task walking) and 5 trials of overground walking while counting backward by 3's (dual-task walking).

RESULTS

All gait measures were impaired by the dual task. Cognitive processing speed correlated with stride length and walking speed. Executive function correlated with step width variability. There were no significant associations with working memory. Regression models relating speed of processing to gait spatiotemporal variables revealed that including dual-task costs in the model significantly improved the fit of the model.

LIMITATIONS

Participants with PD were tested only in the on-medication state.

CONCLUSIONS

Different characteristics of gait are related to distinct types of cognitive processing, which may be differentially affected by dual-task walking due to the pathology of PD.

Impact of bilateral subthalamic stimulation on motor/cognitive functions in Parkinson's disease

It is still unclear whether deep brain stimulation targeted to the bilateral subthalamic nucleus (STN-DBS) affects cognitive function in Parkinson's disease (PD). This prospective study was aimed to systemically evaluate the impact of bilateral STN-DBS on motor and cognitive functions in patients with PD. This study included totally 11 Japanese patients with medically intolerant PD. Neurological and cognitive status was precisely evaluated before and 1 year after bilateral STN-DBS, using unified Parkinson's disease rating scale (UPDRS), levodopa equivalent doses, mini-mental state examination (MMSE), Japanese adult reading test (JART), repeatable battery for the assessment of neuropsychological status (RBANS), and Wechsler adult intelligence scale-revised (WAIS-R). Preoperative RBANS and WAIS-R identified cognitive dysfunction that could not be detected by MMSE and JART. Before surgery, PD patients had significantly impaired immediate memory and attention. Motor function significantly improved 1 year after bilateral STN-DBS. Bilateral STN-DBS did not affect any score on cognitive examinations. However, postoperative improvements of total score on RBANS and performance intelligence quotient (PIQ) scores on WAIS-R were closely related to those of UPDRS part III off (R² = 0.61, P < 0.01; R² = 0.39, P < 0.05, respectively). These findings strongly suggest that bilateral STN-DBS may significantly improve cognitive function in a certain subgroup of patients whose therapeutic effects on motor function are prominent.

Does CSF p-tau181 help to discriminate Alzheimer's disease from other dementias and mild cognitive impairment? A meta-analysis of the literature

To evaluate the clinical importance of cerebrospinal fluid (CSF) phosphorylated tau 181 (p-tau181) in mild cognitive impairment (MCI), Alzheimer's disease (AD) and other dementias, more specifically: frontotemporal degeneration (FTD), dementia with Lewy bodies (DLB), vascular dementia (VaD) and Parkinson's disease (PD) with dementia (PDD). Fifty eligible articles were identified by search of databases including PubMed, EMBASE, Elsevier, Springer Link and the Cochrane Library, up to December 2013. The random effects model was used to calculate the standardized mean difference (SMD) with corresponding 95% CI by STATA 9.0 software. The subgroup analyses were made on the methods or PD with dementia. We found that CSF p-tau181 concentrations were significantly higher in AD compared to MCI [SMD: 0.61, 95% CI: (0.46, 0.76), z = 8.07, P < 0.001], FTD [SMD: 1.23, 95% CI: (0.89, 1.56), z = 7.19, P < 0.001], DLB [SMD: 1.08, 95% CI: (0.80, 1.37), z = 7.41, P < 0.001], PDD [SMD: 1.05, 95% CI: (0.02, 2.07), z = 2.00, P = 0.045] and VaD [SMD: 1.28, 95% CI: (0.68, 1.88), z = 4.19, P < 0.001]. Results from this meta-analysis implied that CSF p-tau181 is a good biomarker for discriminating Alzheimer's disease from other dementias and mild cognitive impairment.

Association of cerebrospinal fluid β-amyloid 1-42, T-tau, P-tau181, and α-synuclein levels with clinical features of drug-naive patients with early Parkinson disease

IMPORTANCE

We observed a significant correlation between cerebrospinal fluid (CSF) levels of tau proteins and α-synuclein, but not β-amyloid 1-42 (Aβ1-42), and lower concentration of CSF biomarkers, as compared with healthy controls, in a cohort of entirely untreated patients with Parkinson disease (PD) at the earliest stage of the disease studied so far.

OBJECTIVE

To evaluate the baseline characteristics and relationship to clinical features of CSF biomarkers (Aβ1-42, total tau [T-tau], tau phosphorylated at threonine 181 [P-tau181], and α-synuclein) in drug-naive patients with early PD and demographically matched healthy controls enrolled in the Parkinson's Progression Markers Initiative (PPMI) study.

