Rivastigmine for dementia associated with Parkinson's disease

Treating hallucinations in Parkinson's disease

Introduction: Hallucinations in Parkinson's disease are common, can complicate medication management and significantly impact upon the quality of life of patients and their carers.Areas covered: This review aims to examine current evidence for the management of hallucinations in Parkinson's disease.Expert opinion: Treatment of hallucinations in Parkinson's disease should be both individualized and multifaceted. Screening, education, medication review and the avoidance of common triggers are important. For well-formed visual hallucinations, acetylcholinesterase inhibitors are recommended first-line. Refractory or severe symptoms may require the cautious use of atypical antipsychotics. Antidepressants may be beneficial in the appropriate setting. Unfortunately, current therapies for hallucinations offer only limited benefits and future research efforts are desperately required to improve the management of these challenging symptoms.

Determining a Short Form Montreal Cognitive Assessment (s-MoCA) Czech Version: Validity in Mild Cognitive Impairment Parkinson's Disease and Cross-Cultural Comparison

The Montreal Cognitive Assessment (MoCA) is one of the most common screening instruments for mild cognitive impairment. However, the standard MoCA is approximately two times longer to administer than the Mini-Mental State Examination. A total of 699 Czech and 175 American participants received the standard MoCA Czech and English versions and in the clinical part, a sample of 102 nondemented patients with Parkinson's disease (PD). We created a validated Czech short version (s-MoCA-CZ) from the original using item response theory. As expected, s-MoCA-CZ scores were highly correlated with the standard version (Pearson r = .94, p < .001). s-MoCA-CZ also had 80% classification accuracy in the differentiation of PD mild cognitive impairment from PD without impairment. The s-MoCA-CZ, a brief screening tool, is shorter to administer than the standard MoCA. It provides high-classification accuracy for PD mild cognitive impairment and is equivalent to that of the standard MoCA-CZ.

Association Between REM Sleep Behavior Disorder and Cognitive Dysfunctions in Parkinson's Disease: A Systematic Review and Meta-Analysis of Observational Studies

Background: Rapid eye movement sleep behavior disorder (RBD) is thought to be a prodromal symptom of Parkinson's disease (PD). RBD is also thought to be involved in cognitive decline and dementia in PD. In PD, although the relationship between RBD and cognitive dysfunctions was confirmed by considerable studies, whether RBD was associated with distinct types of cognitive defects is worth of study. Objectives: This systematic review summarizes the evidence relating to cognitive dysfunction in PD patients with RBD (PD-RBD) and those without and explores their specificity to cognitive domains. Methods: A meta-analysis using a random-effects model was performed for 16 different cognitive domains, including global cognitive function, memory (long-term verbal recall, long-term verbal recognition, long-term visual recall, short-term spatial recall, and short-term verbal recall), executive function (general, fluid reasoning, generativity, shifting, inhibition, and updating), language, processing speed/complex attention/working memory, visuospatial/constructional ability, and psychomotor ability. The cognitive difference between the groups of patients was measured as a standardized mean difference (SMD, Cohen's d). PD-RBD patients were classified into Confirmed-RBD (definite diagnosis with polysomnography, PSG) and Probable-RBD (without PSG re-confirmation). In some domains, RBD patients could not be analyzed separately due to the exiguity of primary studies; this analysis refers to such RBD patients as "Mixed-RBD." Results: Thirty-nine studies with 6,695 PD subjects were finally included. Confirmed-RBD patients showed worse performance than those without in global cognitive function, long-term verbal recall, long-term verbal recognition, generativity, inhibition, shifting, language, and visuospatial/constructional ability; Probable-RBD, in global cognitive function and shifting; and Mixed-RBD, in long-term visual recall, short-term spatial recall, general executive function, and processing speed/complex attention/working memory. Conclusion: This meta-analysis strongly suggests a relationship between RBD, Confirmed-RBD in particular, and cognitive dysfunctions in PD patients. Early and routine screening by sensitive and targeted cognitive tasks is necessary for all PD-RBD patients because it may offer the therapeutic time window before they evolve to irreversible dementia.

Challenges and opportunities for improving the landscape for Lewy body dementia clinical trials

Lewy body dementia (LBD), including dementia with Lewy bodies and Parkinson's disease dementia, affects over a million people in the USA and has a substantial impact on patients, caregivers, and society. Symptomatic treatments for LBD, which can include cognitive, neuropsychiatric, autonomic, sleep, and motor features, are limited with only two drugs (cholinesterase inhibitors) currently approved by regulatory agencies for dementia in LBD. Clinical trials represent a top research priority, but there are many challenges in the development and implementation of trials in LBD. To address these issues and advance the field of clinical trials in the LBDs, the Lewy Body Dementia Association formed an Industry Advisory Council (LBDA IAC), in addition to its Research Center of Excellence program. The LBDA IAC comprises a diverse and collaborative group of experts from academic medical centers, pharmaceutical industries, and the patient advocacy foundation. The inaugural LBDA IAC meeting, held in June 2019, aimed to bring together this group, along with representatives from regulatory agencies, to address the topic of optimizing the landscape of LBD clinical trials. This review highlights the formation of the LBDA IAC, current state of LBD clinical trials, and challenges and opportunities in the field regarding trial design, study populations, diagnostic criteria, and biomarker utilization. Current gaps include a lack of standardized clinical assessment tools and evidence-based management strategies for LBD as well as difficulty and controversy in diagnosing LBD. Challenges in LBD clinical trials include the heterogeneity of LBD pathology and symptomatology, limited understanding of the trajectory of LBD cognitive and core features, absence of LBD-specific outcome measures, and lack of established standardized biologic, imaging, or genetic biomarkers that may inform study design. Demands of study participation (e.g., travel, duration, and frequency of study visits) may also pose challenges and impact trial enrollment, retention, and outcomes. There are opportunities to improve the landscape of LBD clinical trials by harmonizing clinical assessments and biomarkers across cohorts and research studies, developing and validating outcome measures in LBD, engaging the patient community to assess research needs and priorities, and incorporating biomarker and genotype profiling in study design.

Drug Development for Psychotropic, Cognitive-Enhancing, and Disease-Modifying Treatments for Alzheimer's Disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder with limited available therapies. There is progress in developing treatments for neuropsychiatric indications in AD, including agitation, psychosis, apathy, and sleep disorders. Candidate therapies progress from nonclinical and animal assessment to trials in normal volunteers (phase 1), small phase-2 trials, and larger confirmatory phase-3 trials. Biomarkers play an increasingly important role in selecting participants, stratifying populations, demonstrating target engagement, supporting disease modification, and monitoring safety. There are currently 121 agents in clinical trials, including treatments for neuropsychiatric symptoms, cognition enhancement, and disease progression. There are 27 agents in phase-1 trials, 65 in phase-2 trials, and 29 in phase-3 trials. Most of the agents in trials (80%) target disease modification. Treatments are being assessed in secondary prevention trials with cognitively normal individuals at high risk for the development of AD. There is progress in target diversification, trial designs, outcome measures, biomarkers, and trial population definitions that promise to accelerate developing new therapies for those with or at risk for AD.

Rivastigmine in Parkinson's Disease Dementia with Orthostatic Hypotension

OBJECTIVE

The purpose of this study was to evaluate if the cognitive benefit of rivastigmine is affected by the presence of orthostatic hypotension (OH) in patients with Parkinson's disease dementia (PDD).

