Risk of dementia in Parkinson's disease: a community-based, prospective study

Management of Parkinson???s Disease Dementia

Parkinson's disease dementia (PDD) ultimately develops in about 80% of patients with Parkinson's disease (PD), and cross-sectional studies have found that some 30% of these patients will experience neuropsychiatric symptoms, such as visual hallucinations and psychosis. The most consistently reported risk factors for dementia in PD are age, severe parkinsonism and mild cognitive impairment. In PDD, both subcortical cognitive and cortical cognitive profiles are described. Specific disorders of sleep, such as rapid eye movement sleep behaviour disorder, excessive daytime sleepiness and sleep attacks, occur frequently. Alzheimer and Lewy body pathology coexist, but the Lewy body pathology in limbic and cortical areas seems to be the main cause of dementia. Neurochemical changes in the biogenic amines and acetylcholine are common, and magnetic resonance imaging studies have shown cortical atrophy in wide cortical areas, including the hippocampus. All PD patients should be screened for mild cognitive impairment and dementia. A large randomised clinical trial showed that the cholinesterase inhibitor rivastigmine has desirable effects on cognition and neuropsychiatric symptoms in PDD patients. Atypical antipsychotic agents may improve psychosis in PDD, but the evidence for this is poor and adverse effects from such therapy are common and may be severe. Non-pharmacological interventions can also be effective but require further study.

Clinical course in Parkinson's disease with elevated homocysteine

Elevated homocysteine (Hcy), prevalent in Parkinson's disease (PD), is potentially a modifiable risk factor for neurologic deterioration. We measured cognitive, affective and motor changes over 2 years in a cohort of people with early PD. Subjects whose Hcy had been elevated (>14 micromol/L, n = 31) at baseline were compared with the rest (n = 66). Overall progression in 2 years did not significantly differ (p = 0.20). Four subjects with elevated and one with normal Hcy had died (p = 0.03). We conclude that hyperhomocysteinemia does not predict significantly worse progression over 2 years in early PD. The data raised the possibility of higher mortality, but the number of deaths was small.

Comorbid conditions associated with Parkinson's disease: A population-based study

The burden of comorbidity in Parkinson's disease (PD) remains unclear. All Olmsted County, Minnesota, residents with incident PD in 1976-1995 (n = 197) plus one age- and sex-matched non-PD referent subject per case were followed for all clinical diagnoses from 5 years before through 15 years after index (i.e., year of PD onset for each case and same year for the referent subject). Both members of a case-referent pair were censored at death or emigration of either member to ensure equivalent follow-up. Cases and referent subjects were compared for summary comorbidity (Charlson index) and for the likelihood of having one or more diagnoses within each International Classification of Diseases chapter/subchapter. Before index, the groups were similar for all comparisons. After index, cases had a higher likelihood of diagnoses within the chapters "Mental Disorders" and "Diseases of the Genitourinary System," and within the subchapters "Organic Psychotic Conditions," "Other Psychoses," "Neurotic/Personality/Other Nonpsychotic Disorders," "Hereditary/Degenerative Diseases of Central Nervous System," "Symptoms," "Other Diseases of Digestive System," "Other Diseases of Urinary System," "Diseases of Veins/Lymphatics/Other Circulatory System Diseases," "Fractures of Lower Limb," "Other Diseases of Skin/Subcutaneous Tissue," "Osteopathies/Chrondropathies/Acquired Musculoskeletal Deformities," and "Pneumonia and Influenza." The excess morbidity and mortality observed for persons with PD are consistent with recognized PD sequelae.

Cognitive predictors of dementia in Parkinson's disease: a community-based, 4-year longitudinal study

Although mild cognitive impairment and dementia are common and have important clinical consequences for patients with Parkinson's disease (PD) and their caregivers, it is still unclear whether cognitive symptoms may predict the development of dementia in PD patients. The objective of this study was to determine whether cognitive deficits in nondemented PD patients predicted the development of dementia 4 years later. A total of 76 nondemented PD patients from an epidemiological study of PD in the county of Rogaland, Norway, were assessed at baseline and 4 years later with neurological, psychiatric, and neuropsychological evaluations. Twenty-five (42%) new cases of dementia were diagnosed after 4 years. Time to complete the third card of the Stroop test was the only variable that was independently associated with dementia. The authors concluded that poor performance on a test sensitive to executive dysfunction predicted later development of dementia in PD patients. This finding may have important clinical implications as a marker of subsequent development of dementia.

Brain atrophy rates in Parkinson's disease with and without dementia using serial magnetic resonance imaging

Increased rates of brain atrophy are seen in Alzheimer's disease, but whether rates are similarly increased in other dementias such as Parkinson's disease dementia (PDD) has not been well examined. We determined the rates of brain atrophy using serial magnetic resonance imaging (MRI) in PDD and compared this finding to rates seen in cognitively intact Parkinson's disease (PD) patients and age-matched control subjects. Thirty-one patients (PD = 18, PDD = 13) and 24 age-matched controls underwent serial volumetric 1.5 T MRI scans, approximately 1 year apart. Baseline and repeat scans were registered and quantification of the brain boundary shift integral was used to determine whole-brain atrophy rates. Rates of brain atrophy were significantly increased in PDD (1.12 +/- 0.98%/year) compared to PD (0.31 +/- 0.69%/year; P = 0.018) and control subjects (0.34 +/- 0.76%/year; P = 0.015). There were no differences in atrophy rates between controls and PD (P = 0.79). No correlations between increased atrophy rates and age or dementia severity (Mini-Mental State Examination score) were observed. Serial MRI may be a useful tool for monitoring disease progression in PDD and further studies should investigate its utility for early diagnosis.

The effect of quetiapine in psychotic Parkinsonian patients with and without dementia

OBJECTIVES

We studied the effect of quetiapine in drug induced psychosis (DIP) in Parkinson's disease (PD) patients with dementia (PDDEM) and without dementia (PDNODEM) in a 6-month open study.

METHODS

Thirty five consecutive PD patients with DIP (19 of them demented [DSMIV criteria]) were examined. Assessment included Mini-Mental State Examination (MMSE), UPDRS (motor part), Brief Psychiatric Rating Scale (BPRS), Clinical Global Improvement Scale (CGIS) and Hamilton test (for depression). Quetiapine was administered in a flexible dose 25-600 mg daily. Out of the 35 patients included in the study, 24 completed treatment with quetiapine (14 demented and 10 without dementia). Treatment was stopped in 11 patients (5 demented).

RESULTS

Intention to treat patient (ITT) analysis did not show a significant quetiapine effect (BPRS), although in about 30% a good outcome was reported by the family (CGIS). Among the patients who completed the study (n = 24), in the PDNODEM group (n = 10) BPRS improved almost significantly (p = 0.06) while in the PDDEM group the BPRS did not change. According to the CGIS, a good improvement was observed in 50% of the PDDEM group (7/14) and 40% of the PDNODEM group (4/10). Motor features of PD patients worsened mildly (p = 0.05) in the PDDEM group.

CONCLUSION

In this open trial, quetiapine was not beneficial in the ITT group using the BPRS, although families reported improvement in about 30% of patients (CGIS). Among patients who completed the study, quetiapine was more effective in the PDNODEM group. A double blind study with quetiapine is required.

Brain 3D-SSP SPECT analysis in dementia with Lewy bodies, Parkinson's disease with and without dementia, and Alzheimer's disease

OBJECTIVES

Cerebral blood flow was compared among patients with dementia with Lewy bodies (DLB), Parkinson's disease with dementia (PDD), Parkinson's disease without dementia (PD), and Alzheimer's disease (AD) using three-dimensional stereotactic surface projection (3D-SSP) analysis.

