151
|
Gay BE, Taylor KI, Hohl U, Tolnay M, Staehelin HB. The validity of clinical diagnoses of dementia in a group of consecutively autopsied memory clinic patients. J Nutr Health Aging 2008; 12:132-7. [PMID: 18264641 DOI: 10.1007/bf02982566] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Epidemiological studies show that up to 10% of individuals aged 65 years and older suffer from dementia, most commonly from dementia of the Alzheimer Type (DAT) (1). Clinicopathological studies are critical to our understanding of this disease and improving the accuracy of clinical diagnoses. OBJECTIVES Our objectives were to examine the validity of clinical diagnoses of DAT, to determine the prevalence of different forms of dementia in this sample, and to investigate the relationship between age at death and polymorbidity. SUBJECTS AND METHOD Clinical data were available from 221 patients who had been examined at the Basel Memory Clinic between 1986 and 1996. From this population, 34% (75 patients) were autopsied in the Department of Pathology, University Hospital Basel, and neuropathological examinations were additionally performed on 62 (83%) of these patients. Clinical and neuropathological data were retrospectively compared. RESULTS 67.8% of the neuropathologically examined patients received a definitive diagnosis of AD (Alzheimer's disease), vascular dementia (VaD) or mixed dementia (AD and VaD). AD alone or with other histopathological hallmarks of dementia was the most prevalent neuropathological diagnosis (63%). VaD was deemed the only cause of dementia in only 4.8% of patients. The sensitivity for DAT was 75.9%, the specificity 60.6%. Increasing age was associated with an increasing number of clinical and neuropathological diagnoses. CONCLUSION The sensitivity and specificity of the clinical diagnoses of DAT found in our study are similar to previous reports (2-5). Older patients had more etiologies of their dementia than younger patients. This study reaffirms the need for internationally accepted criteria for clinical and neuropathological diagnoses, as well as further clinical-neuropathological investigations to further refine the clinical diagnostic process.
Collapse
Affiliation(s)
- B E Gay
- Geriatric University Clinic, University Hospital Basel, Switzerland.
| | | | | | | | | |
Collapse
|
152
|
Levy-Cooperman N, Lobaugh NJ, Caldwell C, Gao F, Black SE. Subcortical hyperintensities in Alzheimer's disease: no clear relationship with executive function and frontal perfusion on SPECT. Dement Geriatr Cogn Disord 2008; 24:380-8. [PMID: 17934273 DOI: 10.1159/000109570] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/28/2007] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS To investigate relationships between subcortical hyperintensities (SH), frontal perfusion and executive function (EF) in a sample of Alzheimer's disease (AD) patients with varying severities of SH. METHODS A sample of 63 AD patients underwent brain imaging with magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT) scans. Severity of SH was assessed using a standardized visual rating scale on MRI. Patients were classified into severe (n=20), moderate (n=23) or no SH (n=20) groups. Four frontal SPECT regions of interest (anterior cingulate cortex, dorsolateral prefrontal cortex) and neuropsychological assessment of EF were analyzed. RESULTS Overall, no significant relationships were found between severity of SH and measures of SPECT perfusion or EF, except for one subsection of the Dementia Rating Scale, with severe SH scoring slightly worse than the other two groups. CONCLUSION These findings support previous studies which suggest minimal adverse effects of SH on brain function and cognition. Global severity of SH on MRI in AD was not associated with decline in frontal perfusion and only mildly related to a decline in a specific EF task. More accurate measures of SH volume, not just global severity of SH, may be necessary to capture such complex brain behavior relationships; if they do indeed exist.
Collapse
Affiliation(s)
- Naama Levy-Cooperman
- L.C. Campbell Cognitive Neurology Research Unit, Department of Medicine, Sunnybrook Health Sciences Centre, University of Toronto, Ontario, Canada.
| | | | | | | | | |
Collapse
|
153
|
|
154
|
Fernández-Viadero C, González-Mandly A, Verduga R, Crespo D, Cruz-Orive LM. [Stereology as a tool to estimate brain volume and cortical atrophy in elders with dementia]. Rev Esp Geriatr Gerontol 2008; 43:32-43. [PMID: 18684385 DOI: 10.1016/s0211-139x(08)71147-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
INTRODUCTION stereology is a body of methods that allow unbiased and efficient estimation of geometric quantities defined in arbitrary physical structures. In particular, stereology is a valuable tool to assist neuroimaging in the estimation of morphometric parameters in the brain. Therefore, stereology may confer objectivity in the complementary and diagnostic evaluation of dementia by adding disease by adding quantitative data to clinical evaluation. OBJECTIVES AND METHODS our purpose was to illustrate estimation of brain volume and pial surface area by means of quantitative, computer-assisted stereological methods. Both parameters were estimated by means of a vertical design with a single series of parallel Cavalieri sections at a random orientation and perpendicular to a fixed horizontal plane. The sections were obtained by magnetic resonance imaging. Suitable test systems (of test points for volume, and of cycloids for surface area) were superimposed on these sections with the aid of special software. RESULTS to explore the statistical error of the volume estimator due to stereological sampling, 5 or 10 systematic sections were used in combination with two test point densities in a ratio of 1:4, so that the workload varied in the proportions 1:2:4:8. The four resulting estimators varied between 986 and 1120 cm(3). The surface area estimators varied between 1947 and 2096 cm(2), with workloads varying in the proportions of 1:2:2.3:4.6. CONCLUSIONS stereology is a simple and efficient tool to obtain objective brain volume and surface area estimators that are unbiased by design and accurate at a modest cost. Thus the corresponding methods can effectively assist in diagnostic and follow-up evaluation of elders with dementia.
Collapse
Affiliation(s)
- Carlos Fernández-Viadero
- Residencia de Mayores de Santander, Consejería de Sanidad, Gobierno de Cantabria, Santander, España.
| | | | | | | | | |
Collapse
|
155
|
Jarvik L, LaRue A, Blacker D, Gatz M, Kawas C, McArdle JJ, Morris JC, Mortimer JA, Ringman JM, Ercoli L, Freimer N, Gokhman I, Manly JJ, Plassman BL, Rasgon N, Roberts JS, Sunderland T, Swan GE, Wolf PA, Zonderman AB. Children of persons with Alzheimer disease: what does the future hold? Alzheimer Dis Assoc Disord 2008; 22:6-20. [PMID: 18317242 PMCID: PMC3377487 DOI: 10.1097/wad.0b013e31816653ac] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Children of persons with Alzheimer disease (AD), as a group, face an increased risk of developing AD. Many of them, throughout their adult lives, seek input on how to reduce their chances of one day suffering their parent's fate. We examine the state of knowledge with respect to risk and protective factors for AD and recommend a research agenda with special emphasis on AD offspring.
Collapse
Affiliation(s)
- Lissy Jarvik
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, CA 90095, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
156
|
Beach TG, Sue LI, Walker DG, Roher AE, Lue L, Vedders L, Connor DJ, Sabbagh MN, Rogers J. The Sun Health Research Institute Brain Donation Program: description and experience, 1987–2007. Cell Tissue Bank 2007. [DOI: 10.1007/s10561-007-9056-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
157
|
Foy CML, Nicholas H, Hollingworth P, Boothby H, Willams J, Brown RG, Al-Sarraj S, Lovestone S. Diagnosing Alzheimer's disease--non-clinicians and computerised algorithms together are as accurate as the best clinical practice. Int J Geriatr Psychiatry 2007; 22:1154-63. [PMID: 17530621 DOI: 10.1002/gps.1810] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND An accurate diagnosis of Alzheimer's disease and an exclusion of other dementias is important in many clinical studies. Obtaining such a clinical diagnosis in epidemiological studies and clinical trials that recruit large numbers of patients is time consuming. OBJECTIVES To construct an algorithm using a limited number of data points to generate a diagnosis of the commonest forms of dementia using information collected by non clinicians. METHODS We constructed a computer algorithm to generate a diagnosis of Alzheimer's disease (AD), Dementia with Lewy Bodies (DLB), frontotemporal dementia (FTD), vascular dementia or to flag the case as needing a clinical review based on a limited number of data points taken from a largely structured interview using widely used scales. The diagnosis generated in life by the algorithm in a prospective, longitudinal study was compared to definitive diagnosis at post mortem. RESULTS Post mortem diagnosis was available for 43 cases. The positive predictive value of the algorithm was greater than 95%. AD was diagnosed by the algorithm and at post mortem in 36 of the cases. Two cases with FTD were wrongly diagnosed as having AD by the algorithm, five cases were flagged as needing a clinical review due to concomitant medical conditions of whom four had AD and one, who had been diagnosed clinically as having AD, was diagnosed on post mortem with corticobasal degeneration. CONCLUSIONS A combination of non-clinical researchers, a structured interview and a computerised algorithm is as effective at identifying AD as highly trained and skilled clinicians.