METHODS

We conducted a post hoc analysis on 1,047 patients with PDD from 2 randomized controlled trials comparing rivastigmine versus placebo at week 24 (n = 501) and rivastigmine patch versus capsule at week 76 (n = 546). A drop ≥ 20 mm Hg in systolic blood pressure (SBP) or ≥ 10 in diastolic blood pressure (DBP) upon standing classified subjects as OH positive (OH+); otherwise, OH negative (OH-). The primary end point was the Alzheimer's Disease Assessment Scale - Cognitive subscale (ADAS-Cog) at week 24 and the Mattis Dementia Rating Scale (MDRS) at week 76, using intention-to-treat with retrieved dropout at week 24 and observed cases at week 76, consistent with the original analyses.

RESULTS

Overall safety was comparable between OH+ (n = 288, 27.5%) and OH- (n = 730, 69.7%), except for higher frequency of syncope (9.2%) in the OH+ placebo arm. The placebo-adjusted effect of rivastigmine on ADAS-Cog at week 24 was 5.6 ± 1.2 for OH+ and 1.9 ± 0.9 in OH- (p = 0.0165). Among subjects with OH, the MDRS change from baseline at week 76 was higher for rivastigmine capsules versus patch (10.6 ± 2.9 vs -1.5 ± 3.0, p = 0.031). The overall prevalence of OH was lower for rivastigmine than placebo at week 24 (28.3% vs 44.6%, p = 0.0476).

INTERPRETATION

The cognitive benefit from rivastigmine is larger in patients with PDD with OH, possibly mediated by a direct antihypotensive effect. ANN NEUROL 2021;89:91-98.

Effect of biological treatments on psychotic symptoms in lewy body disease: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVES

Parkinson disease and dementia with Lewy bodies (collectively termed Lewy body disease) are common neurodegenerative conditions of later life and are frequently associated with distressing psychotic symptoms. The best approach to manage these symptoms is yet to be established and current treatments carry the risk of serious adverse effects.

METHODS

We performed a systematic review and meta-analysis of 19 randomized controlled trials investigating the efficacy of biological treatments for psychotic symptoms in Lewy body disease.

RESULTS

The summary effect estimate did not show a statistically significant benefit of biological treatments for psychotic symptoms in Lewy body disease (SMD -0.48, 95%CI -1.01 to 0.04). This was irrespective of the choice of intervention (SMD -0.53, 95%CI -1.20 to 0.14 for antipsychotic trials) or disease status (SMD -0.59, 95%CI -1.24 to 0.05 for trials of Parkinson disease). There was a significant effect for biological treatments compared with placebo in trials that lasted at least 6 weeks (SMD -0.25, 95%CI -0.43 to -0.08) and those with sample sizes greater than 100 participants (SMD of -0.28 95%CI -0.45 to -0.11).

CONCLUSIONS

In this systematic review and meta-analysis, treatment of psychotic symptoms by biological means did not improve symptoms compared with placebo. Small sample sizes, modest treatment durations, and other methodological differences across the trials do make it difficult to draw firm conclusions. Longer, adequately powered trials utilizing established and novel treatments are needed to provide more definitive evidence to guide clinicians in the best choice of agent to treat these distressing and often persistent symptoms.

Approach to Cognitive Impairment in Parkinson's Disease

Cognitive dysfunction is common in Parkinson's disease (PD) and predicts poor clinical outcomes. It is associated primarily with pathologic involvement of basal forebrain cholinergic and prefrontal dopaminergic systems. Impairments in executive functions, attention, and visuospatial abilities are its hallmark features with eventual involvement of memory and other domains. Subtle symptoms in the premotor and early phases of PD progress to mild cognitive impairment (MCI) which may be present at the time of diagnosis. Eventually, a large majority of PD patients develop dementia with advancing age and longer disease duration, which is usually accompanied by immobility, hallucinations/psychosis, and dysautonomia. Dopaminergic medications and deep brain stimulation help motor dysfunction, but may have potential cognitive side effects. Central acetylcholinesterase inhibitors, and possibly memantine, provide modest and temporary symptomatic relief for dementia, although there is no evidence-based treatment for MCI. There is no proven disease-modifying treatment for cognitive impairment in PD. The symptomatic and disease-modifying role of physical exercise, cognitive training, and neuromodulation on cognitive impairment in PD is under investigation. Multidisciplinary approaches to cognitive impairment with effective treatment of comorbidities, proper rehabilitation, and maintenance of good support systems in addition to pharmaceutical treatment may improve the quality of life of the patients and caregivers.

Development of Robust Heterogeneous Chiral Rhodium Catalysts Utilizing Acid-Base and Electrostatic Interactions for Efficient Continuous-Flow Asymmetric Hydrogenations

Heterogeneous chiral Rh catalysts based on acid-base and electrostatic interactions have been developed. The robust catalysts demonstrate high activity and selectivity in the continuous-flow asymmetric hydrogenation of a wide variety of enamides and dehydroamino acids, providing optically active amides without leaching of metal species. The chiral environments can be easily tuned by changing the chiral ligands, demonstrating the high versatility of the heterogeneous catalysts. By applying these efficient catalysts, continuous synthesis of several active pharmaceutical ingredient intermediates was achieved.

Minority Enrollment in Parkinson's Disease Clinical Trials: Meta-Analysis and Systematic Review of Studies Evaluating Treatment of Neuropsychiatric Symptoms

BACKGROUND

Randomized clinical trials (RCTs) in Parkinson's disease (PD) have historically enrolled a low number of underrepresented minorities, lessening the generalizability of therapeutic developments. Although there are racial disparities in PD, little is known regarding neuropsychiatric symptoms and other nonmotor manifestations across all races/ethnicities.

OBJECTIVE

To assess minority participation in PD trials evaluating the treatment of neuropsychiatric symptoms and explore underlying reasons.

METHODS

We systematically searched PubMed and Embase for RCTs with a primary goal of treating neuropsychiatric symptoms in PD patients from 2000-2019. The pooled prevalence and 95% confidence interval (CI) of being white and enrolled in a clinical trial was calculated using the inverse variance method. I-square was calculated as a measure of heterogeneity and meta-regression was used to evaluate temporal trends.

RESULTS

We included 63 RCTs with a total of 7,973 patients. In pooled analysis, 11 (17.5%) RCTs reported race/ethnicity. Of studies reporting this data, 5 African American (0.2%), 16 Hispanics (0.64%), and 539 Asians (21.44%) were enrolled. The pooled prevalence of being white in clinical trials was 98% (CI 0.97-0.98, p < 0.001), with 1,908 patients (75.8%). NIH-funded studies were most likely to report racial data when compared to non-NIH trials (p = 0.032).

CONCLUSION

This large pooled analysis found a small percentage of RCTs reporting race/ethnicity when evaluating treatment of neuropsychiatric symptoms in PD. There was a disproportionally high number of white patients when compared to African Americans and Hispanics. More studies are needed to investigate this discrepancy and improve rates of & minority enrollment in PD trials.

Therapeutic strategies for Parkinson's disease: promising agents in early clinical development

INTRODUCTION

To date, no drug has demonstrated clinically indisputable neuroprotective efficacy in Parkinson's disease (PD). We also have no effective symptomatic treatment for disabling symptoms such as balance problems, and dementia, and we need to improve the efficacy and safety profile of drugs currently used in the management of motor complications.

AREAS COVERED

We examine the agents which appear to have most therapeutic promise based on concepts, feasibility in a reasonable time frame, and available clinical data and place an emphasis on disease-modifying treatments. PUBMED and Clinicaltrials.gov databases were searched for Phase I and II randomized trials for symptomatic or disease-modifying treatments considering only studies that began since 2010 or that were completed after 2015, up to 30 April 2020.

EXPERT OPINION

Encouraging progress has been made in our understanding of molecular pathways. We find passive immunization approaches against α-synuclein, LRRK2 kinase inhibitors, and treatment that can increase GCase activity, which have shown some efficacy on both GBA-mutated and non-mutated PD patients. The recognition of non-dopaminergic impairment and the prominent role of non-motor symptoms have prompted the development of trials on compounds that could tackle different neurotransmitter systems. Future approaches will encompass more personalized medicine strategies based on molecular signatures and non-motor phenotypes.