PURPOSE

We attempt to clarify the difference of reduction pattern on SPECT among patients having DLB, PDD, PD, AD.

PATIENTS AND METHODS

Six patients with DLB, 7 patients with PDD who were matched with the DLB patients for age, unified Parkinson's disease rating scale-III (UPDRS-III) score, and degree of cognitive function disorders, 21 patients with PD who were matched with the DLB patients for age, UPDRS-III score, 12 patients with AD who were matched with the DLB patients for age and degree of cognitive function disorders, and 12 control subjects. All patients were examined by N-isopropyl-p[123I] iodoamphetamine single photon emission computed tomography (123I-IMP SPECT), and obtained images were analyzed with 3D-SSP using an image-analysis software, iSSP ver. 3.5.

RESULTS

Although DLB and PDD showed similar cerebral perfusion reduction pattern at the lateral parietal association and lateral temporal association and precuneus on SPECT by the pixel-by-pixel comparison, greater perfusion reduction was observed in DLB than in PDD. Cerebral perfusion was decreased at the occipital lobe of the DLB patients compared with the AD patients.

CONCLUSIONS

The regional pattern of blood flow reduction in the brain was found to be different among DLB, PD, and AD. Greater blood flow reduction was observed in DLB, although DLB and PDD showed similar reduction pattern. These regional differences were considered to suggest different and disease-specific combinations of underlying pathological and neurochemical processes.

Longitudinal study of cerebral blood flow SPECT in Parkinson's disease with dementia, and dementia with Lewy bodies

BACKGROUND

People with Parkinson's disease (PD) have an increased risk of developing dementia (PDD), which often has clinical features similar to dementia with Lewy bodies (DLB). Whilst perfusion studies have shown parieto-occipital hypoperfusion in DLB and PDD relative to controls, there have not been any longitudinal studies of perfusion changes in PDD and DLB.

METHODS

In this study, we measured brain perfusion using Tc99m HMPAO SPECT over one year in 17 PDD, 18 DLB and 34 healthy subjects. We used SPM99 to compare perfusion changes in the two dementia groups against the control group.

RESULTS

We did not see any reductions in perfusion in either of the dementia groups. However, in the DLB, but not PDD group, there was a significant increase in putamen perfusion relative to controls over the year. In both DLB and PDD groups, there was a correlation between striatal perfusion increase over the year, and worsening of parkinsonism. Perfusion changes were not secondary to changes in antiparkinsonian medication.

CONCLUSION

The increase in striatal perfusion may be a compensatory change related to decreasing striatal dopaminergic input from the substantia nigra in PDD and DLB, consistent with the increased predominance of rigidity over tremor symptoms in these groups compared with non-demented PD.

Progression of dopaminergic degeneration in dementia with Lewy bodies and Parkinson’s disease with and without dementia assessed using 123I-FP-CIT SPECT

PURPOSE

The objective of this study was to investigate the rate of progression of nigrostriatal dopaminergic loss in subjects with dementia with Lewy bodies (DLB), Parkinson's disease (PD) and PD with dementia (PDD) using serial 123I-FP-CIT SPECT imaging. We hypothesised that striatal rates of decline in patients would be greater than in controls, and that DLB and PDD would show similar rates, reflecting the similarity in neurobiological mechanisms of dopaminergic loss between the two disorders.

METHODS

We studied 20 patients with DLB, 20 with PD, 15 with PDD and 22 healthy age-matched controls. Semi-automated region of interest (ROI) analysis was performed on both baseline and repeat scans for each subject and mean striatal uptake ratios (caudate, anterior and posterior putamen) were calculated.

RESULTS

Rates of decline in striatal binding between groups were assessed using ANCOVA. Significant differences between patients and controls were observed in caudate (DLB, PD, PDD, p< or =0.01), anterior putamen (DLB, PDD, p< or =0.05; PD, p=0.07) and posterior putamen (DLB, PD, PDD, p<0.006). Rates of decline were similar between DLB, PD and PDD.

CONCLUSION

In conclusion, this is the first study to show that significant progressive dopaminergic loss occurs in DLB and PDD using serial 123I-FP-CIT SPECT. Dementia severity and motor impairment were correlated with decline, suggesting that dopaminergic loss may play an important role in cognitive as well as motor features.

A review of studies describing the use of acetyl cholinesterase inhibitors in Parkinson's disease dementia

OBJECTIVE

To review the literature relating to the use of acetyl cholinesterase inhibitors in Parkinson's disease dementia (PDD).

METHOD

MEDLINE (1966--December 2004), PsychINFO (1972--December 2004), EMBASE (1980--December 2004), CINHAL (1982--December 2004), and the Cochrane Collaboration were searched in December 2004.

RESULTS

Three controlled trials and seven open studies were identified. Efficacy was assessed in three key domains: cognitive, neuropsychiatric and parkinsonian symptoms.

CONCLUSION

Cholinesterase inhibitors have a moderate effect against cognitive symptoms. There is no clear evidence of a noticeable clinical effect against neuropsychiatric symptoms. Tolerability including exacerbation of motor symptoms--in particular tremor--may limit the utility of cholinesterase inhibitors.

Psychiatric aspects of Parkinson's disease

PURPOSE OF REVIEW

Recently, there has been much interest and rapid progress in understanding the neuropsychiatry of Parkinson's disease. This paper reviews the most important papers published during 2004 on dementia and cognitive impairment, depression and psychosis in Parkinson's disease.

RECENT FINDINGS

Many new studies of cognitive impairment and dementia in Parkinson's disease have been published during 2004. Cognitive impairment has been demonstrated even during the first 1-2 years after onset of disease. Whereas executive and attentional impairment is typical, learning deficits occur early in some patients. Both functional and structural imaging suggest that in addition to fronto-subcortical deficits, temporal and parietal changes occur early as well. In the first large placebo-controlled trial, the cholinesterase inhibitor rivastigmine improved cognition, daily functioning and psychiatric symptoms without worsening of parkinsonism. The frequency and characteristics of depression, anxiety and hallucinations have been explored in several studies. Unfortunately, there is still little scientific evidence available to guide the treatment of these important aspects of Parkinson's disease, and adequately designed clinical trials are needed. Although subthalamic stimulation, in addition to improvement of movement, is frequently associated with some affective and cognitive improvement, permanent and significant worsening may occur in some. Future studies should aim at identifying at-risk patients, as well as identifying the optimal pharmacological and stimulation treatments for individual patients.

SUMMARY

These findings provide a deeper understanding of the neurobiological substrate of cognitive impairment and dementia in Parkinson's disease, and provide new information regarding the assessment and management of dementia and other neuropsychiatric aspects of Parkinson's disease.

Clinical deficits correlate with regional cerebral atrophy in progressive supranuclear palsy

Most cerebral imaging studies of patients with progressive supranuclear palsy (PSP) have noted subtle atrophy, although the full extent of atrophy and any correlates to clinical features have not been determined. We used voxel-based morphometry analysis of grey matter, white matter and CSF on MRI brain scans to map the statistical probability of regional tissue atrophy in 21 patients with PSP, 17 patients with Parkinson's disease and 23 controls. PSP and Parkinson's disease cohorts were selected to approximate the mid-stages of their respective disease courses. Where regions of significant tissue atrophy were identified in a disease group relative to controls, the probability of tissue loss within those regions was correlated with global indices of motor disability, and behavioural and cognitive disturbance for that disease group. Minimal regional atrophy was observed in Parkinson's disease. PSP could be distinguished from both controls and Parkinson's disease by symmetrical tissue loss in the frontal cortex (maximal in the orbitofrontal and medial frontal cortices), subcortical nuclei (midbrain, caudate and thalamic) as well as periventricular white matter. For PSP, motor deficits correlated with atrophy of the caudate and motor cingulate, while behavioural changes related to atrophy in the orbitofrontal cortex and midbrain. These data suggest that intrinsic neurodegeneration of specific subcortical nuclei and frontal cortical subregions together contribute to motor and behavioural disturbances in PSP and differentiate this disorder from Parkinson's disease within 2-4 years of symptom onset.