Collapse
Affiliation(s)
- Catherine M L Foy
- MRC Centre for Neurodegeneration Research, King's College London, Institute of Psychiatry, London, UK.
| | | | | | | | | | | | | | | |
Collapse
|
158
|
Gandhi H, Green D, Kounios J, Clark CM, Polikar R. Stacked generalization for early diagnosis of Alzheimer's disease. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2006:5350-3. [PMID: 17947137 DOI: 10.1109/iembs.2006.260644] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The diagnosis of Alzheimer's disease (AD) at an early stage is a major concern due to growing number of elderly population affected by the disease, as well as the lack of a standard diagnosis procedure available to community clinics. Recent studies have used wavelets and other signal processing methods to analyze EEG signals in an attempt to find a non-invasive biomarker for AD. These studies had varying degrees of success, in part due to small cohort size. In this study, multiresolution wavelet analysis is performed on event related potentials of the EEGs of a relatively larger cohort of 44 patients. Particular emphasis was on diagnosis at the earliest stage and feasibility of implementation in a community health clinic setting. Extracted features were then used to train an ensemble of classifiers based stacked generalization approach. We describe the approach, and present our promising preliminary results.
Collapse
Affiliation(s)
- Hardik Gandhi
- Dept. of Electrical & Computer Engineering, Rowan University, Glassboro, NJ, USA
| | | | | | | | | |
Collapse
|
159
|
Clinical diagnosis of dementia. Alzheimers Dement 2007; 3:292-8. [DOI: 10.1016/j.jalz.2007.08.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2007] [Revised: 08/08/2007] [Accepted: 08/09/2007] [Indexed: 11/19/2022]
|
160
|
Gascón-Bayarri J, Reñé R, Del Barrio JL, De Pedro-Cuesta J, Ramón JM, Manubens JM, Sánchez C, Hernández M, Estela J, Juncadella M, Rubio FR. Prevalence of Dementia Subtypes in El Prat de Llobregat, Catalonia, Spain: The PRATICON Study. Neuroepidemiology 2007; 28:224-34. [PMID: 17878737 DOI: 10.1159/000108597] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Studies on dementia subtypes show a wide variation in the prevalence of Alzheimer's disease (AD) and vascular dementia (VD) worldwide. However, studies reporting on Lewy body dementia (LBD) and frontotemporal dementia (FTD) are sparse. AIMS To describe the prevalence of dementia and subtypes. METHOD A 34% sample of 5,150 subjects aged 70 years and over in El Prat de Llobregat (Barcelona) were screened by the Mini-Mental State Examination. When scoring <24, participants were assessed to establish a diagnosis. RESULTS There were 165 subjects diagnosed with dementia (prevalence of 9.4%). Subtypes of dementia were: AD 69.1%, VD 12.7%, LBD 9.1%, FTD 3% and secondary dementia 1.8%. Prevalences were: AD 6.5%, VD 1.2%, LBD 0.9% and FTD 0.3%. CONCLUSIONS AD and VD were the most common type of dementia. Prevalence of dementia, AD and FTD were similar to those reported, while prevalence of VD and LBD were lower.
Collapse
Affiliation(s)
- J Gascón-Bayarri
- Dementia Unit, Department of Neurology, Bellvitge University Hospital, L'Hospitalet de Llobregat, Barcelona, Spain
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
161
|
Management of dementia with a cerebrovascular component. Alzheimers Dement 2007; 3:398-403. [DOI: 10.1016/j.jalz.2007.07.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Accepted: 07/12/2007] [Indexed: 11/21/2022]
|
162
|
Dubois B, Feldman HH, Jacova C, Dekosky ST, Barberger-Gateau P, Cummings J, Delacourte A, Galasko D, Gauthier S, Jicha G, Meguro K, O'brien J, Pasquier F, Robert P, Rossor M, Salloway S, Stern Y, Visser PJ, Scheltens P. Research criteria for the diagnosis of Alzheimer's disease: revising the NINCDS-ADRDA criteria. Lancet Neurol 2007; 6:734-46. [PMID: 17616482 DOI: 10.1016/s1474-4422(07)70178-3] [Citation(s) in RCA: 2796] [Impact Index Per Article: 164.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The NINCDS-ADRDA and the DSM-IV-TR criteria for Alzheimer's disease (AD) are the prevailing diagnostic standards in research; however, they have now fallen behind the unprecedented growth of scientific knowledge. Distinctive and reliable biomarkers of AD are now available through structural MRI, molecular neuroimaging with PET, and cerebrospinal fluid analyses. This progress provides the impetus for our proposal of revised diagnostic criteria for AD. Our framework was developed to capture both the earliest stages, before full-blown dementia, as well as the full spectrum of the illness. These new criteria are centred on a clinical core of early and significant episodic memory impairment. They stipulate that there must also be at least one or more abnormal biomarkers among structural neuroimaging with MRI, molecular neuroimaging with PET, and cerebrospinal fluid analysis of amyloid beta or tau proteins. The timeliness of these criteria is highlighted by the many drugs in development that are directed at changing pathogenesis, particularly at the production and clearance of amyloid beta as well as at the hyperphosphorylation state of tau. Validation studies in existing and prospective cohorts are needed to advance these criteria and optimise their sensitivity, specificity, and accuracy.
Collapse
Affiliation(s)
- Bruno Dubois
- INSERM U610, Hôpital de la Salpêtrière, Paris, France.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
163
|
Höglund K, Blennow K. Effect of HMG-CoA reductase inhibitors on beta-amyloid peptide levels: implications for Alzheimer's disease. CNS Drugs 2007; 21:449-62. [PMID: 17521225 DOI: 10.2165/00023210-200721060-00002] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
To date, a number of hypotheses of the cause of Alzheimer's disease, the most common form of dementia, have been postulated. The beta-amyloid peptide (Abeta) is the major constituent of senile plaques, which together with atrophy and neurofibrillary tangles, is the main neuropathological finding in Alzheimer's disease. It is a widely accepted theory that aggregation of Abeta into plaques is an initial event in the pathogenesis of Alzheimer's disease, driving neurodegeneration. The cholesterol hypothesis, primarily based on in vitro and animal studies, states that increased levels of cholesterol promote the production of Abeta. Furthermore, treating animals with HMG-CoA reductase inhibitors ('statins'; cholesterol-lowering agents), or adding these agents to cell culture, results in decreased production of Abeta. This 'positive' effect of statin treatment has further been verified by some, but not all, longitudinal studies where a reduced prevalence of Alzheimer's disease is seen among patients taking statins. These findings have together been interpreted to indicate that statins act via a cholesterol-dependent mechanism, reducing the production of Abeta and, hence, the risk of developing Alzheimer's disease. This review focuses on the cholesterol hypothesis of Alzheimer's disease and investigations into its validity in the clinical setting, i.e. the outcome of clinical trials where the effect of statin treatment on Abeta production has been studied. To date, the cholesterol hypothesis has not been shown to be valid in clinical trials. We hypothesise that the vascular contributions in Alzheimer's disease may be one possible mechanism for statins to interfere with the disease process and reduce the prevalence of Alzheimer's disease. We also suggest that statins may act through the inflammatory pathway. Both of these mechanistic suggestions are good candidates, supported by the literature, for the underlying mechanistic link between statin treatment and a reduced prevalence for Alzheimer's disease.
Collapse
Affiliation(s)
- Kina Höglund
- Department of Neuroscience and Physiology, Section of Psychiatry and Neurochemistry at the Sahlgrenska Academy, Göteborg University, Göteborg, Sweden.
| | | |
Collapse
|
164
|
Li G, Rhew IC, Shofer JB, Kukull WA, Breitner JCS, Peskind E, Bowen JD, McCormick W, Teri L, Crane PK, Larson EB. Age-Varying Association Between Blood Pressure and Risk of Dementia in Those Aged 65 and Older: A Community-Based Prospective Cohort Study. J Am Geriatr Soc 2007; 55:1161-7. [PMID: 17661953 DOI: 10.1111/j.1532-5415.2007.01233.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To assess variation in the association between blood pressure (BP) and risk for dementia across a spectrum of older ages and to examine BP changes before dementia onset. DESIGN Prospective cohort study. SETTING A large health maintenance organization in Seattle, Washington. PARTICIPANTS A cohort of 2,356 members of a large health maintenance organization aged 65 and older who were initially without dementia. MEASUREMENTS Dementia diagnosis was assessed biennially, and systolic (SBP) and diastolic BP (DBP) were measured at baseline and at four follow-up assessments. Cox proportional hazards models were used to estimate hazard ratios (HRs) for dementia and Alzheimer's disease (AD) associated with baseline BP in different age groups. RESULTS Within the youngest age group (65-74 at enrollment) a greater risk for dementia was found in participants with high SBP (> or = 160 mmHg) (hazard ratio (HR) = 1.60, 95% confidence interval (CI) = 1.01-2.55) or borderline-high DBP (80-89 mmHg) (HR = 1.59, 95% CI = 1.07-2.35) than for those with normal BP (SBP < 140 mmHg and DBP < 80 mmHg). The dementia risk associated with SBP declined with increasing age (SBP-by-age interaction, P=.01). SBP declined similarly with aging in subjects who developed dementia and those who did not. Thus, in this sample, the association between SBP and dementia risk was not dependent on when BP was measured in relation to onset of dementia. CONCLUSION High SBP was associated with greater risk of dementia in the young elderly (< 75) but not in older subjects. Adequate control of hypertension in early old age may reduce the risk for dementia.
