An investigation of clinical correlates of Lewy bodies in autopsy-proven Alzheimer disease

Prevalence of Concomitant Pathologies in Parkinson's Disease: Implications for Prognosis, Diagnosis, and Insights into Common Pathogenic Mechanisms

Pathologies characteristic of Alzheimer's disease (i.e., hyperphosphorylated tau and amyloid-β (Aβ) plaques), cardiovascular disease, and limbic predominant TDP-43 encephalopathy (LATE) often co-exist in patients with Parkinson's disease (PD), in addition to Lewy body pathology (α-synuclein). Numerous studies point to a putative synergistic relationship between hyperphosphorylation tau, Aβ, cardiovascular lesions, and TDP-43 with α-synuclein, which may alter the stereotypical pattern of pathological progression and accelerate cognitive decline. Here we discuss the prevalence and relationships between common concomitant pathologies observed in PD. In addition, we highlight shared genetic risk factors and developing biomarkers that may provide better diagnostic accuracy for patients with PD that have co-existing pathologies. The tremendous heterogeneity observed across the PD spectrum is most likely caused by the complex interplay between pathogenic, genetic, and environmental factors, and increasing our understanding of how these relate to idiopathic PD will drive research into finding accurate diagnostic tools and disease modifying therapies.

Effects of amyloid beta and dopaminergic depletion on perfusion and clinical symptoms

INTRODUCTION

Although mixed pathologies are common in Alzheimer's disease (AD) and dementia with Lewy bodies (DLB), the effects of amyloid beta and dopaminergic depletion on brain perfusion and clinical symptoms have not been elucidated.

METHODS

In 99 cognitive impairment patients due to AD and/or DLB and 32 controls, 18F-florbetaben (FBB) and dual-phase dopamine transporter (DAT) positron emission tomography (PET) were performed to measure the FBB standardized uptake value ratio (SUVR), striatal DAT uptakes, and brain perfusion.

RESULTS

Higher FBB-SUVR and lower ventral striatal DAT uptake were intercorrelated and, respectively, associated with left entorhinal/temporo-parietal-centered hypoperfusion and vermis/hippocampal-centered hyperperfusion, whereas regional perfusion mediated clinical symptoms and cognition.

DISCUSSION

Amyloid beta deposition and striatal dopaminergic depletion contribute to regional perfusion changes, clinical symptoms, and cognition in the spectrum of normal aging and cognitive impairment due to AD and/or LBD.

HIGHLIGHTS

Amyloid beta (Aβ) deposition was associated with ventral striatal dopaminergic depletion. Aβ deposition and dopaminergic depletion correlated with perfusion. Aβ deposition correlated with hypoperfusion centered in the left entorhinal cortex. Dopaminergic depletion correlated with hyperperfusion centered in the vermis. Perfusion mediated the Aβ deposition/dopaminergic depletion's effects on cognition.

Clinical Trajectories at the End of Life in Autopsy-Confirmed Dementia Patients With Alzheimer Disease and Lewy Bodies Pathologies

BACKGROUND AND OBJECTIVES

Evaluating and understanding the heterogeneity in dementia course has important implications for clinical practice, health care decision-making, and research. However, inconsistent findings have been reported with regard to the disease courses of the 2 most common dementias: Alzheimer disease (AD) and dementia with Lewy bodies (DLB). Using autopsy-confirmed diagnoses, we aimed to examine the disease trajectories in the years before death among patients with dementia with pure AD, pure DLB, or mixed (AD and DLB) pathologies.

METHODS

The current retrospective longitudinal study included 62 participants with autopsy-confirmed diagnoses of pure AD (n = 34), mixed AD and DLB (AD + DLB; n = 17), or pure DLB (n = 11) from the Predictors 2 Cohort Study, a prospective, clinic-based, cohort of patients with dementia. Generalized estimating equation models, with time zero at death, were used to examine the trajectory of cognition (Folstein Mini-Mental State Examination [MMSE]), function (activities of daily living [ADL]), and Dependence Scale among patients with different autopsy-confirmed diagnosis (pure AD, AD + DLB, and pure DLB). The models were adjusted for age, sex, education, and baseline features including extrapyramidal signs, MMSE, ADL, and Dependence Scale.

RESULTS

The participants on average received 9.4 ± 4.6 assessments at 6-month intervals during a mean 5.4 ± 2.9 years of follow-up. The 3 groups were similar in both cognition and function status at baseline. Cognition and function were highly correlated among patients with AD + DLB but not in pure AD or pure DLB at baseline. Patients of the 3 groups all declined in both cognition and function but had different trajectories of decline. More specifically, the patients with pure DLB experienced approximately double the rate of both cognitive decline and functional decline than the patients with pure AD, and the mixed pathology group showed double the rate of functional decline as compared to pure AD.

DISCUSSION

In this longitudinal study, we found that among patients with dementia, those with Lewy body pathology experienced faster cognitive and functional decline than those with pure AD pathology.

Associations between Comorbid TDP-43, Lewy Body Pathology, and Neuropsychiatric Symptoms in Alzheimer's Disease

More than half of the patients with Alzheimer's disease (AD) have comorbidities including TDP-43 and Lewy bodies, which are also associated with frontotemporal lobar degeneration and dementia with Lewy bodies, respectively. These comorbidities may help explain the overlapping neuropsychiatric symptoms between AD and other dementias. Data on 221 AD patients with Neuropsychiatric Inventory-Questionnaire were obtained from the National Alzheimer's Coordinating Center. TDP-43 was associated with aberrant motor activity, whereas Lewy bodies were associated with anxiety, irritability, sleep behavior, and appetite problems. The associations between these comorbidities and neuropsychiatric symptoms were more significant for patients with sparse diffuse plaques.