Treatment of behavioural symptoms and dementia in Parkinson's disease

Behavioural symptoms such as anxiety, depression and psychosis are common in Parkinson's disease (PD), and dementia occurs in about 90% of the patients. These symptoms can be more disabling than the motor dysfunction and they negatively impact quality of life, increase caregiver distress and are more frequently associated with nursing home placement. Depression can be treated with counselling and pharmacotherapy. Tricyclic antidepressants or selective serotonin reuptake inhibitors are widely used, but there is still need for controlled clinical trials. Management of psychosis in PD is complex and includes elimination of identifiable risk factors, reduction of polypharmacy and administration of atypical neuroleptics, which can alleviate psychotic symptoms without worsening motor functions. Clozapine is the best documented atypical neuroleptic shown to be effective against psychosis in PD patients. Cholinesterase inhibitors may prove additional benefit in psychotic PD patients. Recent evidence from small double-blind and open-label trials suggests that cholinesterase inhibitors may be effective in the treatment of dementia associated with PD.

Donepezil: a clinical review of current and emerging indications

This article reviews the piperidine derivative, donepezil hydrochloride (E2020, Aricept), a reversible central acetylcholinesterase inhibitor currently approved for treatment of mild-to-moderate Alzheimer's disease. Donepezil is well absorbed orally, unaffected by food or by time of administration; it reaches therapeutic levels in doses of 5-10 mg/day and peak plasma concentrations are obtained 3-4 h after oral administration. A single bedtime dose is recommended due to the long elimination half-life of the drug (70 h). Donepezil does not cause liver toxicity or significant drug interactions and is relatively well-tolerated. Initial side effects include nausea, vomiting, diarrhoea, insomnia, muscle cramps, fatigue, anorexia and syncope. Caution is advised in patients with bradycardia. Long-term use of donepezil in AD has been found to delay nursing-home placement and to result in caregiver respite. Donepezil also slows deterioration of cognition and global function in patients with moderate-to-severe AD, with improvement of abnormal behaviours. In addition to AD, donepezil demonstrates significant improvement in cognition, global function and activities of daily living in comparison with placebo-treated patients with vascular dementia and has potential therapeutic benefit for other neurological conditions.

Mild cognitive impairment in Parkinson's disease: the challenge and the promise

This review addresses the literature surrounding Parkinson's disease (PD) and mild cognitive impairment (MCI). It discusses the neuropsychological, pharmaceutical, and pathological overlap, the socioeconomic impact of PD and MCI, and the value of recognizing, understanding, and treating MCI in PD. It is concluded from this review that MCI in PD does exist and should be considered in clinical and research investigations. Due to the lack of accepted clinical criteria, an inclusive operating definition of MCI in PD is proposed. Research guidelines for studying the presence of MCI in PD and evaluating the efficacy of pharmaceutical interventions are also suggested.

Concurrent administration of donepezil HCl and levodopa/carbidopa in patients with Parkinson's disease: assessment of pharmacokinetic changes and safety following multiple oral doses

AIM

The use of acetylcholinesterase inhibitors for the treatment of comorbid Alzheimer's disease in Parkinson's disease (PD) patients stabilized on a levodopa regimen may potentially disrupt cholinergic balance. This randomized, double-blind, crossover study investigated the safety of, and possible drug-drug interaction between, donepezil HCl and levodopa/carbidopa.

METHODS

Twenty-five patients with PD who were taking physician-optimized doses of levodopa/carbidopa (with daytime dosing intervals of 4-8 h) were administered once-daily doses of either donepezil HCl (5 mg) or placebo for 15 days, in two treatment periods, separated by a washout of at least 2 weeks. Some patients took a second dose of levodopa/carbidopa after 4 h, therefore subanalysis of the levodopa/carbidopa data was conducted up to 4 h and 8 h after dosing. Twenty-six healthy matched controls received open-label donepezil HCl only, for a single 15-day period. Blood samples were collected before, during and after the 15 doses of donepezil HCl for pharmacokinetic (PK) assessments. Pharmacokinetic parameters included maximum attained plasma drug concentration (C(max)), time at which C(max) is attained (t(max)), plasma drug concentration at steady state (C(ss)), and area under the drug concentration-time curve over the dosing interval. Safety assessments included monitoring adverse events, and the Unified Parkinson's Disease Rating Scale (UPDRS) motor examination.

RESULTS

The mean age of all subjects was 72.6 +/- 1.3 years. Donepezil PK assessments of PD patients receiving levodopa/carbidopa were similar to the PK results from healthy controls who received donepezil HCl only (mean AUC(0-12 h)= 281.6 +/- 17.6 and 268.6 +/- 19.9 ng.h ml(-1), respectively). Carbidopa PK were not significantly altered by the concomitant administration of multiple doses of donepezil HCl, compared with when PD patients received placebo (mean AUC(0-8 h)= 921.8 +/- 160 and 821.8 +/- 113 ng.h ml(-1), respectively). Four hours after administration of donepezil HCl in PD patients, AUC(0-4 h), C(max) and C(ss) of levodopa were higher than when PD patients received placebo (P < 0.05). Eight hours after donepezil HCl, however, only C(max) and t(max) were observed to change compared with when PD patients received placebo (mean C(max) = 2652 +/- 429 and 2077 +/- 276 ng ml(-1), respectively; mean t(max) = 1.7 +/- 0.4 and 2.9 +/- 0.5 h, respectively; P< or = 0.05). The number of PD patients who experienced at least one adverse event during the study (13/25) was higher when they received donepezil HCl than when they received placebo (5/25), but was the same as healthy subjects who received donepezil HCl only (13/26). There were no significant differences in change from baseline on the UPDRS motor examination parameters in PD patients when they took donepezil HCl and when they took placebo.

CONCLUSIONS

No clinically significant drug-drug interactions between donepezil HCl and levodopa/carbidopa were observed at steady state. The small changes in the pharmacokinetics of levodopa did not result in any change in motor symptoms. Co-administration of the two drugs led to a small increase in adverse events compared with administration of levodopa/carbidopa alone in PD patients. These adverse events, however, were consistent with donepezil's cholinomimetic effect, and their incidence was comparable to that observed following the administration of donepezil HCl alone.