Early-start vs delayed-start donepezil against cognitive decline in Parkinson disease: a randomized clinical trial

BACKGROUND

Cholinergic neurotransmission regulates neuroinflammation in Parkinson disease (PD).

RESEARCH DESIGN AND METHODS

The authors conducted a delayed-start study of donepezil for cognitive decline in non-demented PD patients. The study consisted of a 96-week randomized placebo-controlled double-blind phase 1, followed by a 24-week donepezil extension phase 2. The primary outcome measure was a change in the Mini-Mental State Examination (MMSE) at week 120.

RESULTS

A total of 98 patients were randomly allocated to the early-start (donepezil-to-donepezil) and delayed-start (placebo-to-donepezil) groups. Mean (SD) of the baseline MMSE was 27.6 (2.0) and 28.0 (2.1), respectively. MMSE change at week 120 was better in the early-start group than in the delayed-start group, but the difference was not significant. The MMSE declined in apolipoprotein ε4 carriers, but not in non-carriers, and the factor interaction (intervention × ε4 genotype) was highly significant (P < 0.001). Analyzed with the interaction, the difference was significant (group difference 1.95 [0.33 to 3.57], P = 0.018). The MMSE decline slope in phase 1 was significantly better in the early-start group than in the delayed-start group (P = 0.048).

CONCLUSIONS

Cognitive function deteriorated in ε4 carriers, but not in non-carriers, and early-start donepezil may postpone cognitive decline in the former.

Treatment of psychosis in Parkinson's disease and dementia with Lewy Bodies: A review

There is a considerable overlap between Parkinson's Disease Dementia (PDD) and Dementia with Lewy Bodies (DLB). They present a challenge therapeutically, with regard to morbidity and mortality risk. In particular, symptoms of psychosis in these conditions augur a considerably increased burden. To date, there has been a myriad of prospective, retrospective and case studies examining the use of neuroleptics in the treatment of psychotic symptoms in PDD/DLB. Clozapine has the most robust evidence base however its use is limited by agranulocytosis risk and the associated need for frequent blood count monitoring. Quetiapine is more readily used, however, it has a more equivocal evidence base, in terms of efficacy. Other neuroleptics have thus far demonstrated mixed results with increased risk of extrapyramidal worsening. In addition to the atypical agents, the introduction of pimavanserin has provided another treatment option for Parkinson's Disease Psychosis (PDP), decreasing concern for deterioration in motor function. We await further research to confidently demonstrate its efficacy and safety in DLB psychosis. Cholinesterase inhibitors likely have a limited role in treating milder psychosis symptomatology in DLB and perhaps PDD. After review of the current literature for antipsychotic therapy in both PDD and DLB, we provide a logical framework for addressing psychotic symptoms in each condition.

Pharmacological treatment of cognitive deficits in nondementing mental health disorders

Evidence for pharmacological remediation of cognitive deficits in three major psychiatric disorders—attention deficit- hyperactivity disorder (ADHD), schizophrenia, and depression—is reviewed. ADHD is effectively treated with the stimulant medications methylphenidate and d-amphetamine, as well as nonstimulants such as atomoxetine, implicating cognitive enhancing effects mediated by noradrenaline and dopamine. However, the precise mechanisms underlying these effects remains unclear. Cognitive deficits in schizophrenia are less effectively treated, but attempts via a variety of neurotransmitter strategies are surveyed. The possibility of treating cognitive deficits in depression via antidepressant medication (eg, selective serotonin reuptake inhibitors) and by adjunctive drug treatment has only recently received attention because of confounding, or possibly interactive, effects on mood. Prospects for future advances in this important area may need to take into account transdiagnostic perspectives on cognition (including neurodegenerative diseases) as well as improvements in neuropsychological, neurobiological, and clinical trial design approaches to cognitive enhancement.


Characterization of imine reductases in reductive amination for the exploration of structure-activity relationships

Imine reductases (IREDs) have shown great potential as catalysts for the asymmetric synthesis of industrially relevant chiral amines, but a limited understanding of sequence activity relationships makes rational engineering challenging. Here, we describe the characterization of 80 putative and 15 previously described IREDs across 10 different transformations and confirm that reductive amination catalysis is not limited to any particular subgroup or sequence motif. Furthermore, we have identified another dehydrogenase subgroup with chemoselectivity for imine reduction. Enantioselectivities were determined for the reduction of the model substrate 2-phenylpiperideine, and the effect of changing the reaction conditions was also studied for the reductive aminations of 1-indanone, acetophenone, and 4-methoxyphenylacetone. We have performed sequence-structure analysis to help explain clusters in activity across a phylogenetic tree and to inform rational engineering, which, in one case, has conferred a change in chemoselectivity that had not been previously observed.

Cognition Deficits in Parkinson's Disease: Mechanisms and Treatment

Parkinson's disease (PD) is the second most common progressive neurodegenerative disorder mainly in middle-elderly population, which represents diverse nonmotor symptoms (NMS) besides such well-documented motor symptoms as bradykinesia, resting tremor, rigidity, and postural instability. With the advancement of aging trend worldwide, the global prevalence of PD is mounting up year after year. Nowadays, accumulating lines of studies have given a comprehensive and thorough coverage of motor symptoms in PD. Yet much less attention as compared has been paid to the nonmotor symptoms of PD, such as cognition deficits. Of note, a patient with PD who suffers from cognitive impairment may harbour a statistically significantly higher risk of progressing toward dementia, which negatively affects their life expectancy and daily functioning and overall lowers the global quality of life. Furthermore, it is a widely held view that cognitive dysfunction does not just occur in the late stage of PD. On the basis of numerous studies, mild cognitive impairment (MCI) is a harbinger of dementia in PD, which is observed as an intermediate state with considerable variability; some patients remain stable and some even revert to normal cognition. Considered that the timing, profile, and rate of cognitive impairment vary greatly among PD individuals, it is extremely urgent for researchers and clinicians alike to identify and predict future cognitive decline in this population. Simultaneously, early screening and canonical management of PD with cognitive deficits are very imperative to postpone the disease progression and improve the prognosis of patients. In our review, we focus on a description of cognitive decline in PD, expound emphatically the pathological mechanisms underlying cognition deficits in PD, then give a comprehensive overview of specific therapeutic strategies, and finally dissect what fresh insights may bring new exciting prospect for the subfield.

Predictors of cognitive impairment in Parkinson's disease: a systematic review and meta-analysis of prospective cohort studies

INTRODUCTION

Cognitive impairment is a debilitating manifestation in Parkinson's disease (PD). We sought to investigate predictors of PD-CI (PD with cognitive impairment).

METHODS

We systematically searched PubMed and Cochrane Library for prospective cohort studies and pooled estimates via random-effects models. Primary analyses for all types of cognitive impairments and subgroup analyses by separate outcomes were conducted.