Assessment of genetic risk for improved clinical-neuropathological correlations

In the clinical diagnosis of dementia with Lewy bodies, distinction from Alzheimer’s disease is suboptimal and complicated by shared genetic risk factors and frequent co-pathology. In the present study we tested the ability of polygenic scores for Alzheimer’s disease, dementia with Lewy bodies, and Parkinson’s disease to differentiate individuals in a 2713-participant, pathologically defined sample. A dementia with Lewy bodies polygenic score that excluded apolipoprotein E due to its overlap with Alzheimer’s disease risk was specifically associated with at least limbic (transitional) Lewy-related pathology and a pathological diagnosis of dementia with Lewy bodies. An Alzheimer’s disease polygenic score was associated with neuritic plaques and neurofibrillary tangles but not Lewy-related pathology, and was most strongly associated with an Alzheimer’s pathological diagnosis. Our results indicate that an assessment of genetic risk may be useful to clinically distinguish between Alzheimer’s disease and dementia with Lewy bodies. Notably, we found no association with a Parkinson’s disease polygenic score, which aligns with evidence that dementia with Lewy bodies has a distinct genetic signature that can be exploited to improve clinical diagnoses.

The Neuropathological Diagnosis of Alzheimer's Disease-The Challenges of Pathological Mimics and Concomitant Pathology

The definitive diagnosis of Alzheimer's disease (AD) rests with post-mortem neuropathology despite the advent of more sensitive scanning and the search for reliable biomarkers. Even though the classic neuropathological features of AD have been known for many years, it was only relatively recently that more sensitive immunohistochemistry for amyloid beta (Aβ) and hyperphosphorylated tau (HP-tau) replaced silver-staining techniques. However, immunohistochemistry against these and other proteins has not only allowed a more scientific evaluation of the pathology of AD but also revealed some mimics of HP-tau pathological patterns of AD, including age-related changes, argyrophilic grain disease and chronic traumatic encephalopathy. It also highlighted a number of cases of AD with significant additional pathology including Lewy bodies, phosphorylated TDP-43 (p-TDP-43) positive neuronal cytoplasmic inclusions and vascular pathology. This concomitant pathology can cause a number of challenges including the evaluation of the significance of each pathological entity in the make-up of the clinical symptoms, and the threshold of each individual pathology to cause dementia. It also raises the possibility of underlying common aetiologies. Furthermore, the concomitant pathologies could provide explanations as to the relative failure of clinical trials of anti-Aβ therapy in AD patients.

Abnormal Sleep Behaviours Across the Spectrum of Alzheimer's Disease Severity: Influence of APOE Genotypes and Lewy Bodies

BACKGROUND

The Apolipoprotein (APOE) ε4 allele is a well-known risk factor for Alzheimer's Disease (AD), and sleep disturbances are commonly associated with AD. However, few studies have investigated the relationship between APOE ε4 and abnormal sleep patterns (N+) in AD.

OBJECTIVE

To examine the relationship between APOE genotype, Lewy body pathology, and abnormal sleep patterns in a large group of subjects with known AD load evaluated upon autopsy.

METHOD

Data from 2,368 cases obtained from the National Alzheimer's Coordinating Centre database were categorized as follows: Braak Stage V/VI and CERAD frequent neuritic plaques as high load AD, Braak Stage III/IV and moderate CERAD as intermediate load AD, and Braak Stage 0/I/II and infrequent CERAD as no to low load AD. Cases discrepant between the two measures were discarded.

RESULTS

Disrupted sleep was more frequent in males (42.4%) compared to females (35.1%), and in carriers (42.3%) as opposed to non-carriers (36.5%) of ε4. Amongst female subjects with high AD load and Lewy body pathology, homozygous (ε4/ε4) carriers experienced disrupted sleep more often compared with heterozygous (ε4/x) or non-carriers of ε4. Such recessive, gender-specific, and Lewy body association is reminiscent of the ε4 effect on psychosis in AD. However, such association was lost after adjusting for covariates. In subjects with no to low AD pathology, female ε4 carriers had significantly more nighttime disturbances than non-carriers; this effect is independent of the presence of Lewy body pathology.

CONCLUSION

The influence of APOE ε4 on sleep disturbances is dependent on gender and severity of AD load.

Influence of Lewy Pathology on Alzheimer's Disease Phenotype: A Retrospective Clinico-Pathological Study

Background:

Studies have shown the frequent coexistence of Lewy pathology (LP) in Alzheimer’s Disease (AD).

Objective:

The aim of this study was to determine the influence of LP on the clinical and cognitive phenotype in a cohort of patients with a neuropathological diagnosis of AD.

Methods:

We reviewed neuropathologically proven AD cases, reaching Braak stages V and VI in the brain banks of Lille and Paris between 1993 and 2016, and classified them according to LP extension (amygdala, brainstem, limbic, or neocortical). We then searched patient files for all available clinical and neuropsychiatric features and neuropsychological data.

Results:

Thirty-three subjects were selected for this study, among which 16 were devoid of LP and 17 presented AD with concomitant LP. The latter were stratified into two subgroups according to LP distribution: 7 were AD with amygdala LP and 10 were AD with ‘classical’ (brainstem, limbic or neocortical) LP. When analyzing the incidence of each clinical feature at any point during the disease course, we found no significant difference in symptom frequency between the three groups. However, fluctuations appeared significantly earlier in patients with classical LP (2±3.5 years) than in patients without LP (7±1.7 years) or with amygdala LP (8±2.8 years; p < 0.01). There was no significant difference in cognitive profiles.