DESIGN, SETTING, AND PARTICIPANTS

Cross-sectional study of the initial 102 research volunteers (63 patients with PD and 39 healthy controls) of the PPMI cohort.

MAIN OUTCOMES AND MEASURES

The CSF biomarkers were measured by INNO-BIA AlzBio3 immunoassay (Aβ1-42, T-tau, and P-tau181; Innogenetics Inc) or by enzyme-linked immunosorbent assay (α-synuclein). Clinical features including diagnosis, demographic characteristics, motor, neuropsychiatric, and cognitive assessments, and DaTscan were systematically assessed according to the PPMI study protocol.

RESULTS

Slightly, but significantly, lower levels of Aβ1-42, T-tau, P-tau181, α-synuclein, and T-tau/Aβ1-42 were seen in subjects with PD compared with healthy controls but with a marked overlap between groups. Using multivariate regression analysis, we found that lower Aβ1-42 and P-tau181 levels were associated with PD diagnosis and that decreased CSF T-tau and α-synuclein were associated with increased motor severity. Notably, when we classified patients with PD by their motor phenotypes, lower CSF Aβ1-42 and P-tau181 concentrations were associated with the postural instability-gait disturbance-dominant phenotype but not with the tremor-dominant or intermediate phenotype. Finally, we found a significant correlation of the levels of α-synuclein with the levels of T-tau and P-tau181.

CONCLUSIONS AND RELEVANCE

In this first report of CSF biomarkers in PPMI study subjects,we found that measures of CSF Aβ1-42, T-tau, P-tau181, and α-synuclein have prognostic and diagnostic potential in early-stage PD. Further investigations using the entire PPMI cohort will test the predictive performance of CSF biomarkers for PD progression

Plasma homocysteine levels in patients treated with levodopa: motor and cognitive associations

OBJECTIVE

The aim of this study was to determine whether hyperhomocysteinemia caused by levodopa used in idiopathic Parkinson's disease (IPD) is associated with cognitive or physical impairments. The role of folate and vitamin B12 levels in this context was also ascertained.

METHODS

Thirty-nine patients who had been followed with the diagnosis of IPD in our clinic for > 2 years and 28 healthy control subjects with similar demographic features were included in the study. The homocysteine, folic acid and vitamin B12 levels and the results of the short test of mental status (STMS) and the clock drawing test of IPD patients were compared with those of the controls. Subsequently, the patients with a homocysteine level of >14 micromol/l were compared with those having a homocysteine level of <14 micromol/l by means of detailed neuropsychometric test batteries.

RESULTS

Homocysteine levels were significantly higher in the patient group in comparison with the controls. There was a negative correlation between hyperhomocysteinemia and the levels of vitamin B12 and folate. On the other hand, a positive correlation between hyperhomocysteinemia and the levodopa dose was detected. There was a positive correlation between hyperhomocysteinemia and unified Parkinson's disease rating scale (UPDRS) motor section. The critical dose of levodopa was observed to be 300 mg/d. In terms of cognitive and frontal functions, no significant difference was detected between the patients and control group. The subgroup with a homocysteine level of >14 micromol/l had a significantly poorer performance in frontal and memory tests.

DISCUSSION

In patients with IPD who are detected to have hyperhomocysteinemia, the assessment of the cognitive performance, folic acid and vitamin B12 levels and the supplementation of folic acid and vitamin B12 to the treatment regimen might be appropriate.

Prevalence of Parkinson disease and Parkinson disease dementia in community nursing homes

OBJECTIVE

To estimate the prevalence of Parkinson disease (PD) and Parkinson disease dementia (PDD) in community nursing homes. To estimate how many residents who meet criteria for PDD have been diagnosed with PDD and prescribed a Federal Drug Administration (FDA)-approved treatment for PDD.

SETTING

Three private Saint Louis metropolitan area nursing homes.

PARTICIPANTS

Fifty-five residents with a chart diagnosis of PD from a total of 714 residents were identified. Sixteen subjects or families did not give consent and two were excluded from the study because advanced stage of the illness impaired evaluation. Thirty-seven subjects with an established diagnosis of PD participated in the study.

DESIGN AND MEASUREMENTS

A chart review was used to identify the study sample: residents with an established diagnosis of PD. Consent was obtained from the nursing home administration, families or guardians, and the residents themselves (where applicable). Study data were obtained from review of residents' medical charts, family/caregiver interview, resident interview, resident cognitive testing (Mini-Mental State Examination, clock drawing test), and resident depression assessment (15-item Geriatric Depression Scale). Diagnosis of PDD was defined using existing literature and described below. Data were analyzed using SPSS version 15.