Cytokine production of activated microglia and decrease in neurotrophic factors of neurons in the hippocampus of Lewy body disease brains

Dementia is a frequent complication of Parkinson's disease (PD) and usually occurs late in the protracted course of the illness. We have already reported numerous MHC class II-positive microglia in the hippocampus in PD patients, and that this phenomenon may be responsible for functional changes in the neurons and the cognitive decline in PD patients. In this study, we have investigated the distribution of activated microglia and the immunohistochemical and the mRNA expression of several cytokines and neurotrophic factors of the hippocampus in PD and dementia with Lewy bodies (DLB). The brains from five cases of PD and five cases of DLB that were clinically and neuropathologically diagnosed, and those from four normal controls (NC) were evaluated by immunohistochemistry using anti-HLA-DP, -DQ, -DR (CR3/43), anti-alpha-synuclein, anti-brain-derived neurotrophic factor (BDNF), and anti-glial fibrillary acidic protein antibodies. In addition, the mRNA expressions of cytokines (IL-1alpha, IL-1beta, TNF-alpha, IL-6, TGF-beta) and neurotrophic factors (BDNF, GDNF, NGF, NT-3) of these brains were evaluated by the reverse transcription-PCR method. MHC class II-positive microglia were distributed diffusely in the hippocampus of PD and DLB brains. Although the cytoplasm of pyramidal and granular cells of the hippocampus in NC brains was strongly stained by anti-BDNF antibodies, it was only weakly stained in PD and DLB brains. The mRNA expression of IL-6 was significantly increased in the hippocampus of PD and DLB brains, and that of BDNF was significantly decreased in the hippocampus of DLB brains. The increased number of activated microglia and the production of neurotrophic cytokines such as IL-6, together with the decreased expression of the neurotrophic factors of neurons in the hippocampus of PD and DLB brains, may be related to functional cellular changes associated with dementia.

Three-dimensional stereotactic surface projection SPECT analysis in Parkinson's disease with and without dementia

We investigated regional cerebral blood flow (rCBF) using three-dimensional stereotactic surface projection (3D-SSP) analysis in 30 patients initially diagnosed as Parkinson's disease (PD), and compared differences in rCBF between patients with and without PD-related manifestations. 3D-SSP analysis of cerebral perfusion was performed by use of a control database. Compared to age-matched controls, there were multiple hypoperfusion areas in cases where the original diagnosis was PD. Temporal bases showed the lowest perfusion; frontal bases and medial parietal lobes the second; visual cortices the third; and parietal association areas exhibited the fourth lowest. During the clinical course, 10 of the patients suffered dementia, 9 had fluctuating cognition, and 19 experienced repeated visual hallucinations. Significant negative correlations were observed between dementia and the bilateral posterior cingulate area, and among fluctuating cognition and bilateral medial parietal lobes, parietal association areas, and dorsal occipital lobes. Repeated visual hallucinations did not show any correlation with any region of interest. We concluded that multiple hypoperfusion areas were observed in the 3D-SSP SPECT analysis. Although the presence of dementia showed a significant relationship with the bilateral posterior cingulate areas, perfusion in the frontal bases, temporal bases, or parietal lobes was markedly more reduced than that seen in the bilateral posterior cingulate areas.

How to diagnose dementia with Lewy bodies: State of the art

Dementia with Lewy bodies (DLB) is the second most common cause of neurodegenerative dementia in older people that has only been recognized in the past decade and that remains widely underdiagnosed. At postmortem examination, affected patients show numerous alpha-synuclein-positive Lewy bodies (LB) in many parts of the cerebral cortex, particularly neocortical and limbic areas in addition to the nigral LB degeneration characteristic of Parkinson's disease (PD). Clinical presentation, unlike PD, is with progressive cognitive decline with particular deficits of visuospatial ability as well as frontal executive function accompanied by usually only mildly to moderately severe parkinsonism, which is often akineto-rigid without the classical parkinsonian rest-tremor. Further accompanying features include spontaneous recurrent visual hallucinations and conspicuous fluctuations in alertness and cognitive performance. The two main differential diagnoses are Alzheimer's disease (AD) and Parkinson's disease dementia (PDD). To improve the differential diagnosis of DLB, consensus criteria have been developed that establish possible and probable levels of clinical diagnostic accuracy. Generally, their sensitivity is variable and low but their specificity is high. Current consensus is to restrict a diagnosis of DLB only to patients with parkinsonism who develop dementia within 12 months of the onset of motor symptoms. Using operationalized criteria, DLB can be diagnosed clinically with an accuracy similar to that achieved for AD or PD. Ancillary investigations, particularly neuroimaging, can aid in differential diagnosis. We review the present state of the best practice in the clinical diagnosis of DLB. Future modifications of diagnostic criteria would ideally include the full range of clinical presentations that can be associated with LB disease.

Abeta deposition is associated with enhanced cortical alpha-synuclein lesions in Lewy body diseases

In order to understand better the neuropathological substrate of dementia in Parkinson's disease (PD) and to examine its interactions with Alzheimer's disease (AD), we examined autopsy brains from 21 cases of PD and Lewy body disease (LBD) with dementia. We separated brains in two groups according to the presence of Abeta deposits. In brains without Abeta, we found few or no Lewy bodies (LB) in the cerebral cortex. By contrast, in brains with Abeta, we observed significant increases in LB in the cerebral cortex (p < 0.01) and alpha-synuclein immunoreactive lesions in the cingulate cortex (p < 0.01). Immunoblots of alpha-synuclein from cingulate cortex in brains with Abeta showed significantly higher levels of insoluble alpha-synuclein compared to brains without Abeta. Our observations indicate that in cases of PD with dementia, the neocortex is not necessarily involved by LB. Furthermore, the presence of Abeta deposits in the cerebral cortex was associated with extensive alpha-synuclein lesions and higher levels of insoluble alpha-synuclein. This suggests that Abeta enhances the development of cortical alpha-synuclein lesions in cases of PD.

Parkinson disease: an update

BACKGROUND

Over the past decade, the treatment of Parkinson disease (PD) has undergone tremendous changes. New drugs have been introduced to manage the cardinal motor symptoms of PD, and other agents have been borrowed to treat the nonmotor manifestations of the illness. For neurologists faced with the task of treating PD patients, the available array of medications may be confusing and intimidating.

REVIEW SUMMARY

In this review, I summarize the newest approved medications for the treatment of PD, including the new dopamine agonists and catechol-O-methyl-transferase inhibitors. I also describe agents that are used to treat common problems in PD patients, including hallucinations, orthostasis, nausea, erectile dysfunction, depression, and memory loss. Guidelines for handling common scenarios in PD patients will be illustrated by 10 case histories. Finally, the most promising PD drugs that are currently in development will be reviewed.

CONCLUSIONS

Neurologists have a vast armamentarium to treat both motor and nonmotor manifestations of PD. Understanding this array allows the astute clinician to improve the lives of their patients with PD.

Risk and incidence of dementia in a cohort of older subjects with Parkinson's disease in the United Kingdom

To determine the incidence and possible risk factors for dementia in patients with clinically probable Parkinson's disease (PD), a cohort (n = 86) of nondemented patients over 65 years of age with PD fulfilling the PD Brain Bank clinical diagnostic criteria were determined from community records. A similarly aged group of control subjects (n = 102) were recruited from the same area. Both groups were assessed at baseline and approximately 4 years later for cognition, mood, and motor function (PD patients only). The presence and severity of cognitive impairments was based on subject and informant interview, neuropsychological assessment based on the Cambridge Cognitive Examination (CAMCOG) and the application of the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV). At 4 years, 51 (59%) of the PD and 72 (71%) of the control cohort were available for reassessment. Of the PD cohort, 18 (35.3%) had developed dementia and 5 (9.4%) had evidence of mild cognitive impairments. In the control group, 5 (7%) had developed dementia. The incidence of dementia per 1,000 person-years in the PD cohort was 107.1 (95% confidence interval [CI], 59.9-159.8) and in the control group was 17.9 (95% CI, 5.8-31.9). The relative risk of patients developing dementia was 5.1 times that of the controls (95% CI, 2.1-12.5). Increasing age, later age of onset of PD, longer duration of PD symptoms, the presence of hallucinations, and impairment of memory and language function were all predictive factors for the development of dementia (P < 0.05). Dementia was also found to be a significant predictor for institutional placement in the PD group. Compared with similarly aged controls, patients with clinically probable PD have a fivefold-increased risk of developing dementia. This finding has significant implications for successful clinical management of this condition.