Conclusion:

Our findings suggest that the influence of LP on the clinical phenotype of AD is subtle. Core features of dementia with Lewy bodies do not allow clinical diagnosis of a concomitant LP on a patient-to-patient basis.

Impact of the biological definition of Alzheimer's disease using amyloid, tau and neurodegeneration (ATN): what about the role of vascular changes, inflammation, Lewy body pathology?

BACKGROUND

The NIA-AA research framework proposes a biological definition of Alzheimer's disease, where asymptomatic persons with amyloid deposition would be considered as having this disease prior to symptoms.

DISCUSSION

Notwithstanding the fact that amyloid deposition in isolation is not associated with dementia, even the combined association of amyloid and tau pathology does not inevitably need to dementia over age 65. Other pathological factors may play a leading or an accelerating role in age-associated cognitive decline, including vascular small vessel disease, neuroinflammation and Lewy Body pathology.

CONCLUSION

Research should aim at understanding the interaction between all these factors, rather than focusing on them individually. Hopefully this will lead to a personalized approach to the prevention of brain aging, based on individual biological, genetic and cognitive profiles.

Association Between Psychosis Phenotype and APOE Genotype on the Clinical Profiles of Alzheimer's Disease

BACKGROUND

Psychosis is a common phenomenon in Alzheimer's disease (AD). The APOE ε4 allele is the strongest genetic risk factor for the development of AD, but its association with psychosis remains unclear.

OBJECTIVE

We investigated the associations between psychosis, subdivided into delusions and hallucinations, as well as APOE ε4 allele on cognitive and functional outcomes. Secondarily, we investigated the associations between APOE ε4, Lewy bodies, and psychosis.

METHODS

Data from the National Alzheimer's Coordinating Center (NACC) were used. Nine hundred patients with a confirmed diagnosis of AD based on the NIA-AA Reagan were included in the analysis. Global cognition was assessed using the Mini-Mental State Exam (MMSE) and functional status was assessed using the Functional Activities Questionnaire (FAQ). Psychosis status was determined using the Neuropsychiatric Inventory Questionnaire (NPI-Q). Factorial design was used to assess the effects of psychosis and APOE ε4, as well as their interaction.

RESULTS

Psychosis and the presence of APOE ε4 were both associated with lower MMSE scores, while only psychosis was associated with higher FAQ scores. Furthermore, patients with hallucinations had lower MMSE and higher FAQ scores than patients with only delusions. There was a significant interaction effect between psychosis and APOE ε4 on MMSE scores, with APOE ε4 negatively affecting patients with hallucinations-only psychosis. APOE ε4 was positively associated with the presence of Lewy body pathology, and both were found to be more prevalent in psychotic patients, with a stronger association with hallucinations.

CONCLUSION

Psychosis in AD was associated with greater cognitive and functional impairments. Patients with hallucinations-with or without delusions-conferred even greater deficits compared to patients with only delusions. The APOE ε4 allele was associated with worse cognition, especially for patients with hallucination-only psychosis. APOE ε4 may mediate cognitive impairment in the hallucinations phenotype through the development of Lewy bodies. Our findings support that subtypes of psychosis should be evaluated separately.

The Predictors study: Development and baseline characteristics of the Predictors 3 cohort

INTRODUCTION

The Predictors study was designed to predict the length of time to major disease outcomes in Alzheimer's disease (AD) patients. Here, we describe the development of a new, Predictors 3, cohort.

METHODS

Patients with prevalent or incident AD and individuals at-risk for developing AD were selected from the North Manhattan community and followed annually with instruments comparable to those used in the original two Predictors cohorts.

RESULTS

The original Predictors cohorts were clinic based and racially/ethnically homogenous (94% white, 6% black; 3% Hispanic). In contrast, the 274 elders in this cohort are community-based and ethnically diverse (39% white, 40% black, 21% other; 78% Hispanic). Confirming previous observations, psychotic features were associated with poorer function and mental status and extrapyramidal signs with poorer function.

DISCUSSION

This new cohort will allow us to test observations made in our original clinic-based cohorts in patients that may be more representative of the general community.

Visual Perceptual Organization Ability in Autopsy-Verified Dementia with Lewy Bodies and Alzheimer's Disease

OBJECTIVES

Prominent impairment of visuospatial processing is a feature of dementia with Lewy bodies (DLB), and diagnosis of this impairment may help clinically distinguish DLB from Alzheimer's disease (AD). The current study compared autopsy-confirmed DLB and AD patients on the Hooper Visual Organization Test (VOT), a test that requires perceptual and mental reorganization of parts of an object into an identifiable whole. The VOT may be particularly sensitive to DLB since it involves integration of visual information processed in separate dorsal and ventral visual "streams".

METHODS

Demographically similar DLB (n=28), AD (n=115), and normal control (NC; n=85) participants were compared on the VOT and additional neuropsychological tests. Patient groups did not differ in dementia severity at time of VOT testing. High and Low AD-Braak stage DLB subgroups were compared to examine the influence of concomitant AD pathology on VOT performance.

RESULTS

Both patient groups were impaired compared to NC participants. VOT scores of DLB patients were significantly lower than those of AD patients. The diagnostic sensitivity and specificity of the VOT for patients versus controls was good, but marginal for DLB versus AD. High-Braak and low-Braak DLB patients did not differ on the VOT, but High-Braak DLB performed worse than Low-Braak DLB on tests of episodic memory and language.

