The validity and reliability of the CAMDEX-DS for assessing dementia in adults with Down syndrome in Brazil

Objective:

Alzheimer’s disease occurs at a higher prevalence and an earlier age in individuals with Down syndrome (DS) than typically developing individuals. However, diagnosing dementia in individuals with intellectual disability remains a challenge due to pre-existing cognitive deficits. The aim of this study was to investigate the validity and reliability of the Brazilian version of the Cambridge Examination for Mental Disorders of Older People with Down’s syndrome and Others with Intellectual Disabilities (CAMDEX-DS) for individuals with DS.

Methods:

Two psychiatrists, working independently, evaluated 92 adults with DS ≥ 30 years of age. The concurrent validity of the CAMDEX-DS was analyzed in relation to the gold standard of established international criteria. In a subgroup of 20 subjects, the concurrent validity of the CAMDEX-DS was analyzed in relation to an independent objective assessment of cognitive decline over three years. We analyzed the inter-rater reliability of cognitive assessment.

Results:

The diagnostic accuracy of the CAMDEX-DS compared to the gold standard was 96.7%. CAMDEX-DS-based diagnosis was considered consistent with cognitive decline. The probability of a participant with dementia having cognitive decline was 83%. Inter-rater reliability for the participant assessment was good, with a kappa of > 0.8 for 93% of the CAMDEX-DS items.

Conclusion:

The CAMDEX-DS can be considered the first valid and reliable instrument for evaluating dementia in adults with DS in Brazil. Its use in such individuals could improve clinical practice and research.

The influence of lithium on hippocampal volume in elderly bipolar patients: a study using voxel-based morphometry

Recent studies have demonstrated that lithium (Li) exerts neuronal protective and regenerative effects both in vitro and in vivo. However, the effects of long-term Li treatment in the brain areas associated with memory impairment of elderly bipolar patients are still unknown. The aim of this study was to compare the hippocampal volumes of elderly bipolar patients using Li, elderly bipolar patients not using Li and healthy controls. Sociodemographic, clinical and magnetic resonance imaging data from 30 elderly euthymic bipolar patients who had been using Li for an average of >61 months; 27 elderly euthymic bipolar patients not taking Li for an average of 45 months; and 22 elderly healthy controls were analyzed. Volumetric differences in the hippocampus between groups were investigated with voxel-based morphometry (VBM) based on the Statistical Parametric Mapping technique. No statistical differences in sociodemographic and clinical characteristics and course of bipolar disorder between the two bipolar groups were observed. Using small volume correction in the VBM analysis (analysis of variance (ANOVA)), one voxel cluster of statistical significance was detected in the left hippocampus (P<0.05 corrected for multiple comparisons, extent threshold >10 voxels). Post hoc unpaired t-tests revealed increased left hippocampal volume in the Li-treated group compared with the non-Li-treated group, and decreased left hippocampal volume in the non-Li group relative to controls. Additional exploratory two-group comparisons indicated trends toward reduced right-hippocampal volumes in the non-Li-treated group relative to both the Li-treated group and controls. The findings suggested that the use of Li may influence the volume of the hippocampus, possibly due to its neuroprotective effects.

A voxel-based morphometry study of temporal lobe gray matter reductions in Alzheimer's disease

Several MRI studies have reported reductions in temporal lobe volumes in Alzheimer's disease (AD). Measures have been usually obtained with regions-of-interest (ROI) drawn manually on selected medial and lateral portions of the temporal lobes, with variable choices of anatomical borders across different studies. We used the fully automated voxel-based morphometry (VBM) approach to investigate gray matter abnormalities over the entire extension of the temporal lobe in 14 AD patients (MMSE 14-25) and 14 healthy controls. Foci of significantly reduced gray matter volume in AD patients were detected in both medial and lateral temporal regions, most significantly in the right and left posterior parahippocampal gyri and the left posterior inferior temporal gyrus/fusiform gyrus (P<0.05, corrected for multiple comparisons). At a more flexible statistical threshold (P<0.001, uncorrected for multiple comparisons), circumscribed foci of significant gray matter reduction were also detected in the right amygdala/enthorinal cortex, the anterior and posterior borders of the superior temporal gyrus bilaterally, and the anterior portion of the left middle temporal gyrus. These VBM results confirm previous findings of temporal lobe atrophic changes in AD, and suggest that these abnormalities may be confined to specific sites within that lobe, rather than showing a widespread distribution.

[Subcortical hyperintensities on magnetic resonance imaging: a comparison of normal and depressed elderly subjects]

Previous studies reported that depressed subjects had more signal hyperintensities on magnetic resonance imaging scans than control subjects, but the subjects had cerebrovascular disease risk factors. This study used subjects with a history of major depression and matched comparison subjects, screened to exclude cerebrovascular risk factors, to determine whether depressed subjects had more white matter hyperintensities and other lesions. We evaluated the prevalence and severity of MRI signal hyperintensities in 30 elderly depressed patients and 20 controls matched for age. Deep matter hyperintensities, periventricular hyperintensities and subcortical gray hyperintensities were rated on a standard 0-3 scale by two radiologists blind to clinical diagnosis. No significant differences were found between groups for the presence of subcortical gray matter, deep white matter and periventricular hyperintensities. These findings suggest that cerebrovascular disease risk factors most likely mediated the relationship between depression and hyperintensities in previous studies.

[Reliability study of the Brazilian version of a structured interview for the diagnosis of dementia]

OBJECTIVES

to evaluate the reliability of the Structured Interwiew for the Diagnosis of Alzheimer's Type Dementia, Multi-Infarct Dementia and Dementia of other Aetiology (SIDAM) Portuguese version; validated as a reliable instrument to be applied to patients with a presumed diagnosis of dementia or mild cognitive impairment.

METHODS

twenty elderly patients of our Service with a clinical diagnosis of dementia were interviewed simultaneously by the authors, utilizing the SIDAM's Portuguese version. The answers were noted down concomitantly, and then compared. The reliable evaluation of the diagnosis of the SIDAM's Portuguese version was based on Kappa's statistics (K).

RESULTS

of the patients studied, ten were women; with an average age of 75.5 years. Nine were maried, two were not and nine widowers. They had attended school for about 5.3 years. The average score on the Mini Mental State was 16.8. As to their professional activities, 12 (60%) were manual workers, eight were not. Everyone had the diagnosis of dementia, being most of them, Alzheimer's Type. The concordance rate between ICD-10, DSM III-R and the SIDAM's questions showed a K > 0.87; and between the interviewers, rarely K < 0.87.

CONCLUSION

K >/= 0.87 suggests that the Brazilian version of SIDAM can be considered a reliable instrument to be applied to outpatients with presumed diagnosis of dementia in Brazil.

Can neuroimaging techniques identify individuals at risk of developing Alzheimer's disease?

Recent studies indicate that neuroimaging techniques such as magnetic resonance imaging, positron emission tomography, and single-photon emission computed tomography can accurately differentiate patients with Alzheimer's disease (AD) from elderly controls. This report reviews the results of neuroimaging studies of two at-risk populations: subjects with the epsilon 4 allele of the apolipoprotein E and those with mild cognitive impairment. The results of the work published to date indicate that the presence of the epsilon 4 allele is a risk factor for AD and that its predictive validity can be enhanced by neuropsychological and/or neuroimaging evaluation. The results also show that patients with mild cognitive impairment display a number of structural and functional imaging abnormalities that are more pronounced in the temporal and parietal lobes. We suggest that the use of neuroimaging techniques can improve the detection of subjects early in the course of AD, although the sensitivity and the specificity of this approach still await a more detailed prospective evaluation.