What happens when donepezil is suddenly withdrawn? An open label trial in dementia with Lewy bodies and Parkinson's disease with dementia

Treatment of dementia in parkinsonian syndromes with cholinesterase inhibitors

In Parkinsonian syndromes behavioural symptoms and dementia can be even more debilitating than motor symptoms and are an important predictor for nursing home placement and mortality. Neuropathologically, dementia seems to be primarily related to cortical changes rather than to subcortical alterations. Concerning neurotransmitter systems, the cholinergic system has been proposed to play a key role in cognitive disturbances. Based on studies with patients with Alzheimer disease, the application of cholinesterase inhibitors is vividly discussed also for dementia associated with parkinsonian syndromes. This review focuses on the specific symptoms of dementia in different parkinsonian syndromes and critically questions the effect of cholinergic treatment on cognitive functions in patients with extrapyramidal syndromes and dementia. There is evidence that medication with some cholinesterase inhibitors can enhance cognition as well as activities of daily living in dementia with Parkinson's disease and seems to reduce behavioural disturbances in both dementia with Parkinson's disease and dementia with Lewy bodies. The effect of treatment with cholinesterase inhibitors in progressive supranuclear palsy and corticobasal degeneration warrants carefully designed studies including a sufficient number of patients and symptom-adopted dementia scales.

Intervening in the neuropsychiatric features of Parkinson's disease

Although Parkinson's disease is considered a movement disorder, it has a wide range and high prevalence of affective, psychotic, cognitive, behavioral and sleep-related features. To treat such features, agents including antidepressants, anxiolytics, antipsychotics and cognition-enhancing agents are commonly prescribed, although the targeted syndromes are often incompletely understood and controlled studies demonstrating a treatment's efficacy and tolerability in Parkinson's disease patients are often lacking. Nevertheless, the available information does suggest the outlines of management methods, pending expanded research to identify optimal strategies specific to Parkinson's disease.

Effects of donepezil on central processing speed and attentional measures in Parkinson's disease with dementia and dementia with Lewy bodies

BACKGROUND

We examined attention-enhancing effects of the cholinesterase inhibitor donepezil in Dementia with Lewy bodies (DLB) and Parkinson's disease with dementia (PDD) by means of open label study.

METHODS

22 DLBs and 23 PDDs were assessed over 20 weeks using the Cognitive Drug Research Computerized Attentional Tasks. We examined how much closer our patients moved towards being normal for their age by comparing them to a non-demented elderly control sample (n = 183, aged 71-75 years).

RESULTS

Donepezil treatment improved power of attention, continuity of attention and reaction time variability. The deficit in responses was moved towards normal by 38 and 56% for power of attention and 22 and 10% for continuity of attention in PDD and DLB, respectively.

CONCLUSIONS

Improvements in attention were found with donepezil in PDD and DLB.

Behavior disorders and subjective burden among caregivers of demented patients

Many patients with dementia live within the community supported by their family and friends. Majority of patient caregivers suffer from high levels of stress.

METHODS

A quasi-experimental study, which compared the effects of nursing interventions on behavior disorders in both patients with moderate to severe dementia and their caregivers, followed over 18 months. The assessments were performed at the outpatient clinic of the Federal University of São Paulo and again at patients' homes with their primary caregiver, after informed consent form. Measurements were performed at baseline and after 18 months (pre and post-test). The instruments used were: The CDR, NPI and NPI-D; Katz Index and FAQ. Simultaneously, caregivers were enrolled onto the Dementia Education Program.

RESULTS

The final sample was composed of 31 subjects, having a mean age of 77.4 y.o. (±8 SD). Nursing interventions were effective in reducing some of the behavioral disturbances (Z= -3.1; p=0.002), such as Aggression (Z= -3.7; p<0.001) and anxiety (Z= -2.3; p=0.023). Caregiver distress also reduced upon interventions (Z= -2.2; p=0.030).

CONCLUSION

Our results indicate nursing interventions may be effective in reducing the frequency and severity of behavioral disorders and subjective burden among caregivers. Education Programs can improve caregiver burden through conveying information on difficulties related to the disease and how to deal with them.

Dementia with lewy bodies: therapeutic opportunities and pitfalls

OBJECTIVE

To review diagnoses and challenges of treating patients with dementia with Lewy bodies (DLB), commonly considered the second most common form of dementia.