RESULTS

A total of 28,009 studies were identified, of which 57 studies with 31 factors were included in the meta-analysis. In the primary analysis, 13 factors were associated with PD-CI, comprising advanced age [relative risk (RR) = 1.07, 95% confidence interval (CI) = 1.03-1.12], age at onset (RR = 4.43, 95% CI = 1.87-10.54), postural-instability-gait disorder (RR = 3.76, 95% CI = 1.36-10.40), higher Hoehn and Yahr stage (RR = 1.83, 95% CI = 1.35-2.47), higher UPDRS III score (RR = 1.04, 95% CI = 1.01-1.08), rapid eye movement sleep behavior disorder (RR = 3.72, 95% CI = 1.20-11.54), hallucinations (RR = 3.09, 95% CI = 1.61-5.93), orthostatic hypotension (RR = 2.98, 95% CI = 1.41-6.28), anxiety (RR = 2.59, 95% CI = 1.18-5.68), APOE ε2 (RR = 6.47, 95% CI = 1.29-32.53), APOE ε4 (RR = 3.04, 95% CI = 1.88-4.91), electroencephalogram theta power > median (RR = 2.93, 95% CI = 1.61-5.33), and alpha power < median (RR = 1.77, 95% CI = 1.07-2.92). In the subgroup analysis, MAPT H1/H1 genotype increased the risk of dementia in PD. Sixty-four studies were included in the systematic review, of which 12 factors were additionally correlated with PD-CI using single studies.

CONCLUSIONS

Advanced age, genetic variation in APOE and MAPT, gait disturbance, motor assessments, non-motor symptoms, and electroencephalogram may be promising predictors for PD-CI.

Cognitive training interventions for dementia and mild cognitive impairment in Parkinson's disease

BACKGROUND

Approximately 60% to 80% of people with Parkinson's disease (PD) experience cognitive impairment that impacts on their quality of life. Cognitive decline is a core feature of the disease and can often present before the onset of motor symptoms. Cognitive training may be a useful non-pharmacological intervention that could help to maintain or improve cognition and quality of life for people with PD dementia (PDD) or PD-related mild cognitive impairment (PD-MCI).

OBJECTIVES

To determine whether cognitive training (targeting single or multiple domains) improves cognition in people with PDD and PD-MCI or other clearly defined forms of cognitive impairment in people with PD.

SEARCH METHODS

We searched the Cochrane Dementia and Cognitive Improvement Group Trials Register (8 August 2019), the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, CINAHL, and PsycINFO. We searched reference lists and trial registers, searched relevant reviews in the area and conference proceedings. We also contacted experts for clarifications on data and ongoing trials.

SELECTION CRITERIA

We included randomised controlled trials where the participants had PDD or PD-MCI, and where the intervention was intended to train general or specific areas of cognitive function, targeting either a single domain or multiple domains of cognition, and was compared to a control condition. Multicomponent interventions that also included motor or other elements were considered eligible.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles, abstracts, and full-text articles for inclusion in the review. Two review authors also independently undertook extraction of data and assessment of methodological quality. We used GRADE methods to assess the overall quality of the evidence.

MAIN RESULTS

Seven studies with a total of 225 participants met the inclusion criteria for this review. All seven studies compared the effects of a cognitive training intervention to a control intervention at the end of treatment periods lasting four to eight weeks. Six studies included people with PD living in the community. These six studies recruited people with single-domain (executive) or multiple-domain mild cognitive impairment in PD. Four of these studies identified participants with MCI using established diagnostic criteria, and two included both people with PD-MCI and people with PD who were not cognitively impaired. One study recruited people with a diagnosis of PD dementia who were living in long-term care settings. The cognitive training intervention in three studies targeted a single cognitive domain, whilst in four studies multiple domains of cognitive function were targeted. The comparison groups either received no intervention or took part in recreational activities (sports, music, arts), speech or language exercises, computerised motor therapy, or motor rehabilitation combined with recreational activity. We found no clear evidence that cognitive training improved global cognition. Although cognitive training was associated with higher scores on global cognition at the end of treatment, the result was imprecise and not statistically significant (6 trials, 178 participants, standardised mean difference (SMD) 0.28, 95% confidence interval (CI) -0.03 to 0.59; low-certainty evidence). There was no evidence of a difference at the end of treatment between cognitive training and control interventions on executive function (5 trials, 112 participants; SMD 0.10, 95% CI -0.28 to 0.48; low-certainty evidence) or visual processing (3 trials, 64 participants; SMD 0.30, 95% CI -0.21 to 0.81; low-certainty evidence). The evidence favoured the cognitive training group on attention (5 trials, 160 participants; SMD 0.36, 95% CI 0.03 to 0.68; low-certainty evidence) and verbal memory (5 trials, 160 participants; SMD 0.37, 95% CI 0.04 to 0.69; low-certainty evidence), but these effects were less certain in sensitivity analyses that excluded a study in which only a minority of the sample were cognitively impaired. There was no evidence of differences between treatment and control groups in activities of daily living (3 trials, 67 participants; SMD 0.03, 95% CI -0.47 to 0.53; low-certainty evidence) or quality of life (5 trials, 147 participants; SMD -0.01, 95% CI -0.35 to 0.33; low-certainty evidence). There was very little information on adverse events. We considered the certainty of the evidence for all outcomes to be low due to risk of bias in the included studies and imprecision of the results. We identified six ongoing trials recruiting participants with PD-MCI, but no ongoing trials of cognitive training for people with PDD.

AUTHORS' CONCLUSIONS

This review found no evidence that people with PD-MCI or PDD who receive cognitive training for four to eight weeks experience any important cognitive improvements at the end of training. However, this conclusion was based on a small number of studies with few participants, limitations of study design and execution, and imprecise results. There is a need for more robust, adequately powered studies of cognitive training before conclusions can be drawn about the effectiveness of cognitive training for people with PDD and PD-MCI. Studies should use formal criteria to diagnose cognitive impairments, and there is a particular need for more studies testing the efficacy of cognitive training in people with PDD.

Diagnosis and Treatment of Parkinson Disease: A Review

IMPORTANCE

Parkinson disease is the most common form of parkinsonism, a group of neurological disorders with Parkinson disease-like movement problems such as rigidity, slowness, and tremor. More than 6 million individuals worldwide have Parkinson disease.

OBSERVATIONS

Diagnosis of Parkinson disease is based on history and examination. History can include prodromal features (eg, rapid eye movement sleep behavior disorder, hyposmia, constipation), characteristic movement difficulty (eg, tremor, stiffness, slowness), and psychological or cognitive problems (eg, cognitive decline, depression, anxiety). Examination typically demonstrates bradykinesia with tremor, rigidity, or both. Dopamine transporter single-photon emission computed tomography can improve the accuracy of diagnosis when the presence of parkinsonism is uncertain. Parkinson disease has multiple disease variants with different prognoses. Individuals with a diffuse malignant subtype (9%-16% of individuals with Parkinson disease) have prominent early motor and nonmotor symptoms, poor response to medication, and faster disease progression. Individuals with mild motor-predominant Parkinson disease (49%-53% of individuals with Parkinson disease) have mild symptoms, a good response to dopaminergic medications (eg, carbidopa-levodopa, dopamine agonists), and slower disease progression. Other individuals have an intermediate subtype. For all patients with Parkinson disease, treatment is symptomatic, focused on improvement in motor (eg, tremor, rigidity, bradykinesia) and nonmotor (eg, constipation, cognition, mood, sleep) signs and symptoms. No disease-modifying pharmacologic treatments are available. Dopamine-based therapies typically help initial motor symptoms. Nonmotor symptoms require nondopaminergic approaches (eg, selective serotonin reuptake inhibitors for psychiatric symptoms, cholinesterase inhibitors for cognition). Rehabilitative therapy and exercise complement pharmacologic treatments. Individuals experiencing complications, such as worsening symptoms and functional impairment when a medication dose wears off ("off periods"), medication-resistant tremor, and dyskinesias, benefit from advanced treatments such as therapy with levodopa-carbidopa enteral suspension or deep brain stimulation. Palliative care is part of Parkinson disease management.

CONCLUSIONS AND RELEVANCE

Parkinson disease is a heterogeneous disease with rapidly and slowly progressive forms. Treatment involves pharmacologic approaches (typically with levodopa preparations prescribed with or without other medications) and nonpharmacologic approaches (such as exercise and physical, occupational, and speech therapies). Approaches such as deep brain stimulation and treatment with levodopa-carbidopa enteral suspension can help individuals with medication-resistant tremor, worsening symptoms when the medication wears off, and dyskinesias.