Sydney multicenter study of Parkinson's disease: Non‐ L ‐dopa–responsive problems dominate at 15 years

One-third of the 149 people recruited 15 to 18 years ago in the Sydney Multicenter Study of Parkinson's disease have survived. The original study compared low-dose levodopa with low-dose bromocriptine. We now report the problems experienced by people who survive 15 years from diagnosis. The standardized mortality ratio is significantly elevated at 1.86 and is not significantly different between treatment arms. Falls occur in 81% of patients, and 23% sustained fractures. Cognitive decline is present in 84%, and 48% fulfill the criteria for dementia. Hallucinations and depression are experienced by 50%. Choking has occurred in 50%, symptomatic postural hypotension in 35%, and urinary incontinence in 41%. No patient is still employed, and 40% of patients live in aged care facilities. Although approximately 95% have experienced L-dopa-induced dyskinesia/dystonia and end of dose failure of medication, in the majority, these symptoms are not disabling. Dyskinesia and dystonia were delayed by early use of bromocriptine, but end-of-dose failure appeared at a similar time once L-dopa was added. The rate of disease progression is similar in both arms of the study. We conclude that the most disabling long-term problems of Parkinson's disease relate to the emergence of symptoms that are not improved by L-dopa. Neuroprotective interventions in Parkinson's disease should be judged by their ability to improve non-L-dopa-responsive aspects of the disease, rather than just by their capacity to delay the introduction of L-dopa or reduce its associated side effects.

Challenges in Parkinson's disease: restoration of the nigrostriatal dopamine system is not enough

Levodopa remains the most effective treatment for Parkinson's disease (PD). However, the drug is complicated by a wide range of adverse effects, most notably motor fluctuations and dyskinesias. Long-acting dopamine agonists are associated with a reduced incidence of these complications and modern surgical approaches and pharmacological methods of providing more continuous dopaminergic stimulation have a substantial ameliorative effect on these problems. Despite these advances, disease progression remains unaffected. For this reason there has been much enthusiasm for cellular therapies designed to replace degenerating nigrostriatal dopaminergic neurons. However, recent fetal transplant trials have failed to show expected benefit and have been complicated by medication dyskinesias". Even if successful, such treatment may be predestined to provide no better outcome than available treatments given current medical and surgical experience that emphasises the increasingly critical role of "non-dopaminergic" symptoms to quality of life in late-stage PD. Knowledge of the widespread, multisystem nature of the neurodegeneration that accounts for these problems suggests that restoration of the nigrostriatal dopamine system should not be the ultimate goal of future research.

Dementia in Parkinson’s disease

One of the more recently recognized problems in treatment of patients with Parkinson's disease (PD) is development of cognitive dysfunction and, in many cases, frank dementia. As patients with PD live longer, because of improved care and treatment of motor symptoms, dementia in PD is becoming a major contributor to morbidity in the illness. Prevalence studies suggest that up to 30% of patients with PD develop dementia. Dementia in PD patients is often a multifactorial condition. Neuropathologic changes caused by PD itself may cause memory loss. However, some patients with PD and memory decline also have pathologic changes that are more consistent with Alzheimer's disease. Many PD patients have a mix of the two types of pathology. Other factors, such as underlying illnesses, medication side effects, and interaction of therapeutic agents, may contribute to cognitive changes in PD patients. Predictors of development of dementia in PD include advancing age and severity of neurologic symptoms, which may interact with one another to produce this effect. Recent work suggests that tobacco use also may increase risk of PD dementia, despite its possible protective effect against development of PD itself. Presence of psychiatric illness, especially depression, may interfere with cognition and exacerbate memory loss. Reduction in the dose of dopaminergic agents and of other medications may be helpful in partially improving cognitive function in some cases. The balance between improvement of motor function and preservation of cognitive abilities must be weighed, and it is important for clinicians to discuss this trade-off with patients and their families. At this time, there is no US Food and Drug Administration-approved pharmacologic treatment for dementia in PD. However, medication used to treat Alzheimer's disease, such as acetylcholinesterase inhibitors, may slow progression of memory loss in some PD patients. Based on work from small double-blind studies, open-label trials, and case reports, cholinesterase inhibitors may be tried for treatment of dementia in PD, as long as the patient and caregivers understand that these agents are being used on an off-label basis. Surgical intervention, such as deep brain stimulation of the subthalamic nucleus or globus pallidus internus, although useful for treatment of motor symptoms in some PD patients, does not improve cognitive function in most cases and may actually worsen cognition in patients with pre-existing dementia. There is no specific exercise regimen or dietary guidelines for patients with PD who develop dementia. However, patients should be encouraged to lead a healthy lifestyle; this may improve overall well-being, which could impact positively on cognition function. Similarly, although assistive devices have not been developed for people with PD who have memory loss, any aid that increases mobility will probably improve mental and physical function. Clinicians should be mindful of the increased caregiver burden posed by PD patients who also have dementia. They should intervene appropriately to prevent caregiver distress and "burn out." Herbal and nutritional supplements have not been shown in clinical trials to be beneficial for treatment of any type of dementia, and thus are not recommended for PD patients with cognitive decline.

Progress in clinical neurosciences: Parkinson's disease with dementia and dementia with Lewy bodies

Dementia occurs in up to 30% of people with Parkinson's disease and is a major cause of disability. Pathologically, Parkinson's dementia, where dementia follows the onset of parkinsonism by at least one year, overlaps with dementia with Lewy bodies. We review the functional impact, definitions, neuropsychology, epidemiology and pathophysiology of Parkinson's dementia, dementia with Lewy bodies and their overlap. Associated psychiatric and imaging findings are also considered. Lastly, current and emerging approaches to assessment and treatment in patients with these Lewy body associated dementias are presented.

What causes mental dysfunction in Parkinson's disease?

Parkinson's disease (PD) is frequently associated with mental dysfunction. Domain-specific cognitive deficits are ubiquitous, and although they may not be clinically apparent in all patients, they are demonstrable by neuropsychological testing. Dementia is less frequent but is present significantly more in PD patients than in controls, with a cumulative prevalence rate up to 40% and up to six-fold increased incidence. Cognitive impairment mainly involves executive and visuospatial functions; memory is secondarily impaired with relatively preserved recognition. Qualitatively, the neuropsychological profile of dementia encompasses the same type of deficits found in nondemented PD patients. The dementia seen in PD, therefore, can be described as a dysexecutive syndrome combined with visuospatial dysfunction and behavioural symptoms. Dopaminergic, noradrenergic, serotoninergic, and cholinergic deficits have all been described as the underlying neurochemical impairment, but the strongest evidence exists for a cholinergic dysfunction. Involvement of brainstem nuclei, limbic structures, and cerebral cortex have been suggested as the site, and Lewy body (LB) degeneration and Alzheimer-type changes as the type of pathology underlying the mental dysfunction in PD. Although there is still some controversy as to the site and type of pathology, recent evidence suggests that LB-type degeneration in limbic structures and cerebral cortex, with consequent synaptic and cell loss, is the main pathological state associated with dementia in PD.