Collapse
Affiliation(s)
- Ge Li
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, Washington, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
165
|
Zhang J. Proteomics of human cerebrospinal fluid - the good, the bad, and the ugly. Proteomics Clin Appl 2007; 1:805-19. [PMID: 21136735 DOI: 10.1002/prca.200700081] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Indexed: 12/16/2022]
Abstract
The development of MALDI ESI in the late 1980s has revolutionized the biological sciences and facilitated the emergence of a new discipline called proteomics. Application of proteomics to human cerebrospinal fluid (CSF) has greatly hastened the advancement of characterizing the CSF proteome as well as revealing novel protein biomarkers that are diagnostic of various neurological diseases. While impressive progressions have been made in this field, it has become increasingly clear that proteomics results generated by various laboratories are highly variable. The underlying issues are vast, including limitations and complications with heterogeneity of patients/testing subjects, experimental design, sample processing, as well as current proteomics technology. Accordingly, this review not only summarizes the current status of characterization of the human CSF proteome and biomarker discovery for major neurodegenerative disorders, i.e., Alzheimer's disease and Parkinson's disease, but also addresses a few essential caveats involved in several steps of CSF proteomics that may contribute to the variable/contradicting results reported by different laboratories. The potential future directions of CSF proteomics are also discussed with this analysis.
Collapse
Affiliation(s)
- Jing Zhang
- Division of Neuropathology, Department of Pathology, University of Washington School of Medicine, Seattle, WA, USA.
| |
Collapse
|
166
|
Abstract
Over the last two decades, numerous studies have been conducted on subjects with mild to moderate Alzheimer's disease. The objective of this paper was to review concerns raised in the literature about the design and methodology of these clinical trials and to make recommendations to deal with the limitations identified. Concerns raised in the literature include the following: undue focus on statistical rather than clinical significance; the need for further pharmacoeconomic evaluations; the nonrepresentativeness of the study populations; perceived inadequacies in the direct-comparison studies conducted to date; the limitations of open-label extension studies; the inability of standard psychometric tools to document all the relevant treatment effects; the ethics of placebo-controlled trials; and, problems caused by the actions of the regulatory authorities. Recommendations are made to deal with the issues raised.
Collapse
Affiliation(s)
- David B Hogan
- Health Sciences Centre, University of Calgary, Calgary, Alberta, Canada
| |
Collapse
|
167
|
Abstract
Vascular dementia (VaD) is a heterogeneous disorder resulting from various cerebrovascular diseases (CVD) causing cognitive impairment that reflects severity and location of damage. Epidemiological studies suggest VaD is the second commonest cause of dementia, but autopsy series report that pure VaD is infrequent, while combined CVD and Alzheimer's Disease(AD) is likely the commonest pathological-dementia correlate. Both diseases share vascular risk factors and benefit from their treatment. The most widely used diagnostic criteria for VaD are highly specific but not sensitive. Vascular Cognitive Impairment (VCI) is a dynamic, evolving concept that embraces VaD, Vascular Cognitive Impairment No Dementia (VCIND) and mixed AD and CVD. Clinical trials to date have focused on probable and possible VaD with beneficial effects evident for different drug classes, including cholinergic agents and NMDA agonists. Limitations have included use of cognitive tools suitable for AD that are insensitive to executive dysfunction. Disease heterogeneity has not been adequately controlled and subtypes require further study. Diagnostic VaD criteria now 13 years old need updating. More homogeneous subgroups need to be defined and therapeutically targeted to improve cognitive-behavioural outcomes including optimal control of vascular risk factors. More sensitive testing of executive function outlined in recent VCI Harmonization criteria and longer trial duration are needed to discern meaningful effects. Imaging criteria must be well-defined, with centralized review and standardized protocols. Serial scanning with quantification of tissue atrophy and lesion burden is becoming feasible, and cognitive interventions, including rehabilitation pharmacotherapy, with drugs strategically coupled to cognitive -behavioural treatments, hold promise and need further development.
Collapse
Affiliation(s)
- Sandra E Black
- Department of Medicine, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
168
|
Abstract
Mixed dementia (MD) refers to a combination of definite Alzheimer disease (AD) and vascular encephalopathy, but the distinction between both disorders is controversial. For the diagnosis of MD the clinical/neuroimaging criteria of possible AD plus cerebrovascular disease (CVD) as separate entities are used, but causal relations between vascular brain lesions and dementia are unclear. We proposed the combination of autopsy-proven AD with multiple vascular or ischemic lesions with about 30-50 ml of infarcted/damaged brain tissue. The population-based prevalence of MD is unknown. In retrospective and prospective autopsy studies, it ranges from 2 to 58% with reasonable means of 6-12%. In a consecutive autopsy series of 1500 demented elderly subjects, 830 of which with clinically probable AD, in Vienna, Austria, 41.5 to 52.0% showed "pure" AD, 7% atypical AD, 16-20% AD plus cerebrovascular lesions, and 9% AD plus Lewy body pathology; MD was diagnosed in 4.6 and 2.4%, and "pure" vascular dementia (VaD) in 11 and 2.0%, respectively, while 16.3/6.1% were other dementing disorders, and 1% showed no specific pathology. Like the MRC-CFAS and other studies, this indicates frequent coexistence of AD with multiple cerebrovascular lesions in cognitively impaired patients. In both AD and VaD, vascular lesions frequently involved subcortical regions (basal ganglia, thalamus, hippocampus, and white matter) or were multiple microinfarcts, whereas in MD, large/hemispheral infarcts and multiple microinfarcts were more frequent, suggesting different pathogenic mechanisms. In early/mild AD, critically located small vascular lesions may induce/promote cognitive decline, but in full-blown AD they appear of minor importance. Discussion of the major pathogenic factors inducing AD, VaD and MD suggests synergistic relations between these disorders. However, currently available morphological criteria for AD and VaD are of limited value for the diagnosis of MD and generally accepted and validated histopathological criteria for the diagnosis of VaD and MD are currently not available. Therefore, more distinct and critically evaluated clinico-pathological criteria are warranted.
Collapse
Affiliation(s)
- K A Jellinger
- Institute of Clinical Neurobiology, 18, Kenyongasse, A-1070 Vienna, Austria.
| | | |
Collapse
|
169
|
Jacques G, Frymiare JL, Kounios J, Clark C, Polikar R. Multiresolution analysis for early diagnosis of Alzheimer's disease. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2006:251-4. [PMID: 17271657 DOI: 10.1109/iembs.2004.1403139] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Early diagnosis of Alzheimer's disease is a major concern due to large portions of the elderly population it affects and the lack of a standard and effective diagnosis procedure that is available to community healthcare providers. Several studies have been performed using wavelets or other signal processing methods to analyze EEG signals in an attempt to find a biomarker for Alzheimer's disease, which showed varying degrees of success. To date, in part due to lack of a large study cohort, the results of these studies remain largely inconclusive. In this paper, we describe a new effort using multiresolution wavelet analysis on event related potentials of the EEG to investigate whether such a link can be established. Several factors sets this study apart from similar prior efforts: We use a larger cohort, compare different mother wavelets, rather then using one generic wavelet, and most importantly, we specifically target early diagnosis of the disease. Our multi-year effort will include a total of 80 patients, whose ERPs will be analyzed with several different wavelets and automated classifiers. We present some preliminary, yet very promising, results on analysis of EEGs of the first 28 patients analyzed thus far using two types of wavelets.
Collapse
|
170
|
Elkins JS. Atherosclerosis and dementia: Leading by association. Ann Neurol 2007; 61:377-9. [PMID: 17358003 DOI: 10.1002/ana.21101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
171
|
Polikar R, Topalis A, Green D, Kounios J, Clark CM. Comparative multiresolution wavelet analysis of ERP spectral bands using an ensemble of classifiers approach for early diagnosis of Alzheimer's disease. Comput Biol Med 2007; 37:542-58. [PMID: 16989799 PMCID: PMC1994255 DOI: 10.1016/j.compbiomed.2006.08.012] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Early diagnosis of Alzheimer's disease (AD) is becoming an increasingly important healthcare concern. Prior approaches analyzing event-related potentials (ERPs) had varying degrees of success, primarily due to smaller study cohorts, and the inherent difficulty of the problem. A new effort using multiresolution analysis of ERPs is described. Distinctions of this study include analyzing a larger cohort, comparing different wavelets and different frequency bands, using ensemble-based decisions and, most importantly, aiming the earliest possible diagnosis of the disease. Surprising yet promising outcomes indicate that ERPs in response to novel sounds of oddball paradigm may be more reliable as a biomarker than the more commonly used responses to target sounds.