CONCLUSIONS

Visual perceptual organization ability is more impaired in DLB than AD but not strongly diagnostic. The disproportionate severity of this visual perceptual deficit in DLB is not related to degree of concomitant AD pathology, which suggests that it might primarily reflect Lewy body pathology. (JINS, 2016, 22, 609-619).

Clinical Features of Alzheimer Disease With and Without Lewy Bodies

IMPORTANCE

Lewy bodies are a frequent coexisting pathology in late-onset Alzheimer disease (AD). Previous studies have examined the contribution of Lewy bodies to the clinical phenotype of late-onset AD with variable findings.

OBJECTIVE

To determine whether the presence of Lewy body pathology influences the clinical phenotype and progression of symptoms in longitudinally assessed participants with AD.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective clinical and pathological cohort study of 531 deceased participants who met the neuropathologic criteria for intermediate or high likelihood of AD according to the National Institute on Aging-Ronald Reagan Institute guidelines for the neuropathologic diagnosis of AD. All participants had a clinical assessment within 2 years of death. The data were obtained from 34 AD centers maintained by the National Alzheimer Coordinating Center and spanned from September 12, 2005, to April 30, 2013.

EXPOSURES

Standardized neuropathologic assessment and then brain autopsy after death.

MAIN OUTCOMES AND MEASURES

Clinical and neuropsychiatric test scores.

RESULTS

The mean (SD) age at death was statistically significantly younger for participants who had AD with Lewy bodies (77.9 [9.5] years) than for participants who had AD without Lewy bodies (80.2 [11.1] years) (P = .01). The mean (SD) age at onset of dementia symptoms was also younger for participants who had AD with Lewy bodies (70.0 [9.9] years) than for participants who had AD without Lewy bodies (72.2 [12.3] years) (P = .03). More men than women had AD with Lewy bodies (P = .01). The frequency of having at least 1 APOE ε4 allele was higher for participants who had AD with Lewy bodies than for participants who had AD without Lewy bodies (P = .03). After adjusting for age, sex, education, frequency of plaques (neuritic and diffuse), and tangle stage, we found that participants who had AD with Lewy bodies had a statistically significantly higher mean (SD) Neuropsychiatric Inventory Questionnaire score (6.59 [1.44] [95% CI, 3.75-9.42] vs 5.49 [1.39] [95% CI, 2.76-8.23]; P = .04) and a statistically significantly higher mean (SD) Unified Parkinson Disease Rating Scale motor score (0.81 [0.18] [95% CI, 0.45-1.17] vs 0.54 [0.18] [95% CI, 0.19-0.88]; P < .001) than did participants who had AD without Lewy bodies.

CONCLUSIONS AND RELEVANCE

Participants with both AD and Lewy body pathology have a clinical phenotype that may be distinguished from AD alone. The frequency of Lewy bodies in AD and the association of Lewy bodies with the APOE ε4 allele suggest potential common mechanisms for AD and Lewy body pathologies.

Molecular imaging biomarkers for dementia with Lewy bodies: an update

BACKGROUND

Dementia with Lewy body (DLB) is considered to be the second most common form of neurodegenerative disorders after Alzheimer's disease (AD), affecting as many as 100,000 people in the UK and up to 1.3 million in the USA. However, nearly half of patients with DLB remain undiagnosed thus depriving many of them from an early and adequate treatment of their distressing symptoms. Accurate and early diagnosis of DLB is important for both patients and their caregivers, since the neuropsychiatric symptoms require specific management.

METHODS

In the current study, we review the most recent developments in the field of molecular nuclear imaging to diagnose DLB.

RESULTS

The review addresses, the neurotransmitter based (dopaminergic, cholinergic, and glutamatergic) nuclear imaging techniques, role of the autonomic dysfunction and its visualization in DLB with myocardial sympathetic imaging and vesicular catecholamine uptake, as well as the use of amyloid polypeptides and glial markers as molecular imaging probes in the clinical diagnosis of DLB.

CONCLUSIONS

Most of the above nuclear imaging methods are restricted to highly specialized clinical centers, and thus not applicable to a large number of patients requiring dementia (e.g. DLB) diagnosis in routine clinical setting. Validating them against more readily accessible peripheral biomarkers, e.g. CSF and blood biomarkers linked to the DLB process, may facilitate their use in wider clinical settings.

A systematic review of cognitive decline in dementia with Lewy bodies versus Alzheimer's disease

INTRODUCTION

The aim of this review was to investigate whether there is a faster cognitive decline in dementia with Lewy bodies (DLB) than in Alzheimer's disease (AD) over time.

METHODS

PsycINFO and Medline were searched from 1946 to February 2013. A quality rating from 1 to 15 (best) was applied to the included studies. A quantitative meta-analysis was done on studies with mini mental state examination (MMSE) as the outcome measure.

RESULTS

A total of 18 studies were included. Of these, six (36%) reported significant differences in the rate of cognitive decline. Three studies reported a faster cognitive decline on MMSE in patients with mixed DLB and AD compared to pure forms, whereas two studies reported a faster decline on delayed recall and recognition in AD and one in DLB on verbal fluency. Mean quality scores for studies that did or did not differ were not significantly different. Six studies reported MMSE scores and were included in the meta-analysis, which showed no significant difference in annual decline on MMSE between DLB (mean 3.4) and AD (mean 3.3).