Neuropsychiatric non-motor aspects of Parkinson's disease

Parkinson's disease is often recognised as a motor disease characterised by rest tremor, rigidity, bradykinesia, and postural disturbances. However, there are several non-motor aspects of the disease that are of at least equal importance in the management of patients with Parkinson's disease. They include depression, cognitive impairment, anxiety, and psychosis among others. It is important to recognise them, as they are common and they contribute significantly to patients' morbidity, quality of life, and institutionalisation to long term care homes. In addition to the disease duration and severity, other factors including drugs may contribute to their occurrence. Pathogenesis of these aspects is not fully understood, though there has been a significant increase in the knowledge in recent years. Management of these aspects involves a multidisciplinary approach.

Modest increase in plasma homocysteine follows levodopa initiation in Parkinson's disease

Levodopa, typically ingested chronically at high daily doses, is predictably methylated by means of a series of reactions using B vitamins, which convert methionine to homocysteine. Elevated total plasma homocysteine (tHcy), a risk factor for dementia, has been found in PD patients using levodopa. We prospectively measured the effects on plasma tHcy and B vitamins of levodopa initiation, and measured the effects of dose changes and of treatment with dopamine agonists and entacapone. We collected paired plasma samples, at baseline and again after several months treatment, from patients initiating levodopa (n = 30), from patients whose levodopa dose was doubled (n = 15), halved or stopped (n = 14), from patients starting or stopping entacapone (n = 15) and from patients initiating or doubling dopamine agonist monotherapy (n = 16). Vitamin B12, folate, and tHcy concentrations were measured. Baseline tHcy concentration of 8.7 (2.8) micromol/L increased to 10.1 (3.1) micromol/L (P = 0.004) an average of 94 (range 36 to 200) days after initiation of 604 (240 to 1050) mg/day of L-dopa. Average concentration of vitamin B12 fell from 380 to 291 pmol/ L (P = 0.01). Patients who doubled their daily levodopa dose experienced tHcy elevations from 9.5 to 11.1 micromol/L (P = 0.05). Levodopa reduction, agonist treatment, and entacapone treatment did not have significant effects. Levodopa elevates tHcy and lowers vitamin B12 concentration to modest degrees. The clinical implications, if any, have not yet been determined.

The role of acetylcholine and dopamine in dementia and psychosis in Parkinson's disease

Parkinson's disease (PD) is a progressive neurological disorder in which there is abnormal degeneration of dopaminergic neurons in the substantia nigra and the ventral tegmental area combined with a varying degree of deterioration of the cholinergic, serotonergic and noradrenergic system, leading to a variety of motor and non-motor abnormalities. Dopamine (DA) depletion in nigrostriatal projections manifests with abnormal spontaneous motor behavior and (subtle) cognitive deficits, whereas more overt cognitive impairment may develop with concomitant DA-deficiency related mesocorticolimbic denervation. In combination with a progressive dysfunction of the ascending neocortical cholinergic (and serotonergic and noradrenergic) projections, mainly due to a loss of cholinergic neurons in the nucleus basalis of Meynert (NbM), these cognitive deficits may proceed into dementia sometimes in combination with psychotic behavior, which might also be associated with dopaminomimetic and/or anticholinergic treatment as well as with cholinergic deficit or dopaminomimetic induced REM sleep disturbances. As these psychiatric symptoms have a substantial negative effect on the patient's quality of life, contribute to caregiver distress and are predictive of nursing home placement, identification and adequate treatment is of great importance. Recent evidence supports a possible role for cholinomimetic therapy in alleviating cognitive dysfunction and psychotic symptoms in PD.

Regional cerebral blood flow in Parkinson's disease with and without dementia

Tc99 HMPAO SPECT and T1 weighted 3D MRI scans were acquired in cognitively intact subjects with Parkinson's disease (PD) (n = 31), and in PD subjects with dementia (PDD) (n = 34), healthy controls (n = 37), those with Alzheimer's disease (AD) (n = 32), and those with dementia with Lewy bodies (DLB) (n = 15). We used SPM99 to look for regions which showed a reduction in perfusion on SPECT not related to associated structural brain changes assessed by a MRI scan. The precuneus and inferior lateral parietal regions showed a perfusion deficit in Parkinson's disease with dementia, similar to the pattern observed in DLB. In comparison, AD showed a perfusion deficit in the midline parietal region, in a more anterior and inferior location than in PDD, involving the posterior cingulate as well as the precuneus. The perfusion deficits in PDD are similar those in DLB, and in a location associated with visual processing, and may be associated with the visuospatial perception deficits which are present in persons with DLB and PDD.

Recognition and treatment of depression in Parkinson's disease

Depression in Parkinson's disease (PD) is common, but little is known about its recognition and treatment. The authors report the antidepressant experience (N = 100) and outcome of depression assessment (n = 77) of a convenience sample of patients at a PD center. Subjects were assessed with a psychiatric and neurological battery, and information was gathered on depression treatment. One third (34%) of subjects met criteria for a depressive disorder, and two thirds (65%) of them were not currently receiving antidepressant treatment. Approximately one quarter (23%) of subjects were taking an antidepressant, but almost half (47%) of them still met criteria for a depressive disorder. Few antidepressant users with persistent depression had received either antidepressant treatment at dosages within the highest recommended range (11%) or more than 1 antidepressant trial (33%). Most depressed patients are untreated, and half of antidepressant users remain depressed, suggesting that even when delivered, treatment is often inadequate or ineffective.

Advances in the pharmacological management of Parkinson disease

Numerous advances have taken place in the pharmacological management of Parkinson disease (PD) in recent years. Some of the more clinically relevant will be discussed in the text that follows. New drugs have been developed to treat or prevent the motor fluctuations and dyskinesias that occur frequently with the continuous use of levodopa. Such drugs include the catechol-O-methyl-transferase (COMT) inhibitors, such as tolcapone and entecapone, and new dopamine (DA) agonists with long half lives such as cabergoline, pramipexole or ropirinole. Also new, atyical, antipsychotics have appeared which have revolutionized the treatment of PD since they allow us to control hallucinations and other psychotic behaviour without worsening of motor function. Finally preliminary reports suggest that cholinesterase inhibitors, such as rivastigmine, can be usefull in the management of cognitive impairment in PD, one of the most difficult clinical problems encountered in the management of this neurodegenerative disorder.

Extrapyramidal features in Parkinson's disease with and without dementia and dementia with Lewy bodies: A cross-sectional comparative study

Risk factors predicting an increased risk of dementia in Parkinson's disease (PD) are not fully established. The dementia associated with PD (PDD) closely resembles dementia with Lewy bodies (DLB). Based upon a high frequency of non-dopaminergic mediated clinical features in DLB, we predicted that a motor subtype comprising postural instability and balance problems would be more common in PDD. We examined extrapyramidal, cognitive, and affective features in 38 PD, 43 PDD, and 26 DLB patients in a cross-sectional study design. Motor subtype was subdivided into postural-instability gait difficulty (PIGD) or tremor (TD) dominant. The PIGD-subtype was more common in PDD (88% of cases) and DLB (69% of cases) groups compared with the PD group (38% of cases), in which TD and PIGD sub-types were more equally represented (P < 0.001). Although the mean depression scores overall were modest, PDD patients scored significantly higher than PD, but not DLB patients (Cornell; P = 0.006, and Geriatric Depression scale, GDS-15; P = 0.001), while within the PD group, those patients with a PIGD subtype had greater depression scores than the TD subtype (GDS-15; P < 0.05). We conclude that non-dopaminergic motor features are frequent in PDD. Neurodegeneration within the cholinergic system is likely to mediate many of these motor problems, as well as playing a significant role in determining the neuropsychiatric symptomatology of both PDD and DLB.