Collapse
Affiliation(s)
- Robi Polikar
- Electrical and Computer Engineering, Rowan University, Glassboro, NJ 08028, USA.
| | | | | | | | | |
Collapse
|
172
|
Abstract
As our population ages, diseases affecting memory and daily functioning will affect an increasing number of individuals, their families and the healthcare system. The social, financial and economic impacts will be profound. This article provides an overview of current dementia syndromes to assist clinicians in evaluating, educating and treating these patients.
Collapse
Affiliation(s)
- Kevin R Scott
- Pennsylvania State University, Department of Neurology, College of Medicine, Milton S. Hershey Medical Center, Hershey, PA 17033, USA.
| | | |
Collapse
|
173
|
Parikh D, Stepenosky N, Topalis A, Green D, Kounios J, Clark C, Polikar R. Ensemble based data fusion for early diagnosis of Alzheimer's disease. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2005:2479-82. [PMID: 17282740 DOI: 10.1109/iembs.2005.1616971] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We describe an ensemble of classifiers based data fusion approach to combine information from two sources, believed to contain complimentary information, for early diagnosis of Alzheimer's disease. Specifically, we use the event related potentials recorded from the Pz and Cz electrodes of the EEG, which are further analyzed using multiresolution wavelet analysis. The proposed data fusion approach includes generating multiple classifiers trained with strategically selected subsets of the training data from each source, which are then combined through a weighted majority voting. Several factors set this study apart from similar prior efforts: we use a larger cohort, specifically target early diagnosis of the disease, use an ensemble based approach rather then a single classifier, and most importantly, we combine information from multiple sources, rather then using a single modality. We present promising results obtained from the first 35 (of 80) patients whose data are analyzed thus far.
Collapse
Affiliation(s)
- Devi Parikh
- Department of Electrical and Computer Engineering, Rowan University, Glassboro, New Jersey, USA
| | | | | | | | | | | | | |
Collapse
|
174
|
Stepenosky N, Topalis A, Syed H, Green D, Kounios J, Clark C, Polikar R. Boosting based classification of event related potentials for early diagnosis of Alzheimer's disease. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2005:2494-7. [PMID: 17282744 DOI: 10.1109/iembs.2005.1616975] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
With the number of the elderly population affected by Alzheimer's disease (AD) rising, the need to find an accurate, inexpensive and non-intrusive procedure that can be made available to community healthcare providers for early diagnosis of Alzheimer's disease is becoming more and more urgent as a major health concern. Several recent studies have looked at analyzing electroencephalogram signals through the use of wavelets and neural networks. In this study, multiresolution wavelet analysis, coupled with the ensemble of classifiers based boosting algorithm is used on the P300 component of the event related potentials (ERP) to determine the feasibility of the approach as a diagnostic tool for early diagnosis of AD. The technique and its promising initial results are presented.
Collapse
Affiliation(s)
- Nicholas Stepenosky
- Department of Electrical and Computer Engineering, Rowan University, Glassboro, New Jersey, USA
| | | | | | | | | | | | | |
Collapse
|
175
|
Jellinger KA. The enigma of mixed dementia. Alzheimers Dement 2007; 3:40-53. [DOI: 10.1016/j.jalz.2006.09.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2006] [Accepted: 09/22/2006] [Indexed: 10/23/2022]
Affiliation(s)
- Kurt A. Jellinger
- Institute of Clinical Neurobiology; Kenyongasse 18, A-1070 Vienna Austria
| |
Collapse
|
176
|
Tsuang D, Simpson K, Larson EB, Peskind E, Kukull W, Bowen JB, McCormick W, Teri L, Montine T, Thompson ML, Leverenz JB. Predicting lewy body pathology in a community-based sample with clinical diagnosis of Alzheimer's disease. J Geriatr Psychiatry Neurol 2006; 19:195-201. [PMID: 17085757 DOI: 10.1177/0891988706292755] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
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.
Collapse
Affiliation(s)
- Debby Tsuang
- University of Washington Departments of Psychiatry and Behavioral Sciences, Seattle, WA, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
177
|
Bennett DA. Postmortem indices linking risk factors to cognition: results from the Religious Order Study and the Memory and Aging Project. Alzheimer Dis Assoc Disord 2006; 20:S63-8. [PMID: 16917198 DOI: 10.1097/00002093-200607001-00009] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We present data from the Religious Orders Study and the Memory and Aging Project linking risk factors to pathology and cognitive function. Both studies involve more than 1000 older persons who agreed to annual clinical evaluation and brain donation at death. Published findings from the studies to date suggest that the relationship between risk factors, pathology, and cognitive impairment is complex. In some cases, known neuropathologic indices mediate the association of risk factors to cognition. In other cases, risk factors modify the relation of pathology to cognition. Finally, some risk factors seem to be related to clinical Alzheimer disease and cognitive decline, even decline in episodic memory, in the absence of any association with amyloid plaques, neurofibrillary tangles, or other pathologic indices that can be identified and quantified at this time. The findings to date illustrate the kinds of insights that can be gained into mechanisms of disease through the incorporation of pathologic indices into well-designed, epidemiologic studies of aging and Alzheimer disease.
Collapse
Affiliation(s)
- David A Bennett
- Rush Alzheimer's Disease Center and Departments of Neurological Sciences, Rush University Medical Center, 600 S. Paulina, Chicago, IL 60612, USA.
| |
Collapse
|
178
|
Abstract
Several studies report that blood pressure is increased in victims of Alzheimer's disease (AD) decades before the onset of the disease. Years before onset of Alzheimer's disease, blood pressure start to decrease and continues to decrease during the disease process. High blood pressure has also been related to pathological manifestations of Alzheimer's disease (senile plaques, neurofibrillary tangles, hippocampal atrophy). The exact mechanism behind these associations is not clear. Hypertension is also a risk factor for stroke, ischemic white matter lesions, silent infarcts, general atherosclerosis, myocardial infarction and cardiovascular diseases, and often clusters with other vascular risk factors, including diabetes mellitus, obesity and hypercholesterolemia. Also these risk factors have been related to Alzheimer's disease. Hypertension may thus cause cerebrovascular disease that may increase the possibility for individuals with AD encephalopathy to express a dementia syndrome. Hypertension may also lead to vessel wall changes in the brain, leading to hypoperfusion, ischemia and hypoxia which may initiate the pathological process of AD. Finally, subclinical AD may lead to increased blood pressure, and similar biological mechanisms may be involved in the pathogenesis of both disorders. Hypertension is a common disorder and often untreated. Several observational studies have reported that use of antihypertensives decreases risk of AD. Even though hypertension only results in a moderately increased risk of AD, or overall dementia, better treatment of hypertension may have an immense effect on the total number of demented individuals.
Collapse
Affiliation(s)
- Ingmar Skoog
- Institute of Neuroscience and Physiology, Section of Psychiatry, Unite of Neuropsychiatric Epidemiology, Sahlgrenska Academy at Göteborg University, Göteborg, Sweden.
| | | |
Collapse
|
179
|
Bennett DA, Schneider JA, Aggarwal NT, Arvanitakis Z, Shah RC, Kelly JF, Fox JH, Cochran EJ, Arends D, Treinkman AD, Wilson RS. Decision rules guiding the clinical diagnosis of Alzheimer's disease in two community-based cohort studies compared to standard practice in a clinic-based cohort study. Neuroepidemiology 2006; 27:169-76. [PMID: 17035694 DOI: 10.1159/000096129] [Citation(s) in RCA: 290] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We developed prediction rules to guide the clinical diagnosis of Alzheimer's disease (AD) in two community-based cohort studies (the Religious Orders Study and the Rush Memory and Aging Project). The rules were implemented without informant interviews, neuroimaging, blood work or routine case conferencing. Autopsies were performed at death and the pathologic diagnosis of AD made with a modified version of the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) criteria. We compared the positive predictive value of the clinical diagnosis in the two community-based studies to the positive predictive value of the clinical diagnosis of AD made by standard clinical practice in a clinic-based cohort study using AD pathology as the gold standard. Of 306 clinic cases with probable AD, 286 (93.5%) met CERAD neuropathologic criteria for AD; the results were comparable for those with possible AD (51 of 54, 94.4%). Of 141 study subjects with probable AD, 130 (92.2%) met CERAD neuropathologic criteria for AD; the results were lower but acceptable for those with possible AD (26 of 37, 70.3%). The results were similar in secondary analyses using alternate neuropathologic criteria for AD. The clinical diagnosis of AD can be made in community-based studies without the use of informant interviews, neuroimaging, blood work or routine case conferencing. This approach holds promise for reducing the operational costs of epidemiologic studies of aging and AD.
