There are a number of ways in which a clinical diagnosis of dementia of the Alzheimer type can be made – the application of clinical criteria is the commonest but ancillary techniques such as neuroima

Clinical Diagnosis of Alzheimer's Disease

The authors report the prevalence of dementia in a community-dwelling Brazilian elderly population and correlate prevalence data with educational and socioeconomic levels. The study was conducted in Catanduva, Brazil. A total of 1,656 randomly selected subjects aged 65 years or more were submitted to a health questionnaire, the Mini-Mental State Examination (MMSE), and the Pfeffer Functional Activities Questionnaire (PFAQ). According to the PFAQ and MMSE scores, selected subjects were submitted to clinical, neurologic, and cognitive evaluations. The subjects diagnosed with dementia underwent laboratory tests and brain computed tomography (CT). Dementia was diagnosed in 118 subjects, corresponding to a prevalence of 7.1%. The main clinical diagnoses were Alzheimer disease (AD; 55.1%), vascular dementia (9.3%), and AD with cerebrovascular disease (14.4%). The prevalence increased with age and was higher in women. There was an inverse association with education (3.5% among persons with 8 or more years of schooling to 12.2% among those who were illiterate). Multivariate analysis disclosed significant association between these three variables and dementia. The prevalence of dementia in this Brazilian population was 7.1%, and AD was the most frequent diagnosis. Age, female gender, and low educational level were significantly associated with a higher prevalence of dementia.

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Epidemiologic survey of dementia in a community-dwelling Brazilian population.

Verbal fluency tests are used as a measure of executive functions and language, and can also be used to evaluate semantic memory. We analyzed the influence of education, gender and age on scores in a verbal fluency test using the animal category, and on number of categories, clustering and switching. We examined 257 healthy participants (152 females and 105 males) with a mean age of 49.42 years (SD = 15.75) and having a mean educational level of 5.58 (SD = 4.25) years. We asked them to name as many animals as they could. Analysis of variance was performed to determine the effect of demographic variables. No significant effect of gender was observed for any of the measures. However, age seemed to influence the number of category changes, as expected for a sensitive frontal measure, after being controlled for the effect of education. Educational level had a statistically significant effect on all measures, except for clustering. Subject performance (mean number of animals named) according to schooling was: illiterates, 12.1; 1 to 4 years, 12.3; 5 to 8 years, 14.0; 9 to 11 years, 16.7, and more than 11 years, 17.8. We observed a decrease in performance in these five educational groups over time (more items recalled during the first 15 s, followed by a progressive reduction until the fourth interval). We conclude that education had the greatest effect on the category fluency test in this Brazilian sample. Therefore, we must take care in evaluating performance in lower educational subjects.

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Category fluency test: effects of age, gender and education on total scores, clustering and switching in Brazilian Portuguese-speaking subjects

Background In 1988, 2 meta-analyses suggested that the prevalence of reversible dementia was significantly lower than had been previously estimated. It was predicted that further work would indicate an even lower rate. The present study represents an updated meta-analysis of the true prevalence of reversible dementia. Methods MEDLINE was searched from 1987 through 2002. References were also gleaned from pertinent articles and relevant textbooks. Data were extracted on the nature and provenance of the studies, dementia etiology, and the proportion of cases that were potentially reversible and reversed. Results Fifty articles were identified of which 39 met the study criteria, representing 7042 patients of whom 5620 (87.2%) had dementia. Patients were classified according to etiology and, where possible (in 23 [59%] of 39 studies), whether the dementia partially or completely resolved. A much higher proportion of studies than was previously the case were either community-based (31%) or observed subjects from outpatient departments (54%). Alzheimer disease was still the commonest cause of dementia (56.3%) followed by a vascular etiology (20.3%). Conditions requiring neuroimaging made up only 2.2% of cases. Potentially reversible causes were seen in 9%, and only 0.6% of dementia cases actually reversed (0.29% partially, 0.31% fully). Conclusions The reported proportion of dementias that reverse is much lower than previously thought. While comorbidity should always be treated for its own sake and in the hope that cognitive decline may at least be delayed, the present findings have significant clinical and economic implications for the workup of dementia.

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The Decreasing Prevalence of Reversible Dementias: An Updated Meta-analysis

Cognitive evaluation in developing countries is a difficult undertaking due to low levels of schooling and particularly the illiteracy still frequent in the elderly. This study was part of the epidemiologic evaluation of dementia in Catanduva, Brazil, and had the objective of comparing the performance of illiterate and literate nondemented elderly individuals in 2 tests of long-term memory-the delayed recall of a word list from the CERAD and the delayed recall of common objects presented as simple drawings from the Brief Cognitive Screening Battery (BCSB). Fifty-one elderly subjects (23 illiterates) were evaluated, and the performance of the illiterates and literates differed in the CERAD memory test, but not in the BCSB memory test. This test may be more suitable for the assessment of long-term memory in populations with a high frequency of illiterates, and therefore might prove to be a useful screening tool for the diagnosis of dementia.