Parkinson's disease is associated with hippocampal atrophy

Patients with Parkinson's disease (PD) may have hippocampal atrophy compared with controls. We compared hippocampal, and extra-hippocampal volumes between PD, PDD (patients with PD who have mild cognitive impairment or dementia), Alzheimer's disease (AD) and controls using volumetric magnetic resonance imaging (MRI). Participants (10 patients with PD, 10 with PDD, 11 with AD, and 12 control subjects) had an informant interview, neurological examination, and psychometric testing. Established, reliable methods were used to measure the hippocampus, parahippocampal gyrus, temporal, frontal, and parieto-occipital lobes. Correction for intracranial volume was carried out before comparison. There was no age difference between groups (mean age, 74 years). On the Clinical Dementia Rating scale (CDR) cognitive impairment was mild (CDR = 0.5) in the majority of PDD and AD patients. Hippocampal (P < 0.0004) volumes were smaller in the patient groups. Effect sizes compared with the control group were: PD, 0.66; PDD, 1.22; and AD, 1.81. The other volumes did not differ significantly. Among PD and PDD patients, recognition memory (r = 0.54, P = 0.015) and Mini-Mental State Examination scores (r = 0.56, P = 0.01) correlated with left, but not right hippocampal volume. In conclusion, hippocampal volume showed a pattern (Control > PD > PDD > AD) suggesting progressive hippocampal volume loss in PD. Volumetric MRI imaging might provide an early marker for dementia in PD.

Designing neuroprotection trials in Parkinson's disease

A major goal of the neuroscience community is to develop neuroprotective treatment strategies that will slow or forestall the progression of Parkinson's disease, one of the most common adult-onset neurodegenerative disorders, affecting approximately 1 million people in North America. Although prior research to identify neuroprotective interventions has not been conclusive, recent advances in the understanding of the pathogenesis of Parkinson's disease, including the development of relevant animal models, provide the opportunity for rational clinical trials to assess neuroprotective treatments.

Dementia associated with Parkinson's disease

Dementia affects about 40% of patients with Parkinson's disease; the incidence of dementia in these patients is up to six times that in healthy people. Clinically, the prototype of dementia in PD is a dysexecutive syndrome. Loss of cholinergic, dopaminergic, and noradrenergic innervation has been suggested to be the underlying neurochemical deficits. Nigral pathology alone is probably not sufficient for the development of dementia. Although there is some controversy with regard to the site and type of pathology involved, dementia is likely to be associated with the spread of pathology to other subcortical nuclei, the limbic system, and the cerebral cortex. On the basis of more recent studies, the main pathology seems to be Lewy-body-type degeneration with associated cellular and synaptic loss in cortical and limbic structures. Alzheimer's disease-type pathology is commonly associated with dementia but less predictive. Recent evidence from small studies suggests that cholinesterase inhibitors may be effective in the treatment of dementia associated with PD.

Cognitive effects of unilateral posteroventral pallidotomy: a 4-year follow-up study

We assessed the long-term neuropsychological effects of unilateral posteroventral pallidotomy in Parkinson's disease. Eleven Parkinson's disease patients, from an original cohort of 15 consecutive patients who underwent pallidotomy, were evaluated. A neuropsychological battery was administered to each patient before (3 days) and after (3 months and 4 years) surgery during the effects of levodopa. The following tests were administered: Rey's Auditory-Verbal Learning Test, Visual Associative Learning test from the Wechsler Memory Scale-Revised, Luria's motor alternation, Benton's Judgment of Line Orientation, Trail Making, phonetic verbal fluency, Stroop test, Petrides' working memory tasks, Beck's depression questionnaire and the Maudsley obsessional-compulsive inventory. In the 3-month postoperative assessment, there was a significant worsening in phonetic verbal fluency and an improvement in Benton's Judgment of Line Orientation test. In the 4-year follow-up assessment, phonetic verbal fluency and Benton's Judgment of Line Orientation test returned to baseline scores. Although there was no significant difference between pre- and postsurgical scores for long-term visual associative memory, there was a significant deterioration between 3-month and 4-year follow-up performances. Our results suggest that unilateral posteroventral pallidotomy may produce transient changes in prefrontal and visuospatial functions, but there is no evidence of permanent neuropsychological effects.

Familial Parkinson's disease: a community-based study

Genetic factors seem to be important in the pathogenesis of Parkinson's disease (PD). It is however, still controversial whether these factors also are reflected in a familial aggregation of PD. The aim of this study was to investigate the frequency of PD patients with a positive PD family history compared with two control groups. The included 245 PD patients were examined by neurologists and information was obtained through a semi-structured interview. The patients and the control groups were examined for the frequency of PD and dementia in their families. The 245 patients with PD were included in this study. A positive PD-family history could be obtained in 53 (21.6%) patients. The frequency was three- and four-fold increased as compared with the control groups (P < 0.001). Age at onset of disease was not different among patients with and without PD in the family. The frequency of dementia did not differ in the family of individuals with and without PD (P > 0.1). As a conclusion our study of PD in a community based population supports previous reports of a three- to fourfold increased risk for PD in the families of patients with the disease. Our results indicate that the familial aggregation of the disease is independent of the age of the proband.

Prevalence of amyloid-beta deposition in the cerebral cortex in Parkinson's disease

The pathological basis for the dementia which occurs in 20 to 40% of patients with idiopathic Parkinson's disease (PD) remains uncertain. In the present postmortem study, we compared the prevalence and severity of parenchymal and vascular amyloid-beta (Abeta) deposition in the cerebral cortex in a group of 57 PD brains, including 13 cases with dementia, and in 100 control brains. A higher proportion of PD brains had vascular Abeta deposition, whereas the proportions and severity of parenchymal Abeta were similar in the PD and control groups. There was a poor correlation between Abeta deposition and neurofibrillary tangles which were present in only small numbers in a minority of cases. Cortical Abeta deposition was present in only 6 of the 13 cases with dementia and only 3 fulfilled the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) criteria for definite Alzheimer's disease. The present findings confirm that dementia in PD is only infrequently due to fully established Alzheimer's disease. However, vascular and parenchymal Abeta deposition could still contribute to dementia and cognitive decline when combined with other changes such as alpha-synuclein deposition in the cerebral cortex and cortical Lewy bodies.

Cognitive slowing in Parkinson's disease resolves after practice

OBJECTIVE

To assess the effect of dopaminergic repletion on working memory in Parkinson's disease.

METHODS

The role of dopaminergic state on working memory in patients with Parkinson's disease was determined using the Sternberg item recognition paradigm, a continuous performance task that dissociates the motor and cognitive components of response time. Ten patients with Parkinson's disease were tested in an "on" state (on dopaminergic drug treatment) and a practical "off" state in two sessions held one week apart in counterbalanced order; 10 controls matched for age and education were studied at the same time points.

RESULTS

Patients with Parkinson's disease showed impaired working memory, independent of motor slowing. During session 1, the performance of the patients was worse than the controls, regardless of dopaminergic state. The patients showed a significant improvement in the cognitive component of task performance during the second session, such that they no longer differed from the controls. The performance of the control subjects remained stable over the two sessions.

CONCLUSIONS

Working memory performance of patients with Parkinson's disease did not change in association with dopaminergic state; rather, the performance improved over time. The pattern of improvement over time suggests a delay in proceduralising the task, similar to the deficits shown by such patients in procedural learning of other tasks.