CONCLUSIONS

Our findings do not support the hypothesis of a faster rate of cognitive decline in DLB compared to AD. Future studies should apply recent diagnostic criteria, as well as extensive diagnostic evaluation and ideally autopsy diagnosis. Studies with large enough samples, detailed cognitive tests, at least two years follow up and multivariate statistical analysis are also needed.

The new Qualitative Scoring MMSE Pentagon Test (QSPT) as a valid screening tool between autopsy-confirmed dementia with Lewy bodies and Alzheimer's disease

Visual-constructional apraxia is a prominent feature of dementia with Lewy bodies (DLB) that might help to clinically distinguish it from Alzheimer's disease (AD). The main goal of this study was to assess performance on the copy intersecting-pentagon item of the Mini-Mental State Examination with the new Qualitative Scoring method for the Pentagon copy Test (QSPT). In order to determine which aspects of the drawings might differentiate DLB from AD, pentagon drawings of autopsy-verified DLB (n = 16) and AD (n = 15) patients were assessed using the QSPT. The qualitative scoring encompasses the assessment of different parameters of the drawing, such as number of angles, distance/intersection, closure/opening, rotation, and closing-in. The QSPT scores were compared between groups using linear analyses and artificial neural network analyses at four different time points. Linear analyses showed that during the first evaluation, number of angles was the only parameter that showed a significant difference between DLB and AD patients. A gradual decline in other parameters and total pentagon score occurred in both groups during subsequent years, with greater decline for the DLB group. The artificial neural network analyses using auto-contractive maps showed that, with disease progression, DLB became related to relatively lower qualitative pentagon scores, whereas AD became related to relatively higher qualitative scores. These findings suggest that the QSPT might be a sensitive measure of visuo-constructive abilities able to differentiate DLB from AD at disease onset and as the diseases progress, but further studies on larger population are necessary in order to establish its clinical relevance.

Cognitive impairment, decline and fluctuations in older community-dwelling subjects with Lewy bodies

Lewy bodies are common in the ageing brain and often co-occur with Alzheimer's disease pathology. There is little known regarding the independent role of Lewy body pathology in cognition impairment, decline and fluctuations in community-dwelling older persons. We examined the contribution of Lewy body pathology to dementia, global cognition, cognitive domains, cognitive decline and fluctuations in 872 autopsied subjects (mean age = 87.9 years) from the Rush Religious Order Study (n = 491) and Memory and Aging Project (n = 381) longitudinal community-based clinical-pathological studies. Dementia was based on a clinical evaluation; annual cognitive performance tests were used to create a measure of global cognition and five cognitive domains. Lewy body type was determined by using α-synuclein immunostained sections of substantia nigra, limbic and neocortical regions. Statistical models included multiple regression models for dementia and cognition and mixed effects models for decline. Cognitive fluctuations were estimated by comparing standard deviations of individual residuals from mean trajectories of decline in those with and without Lewy bodies. All models controlled for age, sex, education, Alzheimer's disease pathology and infarcts. One hundred and fifty-seven subjects (18%) exhibited Lewy body pathology (76 neocortical-type, 54 limbic-type and 27 nigra-predominant). One hundred and three (66%) subjects with Lewy body pathology had a pathologic diagnosis of Alzheimer's disease. Neocortical-type, but not nigral-predominant or limbic-type Lewy body pathology was related to an increased odds of dementia (odds ratio = 3.21; 95% confidence interval = 1.78-5.81) and lower cognition (P < 0.001) including episodic memory function (P < 0.001) proximate to death. Neocortical-type Lewy body pathology was also related to a faster decline in global cognition (P < 0.001), decline in all five specific cognitive domains (all P-values < 0.001), and to fluctuations in decline of working and semantic memory (P-values < 0.001). Limbic-type Lewy body pathology was related to lower and faster decline in visuospatial skills (P = 0.042). The relationship of Lewy body pathology to cognition and dementia was not modified by Alzheimer's disease pathology. Neocortical-type Lewy body pathology is associated with increased odds of dementia; lower and more rapid decline in all cognitive domains including episodic memory and fluctuations in decline in semantic and working memory. Limbic-type Lewy body pathology is specifically associated with lower and more rapid decline in visuospatial skills. The effect of Lewy body pathology on cognition appears to be independent of Alzheimer's disease pathology.

Neuropathologic studies of the Baltimore Longitudinal Study of Aging (BLSA)

The Baltimore Longitudinal Study of Aging (BLSA) was established in 1958 and is one the oldest prospective studies of aging in the USA and the world. The BLSA is supported by the National Institute of Aging (NIA) and its mission is to learn what happens to people as they get old and how to sort out changes due to aging from those due to disease or other causes. In 1986, an autopsy program combined with comprehensive neurologic and cognitive evaluations was established in collaboration with the Johns Hopkins University Alzheimer's Disease Research Center (ADRC). Since then, 211 subjects have undergone autopsy. Here we review the key clinical neuropathological correlations from this autopsy series. The focus is on the morphological and biochemical changes that occur in normal aging, and the early neuropathological changes of neurodegenerative diseases, especially Alzheimer's disease (AD). We highlight the combined clinical, pathologic, morphometric, and biochemical evidence of asymptomatic AD, a state characterized by normal clinical evaluations in subjects with abundant AD pathology. We conclude that in some individuals, successful cognitive aging results from compensatory mechanisms that occur at the neuronal level (i.e., neuronal hypertrophy and synaptic plasticity) whereas a failure of compensation may culminate in disease.