DATA SOURCES

MEDLINE, Web of Science, and International Pharmaceutical Abstracts databases were searched in January 2006 for clinical studies, case series, case studies, letters, and review articles on the treatment of DLB. Search terms included: aripiprazole, cholinesterase inhibitors, clozapine, dementia with Lewy bodies, donepezil, galantamine, Lewy body dementia, neuroleptics, olanzapine, quetiapine, risperidone, rivastigmine, tacrine, ziprasidone. Applicable articles in the English language were reviewed. The bibliographies of these articles provided additional references.

STUDY SELECTION

Articles describing studies, case series, and case studies are included in this review.

DATA SYNTHESIS

DLB is commonly considered the second most common form of dementia, although some experts believe vascular dementia to be the second most common form. DLB is often under-diagnosed and misdiagnosed as Alzheimer's disease or Parkinson's related dementia. The core features of dementia with Lewy bodies are cognitive decline plus at least one of the following: fluctuations in cognition, visual hallucinations, and parkinsonism. Other supportive features include: neuroleptic sensitivity, repeated falls, syncope, transient loss of consciousness, REM sleep disturbances, depression, delusions, and nonvisual hallucinations.

CONCLUSION

Increased prudence with the use of neuroleptic agents is essential in DLBs because the use of these agents is associated with physical and cognitive decline and increased mortality. While neuroleptic sensitivity has been reported with the use of both typical and atypical antipsychotic medications, these medications are often necessary for the treatment of psychotic symptoms. Decreases in neuroleptic sensitivity can often be achieved by dose reductions, although neuroleptic discontinuation is sometimes necessary. Cholinesterase inhibitors may be especially useful in the treatment of DLB. Cholinergic deficits are associated with visual hallucinations, and cholinesterase inhibitors often result in resolution of hallucinations, improved cognition, and decreased behavioral disturbances.

Clinical practice with anti-dementia drugs: a consensus statement from British Association for Psychopharmacology

The British Association for Psychopharmacology (BAP) coordinated a meeting of experts to review the evidence on the drug treatment for dementia. The level of evidence (types) was rated using a standard system: Types 1a and 1b (evidence from meta-analysis of randomised controlled trials or at least one controlled trial respectively); types 2a and 2b (one well-designed study or one other type of quasi experimental study respectively); type 3 (non-experimental descriptive studies); and type 4 (expert opinion). There is type 1a evidence for cholinesterase inhibitors (donepezil, rivastigmine and galantamine) for mild to moderate Alzheimer's disease; memantine for moderate to severe Alzheimer's disease; and for the use of bright light therapy and aromatherapy. There is type 1a evidence of no effect of anti inflammatory drugs or statins. There is conflicting evidence regarding oestrogens, with type 2a evidence of a protective effect of oestrogens but 1b evidence of a harmful effect. Type 1a evidence for any effect of B12 and folate will be forthcoming when current trials report. There is type 1b evidence for gingko biloba in producing a modest benefit of cognitive function; cholinesterase inhibitors for the treatment of people with Lewy body disease (particularly neuropsychiatric symptoms); cholinesterase inhibitors and memantine in treatment cognitive impairment associated with vascular dementia; and the effect of metal collating agents (although these should not be prescribed until more data on safety and efficacy are available). There is type 1b evidence to show that neither cholinesterase inhibitors nor vitamin E reduce the risk of developing Alzheimer's disease in people with mild cognitive impairment; and there is no evidence that there is any intervention that can prevent the onset of dementia. There is type 1b evidence for the beneficial effects of adding memantine to cholinesterase inhibitors, and type 2b evidence of positive switching outcomes from one cholinesterase inhibitor to another. There is type 2a evidence for a positive effect of reminiscence therapy, and type 2a evidence that cognitive training does not work. There is type 3 evidence to support the use of psychological interventions in dementia. There is type 2 evidence that a clinical diagnosis of dementia can be made accurately and that brain imaging increases that accuracy. Although the consensus statement dealt largely with medication, the role of dementia care in secondary services (geriatric medicine and old age psychiatry) and primary care, along with health economics, was discussed. There is ample evidence that there are effective treatments for people with dementia, and Alzheimer's disease in particular. Patients, their carers, and clinicians deserve to be optimistic in a field which often attracts therapeutic nihilism.

Non-dopaminergic treatment of cognitive impairment and dementia in Parkinson's disease: A review

OBJECTIVE

To review the clinical management of cognitive impairment and dementia related to Parkinson's disease (PD), with emphasis on pharmacologic intervention strategies such as cholinesterase inhibitors.