Effectiveness of clozapine, oxcarbazepine and rivastigmine combination in a bipolar disorder patient with initial cerebral atrophy

This paper reports the case of a 46-year-old woman suffering from bipolar disorder of type I with mixed features with initial fronto-temporal atrophy. Although considered treatment-resistant to conventional strategies, she successfully responded to a combination of rivastigmine, clozapine, and oxcarbazepine.

[Parkinson's syndromes in geriatric patients : Epidemiological, clinical and therapeutic characteristics]

Due to their high prevalence, Parkinson's syndromes are exemplary geriatric syndromes. In addition to idiopathic Parkinson's disease, drug-induced and vascular Parkinson's syndromes are especially relevant in older age. A comprehensive anamnesis, thorough clinical neurological examination and rational additional diagnostics ensure the correct differential diagnostic classification. The multidimensional geriatric assessment is used to quantify the syndrome-specific ability impairments. The primary therapeutic objective in old age is the preservation of everyday competences. Drug treatment is centered around L‑dopa because of its favorable effect-side effect ratio. In cases of motor fluctuations, entacapone, opicapone or safinamide can be added, whereas dopamine agonists are generally unsuitable. Rivastigmine is indicated in mild to moderate Parkinson's dementia and furthermore can possibly improve gait stability. Speech therapy, as well as physical and occupational therapy, including the Parkinson's disease-specific Lee Silverman voice treatment are indispensable components of the multiprofessional treatment concept.

Use of Cholinesterase Inhibitors in Non-Alzheimer's Dementias

Non-Alzheimer's dementias constitute 30% of all dementias and present with major cognitive and behavioral disturbances. Cholinesterase inhibitors improve memory by increasing brain acetylcholine levels and are approved symptomatic therapies for Alzheimer's disease (AD). They have also been investigated in other types of dementias with potential cholinergic dysfunction. There is compelling evidence for a profound cholinergic deficit in Lewy Body dementia (LBD) and Parkinson's disease dementia (PDD), even to a greater extent than AD. However, this deficit is difficult to objectivize in vascular dementia (VaD) given the increased comorbidity with AD. Furthermore, there is minimal to no evidence for cholinergic loss in frontotemporal dementia (FTD). Although cholinesterase inhibitors showed significant improvement in cognitive, behavioral, and functional measures in both LBD and PDD clinical trials, only rivastigmine is approved for PDD, due to the heterogeneity of the scales used, the duration of trials, and the limited sample sizes impacting data interpretation. Similarly, the interpretation of findings in VaD trials are limited by the lack of pre-defined inclusion criteria for 'pure VaD' and the wide heterogeneity of patients enrolled with respect to location and extent of cerebrovascular disease. In FTD patients, cholinesterase inhibitors were mostly associated with worsening of cognitive and behavioral symptoms. In non-AD dementias, cholinesterase inhibitors were well tolerated, with increased reports of mild to moderate cholinergic side effects and a non-significant trend for increased cardio and cerebrovascular events with rivastigmine in VaD, justifying their cautious use on a case-by-case basis, especially when there is evidence for cholinergic deficit.

Patterns of Dementia Treatment and Frank Prescribing Errors in Older Adults With Parkinson Disease

Importance

Dementia is common in Parkinson disease, but few data exist on dementia treatment patterns or the concurrent use of acetylcholinesterase inhibitors (ACHEIs) and anticholinergic medications, a frank prescribing error.

Objectives

To describe dementia treatment patterns, and to determine the extent to which the concurrent use of ACHEIs and drugs with strong anticholinergic activity occurs among individuals with Parkinson disease in the United States.

Design, Setting, and Participants

This cross-sectional analysis included adult Medicare beneficiaries (aged 65 years or older) with Parkinson disease diagnosis with 12 consecutive months of inpatient, outpatient, and prescription drug coverage from January 1, 2014, through December 31, 2014. Beneficiaries with other parkinsonian syndromes were excluded. Demographic, geographic, prescription claims, and other data were extracted from the 2014 Carrier, Beneficiary Summary, and Prescription Drug Event research identifiable files of the Centers for Medicare & Medicaid Services. Data analysis was conducted from August 1, 2017, to November 30, 2017.

Main Outcomes and Measures

Primary outcomes were use of dementia drug, specific dementia medication, and concurrent exposure to a high-potency anticholinergic drug and an ACHEI. Descriptive analyses and multivariable logistic regression models determined the extent to which patient characteristics and comorbid conditions were associated with dementia treatment or with a high-potency anticholinergic and ACHEI never event.

Results

Of 268 407 Medicare beneficiaries with Parkinson disease (mean [SD] age, 78.9 [7.5]; 134 575 male [50.1%]), most were identified in the files as white (232 831 [86.7%]), followed by black (14 629 [5.5%]), Hispanic (7176 [2.7%]), Asian (7115 [2.7%]), and Native American (874 [0.3%]). Among these beneficiaries, 73 093 (27.2%) were given a prescription for at least 1 antidementia medication. The most commonly prescribed medication was donepezil hydrochloride (46 027 [63.0%] users), followed by memantine hydrochloride (30 578 [41.8%] users) and rivastigmine tartrate (19 278 [26.4%] users). Dementia drugs were more likely to be prescribed to black (adjusted odds ratio [AOR], 1.33; 95% CI, 1.28-1.38) and Hispanic (AOR, 1.28; 95% CI, 1.22-1.35) beneficiaries and less likely for Native American beneficiaries (AOR, 0.62; 95% CI, 0.51-0.74). Women were less likely than men to be given a prescription for dementia medication (AOR, 0.85; 95% CI, 0.84-0.87). Of the 64 017 beneficiaries receiving an ACHEI, 28 495 (44.5%) experienced at least 1 high-potency anticholinergic-ACHEI event. Hispanic (AOR, 1.11; 95% CI, 1.00-1.23) and women (AOR, 1.30; 95% CI, 1.25-1.35) beneficiaries had greater odds of experiencing this never event. Statistically significant clusters of the prevalence of this prescribing error were observed across the United States (Moran I = 0.24; P < .001), with clusters of high prevalence in the southern and midwestern states.

Conclusions and Relevance

Dementia medication use by persons with Parkinson disease varies by race/ethnicity and sex; potentially inappropriate prescribing is common among those being treated for cognitive impairment and varies by race/ethnicity, sex, and geography. These findings may serve as national and local targets for improving care quality and outcomes for persons with Parkinson disease.

Computational Drug Repositioning with Random Walk on a Heterogeneous Network

Drug repositioning is an efficient and promising strategy to identify new indications for existing drugs, which can improve the productivity of traditional drug discovery and development. Rapid advances in high-throughput technologies have generated various types of biomedical data over the past decades, which lay the foundations for furthering the development of computational drug repositioning approaches. Although many researches have tried to improve the repositioning accuracy by integrating information from multiple sources and different levels, it is still appealing to further investigate how to efficiently exploit valuable data for drug repositioning. In this study, we propose an efficient approach, Random Walk on a Heterogeneous Network for Drug Repositioning (RWHNDR), to prioritize candidate drugs for diseases. First, an integrated heterogeneous network is constructed by combining multiple sources including drugs, drug targets, diseases and disease genes data. Then, a random walk model is developed to capture the global information of the heterogeneous network. RWHNDR takes advantage of drug targets and disease genes data more comprehensively for drug repositioning. The experiment results show that our approach can achieve better performance, compared with other state-of-the-art approaches which prioritized candidate drugs based on multi-source data.