Memory and executive function impairment predict dementia in Parkinson's disease

We analyzed the association of neuropsychological test impairment at baseline with the development of dementia in idiopathic Parkinson's disease (PD) patients. A cohort of nondemented PD patients from northern Manhattan, NY was followed annually with neurological and neuropsychological evaluations. The neuropsychological battery included tests of verbal and nonverbal memory, orientation, visuospatial ability, language, and abstract reasoning. The association of baseline neuropsychological tests scores with incident dementia was analyzed using Cox proportional hazards models. The analysis controlled for age, gender, education, duration of PD, and the total Unified Parkinson's Disease Rating Scale motor score at baseline. Forty-five out of 164 patients (27%) became demented during a mean follow-up of 3.7 +/- 2.3 years. Four neuropsychological test scores were significantly associated with incident dementia in the Cox model: total immediate recall (RR: 0.92, 95% CI: 0.87-0.97, P = 0.001) and delayed recall (RR: 0.73, 95% CI: 0.59-0.91, P = 0.005) of the Selective Reminding Test (SRT), letter fluency (RR: 0.87, 95% CI: 0.77-0.99, P = 0.03), and Identities and Oddities of the Mattis Dementia Rating Scale (RR: 0.85, 95% CI: 0.73-0.98, P = 0.03). When the analysis was performed excluding patients with a clinical dementia rating of 0.5 (questionable dementia) at baseline evaluation, total immediate recall and delayed recall were still predictive of dementia in PD. Our results indicate that impairment in verbal memory and executive function are associated with the development of dementia in patients with PD.

Markers for depression in Parkinson's disease

OBJECTIVE

To assess whether general risk factors for depression are also markers of depression in patients with Parkinson's disease (PD) and to identify additional disease-specific markers.

METHOD

A two-step logistic regression was performed on data from 161 consecutively referred PD patients, 40 of whom suffered from major depressive disorder. A first logistic model was created with five general risk factors for depression. Next, five potential disease-specific markers were added to see whether this would improve the model.

RESULTS

The logistic model of general risk factors for depression also predicted depression in PD patients. A family history of depression was the most important marker. 'Right-sided onset' was the only disease-specific marker that improved the model.

CONCLUSION

Established risk factors for depression in the general population are also markers of depression in PD. The importance of correcting for general risk factors for depression in the search for disease-specific risk factors is stressed.

Combined effect of age and severity on the risk of dementia in Parkinson's disease

Age and severity of extrapyramidal signs have been consistently associated with incident dementia in Parkinson's disease. We evaluated the separate and combined effects of age and severity of extrapyramidal signs on the risk of incident dementia in Parkinson's disease in the setting of a population-based prospective cohort study. Age and the total Unified Parkinson's Disease Rating Scale motor score at baseline evaluation were dichotomized at the median. Four groups of Parkinson's disease patients were defined: younger age/low severity (reference), younger age/high severity, older age/low severity, and older age/high severity. Risk ratios for incident dementia were calculated with Cox proportional hazards models controlling for gender, education, ethnicity, and duration of Parkinson's disease. Of 180 patients, 52 (28.9%) became demented during a mean follow-up period of 3.6 +/- 2.2 years. The median age at baseline of the Parkinson's disease patients was 71.8 years (range, 38.5-95.9 years), and the median total Unified Parkinson's Disease Rating Scale motor score was 24 (range, 2-65). The group with older age/high severity had a significantly increased risk of incident dementia (relative risk, 9.7; 95% confidence interval, 3.9-24.4) compared with the group with younger age/low severity (reference), whereas the groups with older age/low severity (relative risk, 1.6; 95% confidence interval, 0.5-4.8) and younger age/high severity (relative risk, 1.2; 95% confidence interval, 0.5-3.2) did not. These findings suggest that the increased risk of incident dementia in Parkinson's disease associated with age and severity of extrapyramidal signs is related primarily to their combined effect rather than separate effects.

Donepezil for cognitive impairment in Parkinson's disease: a randomised controlled study

OBJECTIVE

To study the safety and efficacy of the cholinesterase inhibitor donepezil in patients with Parkinson's disease (PD) and cognitive impairment.

METHODS

This was a double blind, randomised and placebo controlled, crossover study in which 14 patients with PD and cognitive impairment received donepezil (5 or 10 mg per day) or matching placebo during two sequential periods lasting 10 weeks each. The primary outcome measures were the mini mental state examination (MMSE) score, the clinician's interview based impression of change plus caregiver input (CIBIC+) score, and the motor subscale of the unified Parkinson's disease rating scale (UPDRS).

RESULTS

Two patients on donepezil (14%) dropped out after one and four weeks of the first treatment period because of peripheral cholinergic side effects, otherwise the adverse effects were few and not severe. Carryover or residual effects were not observed. Parkinsonism did not increase during donepezil treatment. After 10 weeks of treatment, the mean MMSE score was increased by 2.1(SD 2.7) points on donepezil and 0.3 (SD 3.2) points on placebo, and the CIBIC+ score was 3.3 (SD 0.9) on donepezil and 4.1 (SD 0.8) on placebo. Statistical analysis of the repeated measurements and crossover study design showed significant effects of donepezil compared with placebo for MMSE (p=0.013) and CIBIC+ (p=0.034). Five (42%) patients on donepezil and two (17%) on placebo were rated as improved on the basis of the CIBIC+ score.

CONCLUSIONS

Donepezil improves cognition, and seems to be well tolerated and not to worsen parkinsonism in patients with cognitive impairment.

Do risk factors for Alzheimer's disease predict dementia in Parkinson's disease? An exploratory study

The extent to which concomitant Alzheimer's disease (AD) is etiologically related to the development of dementia in Parkinson's disease (PD) remains controversial. We explored the association of four risk factors associated with AD, including head injury, smoking, hypertension, and diabetes mellitus, with incident dementia in PD. A cohort of 180 nondemented PD patients from the Washington Heights community in northern Manhattan, New York, completed a risk factor questionnaire at baseline and was followed annually with neurological and neuropsychological evaluations. The association of baseline variables with incident dementia was analyzed by using Cox proportional hazards models. All analyses controlled for age at baseline, gender, years of education, duration of PD, and total Unified Parkinson's Disease Rating Scale (UPDRS) motor score at baseline. Of 180 patients (mean age, 71.0 +/- 10.3 years), 52 (29%) became demented during a mean follow-up period of 3.6 +/- 2.2 years. Head injury risk ratio ([RR] 0.9; 95% confidence interval [CI], 0.4-2.2; P = 0.9), hypertension (RR, 0.7; 95% CI, 0.4-1.4, P = 0.3), and diabetes mellitus (RR, 0.8; 95% CI, 0.3-2.3; P = 0.7) were not significantly associated with incident dementia in the Cox models. Patients who reported having ever smoked were at increased risk for the development of dementia compared with nonsmokers (RR, 2.0; 95% CI, 1.0-3.9; P = 0.05). Current smoking was significantly associated with incident dementia (RR, 4.5; 95% CI, 1.2-16.4; P = 0.02), whereas past smoking approached significance (RR, 1.9; 95% CI, 0.9-3.7; P = 0.07). Although an inverse association between smoking and PD has been reported in several studies, our study showed a positive association between smoking and dementia in the setting of PD. The association of smoking with incident dementia in PD deserves further study.

Management of Parkinson's disease

Parkinson's disease is one of the most common and debilitating movement disorders. It affects a large number of the aging population and as the life expectancy of the average person increases, it will affect ever increasing numbers of people. Diagnostic accuracy remains problematic and treatment for some is unsatisfactory. New understanding of the mechanism behind neurodegeneration in this disease and the pathophysiology of the basal ganglia has helped in designing therapeutic paradigms. Patients diagnosed today have a far better quality of life than those diagnosed even 10 years ago, while patients diagnosed 10 years from now will fair even better. Research is advancing rapidly and will help to cure this disease in the next century.