DATA SOURCES

A MEDLINE, EMBASE, PsychINFO, and Cochrane Collaboration search of English language literature from 1970 to 2004 was performed to identify reviews, studies, case reports, and letters pertaining to the treatment of cognitive impairment in PD. The bibliographies of selected articles were reviewed for additional references.

STUDY SELECTION

Human studies or case reports in adults with PD describing the use of drug and other therapies for the treatment of cognitive impairment in PD.

DATA EXTRACTION

Studies were reviewed for study design, number of subjects, outcome measures, dosage, side-effects, particularly, worsening of PD motor symptoms.

CONCLUSION

The strongest evidence for the pharmacological treatment of cognitive impairment and dementia in PD supports the use of cholinesterase inhibitors. Evidence for the efficacy and safety of other agents in PD dementia is either insufficient or inconclusive, but offers intriguing clues for potential future treatments. No reports from the Cochrane Collaboration were found.

Anticholinesterase effect on motor kinematic measures and brain activation in Parkinson's disease

Anticholinesterase (AChE) drugs are being prescribed off label for nonmotor symptoms in Parkinson's disease (PD). Theoretically, these drugs can impair motor function. A small literature suggests AChE therapy has little effect on clinical motor evaluation; however, no study has made objective motor kinematic measures or evaluated brain function. We hypothesized that even if clinical examination was normal in PD patients on dopamine therapy, (1) sensitive kinematic measures would be abnormal during AChE therapy or (2) normal kinematic measures would be maintained by compensatory brain activation. We carried out a randomized, double-blind, placebo-controlled trial of 8 weeks donepezil (10 mg/day) in 17 PD subjects. Subjects carried out a computerized motor task during a positron emission tomography (PET) scan before starting the drug and again after 8 weeks of donepezil or placebo. Kinematic measures of motor function and PET scans were analyzed to compare the effects of donepezil and placebo. Neither placebo nor donepezil altered motor kinematic measures. Furthermore, movement integrity while on donepezil was maintained without compensatory brain activity. Donepezil 10 mg/day can be given for nonmotor symptoms in PD without adverse motor effects or compensatory brain activity.

Utility of the Mattis dementia rating scale to assess the efficacy of rivastigmine in dementia associated with Parkinson’s disease

INTRODUCTION

The severe, cortical, cholinergic depletion accompanying Parkinson's disease (PD) is considered as a highly probable correlate of cognitive and behavioural dysfunction. Recent studies have demonstrated that cholinesterase inhibitors (notably rivastigmine) are beneficial in patients suffering from dementia associated with PD (PDD). However, the primary efficacy variables used in such work came from scales designed for Alzheimer's disease (AD), even though the cognitive symptoms in PD and AD dementia do not overlap completely. The aim of the present study (a double-blind, placebo-controlled clinical trial) was to determine the utility of the Mattis dementia rating scale - the most commonly used scale in PD patients - to assess the efficacy of a 24-week rivastigmine treatment.

METHODS

Twenty-eight patients with PD, who constituted a subgroup of patients enrolled to the EXPRESS study (Emre et al, N Engl J Med 2004) participated in this study. They suffered from mild to moderately severe dementia (MMSE scores above 10 and below 24), with an onset of cognitive symptoms occurring at least two years after the diagnosis of PD. Patients were randomly assigned to treatment with rivastigmine (3 to 12 mg per day) or placebo. The Mattis dementia rating scale was administered to patients from six centres in France at the baseline and end-point visits.

RESULTS

Compared with placebo, a 24-week rivastigmine treatment led to a significant improvement in the overall score on the Mattis dementia rating scale (p = 0.031), with a trend towards a significant improvement in the "Attention" subscale score (p = 0.061). Correlation analysis showed that in the rivastigmine group, performance on the Mattis "Attention" and "Initiation" subscales appeared to contribute heavily to the improvement in the overall score. Moreover, the latter was also related to an improvement in activities of daily living and a reduction in behavioural disturbances.

DISCUSSION

By using the Mattis dementia rating scale (which comprises items that are sensitive to executive dysfunction), the present study confirmed that rivastigmine has a beneficial effect on cognitive function in PDD. Despite our study's small sample size, the Mattis scale was able to detect this improvement and could thus be considered as an interesting outcome measure in further work.