Circuit Mechanisms of Neurodegenerative Diseases: A New Frontier With Miniature Fluorescence Microscopy

Neurodegenerative diseases (NDDs), such as Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), amyotrophic lateral sclerosis (ALS), and frontotemporal dementia (FTD), are devastating age-associated brain disorders. Significant efforts have been made to uncover the molecular and cellular pathogenic mechanisms that underlie NDDs. However, our understanding of the neural circuit mechanisms that mediate NDDs and associated symptomatic features have been hindered by technological limitations. Our inability to identify and track individual neurons longitudinally in subcortical brain regions that are preferentially targeted in NDDs has left gaping holes in our knowledge of NDDs. Recent development and advancement of the miniature fluorescence microscope (miniscope) has opened up new avenues for examining spatially and temporally coordinated activity from hundreds of cells in deep brain structures in freely moving rodents. In the present mini-review, we examine the capabilities of current and future miniscope tools and discuss the innovative applications of miniscope imaging techniques that can push the boundaries of our understanding of neural circuit mechanisms of NDDs into new territories.

Continuous Drug Delivery Aiming Continuous Dopaminergic Stimulation in Parkinson's Disease

Continuous dopaminergic stimulation in Parkinson's disease (PD) has several advantages over pulsatile, non-continuous, stimulation. These therapies currently consist of pump-based and transcutaneous therapies and are based on a more constant delivery of the dopaminergic drug resulting in continuous dopaminergic stimulation and a more stable treatment effect. Several clinical and experimental observations have shown that continuous stimulation of dopaminergic receptors induces fewer complications, such as dyskinesia, compared to pulsatile stimulation. Currently available non-oral pharmacological continuous therapies in PD include the transdermal Rotigotine (RTG) patch, infusion therapies with Apomorphine and Intrajejunal Levodopa (IJLI) and the Rivastigmine patch. Here we aim to provide a concise review of these current therapies and discuss ongoing and future developments of continuous non-oral pharmacological dopaminergic therapies in PD.

Bilateral Deep Brain Stimulation of the Nucleus Basalis of Meynert for Parkinson Disease Dementia: A Randomized Clinical Trial

Importance

Deep brain stimulation of the nucleus basalis of Meynert (NBM DBS) has been proposed as a treatment option for Parkinson disease dementia.

Objective

To evaluate the safety and potential symptomatic effects of NBM DBS in patients with Parkinson disease dementia.

Design, Setting, and Participants

A randomized, double-blind, crossover clinical trial evaluated the results of 6 patients with Parkinson disease dementia who were treated with NBM DBS at a neurosurgical referral center in the United Kingdom from October 26, 2012, to July 31, 2015. Eligible patients met the diagnostic criteria for Parkinson disease dementia, had motor fluctuations, were appropriate surgical candidates aside from the coexistence of dementia, were age 35 to 80 years, were able to give informed consent, had a Mini-Mental State Examination score of 21 to 26, had minimal atrophy seen on results of brain magnetic resonance imaging, and lived at home with a caregiver-informant.

Interventions

After surgery, patients were assigned to receive either active stimulation (bilateral, low-frequency [20 Hz] NBM DBS) or sham stimulation for 6 weeks, followed by the opposite condition for 6 weeks.

Main Outcomes and Measures

The primary outcome was the difference in scores on each item of an abbreviated cognitive battery (California Verbal Learning Test-II, Wechsler Adult Intelligence Scale-III digit span, verbal fluency, Posner covert attention test, and simple and choice reaction times) between the 2 conditions. Secondary outcomes were exploratory and included differences in scores on standardized measurements of cognitive, psychiatric, and motor symptoms and resting state functional magnetic resonance imaging.

Results

Surgery and stimulation were well tolerated by all 6 patients (all men; mean [SD] age, 65.2 [10.7] years), with no serious adverse events during the trial. No consistent improvements were observed in the primary cognitive outcomes or in results of resting state functional magnetic resonance imaging. An improvement in scores on the Neuropsychiatric Inventory was observed with NBM DBS (8.5 points [range, 4-26 points]) compared with sham stimulation (12 points [range, 8-38 points]; median difference, 5 points; 95% CI, 2.5-8.5 points; P = .03) and the preoperative baseline (13 points [range, 5-25 points]; median difference, 2 points; 95% CI, -8 to 5.5 points; P = .69).

Conclusions and Relevance

Low-frequency NBM DBS was safely conducted in patients with Parkinson disease dementia; however, no improvements were observed in the primary cognitive outcomes. Further studies may be warranted to explore its potential to improve troublesome neuropsychiatric symptoms.

Trial Registration

clinicaltrials.gov Identifier: NCT01701544.

Dementia

Alzheimer disease (AD) and other dementia syndromes are becoming more common; an estimated 5.5 million adults aged 65 years or older are living with AD in the United States. It is important for primary care physicians to gain knowledge in this field because most community-dwelling older adults receive their care from them. This article discusses the latest findings in approaches to prevent cognitive decline as well as dementia screening, diagnosis, and treatment. Approaches to address quality of life for persons with dementia and their caregivers are also discussed.

The Neuropsychiatry of Parkinson Disease: A Perfect Storm

Affective disorders, cognitive decline, and psychosis have long been recognized as common in Parkinson disease (PD), and other psychiatric disorders include impulse control disorders, anxiety symptoms, disorders of sleep and wakefulness, and apathy. Psychiatric aspects of PD are associated with numerous adverse outcomes, yet in spite of this and their frequent occurrence, there is incomplete understanding of epidemiology, presentation, risk factors, neural substrate, and management strategies. Psychiatric features are typically multimorbid, and there is great intra- and interindividual variability in presentation. The hallmark neuropathophysiological changes that occur in PD, plus the association between exposure to dopaminergic medications and certain psychiatric disorders, suggest a neurobiological basis for many psychiatric symptoms, although psychological factors are involved as well. There is evidence that psychiatric disorders in PD are still under-recognized and undertreated and although psychotropic medication use is common, controlled studies demonstrating efficacy and tolerability are largely lacking. Future research on neuropsychiatric complications in PD should be oriented toward determining modifiable correlates or risk factors and establishing efficacious and well-tolerated treatment strategies.

Feasibility and Acceptability of Computerised Cognitive Training of Everyday Cognition in Parkinson's Disease

Objectives

We piloted a computerised cognitive training battery in a group of participants with Parkinson's disease without dementia to investigate the relevance of the training to daily life and the feasibility and the acceptability of the tasks. Previous studies of CT have had limited success in the benefits of training, extending to improvements in everyday function. By taking a pragmatic approach and targeting training to the cognitive skills affected by Parkinson's disease (planning, attention, and recollection), whilst using tasks that emulated real-life scenarios, we sought to understand whether participants perceived the training to be effective and to identify the elements of the training that elicited beneficial effects.

Methods

Four participants completed a cognitive training session comprising three distinct tasks 5 days a week over two weeks. Participants completed baseline questionnaires examining health-related quality of life, everyday cognition, and apathy before the training period, after the last session, and two weeks after the last session. An interview was held after participants had completed the training.

Results

The findings indicated that participants felt the training was acceptable, enhanced their awareness, and encouraged them to monitor their thinking abilities. The group interview indicated that the training was feasible; participants felt the tasks had potential to improve everyday performance, but more supporting information should be provided to facilitate this transfer. Responses to the questionnaires reflected these findings, indicating improvement for some participants' cognition and quality of life. Objective measures supported the subjective reports; there were improvements in some but not all domains. Performance on the planning and recollection tasks improved over the training period, and the evidence for improvement on the attention task was mixed.

Conclusion

This study has found that pragmatic computer-based training with real-life outcomes is both feasible and acceptable and should be evaluated more extensively using controlled methods.