RESULT

Of the 714 nursing home residents, 55 (7.7%) met criteria for PD. Of these, 37 participated in the study and 18 (48.6%) met criteria for PDD. None were diagnosed with PDD in the charts and 11.1% (2 of 18) were on FDA-approved treatment.

CONCLUSION

In this sample of nursing home residents, the prevalence of PD was 7.7% and the overall prevalence of PDD was 3.7%. PDD remains an unrecognized entity in the nursing home setting. Close to half (48.65%) of nursing home residents with PD may have PDD at any given time and they remain undiagnosed and largely undertreated.

Microglia, amyloid, and glucose metabolism in Parkinson's disease with and without dementia

[(11)C](R)PK11195-PET measures upregulation of translocator protein, which is associated with microglial activation, [(11)C]PIB-PET is a marker of amyloid, while [(18)F]FDG-PET measures cerebral glucose metabolism (rCMRGlc). We hypothesize that microglial activation is an early event in the Parkinson's disease (PD) spectrum and is independent of the amyloid pathology. The aim of this study is to evaluate in vivo the relationship between microglial activation, amyloid deposition, and glucose metabolism in Parkinson's disease dementia (PDD) and PD subjects without dementia. Here, we evaluated 11 PDD subjects, 8 PD subjects without dementia, and 24 control subjects. Subjects underwent T1 and T2 MRI, [(11)C](R)PK11195, [(18)F]FDG, and [(11)C]PIB PET scans. Parametric maps of [(11)C](R)PK11195 binding potential, rCMRGlc, and [(11)C]PIB uptake were interrogated using region of interest and SPM (statistical parametric mapping) analysis. The PDD patients showed a significant increase of microglial activation in anterior and posterior cingulate, striatum, frontal, temporal, parietal, and occipital cortical regions compared with the controls. The PD subjects also showed a statistically significant increase in microglial activation in temporal, parietal, and occipital regions. [(11)C]PIB uptake was marginally increased in PDD and PD. There was a significant reduction in glucose metabolism in PDD and PD. We have also demonstrated pixel-by-pixel correlation between mini-mental state examination (MMSE) score and microglial activation, and MMSE score and rCMRGlc. In conclusion, we have demonstrated that cortical microglial activation and reduced glucose metabolism can be detected early on in this disease spectrum. Significant microglial activation may be a factor in driving the disease process in PDD. Given this, agents that affect microglial activation could have an influence on disease progression.

The neurobiology and neural circuitry of cognitive changes in Parkinson's disease revealed by functional neuroimaging

Patients with Parkinson's disease (PD) often develop a spectrum of cognitive symptoms that can evolve into dementia. Dopamine (DA) replacement medications, though improving motor symptoms, can exert both positive and negative effects on cognitive ability, depending on the severity of the disease and the specific skill being tested. By considering the behavioral and clinical aspects of disease- and treatment-mediated changes in cognition alongside the pathophysiology of PD, an understanding of the factors that govern the heterogeneous expression of cognitive impairment in PD is beginning to emerge. Here, we review the neuroimaging studies revealing the neural correlates of cognitive changes after DA loss and DA replacement as well as those that may accompany the conversion from milder stages of cognitive impairment to frank dementia.

A longitudinal of Parkinson's disease: clinical and neuropsychological correlates of dementia

Neuropsychological assessments were performed in ninety-one de novo patients participating in the Sydney Multicentre Study of Parkinson's disease. Assessments were made at baseline and after 3 and 5 years. Performance at baseline and after 5 years was compared with controls. At baseline 37% of patients whose symptoms of Parkinson's disease had begun after the age of 70 years were demented. This compared with a prevalence of dementia of 8.8% in patients whose symptoms had begun before the age of 70 years. By 5 years the prevalence of dementia in the two groups had risen to 62.3% and 17.3% respectively. The death rate was higher over the 5 year period in the demented patients. Demented patients had more symmetrical signs, higher disability and bradykinesia scores and more impairment of gait and balance at baseline than non-demented patients. The presence of dementia at baseline predicted a poor response to treatment. The dementia at baseline had features of a subcortical dementia. Subsequently, aphasia, apraxia and agnosia emerged, making the dementia indistinguishable from that of Alzheimer's disease. Patients with well preserved cognitive function at baseline had a good response to levodopa and were more likely to develop levodopa induced dyskinesia. These results show that the clinical features of Parkinson's disease and response to treatment are influenced by the age of onset of symptoms and by the presence of dementia.