Collapse
|
180
|
Sunderland T, Hampel H, Takeda M, Putnam KT, Cohen RM. Biomarkers in the diagnosis of Alzheimer's disease: are we ready? J Geriatr Psychiatry Neurol 2006; 19:172-9. [PMID: 16880359 DOI: 10.1177/0891988706291088] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Although clinical manifestations of cognitive dysfunction and impairments of activities of daily living are the current standard measures for the diagnosis of Alzheimer's disease, biomarkers are receiving increasing attention in research centers as possible early diagnostic measures or as surrogate measures of the ongoing pathology. In preparation for the upcoming development of the Diagnostic and Statistical Manual of Mental Disorders (5th ed; DSM-V) nosology, the American Psychiatric Association has sponsored an effort to reassess the current approaches to diagnosis in dementia in general and Alzheimer's disease in particular. This article focuses on the potential use of biomarkers in the diagnosis of Alzheimer's disease, in the monitoring of mild cognitive impairment, and as possible prognostic markers in normal controls at risk for dementia. Most advanced information is available with the biomarkers found in the cerebrospinal fluid, but there are many other potential biomarkers using blood, brain imaging, or a combination. The current biomarker approaches to diagnosis are reviewed along with a special emphasis on near-term recommendations and further research directions.
Collapse
Affiliation(s)
- Trey Sunderland
- Geriatric Psychiatry Branch, National Institute of Mental Health, Bethesda, MD 20892, USA.
| | | | | | | | | |
Collapse
|
181
|
Hachinski V, Iadecola C, Petersen RC, Breteler MM, Nyenhuis DL, Black SE, Powers WJ, DeCarli C, Merino JG, Kalaria RN, Vinters HV, Holtzman DM, Rosenberg GA, Wallin A, Dichgans M, Marler JR, Leblanc GG. National Institute of Neurological Disorders and Stroke-Canadian Stroke Network vascular cognitive impairment harmonization standards. Stroke 2006; 37:2220-41. [PMID: 16917086 DOI: 10.1161/01.str.0000237236.88823.47] [Citation(s) in RCA: 1090] [Impact Index Per Article: 60.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND AND PURPOSE One in 3 individuals will experience a stroke, dementia or both. Moreover, twice as many individuals will have cognitive impairment short of dementia as either stroke or dementia. The commonly used stroke scales do not measure cognition, while dementia criteria focus on the late stages of cognitive impairment, and are heavily biased toward the diagnosis of Alzheimer disease. No commonly agreed standards exist for identifying and describing individuals with cognitive impairment, particularly in the early stages, and especially with cognitive impairment related to vascular factors, or vascular cognitive impairment. METHODS The National Institute for Neurological Disorders and Stroke (NINDS) and the Canadian Stroke Network (CSN) convened researchers in clinical diagnosis, epidemiology, neuropsychology, brain imaging, neuropathology, experimental models, biomarkers, genetics, and clinical trials to recommend minimum, common, clinical and research standards for the description and study of vascular cognitive impairment. RESULTS The results of these discussions are reported herein. CONCLUSIONS The development of common standards represents a first step in a process of use, validation and refinement. Using the same standards will help identify individuals in the early stages of cognitive impairment, will make studies comparable, and by integrating knowledge, will accelerate the pace of progress.
Collapse
Affiliation(s)
- Vladimir Hachinski
- London Health Sciences Centre, University Campus, London, Ontario, Canada
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
182
|
Abstract
Alzheimer's disease is the most common cause of dementia. Research advances have enabled detailed understanding of the molecular pathogenesis of the hallmarks of the disease--ie, plaques, composed of amyloid beta (Abeta), and tangles, composed of hyperphosphorylated tau. However, as our knowledge increases so does our appreciation for the pathogenic complexity of the disorder. Familial Alzheimer's disease is a very rare autosomal dominant disease with early onset, caused by mutations in the amyloid precursor protein and presenilin genes, both linked to Abeta metabolism. By contrast with familial disease, sporadic Alzheimer's disease is very common with more than 15 million people affected worldwide. The cause of the sporadic form of the disease is unknown, probably because the disease is heterogeneous, caused by ageing in concert with a complex interaction of both genetic and environmental risk factors. This seminar reviews the key aspects of the disease, including epidemiology, genetics, pathogenesis, diagnosis, and treatment, as well as recent developments and controversies.
Collapse
Affiliation(s)
- Kaj Blennow
- Clinical Neurochemistry Laboratory, Department of Neuroscience and Physiology, Sahlgren's University Hospital, Mölndal, Sweden.
| | | | | |
Collapse
|
183
|
Jellinger KA, Attems J. Prevalence and impact of cerebrovascular pathology in Alzheimer's disease and parkinsonism. Acta Neurol Scand 2006; 114:38-46. [PMID: 16774626 DOI: 10.1111/j.1600-0404.2006.00665.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE To study the prevalence and impact of cerebrovascular lesions (CVL) in Alzheimer's disease (AD) and their effects on cognitive impairment. MATERIAL AND METHODS In study I, the prevalence of vascular lesions in a prospective series of 244 autopsy-proved AD cases (mean age 83.1+/-8.4 years) and 230 age-matched non-demented controls was examined using immunochemistry and current morphological diagnostic criteria. In study II, in 100 consecutive autopsy cases (mean age 84.3+/-9.3 years), the incidence of general and capillary cerebral amyloid angiopathy (CAA, CapCAA) was examined. RESULTS In study I, AD cases showed significantly more frequent CVL than age-matched controls without differences in the Braak stages, but the severity of CAA was significantly higher in AD brain with associated vascular lesions. In study II, CAA was more frequent in demented than in non-demented patients, but did neither correlate with high-grade AD pathology nor with clinical dementia, whereas CapCAA correlated with both dementia and high Braak stages; the severity of both types of CAA showed only low correlation with each other. CONCLUSIONS The present data and other studies confirm the importance of CVL in AD and Parkinson's disease without considerable impact on cognitive impairment in progressed stages of AD, and the close association of CapCAA but not of general CAA with clinical dementia and AD pathology.
Collapse
Affiliation(s)
- K A Jellinger
- Institute of Clinical Neurobiology, Vienna, Austria.
| | | |
Collapse
|
184
|
Martínez-Vila E, Murie-Fernández M, Gállego Pérez-Larraya J, Irimia P. Neuroprotection in Vascular Dementia. Cerebrovasc Dis 2006; 21 Suppl 2:106-17. [PMID: 16651821 DOI: 10.1159/000091710] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Vascular dementia (VaD) is the second most common form of dementia after Alzheimer's disease (AD), and one of the major causes of mental and physical disability in developed countries. As such, the identification and implementation of strategies which prevent the development of the condition or enable improvements in patients with VaD are healthcare objectives of the first order. VaD is now regarded as a combined group of clinical-pathological entities rather than one disease, that is, multiple pathogenic mechanisms and lesion types underlie a cognitive impairment of vascular origin. The clinical diagnosis of VaD is complex and difficult because of the heterogeneous nature of its clinical presentation and progression and the low sensitivity of existing clinical criteria. Moreover, there is growing evidence of the epidemiological significance of mixed forms of dementia, and that ischemic processes may precipitate and exacerbate cognitive impairment in AD. Numerous compounds have been proposed as potentially useful in the treatment of patients with VaD, comprising vasodilatative, antithrombotic, hemorrheological, nootropic, antiserotoninergic and, most recently, antiglutamatergic and cholinergic approaches. In spite of some initially favorable reports based on the use of memantine, donepezil and galantamine, there is as yet no conclusive evidence of a definitive treatment for VaD. Unsatisfactory results from VaD drug trials may be attributed in part to the diversity of the patients included (underlying pathogenic mechanisms, number, type, and location of vascular lesions), and to methodological limitations in the design of the trials (outcome measures, end-points, size, follow-up period). The treatment of modifiable vascular risk factors - hypertension, diabetes mellitus, hypercholesterolemia and heart disease - is an important strategy for the reduction of the risk of dementia, and is likely to slow the progress of cognitive decline.