Apathy predicts more severe parkinsonism in Alzheimer's disease

OBJECTIVES

Parkinsonian signs are frequent in Alzheimer disease (AD) and are associated with a faster cognitive decline, worse quality of life, and early nursing home admission. Cross-sectional studies in AD reported a significant association between parkinsonism and apathy. The aim of this study was to assess the chronological association between apathy and parkinsonism in AD.

DESIGN

Longitudinal study of a consecutive series of patients with AD.

SETTING

Dementia clinic from a tertiary clinical center.

PARTICIPANTS

One hundred sixty-nine patients meeting diagnostic criteria for AD.

INTERVENTION

A consecutive series of 169 patients with probable AD were assessed for the presence of parkinsonism, cognitive deficits, apathy, and depression with the Unified Parkinson's Disease Rating Scale and a comprehensive neuropsychiatry assessment. One hundred thirty-six (80%) of the patients had a follow-up assessment between 1 and 4 years after the baseline evaluation.

MEASUREMENTS

Scores on apathy, parkinsonism, and depression scales at follow-up were the main outcome measures.

RESULTS

Patients with apathy at baseline or those who developed apathy during follow-up had a significant increase in parkinsonism at follow-up when compared with patients with no apathy at both assessments. The association between apathy and increasing parkinsonism was unrelated to age, gender, the severity of cognitive deficits, the presence of depression, or use of psychotropic medications. On the other hand, neither the presence of parkinsonism nor depression at baseline was significantly associated with more severe apathy at follow-up.

CONCLUSION

Apathy may be an early manifestation of a more aggressive AD phenotype characterized by loss of motivation, increasing parkinsonism, a faster cognitive and functional decline, and more severe depression.

Acetylcholinesterase inhibitor treatment is associated with relatively slow cognitive decline in patients with Alzheimer's disease and AD + DLB

Dementia can be caused by different diseases including Alzheimer's disease (AD), dementia with Lewy bodies (DLB), or both (AD + DLB). University of Kentucky AD Center pathologically-diagnosed AD and AD + DLB cases were evaluated who had three or more longitudinal antemortem mental status examinations (n = 156). Patients with important concomitant pathology (n = 5) or patients that were profoundly demented at recruitment (intake MMSE < 20; n = 86) were excluded to strengthen our ability to test the association of specific clinical and pathological indices. Patients with pathologically-diagnosed AD + DLB (n = 25) lost cognitive capacity faster than patients with AD alone (n = 40). In both diseases, treatment with acetylcholinesterase inhibitors was associated with a slower rate of cognitive decline.

Visuoperceptual repetition priming and progression of parkinsonian signs in aging

Parkinsonian signs in older persons are associated with numerous adverse health outcomes, however there is limited information about factors which predict progression of these signs. Using generalized linear models, we examined the association between efficiency in visuoperceptual and conceptual processing, measured by repetition priming, and rate of change in parkinsonian signs in a large sample of older persons without cognitive impairment or Parkinson's disease. Subjects with better visuoperceptual priming, measured by threshold word-identification and word-stem completion, at study baseline, progressed more slowly during follow-up of up to 11 years. Conceptual priming was not associated with change in parkinsonian signs. The findings demonstrate that individual differences in visuoperceptual processing efficiency, measured by repetition priming, occur in older persons without cognitive impairment and predict important changes in motor function. Reduced visuoperceptual priming in aging may be an early signal of vulnerability in a corticostrial circuit that contributes to sensorimotor integration.

Visuospatial deficits predict rate of cognitive decline in autopsy-verified dementia with Lewy bodies

Dementia with Lewy bodies (DLB) is often characterized by pronounced impairment in visuospatial skills, attention, and executive functions. However, the strength of the phenotypic expression of DLB varies and may be weaker in patients with extensive concomitant Alzheimer's disease (AD). To determine whether strength of the DLB clinical phenotype impacts cognitive decline, visuospatial and language tests were retrospectively used to predict 2-year rate of global cognitive decline in 22 autopsy-confirmed DLB patients (21 with concomitant AD) and 44 autopsy-confirmed "pure" AD patients. Generalized estimating equations (GEE) revealed a significant interaction such that poor baseline performances on tests of visuospatial skills were strongly associated with a rapid rate of cognitive decline in DLB but not AD (p < .001). No effect of confrontation naming was found. DLB patients with poor visuospatial skills had fewer neurofibrillary tangles and were more likely to experience visual hallucinations than those with better visuospatial skills. These results suggest that the severity of visuospatial deficits in DLB may identify those facing a particularly malignant disease course and may designate individuals whose clinical syndrome is impacted more by Lewy body formation than AD pathology.

Predicting lewy body pathology in a community-based sample with clinical diagnosis of Alzheimer's disease

Accurate antemortem prediction of Lewy body pathology in patients with dementia is problematic. This study generates a model that better predicts Lewy body pathology in community-based patients with clinical Alzheimer's disease. Lewy body pathology was detected in 80 of 152 participants (52.6%) with an initial diagnosis of probable Alzheimer's disease. In a stepwise logistic regression model, female gender, lower education, being married, bradykinesia, hallucinations, and absence of irritability predicted the greatest likelihood of Lewy body pathology. The predictive model correctly diagnosed Lewy body pathology with an estimated sensitivity of 75%, specificity of 68%, and accuracy of 72%; the area under the receiver operating characteristic curve was 0.75. In a community-based autopsy sample, this predictive model confirmed parkinsonism and hallucinations as important predictors of Lewy body pathology in patients with clinical Alzheimer's disease. The model also identified other demographic and clinical characteristics that might enhance the prediction of Lewy body pathology.