Cognitive deficits and psychosis in Parkinson's disease: a review of pathophysiology and therapeutic options

Parkinson's disease is a neurodegenerative disorder causing not only motor dysfunction but also cognitive, psychiatric, autonomic and sensory disturbances. Symptoms of dementia and psychosis are common: longitudinal studies suggest that up to 75% of patients with Parkinson's disease may eventually develop dementia, and the prevalence of hallucinations ranges from 16-17% in population-based surveys to 30-40% in hospital-based series. These cognitive and behavioural features are important in terms of prognosis, nursing home placement and mortality. The pattern of cognitive deficits in Parkinson's disease is variable, but often includes executive impairment similar to that seen in patients with frontal lesions, as well as episodic memory impairment, visuospatial dysfunction and impaired verbal fluency. The most common manifestation of psychosis in Parkinson's disease is visual hallucinations, but delusions, paranoid beliefs, agitation and florid psychosis can also occur. An understanding of the pathophysiology underlying these symptoms is essential to the development of targeted therapeutic strategies. Post-mortem studies suggest an association between Lewy body deposition and dementia in Parkinson's disease, and indeed Parkinson's disease and dementia with Lewy bodies may form part of the same disease spectrum. Whether Lewy bodies actually play a causative role in cognitive dysfunction, however, is unknown. Deficits in neurotransmitter systems provide more obvious therapeutic targets and dysfunction of dopaminergic, cholinergic, noradrenergic and serotonergic systems have all been implicated; these may each underlie different features of Parkinson's disease dementia, perhaps explaining some of the heterogeneity of the syndrome. Psychosis has traditionally been considered as a dopaminergic drug-induced phenomenon, but factors intrinsic to the disease process itself also cause hallucinations and delusions. These factors may include Lewy body deposition in the limbic system, cholinergic deficits and impairments of primary visual processing. Therapeutic intervention for cognitive and behavioural symptoms in Parkinson's disease currently focuses on two main groups of drugs: cholinesterase inhibitors and atypical antipsychotics. A recent large, randomised, controlled trial suggests that cholinesterase inhibitors can produce a modest improvement in cognitive function, as well as psychotic symptoms, generally without an adverse effect on motor function. Certain atypical antipsychotics allow hallucinations, delusions and behavioural problems to be brought under control with minimal deleterious effects on motor function and cognition, but their safety in elderly patients has recently been called into question. Deep brain stimulation does not appear to be a useful treatment for cognitive and psychiatric dysfunction in patients with Parkinson's disease. Modafinil improves alertness in Parkinson's disease and warrants further investigation to establish its effects on cognitive performance.

Cholinesterase inhibitors in advanced Dementia with Lewy bodies: increase or stop?

INTRODUCTION

There is little data on stopping cholinesterase inhibitors in Dementia with Lewy bodies (DLB). Equally, it is not known if increasing the dose of cholinesterase inhibitors may help neuropsychiatric symptoms in advanced DLB.

METHOD

We conducted an open label trial with donepezil involving 16 patients with LBD when the dose was reduced and treatment stopped over 4 weeks. Another 7 patients were given a trial of an increased dose of donepezil (15 mg) to resolve rehyphen;emergent neuropsychiatric symptoms.

RESULTS

The slow discontinuation protocol was well tolerated in advanced DLB. Five of the seven patients given a trial of a higher dose of donepezil were rated as clinically improved after 12 weeks treatment.

CONCLUSION

Cholinesterase inhibitors can be discontinued slowly in advanced DLB. Increasing the dose of donepezil may be of benefit to some patients with DLB who experience a recurrence in their neuropsychiatric symptoms.

Effects of donepezil on cortical metabolic response to activation during (18)FDG-PET in Alzheimer's disease: a double-blind cross-over trial

RATIONALE

Cholinergic enhancement is among the best established treatments of Alzheimer's disease (AD). The cognitive effects of treatment are thought to be mediated by improvement of neuronal transmission. Positron emission tomography using 18F-fluorodeoxyglucose (FDG-PET) by measuring cortical metabolic response to activation assesses integrity of neuronal transmission in vivo.

OBJECTIVE

To determine the effects of treatment with donepezil, a centrally selective acetylcholinesterase inhibitor, on cortical metabolism in AD using 18FDG-PET.

METHODS

We enrolled 23 patients, 18 of which completed the study, with mild to moderate probable AD (mini-mental status exam scores of 15-28, inclusive) in a double-blind cross over trial of 8 weeks donepezil compared to 8 weeks placebo with repeated double 18FDG-PET examinations during passive audio-visual stimulation. Effects of treatment on cortical metabolic response to stimulation were determined with a linear model on a voxel level using Statistical Parametric Mapping (SPM 99, Wellcome Department of Imaging Neuroscience, London).