Collapse
Affiliation(s)
- Eduardo Martínez-Vila
- Stroke Unit, Department of Neurology, University Clinic, Faculty of Medicine, University of Navarra, Pamplona, Spain.
| | | | | | | |
Collapse
|
185
|
Leverenz JB, Fishel MA, Peskind ER, Montine TJ, Nochlin D, Steinbart E, Raskind MA, Schellenberg GD, Bird TD, Tsuang D. Lewy body pathology in familial Alzheimer disease: evidence for disease- and mutation-specific pathologic phenotype. ACTA ACUST UNITED AC 2006; 63:370-6. [PMID: 16533963 PMCID: PMC1892620 DOI: 10.1001/archneur.63.3.370] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND The origin and significance of Lewy bodies and neurites (Lewy body pathology [LBP]) in Alzheimer disease (AD) are poorly understood. OBJECTIVE To examine LBP in the brainstem, limbic cortex, and neocortex of a large number of familial AD cases with mutations in 2 presenilin (PSEN) genes. METHODS Twenty-five familial AD cases with 9 known PSEN 1 mutations and 14 familial AD cases with a single PSEN 2 mutation (N141I) were examined for LBP using alpha-synuclein immunohistochemistry and sampling of multiple brainstem and cortical regions. RESULTS The amygdala was the most vulnerable site for LBP. In fact, virtually all (24 [96%] of 25 cases) of the PSEN 1 mutation cases had LBP in the amygdala. The PSEN 1 mutation cases also had more frequent LBP in the amygdala and neocortex than those with the PSEN 2 mutation. However, within families with a single mutation of either PSEN 1 or PSEN 2, there was frequent variability of the LBP. CONCLUSION These findings suggest that there are genetic influences on the presence of LBP in familial AD as demonstrated by the differences between PSEN 1 and PSEN 2 mutation cases.
Collapse
Affiliation(s)
- James B Leverenz
- Parkinson's Disease, Mental Illness Research, Education, and Clinical Centers, Veterans Affairs Puget Sound Health Care System, Seattle, Wash, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
186
|
Kantarci K, Petersen RC, Boeve BF, Knopman DS, Tang-Wai DF, O'Brien PC, Weigand SD, Edland SD, Smith GE, Ivnik RJ, Ferman TJ, Tangalos EG, Jack CR. 1H MR spectroscopy in common dementias. Neurology 2006; 63:1393-8. [PMID: 15505154 PMCID: PMC2766798 DOI: 10.1212/01.wnl.0000141849.21256.ac] [Citation(s) in RCA: 178] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To determine the 1H MR spectroscopic (MRS) findings and intergroup differences among common dementias: Alzheimer disease (AD), vascular dementia (VaD), dementia with Lewy bodies (DLB), and frontotemporal lobar degeneration (FTLD). METHODS The authors consecutively recruited 206 normal elderly subjects and 121 patients with AD, 41 with FTLD, 20 with DLB, and 8 with VaD. The 1H MRS metabolite ratio changes in common dementias were evaluated with respect to normal and also differences among the common dementias. RESULTS N-acetylaspartate (NAA)/creatine (Cr) was lower than normal in patients with AD, FTLD, and VaD. Myo-inositol (mI)/Cr was higher than normal in patients with AD and FTLD. Choline (Cho)/Cr was higher than normal in patients with AD, FTLD, and DLB. There were no metabolite differences between patients with AD and FTLD or between patients with DLB and VaD. NAA/Cr was lower in patients with AD and FTLD than DLB. MI/Cr was higher in patients with AD and FTLD than VaD. MI/Cr was also higher in patients with FTLD than DLB. CONCLUSIONS NAA/Cr levels are decreased in dementias that are characterized by neuron loss, such as AD, FTLD, and VaD. MI/Cr levels are elevated in dementias that are pathologically characterized by gliosis, such as AD and FTLD. Cho/Cr levels are elevated in dementias that are characterized by a profound cholinergic deficit, such as AD and DLB.
Collapse
Affiliation(s)
- Kejal Kantarci
- Department of Diagnostic Radiology, Mayo Clinic, Rochester, Minnesota
| | - Ronald C. Petersen
- Department of Neurology, Mayo Clinic, Rochester, Minnesota
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota
| | | | | | | | - Peter C. O'Brien
- Department of Clinical Epidemiology, Mayo Clinic, Rochester, Minnesota
| | | | - Steven D. Edland
- Department of Clinical Epidemiology, Mayo Clinic, Rochester, Minnesota
| | - Glenn E. Smith
- Departments of Psychiatry and Psychology, Mayo Clinic, Rochester, Minnesota
| | - Robert J. Ivnik
- Departments of Psychiatry and Psychology, Mayo Clinic, Rochester, Minnesota
| | - Tanis J. Ferman
- Departments of Psychiatry and Psychology, Mayo Clinic, Jacksonville, Florida
| | - Eric G. Tangalos
- Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota
| | - Clifford R. Jack
- Department of Diagnostic Radiology, Mayo Clinic, Rochester, Minnesota
| |
Collapse
|
187
|
Tsuang D, Simpson KL, Li G, Barnhart RL, Edland SD, Bowen J, McCormick W, Teri L, Nochlin D, Larson EB, Thompson ML, Leverenz JB. Evaluation of selection bias in an incident-based dementia autopsy case series. Alzheimer Dis Assoc Disord 2006; 19:67-73. [PMID: 15942323 PMCID: PMC1524825 DOI: 10.1097/01.wad.0000165507.67993.47] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Neuropathological (np) relative frequency estimates of dementia may be biased if the autopsied subjects are not representative of all dementia subjects within a target population. We identified characteristics that differed between autopsied and non-autopsied subjects from an incident-based dementia case series and compared autopsy-based estimates of the relative frequency of np diagnoses before and after adjusting for potential selection bias. Clinically demented subjects who were autopsied (n = 206), had died but were not autopsied (n = 271), were still alive (n = 71), or had dropped out of the study (n = 82) were included. Compared with non-autopsied subjects, autopsied subjects were more likely to be Caucasian, educated beyond high school, and married. They also tended to have a lower baseline Mini-Mental State Examination score and were more likely to have a clinical diagnosis of Alzheimer disease (AD) than non-autopsied subjects. Neuropathological AD with Lewy bodies (LB) had the largest crude relative frequency estimate at 38% of the autopsy sample, followed by 25% for AD with vascular lesions, 13% for pure AD, 13% for LB (with or without vascular lesions), and 8% for pure vascular pathologies. Adjustment for potential sources of selection bias had little effect on relative frequency estimates, suggesting that np diagnoses in the autopsied subjects provide reasonable dementia relative frequency estimates among all clinically demented cases in this series.
Collapse
Affiliation(s)
- Debby Tsuang
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, Washington, USA.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
188
|
Abstract
The number of elderly people is increasing rapidly and, therefore, an increase in neurodegenerative and cerebrovascular disorders causing dementia is expected. Alzheimer disease (AD) is the most common cause of dementia. Vascular dementia, dementia with Lewy bodies, and frontotemporal dementia are the most frequent causes after AD, but a large proportion of patients have a combination of degenerative and vascular brain pathology. Characteristic magnetic resonance (MR) imaging findings can contribute to the identification of different diseases causing dementia. The MR imaging protocol should include axial T2-weighted images (T2-WI), axial fluid-attenuated inversion recovery (FLAIR) or proton density-weighted images, and axial gradient-echo T2*-weighted images, for the detection of cerebrovascular pathology. Structural neuroimaging in dementia is focused on detection of brain atrophy, especially in the medial temporal lobe, for which coronal high resolution T1-weighted images perpendicular to the long axis of the temporal lobe are extremely important. Single photon emission computed tomography and positron emission tomography may have added value in the diagnosis of dementia and may become more important in the future, due to the development of radioligands for in vivo detection of AD pathology. New functional MR techniques and serial volumetric imaging studies to identify subtle brain abnormalities may also provide surrogate markers for pathologic processes that occur in diseases causing dementia and, in conjunction with clinical evaluation, may enable a more rigorous and early diagnosis, approaching the accuracy of neuropathology.