Motor signs predict poor outcomes in Alzheimer disease

OBJECTIVE

To examine whether the presence of motor signs has predictive value for important outcomes in Alzheimer disease (AD).

METHODS

A total of 533 patients with AD at early stages (mean Folstein Mini-Mental State Examination [MMSE] 21/30 at entry) were recruited and followed semiannually for up to 13.1 years (mean 3) in five University-based AD centers in the United States and European Union. Four outcomes, assessed every 6 months, were used in Cox models: cognitive endpoint (Columbia Mini-Mental State Examination < or = 20/57 [ approximately MMSE < or = 10/30]), functional endpoint (Blessed Dementia Rating Scale > or = 10), institutionalization equivalent index, and death. Using a standardized portion of the Unified PD Rating Scale (administered every 6 months for a total of 3,149 visit-assessments, average 5.9 per patient), the presence of motor signs, as well as of individual motor sign domains, was examined as time-dependent predictor. The models controlled for cohort, recruitment center, sex, age, education, a comorbidity index, and baseline cognitive and functional performance.

RESULTS

A total of 39% of the patients reached the cognitive, 41% the functional, 54% the institutionalization, and 47% the mortality endpoint. Motor signs were noted for 14% of patients at baseline and for 45% at any evaluation. Their presence was associated with increased risk for cognitive decline (RR, 1.72; 95% CI, 1.24 to 2.38), functional decline (1.80 [1.33 to 2.45]), institutionalization (1.68 [1.26 to 2.25]), and death (1.38 [1.05 to 1.82]). Tremor was associated with increased risk for reaching the cognitive and bradykinesia for reaching the functional endpoints. Postural-gait abnormalities carried increased risk for institutionalization and mortality. Faster rates of motor sign accumulation were associated with increased risk for all outcomes.

CONCLUSIONS

Motor signs predict cognitive and functional decline, institutionalization, and mortality in Alzheimer disease. Different motor sign domains predict different outcomes.

Pathophysiology of synuclein aggregation in Lewy body disease

We provide an overview of synaptic pathology in dementia with Lewy bodies (DLB) and related neurodegenerative disorders that are characterised by intraneuronal accumulation of alpha-synuclein aggregates. The review addresses the clinico-neuropathological correlates of synaptic pathology in Lewy body disease, and concentrates on: altered alpha-synuclein metabolism, mechanisms leading to alpha-synuclein fibril formation (self-polymerisation, alpha-synuclein mutations and post-translational modifications) and how these influence the axonal transport and synaptic network in ageing and disease process. Understanding the mechanisms leading to intraneuronal alpha-synuclein accumulation are crucial for the development of novel therapies for treatment of Lewy body disease.

What best differentiates Lewy body from Alzheimer's disease in early-stage dementia?

To determine which clinical feature(s) [among visual hallucinations (VH), extrapyramidal signs (EPS) and visuospatial impairment] in the earliest stages of disease best predicted a diagnosis of dementia with Lewy bodies (DLB) at autopsy, first-visit data of 23 pathologically proven DLB and 94 Alzheimer's disease cases were compared. There were no group differences with regard to age, gender, education or global severity of dementia at presentation (mean Mini-Mental State Examination: 24.0 versus 25.0, mean Dementia Rating Scale: 123.6 versus 125.7). DLB patients at initial presentation displayed an increased frequency of VH (P = 0.001), but not EPS (P = 0.3), compared to Alzheimer's disease patients. However, only a minority of DLB cases had either VH (22%), EPS (26%) or both (13%). In contrast, although not a core feature, visuospatial/constructional impairment was observed in most of the DLB cases (74%). Among clinical variables, presence/recent history of VH was the most specific to DLB (99%), and visuospatial impairment was the most sensitive (74%). As a result, VH at presentation were the best positive predictor of DLB at autopsy (positive predictive value: 83% versus 32% or less for all other variables), while lack of visuospatial impairment was the best negative predictor (negative predictive value: 90%). We conclude that the best model for differentiating DLB from Alzheimer's disease in the earliest stages of disease includes VH and visuospatial/constructional dysfunction, but not spontaneous EPS, as predictors. This suggests that clinical history plus a brief assessment of visuospatial function may be of the greatest value in correctly identifying DLB early during the course of disease.

Delusions and hallucinations are associated with worse outcome in Alzheimer disease

BACKGROUND

Delusions and hallucinations are common in Alzheimer disease (AD) and there are conflicting reports regarding their ability to predict cognitive decline, functional decline, and institutionalization. According to all previous literature, they are not associated with mortality.

OBJECTIVE

To examine whether the presence of delusions or hallucinations has predictive value for important outcomes in AD.

DESIGN, SETTING, AND PARTICIPANTS

A total of 456 patients with AD at early stages (mean Folstein Mini-Mental State Examination [MMSE] score of 21 of 30 at entry) were recruited and followed up semiannually for up to 14 years (mean, 4.5 years) in 5 university-based AD centers in the United States and Europe. Using the Columbia University Scale for Psychopathology in AD (administered every 6 months, for a total of 3266 visit-assessments, average of 7.2 per patient), the presence of delusions and hallucinations was extracted and examined as time-dependent predictors in Cox models. The models controlled for cohort effect, recruitment center, informant status, sex, age, education, a comorbidity index, baseline cognitive and baseline functional performance, behavioral symptoms, and use of neuroleptics and cholinesterase inhibitors.