RESULTS

Effects of treatment on cognitive measures were not different between donepezil and placebo. During passive audio-visual stimulation, patients showed activation in posterior visual and auditory areas and decreased activation in frontal cortex and basal ganglia. Resting state metabolism was increased with donepezil in left prefrontal cortex and decreased in right hippocampus. Cortical response to activation was increased in right hippocampus with donepezil compared to placebo.

CONCLUSION

Donepezil treatment shows a spatially limited functional effect on right hippocampus and left prefrontal cortical metabolism, independently of clinical response to treatment.

Treatments for behavioural disorders in neurodegenerative diseases: drug development strategies

Neuropsychiatric symptoms and behavioural alterations are common in neurodegenerative diseases, and effective treatment of these changes represents an important unmet public health need. Imaging, neuropathological, neurotransmitter and molecular genetic studies increasingly identify specific mechanisms that mediate behavioural changes in neurodegenerative disorders and provide a platform for seeking effective therapeutic interventions. Measuring behavioural outcomes in clinical trials of antidementia agents represents an important means of evaluating treatment effectiveness, and clinical trial methodologies and behavioural instrumentation are evolving to facilitate drug development in this important therapeutic target area.

Psychiatric complications in Parkinson disease

Although Parkinson disease (PD) is primarily considered a movement disorder, the high prevalence of psychiatric complications suggests that it is more accurately conceptualized as a neuropsychiatric disease. Affective disorders, cognitive impairment, and psychosis are particularly common in PD and are associated with excess disability, worse quality of life, poorer outcomes, and caregiver distress. Yet, in spite of this and their frequent occurrence, there is incomplete understanding of the epidemiology, phenomenology, risk factors, neuropathophysiology, and optimal treatment strategies for these disorders. Psychiatric complications are typically comorbid, and there is great intra- and inter-individual 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 most psychiatric symptoms, although psychological factors are probably involved in the development of affective disorders. Although antidepressants, antipsychotics, and cognition-enhancing agents are commonly prescribed in PD, controlled studies demonstrating efficacy and tolerability of these drugs are virtually nonexistent. Because of the high prevalence and complexity of psychiatric complications in PD, geriatric psychiatrists are in a position to offer valuable consultation and clinical care to this population. This article provides an overview of the epidemiology, pathophysiology, clinical presentation, and management of the most common psychiatric complications in PD.

Dementia with Lewy bodies: current concepts

As life expectancy continues to increase over time, dementia is becoming an increasingly more common problem and a major cause of disability in older persons. It is now more important than ever to identify and manage common causes of dementia given variations in disease course, treatments and the possibility for modification of risk factors. Dementia with Lewy bodies (DLB) is a dementia syndrome characterized by progressive cognitive decline, with fluctuating cognition, recurrent detailed and well-formed hallucinations, and parkinsonism. This article aims to provide an overview of current concepts of DLB, including a description of the key clinical features and neuropathology, neurochemistry, and genetics of DLB, then a discussion of the relationship of DLB with Alzheimer's disease and Parkinson's disease, and, finally, a summary of current management strategies available for this disorder.

A comparison of the efficacy of donepezil in Parkinson's disease with dementia and dementia with Lewy bodies

BACKGROUND

Parkinson's disease with dementia (PDD) and dementia with Lewy bodies (DLB) overlap in phenomenology and neurochemical deficits. We hypothesised they would not differ in their response to the cholinesterase inhibitor donepezil.

METHODS

We recruited 70 subjects, 30 DLB and 40 PDD, in an open label study to compare the efficacy of donepezil in these two patient groups. They were assessed at baseline, 4, 12 and 20 weeks. The main outcome measures were the Mini-Mental State Examination (MMSE), Neuropsychiatric Inventory (NPI) and motor sub-section of the Unified Parkinson's Disease Rating Scale (UPDRS III).

RESULTS

PDD patients were younger than DLB and had more severe parkinsonism at baseline. The groups were similar on all other variables of interest. By 20 weeks the mean MMSE score increased by 3.9 points in the DLB group and by 3.2 points in PDD. The mean NPI score reduced by 14.6 points for DLB and 12.0 points for PDD. These treatment effects were all significant compared to baseline (p < 0.001) but there were no significant between-group treatment differences (MMSE p = 0.56, NPI p = 0.39). UPDRS III motor scores did not change significantly from baseline values in either group. Although adverse effects were common (69%) they were usually mild and 64 patients (91%) completed the study. The four patients who did withdraw with adverse effects all had a PDD diagnosis.