Collapse
Affiliation(s)
- António J Bastos Leite
- Department of Radiology, Vrije Universiteit (VU) Medical Center, Amsterdam, the Netherlands.
| | | | | |
Collapse
|
189
|
Newman AB, Fitzpatrick AL, Lopez O, Jackson S, Lyketsos C, Jagust W, Ives D, Dekosky ST, Kuller LH. Dementia and Alzheimer's disease incidence in relationship to cardiovascular disease in the Cardiovascular Health Study cohort. J Am Geriatr Soc 2005; 53:1101-7. [PMID: 16108925 DOI: 10.1111/j.1532-5415.2005.53360.x] [Citation(s) in RCA: 338] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To determine whether coronary artery disease, peripheral arterial disease (PAD), or noninvasive markers of cardiovascular disease (CVD) predict the onset of dementia and Alzheimer's disease (AD). DESIGN Longitudinal cohort study. SETTING Four U.S. communities. PARTICIPANTS Men and women (N=3,602) with a brain magnetic resonance imaging (MRI) scan but no dementia were followed for 5.4 years. Participants with stroke were excluded. MEASUREMENTS Neurologists and psychiatrists classified incident cases of dementia and subtype using neuropsychological tests, examination, medical records and informant interviews. CVD was defined at the time of the MRI scan. Noninvasive tests of CVD were assessed within 1 year of the MRI. Apolipoprotein E allele status, age, race, sex, education, Mini-Mental State Examination score, and income were assessed as potential confounders. RESULTS The incidence of dementia was higher in those with prevalent CVD, particularly in the subgroup with PAD. The rate of AD was 34.4 per 1,000 person-years for those with a history of CVD, versus 22.2 per 1,000 person-years without a history of CVD (adjusted hazard ratio (HR)=1.3, 95% confidence interval (CI)=1.0-1.7). Rates of AD were highest in those with PAD (57.4 vs 23.7 per 100 person-years, adjusted HR=2.4, 95% CI=1.4-4.2). Results were similar with further exclusion of those with vascular dementia from the AD group. A gradient of increasing risk was noted with the extent of vascular disease. CONCLUSION Older adults with CVD other than stroke had a higher risk of dementia and AD than did those without CVD. The risk was highest in people with PAD, suggesting that extensive peripheral atherosclerosis is a risk factor for AD.
Collapse
Affiliation(s)
- Anne B Newman
- Department of Epidemiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
190
|
Brooks DJ. Positron emission tomography and single-photon emission computed tomography in central nervous system drug development. NeuroRx 2005; 2:226-36. [PMID: 15897947 PMCID: PMC1064988 DOI: 10.1602/neurorx.2.2.226] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In this review, the value of functional imaging [positron emission tomography (PET)/single-photon emission computed tomography (SPECT)] in drug development is considered. Radionuclide imaging can help establish the diagnosis of neurodegenerative disorders where this is in doubt and provides a potential biomarker for following drug effects on disease progression. PET and SPECT can help understand mechanisms of disease and determine the functional effects of therapeutic approaches on neurotransmission and metabolism. Synthesizing radiotracer analogs of novel drugs can provide proof of principle that these agents reach their enzyme or receptor targets and delineate their regional brain distribution. If such radiotracers do not prove to have ideal properties for imaging, the concept of microdosing potentially allows multiple other drug analogs to be tested with less stringent regulatory requirements than for novel medicinals. Finally, PET tracers can provide receptor and enzyme active site dose occupancy profiles, thereby guiding dosage selection for phase 1 and phase 2 trials. The eventual hope is that radiotracer imaging will provide a surrogate marker for drug efficacy, although this has yet to be realized, and progress the concept of personalized medicine where receptor/enzyme binding profiles help predict therapeutic outcome.
Collapse
Affiliation(s)
- David J Brooks
- Medical Research Council Clinical Sciences Centre and Division of Neuroscience, Faculty of Medicine, Imperial College, Hammersmith Hospital, London W12 0NN, United Kingdom.
| |
Collapse
|
191
|
Bennett DA, Schneider JA, Buchman AS, Mendes de Leon C, Bienias JL, Wilson RS. The Rush Memory and Aging Project: study design and baseline characteristics of the study cohort. Neuroepidemiology 2005; 25:163-75. [PMID: 16103727 DOI: 10.1159/000087446] [Citation(s) in RCA: 302] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The long-term objective of the Rush Memory and Aging Project is to identify the postmortem indices linking genetic and environmental risk factors to the development of Alzheimer's disease (AD). The overall study design involves a detailed assessment of risk factors for AD in older persons without known dementia who agree to annual clinical evaluation and organ donation at the time of death. In contrast to other clinical-pathologic studies which are conducted on special populations, the Rush Memory and Aging Project enrolled a cohort with much greater diversity in terms of educational attainment, in addition to gender, race, and ethnicity. From September of 1997 through April of 2005, more than 1,000 older persons without known dementia from more than 30 residential facilities across the Chicago metropolitan area agreed to participate. Their mean age was 81 years, about a third had 12 or fewer years of education, a third were men, and about 10% were members of a racial or ethnic minority group. More than 950 already have completed their baseline clinical evaluation.
Collapse
Affiliation(s)
- David A Bennett
- Rush Alzheimer's Disease Center, Rush University Medical Center, 600 S. Paulina, Suite 1028, Chicago, IL 60612, USA.
| | | | | | | | | | | |
Collapse
|
192
|
Sunderland T, Gur RE, Arnold SE. The use of biomarkers in the elderly: current and future challenges. Biol Psychiatry 2005; 58:272-6. [PMID: 16018985 DOI: 10.1016/j.biopsych.2005.05.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2004] [Revised: 05/04/2005] [Accepted: 05/10/2005] [Indexed: 10/25/2022]
Abstract
Biomarkers are hypothesized but not frequently used in research with the elderly because of a general paucity of supportive scientific data. However, there is an obvious need for greater diagnostic specificity and sensitivity across many diagnoses in the elderly, as well as good targets for therapeutic trials. The authors reviewed the available information in this field as part of a general review of geriatric research for the . Potential biomarkers with pathophysiologic significance have been studied in the field of Alzheimer disease research with some success, especially in the area of genetic markers (apolipoprotein E [APOE] epsilon4 allele), neuroimaging, and cerebrospinal fluid markers (beta-amyloid and tau). While some progress has been made in the search for adequate biomarkers in the elderly, in particular with Alzheimer disease, much more work is needed before these potential biomarkers can be reliably used in clinical practice.
Collapse
Affiliation(s)
- Trey Sunderland
- Geriatric Psychiatry Branch, National Institute of Mental Health, Bethesda, Maryland 20892, USA.
| | | | | |
Collapse
|
193
|
Mohs RC. The clinical syndrome of Alzheimer's disease: aspects particularly relevant to clinical trials. GENES BRAIN AND BEHAVIOR 2005; 4:129-33. [PMID: 15810901 DOI: 10.1111/j.1601-183x.2004.00112.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
This paper describes the natural history of the clinical syndrome of Alzheimer's disease (AD) including the cognitive deficit, the neuropsychiatric symptoms, impact on daily functioning, risk factors, medical complications and impact on the use of health-care resources. The clinical presentation of the disease varies greatly from the prodrome through end stage; instruments used to quantify the severity of each aspect of the disease have been developed and are described along with their use in clinical drug trials. Drug treatments for AD are usually developed by first showing a positive effect on the cognitive deficit, with later studies investigating drug effects on other clinical aspects of the disease.
Collapse
Affiliation(s)
- R C Mohs
- Eli Lilly and Company, Indianapolis, IN 46285, USA.
| |
Collapse
|
194
|
Knopman D. Commentary: “Treatment of hypertension and prevention of dementia” by Oliver Hanon and Françoise Forette. Alzheimers Dement 2005; 1:41-2. [DOI: 10.1016/j.jalz.2005.06.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
195
|
Moulin-Romsee G, Maes A, Silverman D, Mortelmans L, Van Laere K. Cost-effectiveness of 18F-fluorodeoxyglucose positron emission tomography in the assessment of early dementia from a Belgian and European perspective. Eur J Neurol 2005; 12:254-63. [PMID: 15804241 DOI: 10.1111/j.1468-1331.2004.00940.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
(18)F-fluoro-deoxyglucose positron emission tomography (FDG PET) can aid to predict AD in an early stage. The aim of this study was to estimate the economic effects of incorporating FDG PET in the diagnostic work-up of AD in a Belgian and European setting. A decision tree analysis was followed comparing a conventional algorithm using diagnostic clinical criteria and one that also incorporates PET. Major outcome terms were overall cost per patient in either strategy; diagnostic accuracy and cost per accurate diagnosis. A sensitivity analysis was performed for four critical variables: cost of PET, sensitivity and specificity of PET and delay in cognitive decline because of appropriate medication. Cost-savings per accurate diagnosis ranged from 623-6110 Euro in favour of the proposed algorithm with PET. For the same cost, more accurate diagnoses were made, resulting in benefit for patients and society. The positive results were maintained over a wide range of values for the critical variables and were expandable to other European countries with a similar health system. Therefore, incorporation of FDG PET into the clinical diagnostic work up of patients with early symptoms of cognitive decline can be advocated.