Closing the gap between clinic and cage: sensori-motor and cognitive behavioural testing regimens in neurotoxin-induced animal models of Parkinson's disease

Animal models that make use of chemical toxins to adversely affect the nigrostriatal dopaminergic pathway of rodents and primates have contributed significantly towards the development of symptomatic therapies for Parkinson's disease (PD) patients. Although their use in developing neuro-therapeutic and -regenerative compounds remains to be ascertained, toxin-based mammalian and a range of non-mammalian models of PD are important tools in the identification and validation of candidate biomarkers for earlier diagnosis, as well as in the development of novel treatments that are currently working their way into the clinic. Toxin models of PD have and continue to be important models to use for understanding the consequences of nigrostriatal dopamine cell loss. Functional assessment of these models is also a critical component for eventual translational success. Sensitive behavioural testing regimens for assessing the extent of dysfunction exhibited in the toxin models, the degree of protection or improvement afforded by potential treatment modalities, and the correlation of these findings with what is observed clinically in PD patients, ultimately determines whether a potential treatment moves to clinical trials. Here, we review existing published work that describes the use of such behavioural outcome measures associated with toxin models of parkinsonism. In particular, we focus on tests assessing sensorimotor and cognitive function, both of which are significantly and progressively impaired in PD.

Cholinergic deficit and response to donepezil therapy in Parkinson's disease with dementia

BACKGROUND

Although donepezil, an acetylcholinesterase inhibitor, has been proved to be effective in ameliorating cognitive impairment in Parkinson's disease with dementia (PDD), the responsiveness of patients to donepezil therapy varies. [5-(11)C-methoxy]donepezil, the radiolabeled form of donepezil, is a ligand for positron emission tomography (PET), which can be exploited for the quantitative analysis of donepezil binding to acetylcholinesterase and for cholinergic imaging.

OBJECTIVES

To investigate the deficits of the cholinergic system in the brain in PDD and its association with response to donepezil therapy.

METHODS

Twelve patients with PDD and 13 normal control subjects underwent [5-(11)C-methoxy]donepezil-PET imaging. For patients with PDD, daily administration of donepezil was started after [5-(11)C-methoxy]donepezil-PET imaging and continued for 3 months.

RESULTS

In the PDD group, the mean total distribution volume of the cerebral cortices was 22.7% lower than that of the normal control group. The mean total distribution volume of the patients with PDD was significantly correlated with improvement of visuoperceptual function after 3 months of donepezil therapy.

CONCLUSION

The results suggest that donepezil therapy is more effective in patients with less decrease in acetylcholinesterase, a binding site of donepezil, at least in the specific cognitive domain.

Cognitive impairment and dementia in Parkinson's disease

Relatively subtle cognitive disturbances may be present from the initial stages of Parkinson's disease (PD) that progress in many patients to a more severe cognitive impairment and dementia. Several of the initial deficits are ascribed to failure in the frontal-striatal basal ganglia circuits and involve executive defects in planning, initiation, monitoring of goal-directed behaviors and working-memory. Other non-demented PD patients also exhibit visuospatial and memory deficits more representative of posterior cortical functioning and fail performing naming or copying tasks. Major differences in the overall rate of cognitive decline among PD patients support the co-existence of at least two patterns of involution, differentiating a relatively slow decline of fronto-striatal deficits from a more rapid decline of posterior-cortical deficits, with different pathophysiological substrates, genetics, prognosis and response to drugs used to treat the motor symptoms of PD.

Neuropsychology, neuroimaging or motor phenotype in diagnosis of Parkinson's disease-dementia: which matters most?