CONCLUSIONS

Donepezil produced similar improvements in cognition and behaviour in DLB and PDD. This supports the hypothesis that the two disorders are closely related clinically and neurobiologically. Larger scale, placebo controlled clinical trials are needed to provide an evidence base to guide the clinical use of cholinesterase inhibitors in Lewy body disease.

Change in perfusion, hallucinations and fluctuations in consciousness in dementia with Lewy bodies

Fluctuations in consciousness and visual hallucinations are common neuropsychiatric features of dementia with Lewy bodies and Parkinson's disease dementia. To investigate potential neural correlates, we compared how changes in brain perfusion over a 1-year period were related to changes in the severity of these key clinical features. We recruited 29 subjects with either Parkinson's disease with dementia (15 subjects) or dementia with Lewy bodies (14 subjects). Cerebral perfusion was measured using HMPAO SPECT at baseline, and repeated 1 year later. The presence of hallucinations (Neuropsychiatric Inventory), severity of fluctuations in consciousness (fluctuation assessment scale) and cognitive ability (CAMCOG) were assessed at both time points. After controlling for changes in cognitive ability and effect of cholinesterase medication, we found a significant correlation between an increase in perfusion in midline posterior cingulate and decrease in hallucination severity. There was also a significant correlation between increased fluctuations of consciousness and increased thalamic and decreased inferior occipital perfusion. We have identified important neural correlates of key clinical features in Lewy body dementia and postulate that the associations can be understood through the influence of the cholinergic system on attention.

Psychosis in Parkinson's disease

Psychosis in Parkinson's disease (PD) is a fairly common and vexing problem. Although it can occur at any stage of the illness, it is a particularly important issue for patients who are in the later stages of PD and have been chronically treated with anti-PD medications. The exact pathophysiology of PD-related psychosis remains a mystery. Neurochemical imbalances, sleep disturbances, and visual processing abnormalities in PD have been implicated in its pathogenesis. Treatment of psychotic symptoms should occur only after potential medical and environmental causes of delirium have been eliminated or addressed. Initial pharmacologic changes should include limiting the patient's anti-PD medications to those that are necessary to preserve motor function. Should that fail, an atypical antipsychotic agent is presently the treatment of choice. An emerging treatment option is the use of acetylcholinesterase inhibitors. This article reviews what is known about the epidemiology, risk factors, pathophysiology, and treatment of PD-related psychosis.

Are Parkinson's disease with dementia and dementia with Lewy bodies the same entity?

The diagnosis of Parkinson's disease with dementia (PDD) or dementia with Lewy bodies (DLB) is based on an arbitary distinction between the time of onset of motor and cognitive symptoms. These syndromes share many neurobiological similarities, but there are also differences. Deposition of beta-amyloid protein is more marked and more closely related to cognitive impairment in DLB than PDD, possibly contributing to dementia at onset. The relatively more severe executive impairment in DLB than PDD may relate to the loss of frontohippocampal projections in DLB. Visual hallucinations and delusions associate with more abundant Lewy body pathology in temporal cortex in DLB. The differential involvement of pathology in the striatum may account for the differences in parkinsonism. Longitudinal studies with neuropathological and neurochemical evaluations will be essential to enable more robust comparisons and determine pathological substrates contributing to the differences in cognitive, motor, and psychiatric symptoms.

Role of cholinesterase inhibitors in Parkinson's disease and dementia with Lewy bodies

This article reviews the cholinergic changes in Parkinson's disease and dementia (PDD) and dementia with Lewy bodies (DLB), their potential clinical implications, and the available evidence for cholinesterase inhibitors in the treatment of PDD and DLB. Marked neuronal loss of cholinergic nuclei, reduced cholinergic markers in the neocortex, hippocampus, and selected thalamic nuclei, and receptor changes have been reported. One large and 2 small placebo-controlled trials and nearly 20 open-label studies suggest that cholinesterase inhibitors have a positive effect on cognition, psychiatric symptoms, and global function in patients with DLB and PDD. The treatment is well tolerated in most patients without any apparent worsening of extrapyramidal motor features. Given the high risk of severe sensitivity reactions and increased risk of cerebrovascular incidents during treatment with neuroleptics, more clinical trials of cholinesterase inhibitors are encouraged to establish their precise role in DLB and PDD.