MAIN OUTCOME MEASURES

Cognitive (Columbia MMSE score of < or =20/57 [approximate Folstein MMSE score of < or =10/30]), functional (Blessed Dementia Rating Scale [parts I and II] score of > or =10), institutionalization equivalent index, and death.

RESULTS

During the full course of follow-up, 38% of patients reached the cognitive, 41% the functional, 54% the institutionalization, and 49% the mortality end point. Delusions were noted for 34% of patients at baseline and 70% at any evaluation. Their presence was associated with increased risk for cognitive (risk ratio [RR], 1.50; 95% confidence interval [CI], 1.07-2.08) and functional decline (RR, 1.41; 95% CI, 1.02-1.94). Hallucinations were present in 7% of patients at initial visit and in 33% at any visit. Their presence was associated with increased risk for cognitive decline (RR, 1.62; 95% CI, 1.06-2.47), functional decline (RR, 2.25; 95% CI, 1.54-2.27), institutionalization (RR, 1.60; 95% CI, 1.13-2.28), and death (RR, 1.49; 95% CI, 1.03-2.14).

CONCLUSIONS

Delusions and hallucinations are very common in AD and predict cognitive and functional decline. Presence of hallucinations is also associated with institutionalization and mortality.

Motor signs during the course of Alzheimer disease

BACKGROUND

Motor signs (MOSIs) are common in Alzheimer disease (AD) and may be associated with rates of cognitive decline, mortality, and cost of care.

OBJECTIVE

To describe the progression and identify predictors of individual MOSIs in AD.

METHODS

A cohort of 474 patients with AD at early stages was followed semiannually for up to 13.1 years (mean 3.6 years) in five centers in Europe and the United States. MOSIs were rated using a standardized portion of the Unified Parkinson's Disease Rating Scale. Overall, 3,030 visits/assessments of MOSIs (average 6.4/patient) were performed. Prevalence and incidence rates were calculated, and cumulative risk graphs were plotted for individual non-drug-induced MOSI domains. Rates of change over time taking into account potential covariates were also estimated. With use of each MOSI domain as outcome in Cox models, predictors of MOSI incidence were identified.

RESULTS

At least one MOSI was detected in 13% of patients at first examination and in 36% for the last evaluation. Total MOSI score increased at an annual rate of 3% of total possible score. Rates of annual change for speech/facial expression (4%), rigidity (2.45%), posture/gait (3.9%), and bradykinesia (3.75%) were of similar magnitude, and their occurrence increased from first (3 to 6%) to last (22 to 29%) evaluation. Tremor was less frequent throughout the course of the disease (4% at first and 7% at last evaluation) and worsened less (0.75% increase/year).

CONCLUSIONS

Most motor signs occur frequently and progress rapidly in Alzheimer disease. Tremor is an exception in that it occurs less frequently and advances at slower rates.

Dementia update 2003

Clinical and scientific investigations in the field of dementia expanded greatly in the past two decades. Medline citations that addressed Alzheimer disease (AD), the most common dementing disorder, rose from 78 in 1980 to 987 in 1990 and to 1772 in 2000. Underscoring this increased body of knowledge, three practice parameters on dementia were published in 2001 by the Quality Standards Subcommittee of the American Academy of Neurology. Although some older studies are included for context, this review focuses on selected recent advances in dementia that are relevant for the practicing physician. Topics covered include: 1) diagnosis of dementia; 2) risk factors and biomarkers; 3) mild cognitive impairment; 4) the scientific basis for treatment advances in AD; and 5) other dementing disorders.

Can alzheimer's disease and dementias with Lewy bodies be distinguished clinically?

To determine if Alzheimer's disease (AD), its Lewy body (LB) variant (LBV), and diffuse LB disease (DLBD) are distinguishable at initial clinical evaluation, data from autopsy-confirmed AD, LBV, and DLBD were examined. No significant differences were found in age at onset, age at death, total duration of illness, duration of illness before initial visit, duration of illness from initial visit to death, or severity of illness at initial evaluation. Hallucinations and delusions were significantly more frequent for LBV and DLBD, respectively, than for AD, and falls were more frequent for DLBD than for AD. Extrapyramidal symptoms (EPS) were less frequent in neuroleptic-free AD subjects than in LB subjects; the percentage of AD patients with EPS after neuroleptic exposure was less than that among LB patients. Seizures were significantly more common for DLBD than for AD or LBV. LB dementias differed from AD at initial evaluation, with more frequent hallucinations and delusions, EPSs, and seizures, and longitudinally in neuroleptic sensitivity, but the data did not distinguish LBV from DLBD.

Pharmacologic therapy of dementia with Lewy bodies

As a clinicopathologically defined entity, dementia with Lewy bodies (DLB) has overlapping features of Alzheimer's disease (AD) and Parkinson's disease (PD). Analogous characteristics of DLB offer a provisional rationale for pharmacologic therapy based on remediating cholinergic and dopaminergic deficits, respectively. However, the distinct clinical manifestations and pathophysiologic substrates of DLB pose unique therapeutic opportunities and challenges. More severe cholinergic deficits in DLB relative to AD support clinical evidence that cholinergic therapy may be particularly beneficial in DLB patients. In contrast, DLB patients are generally more sensitive to the adverse effects of antipsychotic agents, warranting caution in treating visual hallucinations and other psychotic symptoms. Similarly, parkinsonian motor signs in DLB, often manifest as rigidity and bradykinesia, may be less amenable to dopaminergic therapies than in PD. Increasing recognition of DLB as a common form of dementia in the elderly underscores the need for large-scale, placebo-controlled therapeutic trials.