COGTIPS: a double-blind randomized active controlled trial protocol to study the effect of home-based, online cognitive training on cognition and brain networks in Parkinson's disease

Background

Cognitive dysfunction is highly prevalent in Parkinson’s disease (PD) and a large proportion of patients eventually develops PD-related dementia. Currently, no effective treatment is available. Cognitive training is effective in relieving cognitive dysfunctions in several –neurodegenerative– diseases, and earlier small-scale trials have shown positive results for PD. In this randomized controlled trial, we assess the efficacy of online home-based cognitive training, its long-term effects, as well as the underlying neural correlates in a large group of PD patients.

Methods

In this double-blind randomized controlled trial we will include 140 non-demented patients with idiopathic PD that experience significant subjective cognitive complaints. Participants will be randomized into a cognitive training group and an active control group. In both groups, participants will individually perform an online home-based intervention for eight weeks, three times a week during 45 min. The cognitive training consists of thirteen games that focus on executive functions, attention and processing speed with an adaptive difficulty. The active control comprises three games that keep participants cognitively engaged without a training component. Participants will be subjected to extensive neuropsychological assessments at baseline and after the intervention, and at six months, one year and two years of follow-up. A subset of participants (40 in each treatment condition) will undergo structural and functional magnetic resonance imaging. The primary outcome of this study is the performance on the Tower of London task. Secondary outcomes are objective and subjective cognitive functioning, conversion to PD-related mild cognitive impairment or dementia, functional and structural connectivity and network topological indices measured with magnetic resonance imaging. None of the outcome measures are part of the cognitive training program. Data will be analyzed using multivariate mixed-model analyses and odds ratios.

Discussion

This study is a large-scale cognitive training study in PD patients that evaluates the efficacy in relieving cognitive dysfunction, and the underlying mechanisms. The strengths of this study are the large sample size, the long follow-up period and the use of neuroimaging in a large subsample. The study is expected to have a low attrition and a high compliance rate given the home-based and easily-accessible intervention in both conditions.

Trial registration

ClinicalTrials.gov ID NCT02920632. Registered September 30, 2016.

Electronic supplementary material

The online version of this article (10.1186/s12883-019-1403-6) contains supplementary material, which is available to authorized users.

Positive allosteric modulators of the dopamine D1 receptor: A new mechanism for the treatment of neuropsychiatric disorders

The dopamine D1 receptor plays an important role in motor activity, reward, and cognition. Efforts to develop D1 agonists have been mixed due to poor drug-like properties, tachyphylaxis, and inverted U-shaped dose-response curves. Recently, positive allosteric modulators (PAMs) for the dopamine D1 receptor were discovered and initial pharmacological profiling has suggested that several of the above issues could be addressed with this mechanism. This paper presents an overview of key findings for DETQ (2-(2,6-dichlorophenyl)-1-((1S,3R)-3-(hydroxymethyl)-5-(2-hydroxypropan-2-yl)-1-methyl-3,4-dihydroisoquinolin-2(1H)-yl)ethan-1-one), which is currently the only D1 PAM for which published in vivo data is available. In vitro studies showed selective potentiation of the human D1 receptor without significant allosteric agonist effects. Due to a species difference in affinity for DETQ, transgenic mice expressing the human D1 receptor (hD1 mice) were used in vivo. In contrast to D1 agonists, DETQ increased locomotor activity over a wide dose-range without inverted U-shaped dose response or tachyphylaxis. DETQ also reversed hypo-activity in mice with dopamine depletion due to reserpine pretreatment, suggesting potential for treatment of motor symptoms in Parkinson's disease. Potential pro-cognitive effects were supported by improved performance in the novel object recognition task, enhanced release of cortical acetylcholine and histamine, and increased phosphorylation of the AMPA receptor (GluR1) and the transcription factor CREB. In addition, DETQ enhanced wakefulness in EEG studies and decreased immobility in the forced-swim test. Together, these results provide support for potential utility of D1 PAMs in the treatment of several neuropsychiatric disorders. LY3154207, a close analog of DETQ, is currently in phase 2 clinical trials.

Scopolamine and Medial Frontal Stimulus-Processing during Interval Timing

Neurodegenerative diseases such as Parkinson's disease (PD), dementia with Lewy bodies (DLB), and Alzheimer's disease (AD) involve loss of cholinergic neurons in the basal forebrain. Here, we investigate how cholinergic dysfunction impacts the frontal cortex during interval timing, a process that can be impaired in PD and AD patients. Interval timing requires participants to estimate an interval of several seconds by making a motor response, and depends on the medial frontal cortex (MFC), which is richly innervated by basal forebrain cholinergic projections. Past work has shown that scopolamine, a muscarinic cholinergic receptor antagonist, reliably impairs interval timing. We tested the hypothesis that scopolamine would attenuate time-related ramping, a key form of temporal processing in the MFC. We recorded neuronal ensembles from eight mice during performance of a 12-s fixed-interval timing task, which was impaired by the administration of scopolamine. Consistent with past work, scopolamine impaired timing. To our surprise, we found that time-related ramping was unchanged, but stimulus-related activity was enhanced in the MFC. Principal component analyses revealed no consistent changes in time-related ramping components, but did reveal changes in higher components. Taken together, these data indicate that scopolamine changes stimulus processing rather than temporal processing in the MFC. These data could help understand how cholinergic dysfunction affects cortical circuits in diseases such as PD, DLB, and AD.

Treatment Options for Agitation in Dementia

PURPOSE OF REVIEW

The goal of the current review is to provide an update on the management of agitation in persons with dementia with a focus on pharmacological management of persons with Alzheimer's disease.

RECENT FINDINGS

As consistently effective and safe pharmacologic interventions are still lacking, identifying and addressing medical and environmental precipitants remain a priority. Acetylcholinesterase inhibitors and memantine should be initiated to enhance cognition, and if present, management of insomnia or sundowning with trazodone is indicated. If agitation persists, treatment with citalopram can be initiated with attention paid to potential prolongation of the QT interval. Treatment with low doses of atypical antipsychotics such as risperidone or quetiapine can be effective after appropriate consideration of and disclosure of potential adverse effects. In light of the lack of consistently effective treatments for agitation in dementia, there have been renewed efforts to define the condition and improve the design of trials of medications to treat it. Considering the heterogeneity of patients and their comorbidities as well as the specific nature of their "agitation", there is no "one-size fits all" approach to agitation in AD. However, many options exist that can be prudently pursued for this common problem in this delicate population.

Clinical Trials for Disease-Modifying Therapies in Alzheimer's Disease: A Primer, Lessons Learned, and a Blueprint for the Future

Alzheimer’s disease (AD) has no currently approved disease-modifying therapies (DMTs), and treatments to prevent, delay the onset, or slow the progression are urgently needed. A delay of 5 years if available by 2025 would decrease the total number of patients with AD by 50% in 2050. To meet the definition of DMT, an agent must produce an enduring change in the course of AD; clinical trials of DMTs have the goal of demonstrating this effect. AD drug discovery entails target identification followed by high throughput screening and lead optimization of drug-like compounds. Once an optimized agent is available and has been assessed for efficacy and toxicity in animals, it progresses through Phase I testing with healthy volunteers, Phase II learning trials to establish proof-of-mechanism and dose, and Phase III confirmatory trials to demonstrate efficacy and safety in larger populations. Phase III is followed by Food and Drug Administration review and, if appropriate, market access. Trial populations include cognitively normal at-risk participants in prevention trials, mildly impaired participants with biomarker evidence of AD in prodromal AD trials, and subjects with cognitive and functional impairment in AD dementia trials. Biomarkers are critical in trials of DMTs, assisting in participant characterization and diagnosis, target engagement and proof-of-pharmacology, demonstration of disease-modification, and monitoring side effects. Clinical trial designs include randomized, parallel group; delayed start; staggered withdrawal; and adaptive. Lessons learned from completed trials inform future trials and increase the likelihood of success.