Parkinson's disease (PD) is a neurodegenerative disorder affecting not only the motor system but also the cognitive and behavioral domains. Although there are many studies addressing the issue of cognition, a universally recognized method to diagnose patients with dementia is still lacking. The aim of this study was to determine which neuropsychological test is the most reliable in the diagnosis of dementia in PD and to establish if mini mental state examination (MMSE) is enough to detect this condition. We studied 200 consecutive PD patients through an extensive neuropsychological battery, clinical evaluation and brain magnetic resonance imaging over a period of 4 years. A logistic regression model was used to evaluate the interplay between possible risk factors and the accuracy of different neuropsychological tests. PD patients with dementia performed significantly worse in all the tests as compared to patients with PD alone: phonological verbal fluency, attentional matrices, Rey auditory verbal learning test and digit span were the most useful tools. Age and disease duration were correlated with cognitive impairment. No relevant differences were detected in phenotype, affected body side at onset, levodopa equivalent daily dose or neuroimaging findings (except for the occurrence of atrophy). Despite reasonable accuracy of MMSE (90%), its positive predictive value is only 74%. Using at least 3 neuropsychological tests, among those more significant detected with logistic regression analysis, the positive predictive value rises to 91%. In conclusion, the use of an extensive neuropsychological battery is still recommended in the diagnosis of dementia in PD.

Lewy- and Alzheimer-type pathologies in Parkinson's disease dementia: which is more important?

The relative importance of Lewy- and Alzheimer-type pathologies to dementia in Parkinson's disease remains unclear. We have examined the combined associations of α-synuclein, tau and amyloid-β accumulation in 56 pathologically confirmed Parkinson's disease cases, 29 of whom had developed dementia. Cortical and subcortical amyloid-β scores were obtained, while tau and α-synuclein pathologies were rated according to the respective Braak stages. Additionally, cortical Lewy body and Lewy neurite scores were determined and Lewy body densities were generated using morphometry. Non-parametric statistics, together with regression models, receiver-operating characteristic curves and survival analyses were applied. Cortical and striatal amyloid-β scores, Braak tau stages, cortical Lewy body, Lewy neurite scores and Lewy body densities, but not Braak α-synuclein stages, were all significantly greater in the Parkinson's disease-dementia group (P<0.05), with all the pathologies showing a significant positive correlation to each other (P<0.05). A combination of pathologies [area under the receiver-operating characteristic curve=0.95 (0.88-1.00); P<0.0001] was a better predictor of dementia than the severity of any single pathology. Additionally, cortical amyloid-β scores (r=-0.62; P=0.043) and Braak tau stages (r=-0.52; P=0.028), but not Lewy body scores (r=-0.25; P=0.41) or Braak α-synuclein stages (r=-0.44; P=0.13), significantly correlated with mini-mental state examination scores in the subset of cases with this information available within the last year of life (n=15). High cortical amyloid-β score (P=0.017) along with an older age at onset (P=0.001) were associated with a shorter time-to-dementia period. A combination of Lewy- and Alzheimer-type pathologies is a robust pathological correlate of dementia in Parkinson's disease, with quantitative and semi-quantitative assessment of Lewy pathology being more informative than Braak α-synuclein stages. Cortical amyloid-β and age at disease onset seem to determine the rate to dementia.

The epidemiology of dementia associated with Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative illness after Alzheimer's disease (AD). Cognitive impairment and dementia are common features in PD and characterized by a wide range of cognitive deficits distinct from those seen in AD. Mild cognitive impairment occurs even early in PD and is associated with shorter time to dementia. The purpose of this review is to present recent findings on clinical aspects of dementia in PD and to elucidate underlying clinical and neurobiological risk factors.

Lewy body and parkinsonian dementia: common, but often misdiagnosed conditions

BACKGROUND

Dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD) are the two most common types of dementing neurodegenerative disease after Alzheimer's disease (AD). Both of these conditions are often diagnosed late or not at all.

METHODS

Selective literature review.

RESULTS

The severe cholinergic and dopaminergic deficits that are present in both DLB and PDD produce not only motor manifestations, but also cognitive deficits, mainly in the executive and visual-constructive areas, as well as psychotic manifestations such as visual hallucinations, delusions, and agitation. The intensity of these manifestations can fluctuate markedly over the course of the day, particularly in DLB. Useful tests for differential diagnosis include magnetic resonance imaging and electroencephalography; in case of clinical uncertainty, nuclear medical procedures and cerebrospinal fluid analysis can be helpful as well. Neuropathological studies have revealed progressive alpha-synuclein aggregation in affected areas of the brain. In DLB, beta-amyloid abnormalities are often seen as well.

CONCLUSION

DLB should be included in the differential diagnosis of early dementia. If motor manifestations arise within one year (DLB), dopaminergic treatment should be initiated. On the other hand, patients with Parkinson's disease should undergo early screening for signs of dementia so that further diagnostic and therapeutic steps can be taken in timely fashion, as indicated. Cholinesterase inhibitors are useful for the treatment of cognitive deficits and experiential/behavioral disturbances in both DLB (off-label indication) and PDD (approved indication).