Collapse
Affiliation(s)
- G Moulin-Romsee
- Division of Nuclear Medicine, University Hospital Gasthuisberg, Katholieke Universiteit Leuven, Leuven, Belgium
| | | | | | | | | |
Collapse
|
196
|
Knopman DS, Boeve BF, Parisi JE, Dickson DW, Smith GE, Ivnik RJ, Josephs KA, Petersen RC. Antemortem diagnosis of frontotemporal lobar degeneration. Ann Neurol 2005; 57:480-8. [PMID: 15786453 DOI: 10.1002/ana.20425] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The objective of this article is to study the accuracy of antemortem clinical diagnoses of frontotemporal lobar degenerations (FTLDs). From brain autopsies performed on subjects enrolled in the Mayo Alzheimer Center between 1991 and 2003, cases with neuropathological diagnoses of FTLD were identified. Neuropathological diagnoses of FTLDs were based on consensus criteria for FTLD. The initial clinical histories, neuropsychological test results, brain imaging studies, and initial clinical diagnoses were reviewed. There were 34 pathological FTLD cases among 433 subjects who underwent autopsy; 29 of these 34 cases were diagnosed as FTLD antemortem based on the sum of clinical, neuropsychological, and imaging features (sensitivity, 85%). The specificity was 99%. Among the 34 cases with pathological FTLD, 27 (79%) had clinical histories diagnostic of an FTLD syndrome, 20 (62%) had neuropsychological profiles consistent with FTLD, 17 (50%) had magnetic resonance scans consistent with FTLD, and 7 of 8 who had functional imaging studies had ones consistent with FTLD. In those with incorrect antemortem diagnoses, three were thought to have Alzheimer's disease, one was considered hard to classify, and one was diagnosed with vascular dementia. The antemortem consensus diagnosis of FTLD was moderately sensitive and very specific. With experienced clinicians and awareness of the unique manifestations of FTLD, accurate antemortem diagnosis was feasible.
Collapse
Affiliation(s)
- David S Knopman
- Department of Neurology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | | | | | | | | | | | | | | |
Collapse
|
197
|
Chakravarty A. Unifying concept for Alzheimer's disease, vascular dementia and normal pressure hydrocephalus - a hypothesis. Med Hypotheses 2005; 63:827-33. [PMID: 15488655 DOI: 10.1016/j.mehy.2004.03.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2004] [Accepted: 03/16/2004] [Indexed: 11/16/2022]
Abstract
The three common forms of dementias in the elderly include Alzheimer's disease (AD), vascular dementia (VD) and normal pressure hydrocephalus (NPH). These disorders are distinguished by their specific pathological features. However, overlapping clinical and imaging features in a given case are not too uncommon. Based on alterations in CSF dynamics study, a unifying concept in the pathogenesis of AD and NPH has been proposed recently which may have therapeutic implications. Altered CSF dynamics by affecting the absorptive process may lead to hydrocephalic change. This may also affect clearance of amyloid protein leading to increased amyloid deposition in brain parenchyma resulting in AD pathology. Hence it is likely that a subgroup of patients may have an AD-NPH syndrome who may be benefitted by CSF drainage procedure. The present author attempts to extend this concept to hypothesise a unifying concept to explain the pathophysiology of all the three disorders which may explain overlapping features observed clinically and in neuroimaging studies. It is surmised that altered CSF dynamics and hypoperfusion from vascular disease may be interlinked. The defective clearance of amyloid may also lead to amyloid angiopathy perpetuating hypoperfusion. Hypoperfusion may also affect formation as well as absorption of CSF altering clearance of amyloid and promoting vascular and parenchymal deposition. Thus the pathologies of AD, VaD and NPH get interrelated.
Collapse
Affiliation(s)
- Ambar Chakravarty
- Department of Neurology, Vivekananda Institute of Medical Sciences, 59 Beadon Street, Calcutta 700006, India.
| |
Collapse
|
198
|
Abstract
Vascular dementia (VaD) is the second most common type of dementia in the elderly after Alzheimer's disease (AD). Evidence is presented indicating the occurrence of cholinergic dysfunction in VaD, independent from AD. Controlled clinical trials of cholinesterase inhibitors (ChEIs) in VaD and in patients with AD plus cerebrovascular disease are reviewed. Compared with placebo, ChEI treatment improves cognition, behavior, and activities of daily living. Cholinergic deficits in patients with VaD may result from ischemia of basal forebrain cholinergic nuclei that are irrigated by penetrating arteries that are highly susceptible to arterial hypertension, or from ischemic lesions in basal ganglia or white matter that sever the extensive cholinergic cortical projections. Cholinergic stimulation produces increases in cortical cerebral blood flow that may be relevant to the therapeutic effect of ChEIs.
Collapse
Affiliation(s)
- Gustavo C Román
- Department of Medicine/Neurology, University of Texas Health Science Center at San Antonio, and the Audie Murphy Veterans Administration Hospital, San Antonio, TX 78232, USA.
| |
Collapse
|
199
|
Sunderland T, Mirza N, Putnam KT, Linker G, Bhupali D, Durham R, Soares H, Kimmel L, Friedman D, Bergeson J, Csako G, Levy JA, Bartko JJ, Cohen RM. Cerebrospinal fluid beta-amyloid1-42 and tau in control subjects at risk for Alzheimer's disease: the effect of APOE epsilon4 allele. Biol Psychiatry 2004; 56:670-6. [PMID: 15522251 DOI: 10.1016/j.biopsych.2004.07.021] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2004] [Revised: 07/30/2004] [Accepted: 07/31/2004] [Indexed: 11/26/2022]
Abstract
BACKGROUND Cerebrospinal fluid (CSF) measures of beta-amyloid(1-42) and tau are linked with the known neuropathology of Alzheimer's disease (AD). Numerous lines of evidence have also suggested that individuals with at least one APOE epsilon4 allele on chromosome 19 are at increased risk of developing AD. We tested these CSF markers in groups of subjects with AD and healthy older control subjects, using the absence or presence of the APOE epsilon4 allele as a predictive variable in the search for possible prognostic biomarkers of AD. METHODS We assessed the levels of beta-amyloid(1-42) and total tau in the CSF of 292 subjects (142 control subjects and 150 subjects with mild-to-moderate AD), who were research participants at the National Institute of Mental Health. The group of control subjects was enriched with a high percentage of subjects with a positive family history of AD. All subjects underwent extensive global cognitive testing. RESULTS When divided according to the absence or presence of the APOE epsilon4 allele, the control subjects with at least one epsilon4 allele had significantly lower CSF beta-amyloid(1-42) but not tau levels than control subjects without an APOE epsilon4 allele (p < .01). As expected, the AD patients had lower levels of CSF beta-amyloid(1-42) and higher CSF tau levels than the normal control group (p < .01). CONCLUSIONS The association of APOE epsilon4 allele and lower, more AD-like levels of CSF beta-amyloid(1-42) in older control subjects is consistent with previous studies showing possible neuroimaging and cognitive abnormalities with epsilon4 carriers and suggests that CSF beta-amyloid(1-42) decreases might represent an early biomarker of AD. Longitudinal follow-up is of course required to verify whether this biomarker is indeed predictive of clinical conversion to AD.
Collapse
Affiliation(s)
- Trey Sunderland
- National Institute of Mental Health, Geriatric Psychiatry Branch, Building 10, Room 3N228, 9000 Rockville Pike, Bethesda, MD 20892, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
200
|
Riekse RG, Leverenz JB, McCormick W, Bowen JD, Teri L, Nochlin D, Simpson K, Eugenio C, Larson EB, Tsuang D. Effect of vascular lesions on cognition in Alzheimer's disease: a community-based study. J Am Geriatr Soc 2004; 52:1442-8. [PMID: 15341544 PMCID: PMC1487184 DOI: 10.1111/j.1532-5415.2004.52405.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To investigate whether clinical and neuropathological differences exist between Alzheimer's disease (AD) cases with and without vascular lesions neuropathologically diagnosed using Consortium to Establish a Registry for Alzheimer's Disease (CERAD) criteria. DESIGN Descriptive observational study. SETTING A community-based registry that identified incident dementia cases. PARTICIPANTS Of the 124 subjects with available clinical and neuropathological assessments, 30 had AD lesions alone, and 18 had AD with vascular lesions. Patients with other neuropathological findings were excluded. MEASUREMENTS Dependent measures included demographic, clinical, and neuropathological characteristics. Neuropathological diagnoses were made using the CERAD criteria and Braak and Braak staging. RESULTS Of the 124 autopsied cases, 85 cases were diagnosed with neuropathological AD. Of these, 30 had pathology consistent with "pure" AD, whereas 18 had AD pathology with significant vascular lesions (AD/V). There were no differences in age, sex, or education between groups. AD/V cases had higher baseline and final Mini-Mental State Examination (MMSE) scores than pure AD cases, but after adjusting for education, differences in MMSE scores were not statistically significant. The AD/V group had significantly lower Braak staging than the pure AD group, after adjusting for education and final MMSE scores. CONCLUSION In this comparison study of AD cases with and without vascular lesions, AD/V cases had less severe AD pathology than those with AD alone, indicating that cerebrovascular disease likely contributes to the severity of cognitive impairment in those with AD. Controlling for vascular risk factors in patients with AD may have a significant effect on severity of dementia.
Collapse
Affiliation(s)
- Robert G Riekse
- Department of Medicine, University of Washington, Seattle, Washington, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|