Aging, lifestyle and dementia

Aging is the greatest risk factor for most diseases including cancer, cardiovascular disorders, and neurodegenerative disease. There is emerging evidence that interventions that improve metabolic health with aging may also be effective for brain health. The most robust interventions are non-pharmacological and include limiting calorie or protein intake, increasing aerobic exercise, or environmental enrichment. In humans, dietary patterns including the Mediterranean, Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) and Okinawan diets are associated with improved age-related health and may reduce neurodegenerative disease including dementia. Rapamycin, metformin and resveratrol act on nutrient sensing pathways that improve cardiometabolic health and decrease the risk for age-associated disease. There is some evidence that they may reduce the risk for dementia in rodents. There is a growing recognition that improving metabolic function may be an effective way to optimize brain health during aging.

Circulatory responses at the onset of handgrip exercise in patients with Parkinson's disease

NEW FINDINGS

What is the central question of this study? The initial circulatory response to isometric exercise in young healthy subjects is thought to be cholinergically mediated. Do patients with Parkinson's disease, a specific population known to present cholinergic dysfunction, present impairment in these initial circulatory responses? What is the main finding and its importance? The initial reduction in total peripheral resistance was absent in patients with Parkinson's disease and in older subjects, which augmented the pressor response at the onset of isometric handgrip exercise. Given that cholinergic mechanisms play an important role in the circulatory responses at the onset of isometric exercise in humans, our data suggest that cholinergic mechanisms might be compromised with ageing.

ABSTRACT

Physical exercise has been used as coping strategy for Parkinson's disease (PD). Thus, a better understanding of circulatory responses to exercise in this population is warranted. During the onset of isometric handgrip (IHG) exercise there is an increase in blood pressure (BP) and a reduction in the total peripheral resistance (TPR) in young subjects. This immediate reduction of TPR is thought to be mediated by a cholinergic mechanism. Given that PD also affects cholinergic neurons, we hypothesized that patients with PD would present blunted circulatory responses at the onset of IHG exercise. Mean BP, stroke volume, heart rate, cardiac output and TPR were measured during performance of 20 s of IHG at 40% maximal voluntary contraction in 12 patients with PD (66 ± 2 years old, 171 ± 7 cm, 74 ± 7 kg), 11 older subjects (65 ± 9 years old, 171 ± 7 cm, 74 ± 10 kg) and 10 young subjects (21 ± 1 years old, 178 ± 6 cm, 79 ± 9 kg). Isometric handgrip elicited an augmented BP increase in patients with PD and older subjects at 10 and 20 s compared with young subjects. However, the BP augmentation was lower at 20 s in patients with PD. The IHG-induced reduction in TPR was attenuated in patients with PD and older subjects compared with young subjects. Our results show that the circulatory responses at the onset of IHG are impaired in patients with PD and older subjects. Overall, these findings suggest that the cholinergic mechanism might be compromised with ageing.

Current treatment of behavioral and cognitive symptoms of Parkinson's disease

Cognitive and behavioral symptoms are common in Parkinson's disease, may occur even in the prodromal stages of the disease, worsen with disease progression, and surpass motor symptoms as the major factors affecting patient quality of life and caregiver burden. The symptoms may be caused by the disease pathology or they may represent adverse effects of treatment, or both etiological factors may contribute. Although many of these symptoms are related to dopaminergic dysfunction or dopaminergic medication, other neurotransmitters are involved as well. Behavioral symptoms including impulse control disorders, apathy, psychosis, as well as mild cognitive impairment and dementia are reviewed with a special focus on current treatment approaches.

Ambroxol as a novel disease-modifying treatment for Parkinson's disease dementia: protocol for a single-centre, randomized, double-blind, placebo-controlled trial

BACKGROUND

Currently there are no disease-modifying treatments for Parkinson's disease dementia (PDD), a condition linked to aggregation of the protein α-synuclein in subcortical and cortical brain areas. One of the leading genetic risk factors for Parkinson's disease is being a carrier in the gene for β-Glucocerebrosidase (GCase; gene name GBA1). Studies in cell culture and animal models have shown that raising the levels of GCase can decrease levels of α-synuclein. Ambroxol is a pharmacological chaperone for GCase and is able to raise the levels of GCase and could therefore be a disease-modifying treatment for PDD. The aims of this trial are to determine if Ambroxol is safe and well-tolerated by individuals with PDD and if Ambroxol affects cognitive, biochemical, and neuroimaging measures.

METHODS

This is a phase II, single-centre, double-blind, randomized placebo-controlled trial involving 75 individuals with mild to moderate PDD. Participants will be randomized into Ambroxol high-dose (1050 mg/day), low-dose (525 mg/day), or placebo treatment arms. Assessments will be undertaken at baseline, 6-months, and 12-months follow up times. Primary outcome measures will be the Alzheimer's disease Assessment Scale-cognitive subscale (ADAS-Cog) and the ADCS Clinician's Global Impression of Change (CGIC). Secondary measures will include the Parkinson's disease Cognitive Rating Scale, Clinical Dementia Rating, Trail Making Test, Stroop Test, Unified Parkinson's disease Rating Scale, Purdue Pegboard, Timed Up and Go, and gait kinematics. Markers of neurodegeneration will include MRI and CSF measures. Pharmacokinetics and pharmacodynamics of Ambroxol will be examined through plasma levels during dose titration phase and evaluation of GCase activity in lymphocytes.

DISCUSSION

If found effective and safe, Ambroxol will be one of the first disease-modifying treatments for PDD.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02914366, 26 Sep 2016/retrospectively registered.

Available and future treatments for atypical parkinsonism. A systematic review

AIMS

Success in treating patients with atypical parkinsonian syndromes, namely progressive supranuclear palsy (PSP), cortico-basal degeneration (CBD), multiple system atrophy (MSA), Parkinson's disease with dementia (PDD), and Lewy body dementia with (LBD), remains exceedingly low. The present work overviews the most influential research literature collected on MEDLINE, ISI Web of Science, Cochrane Library, and Scopus for available treatment in atypical parkinsonisms without time restriction.

DISCUSSION

Transdermal rotigotine, autologous mesenchymal stem cells, tideglusib, and coenzyme Q10 along with donepezil, rivastigmine, memantine, and the deep brain stimulation have shown some benefits in alleviating symptoms in APS. Moreover, many new clinical trials are ongoing testing microtubule stabilizer, antitau monoclonal antibody, tau acetylation inhibition, cell replacement, selective serotonin reuptake inhibitor, active immunization, inhibition of toxic α-synuclein oligomers formation, and inhibition of microglia.

CONCLUSION

A detailed knowledge of the pathological mechanism underlying the disorders is needed, and disease-modifying therapies are required to offer better therapeutic options to physician and caregivers of APS patients.

Novel Treatment Opportunities Against Cognitive Impairment in Parkinson's Disease with an Emphasis on Diabetes-Related Pathways

Cognitive impairment is highly prevalent in patients with Parkinson's disease (PD) and causes adverse health outcomes. Novel procognitive therapies are needed to address this unmet need. It is now established that there is an increased risk of dementia in patients with type 2 diabetes mellitus (T2DM) and, moreover, T2DM and PD may have common underlying biological mechanisms. As such, T2DM medications are emerging as potential therapies in the context of PD dementia (PDD). In this review, we provide an update on pathophysiological mechanisms underlying cognitive impairments and PDD, focusing on diabetes-related pathways. Finally, we have conducted a review of ongoing clinical trials in PD patients with dementia, highlighting the multiple pharmacological mechanisms that are targeted to achieve cognitive enhancement.