Performance of illiterate and literate nondemented elderly subjects in two tests of long-term memory

Thirty patients with dementia defined by DSM-III-R criteria (Alzheimer's disease (22), vascular dementia (3), Parkinson's disease, frontal lobe dementia, possible diffuse Lewy body dementia, normal pressure hydrocephalus and uncertain diagnosis), with scores below 24 points in the Mini-Mental Status Examination and more than 4 years of education were submitted to a neuropsychological evaluation. The scores in the neuropsychological tests were compared to those obtained by thirty normal volunteers paired for age, sex and education. Sensivity, specificity and accuracy of the tests in the distinction of demented and normal volunteers were determined. The accuracies were calculated using ROC curves. Blessed's information-memory-concentration test showed greatest accuracy, followed by copy of simple figures, delayed memory of 10 figures (after 5 minutes), recognition of 10 figures and verbal fluency test (animals). A linear discriminant function, composed by 6 tests: visual perception, incidental memory, delayed memory (after 5 minutes), drawing of a clock, verbal fluency (animals) and calculation tests, was able to discriminate all controls from patients and only one patient was wrongly classified as normal control. These tests were chosen because they can be applied in less than 10 minutes and are very easy to interpret. This discriminant function must be applied in another group of patients and controls in order to demonstrate its value. When associated to the MMSE it may be useful to discriminate patients with dementia from normal people in epidemiological studies.

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Testes neuropsicológicos de aplicação simples para o diagnóstico de demência

Thirty patients with dementia defined by DSM-III-R criteria (Alzheimer's disease (22), vascular dementia (3), Parkinson's disease, frontal lobe dementia, possible diffuse Lewy body dementia, normal pressure hydrocephalus and uncertain diagnosis), with scores below 24 points in the Mini-Mental Status Examination and more than 4 years of education were submitted to a neuropsychological evaluation. The scores in the neuropsychological tests were compared to those obtained by thirty normal volunteers paired for age, sex and education. Sensitivity, specificity and accuracy of the tests in the distinction of demented and normal volunteers were determined. The accuracies were calculated using ROC curves. Blessed's information-memory-concentration test showed greatest accuracy, followed by copy of simple figures, delayed memory of 10 figures (after 5 minutes), recognition of 10 figures and verbal fluency test (animals). A linear discriminant function, composed by 6 tests: visual perception, incidental memory, delayed memory (after 5 minutes), drawing of a clock, verbal fluency (animals) and calculation tests, was able to discriminate all controls from patients and only one patient was wrongly classified as normal control. These tests were chosen because they can be applied in less than 10 minutes and are very easy to interpret. This discriminant function must be applied in another group of patients and controls in order to demonstrate its value. When associated to the MMSE it may be useful to discriminate patients with dementia from normal people in epidemiological studies.

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Neuropsychological tests of simple application for diagnosing dementia

Objective– To investigate why bilateral parietotemporal hypoperfusion, the typical SPECT pattern of Alzheimer's disease (AD), occurs in some but not in all patients with probable AD. Methods– We reviewed the SPECT scans of 220 patients presenting with cognitive impairment. Among them, 104 patients fulfilled NINCDS–ADRDA criteria for probable AD, 48 (32 women) with early onset (before age of 65) and 56 (40 women) with late onset of the symptoms. Dementia severity was assessed by the Mini-Mental State Examination. The SPECT scans were classified by visual inspection blind to clinical diagnoses. Results– Bilateral parietotemporal hypoperfusion was more frequent in patients with severe AD, in those with early onset of the symptoms, and in men. Duration of symptoms, type of gamma-camera or radiopharmaceutical agent used were not associated with this SPECT pattern. Conclusion– These findings may be useful in the clinical setting and point to heterogeneity of AD according to age at onset.

SPECT in Alzheimer's disease: features associated with bilateral parietotemporal hypoperfusion.

One hundred consecutive outpatients with dementia were prospectively studied to investigate the diagnoses of dementing diseases and to correlate these diagnoses with socioeconomic status and with education. Alzheimer disease was the most common cause of dementia (54%), followed by vascular dementia (20%). Eight patients presented with potentially reversible causes of dementia. These frequencies are similar to those reported by case register studies from Western Europe and the United States. We did not find differences in the frequencies of the dementing diseases according to socioeconomic status or education. Alzheimer disease was the most common cause of dementia in all socioeconomic classes. Potentially reversible dementias, vascular dementias, and other secondary dementias were not more frequent in the lower socioeconomic strata. There was a trend to a higher frequency of vascular dementia among patients with less education, but this was not statistically significant.

Evaluation of 100 patients with dementia in São Paulo, Brazil: correlation with socioeconomic status and education.

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S. C. Mathias

Papers

Testes neuropsicológicos de aplicação simples para o diagnóstico de demência

Neuropsychological tests of simple application for diagnosing dementia

SPECT in Alzheimer's disease: features associated with bilateral parietotemporal hypoperfusion.

Evaluation of 100 patients with dementia in São Paulo, Brazil: correlation with socioeconomic status and education.

Brief and easy-to-administer neuropsychological tests in the diagnosis of dementia