An informant-based screening tool for dementia may be useful in population-based studies of minority populations.
Investigate the feasibility of screening for very mild dementia in a community sample of African Americans using an informant-based screening tool (AD8).
One hundred forty-seven persons from the African American Health (AAH) project were screened for dementia; 61 of 93 who were invited had follow-up clinical assessments for dementia diagnosis.
The AD8, Mini-Mental State Examination, Short Blessed Test, Brief Instrument for Dementia Detection, and a neuropsychologic battery were administered at visit 1. The Clinical Dementia Rating (CDR) was administered at visit 2 by clinicians blinded to visit 1 results; the presence of dementia was determined by a CDR greater than 0.
Four hundred sixty-five individuals from the AAH cohort were sent a letter describing the study and, among this group, 252 individuals were contacted by phone to request participation in this study. Six percent (14/252) of the participants contacted by phone were unable to identify an informant (required for the AD8). One hundred fifty individuals agreed by phone to participate of which 2% (n=3) did not have an informant available at the time of participation. The AD8 alone was effective at discriminating between CDR 0 and CDR 0.5 (area under the curve=0.847; P<0.001; 95% confidence interval, 0.73-0.96).
A brief informant-based instrument, the AD8, has high sensitivity and specificity for distinguishing CDR 0 from CDR 0.5 in the community. Informant availability may not be a barrier for using the AD8 in an African American community sample; however, further study in larger samples with a higher response rate, different community settings (eg, community clinics), and among older age groups (eg, age 75+) is warranted to confirm this.
"The AD8 uses informant information; the absence of an observant informant may limit use in certain clinical situations. However, informant interviews can be successfully applied in populations with lower educational attainment (Galvin et al., 2007a; Espinosa et al., 2008; Malmstrom et al., 2009). Additionally, the AD8 can be used as a patient interview in the absence of an informant (Galvin et al., 2007a) and can be administered in person or by phone (Galvin et al., 2006). "
[Show abstract][Hide abstract] ABSTRACT: Screening tests for Alzheimer's disease lack sensitivity and specificity. We developed the AD8, a brief dementia screening interview validated against clinical and cognitive evaluations, as an improvement over current screening methods. Because insufficient follow-up has occurred to validate the AD8 against the neuropathologic findings of Alzheimer's disease, we investigated whether AD8 scores correspond to impairment in episodic memory testing and changes in biomarkers of Alzheimer's disease (cerebrospinal fluid and amyloid imaging with Pittsburgh compound B) characteristic of symptomatic Alzheimer's disease. We also compared informant-based assessments with brief performance-based dementia screening measurements such as the Mini Mental State Exam. The sample (n = 257) had a mean age of 75.4 years with 15.1 years of education; 88.7% were Caucasian and 45.5% were male. The sample was divided into two groups based on their AD8 scores: those with a negative dementia screening test (AD8 score 0 or 1, n = 137) and those with a positive dementia screening test (AD8 score ≥2, n = 120). Individuals with positive AD8 scores had abnormal Pittsburgh compound B binding (P < 0.001) and cerebrospinal fluid biomarkers (P < 0.001) compared with individuals with negative AD8 scores. Individuals with positive AD8 tests and positive biomarkers scored in the impaired range on the Wechsler Logical Memory Story A (mean score 7.0 ± 4.5 for Pittsburgh compound B; mean score 7.6 ± 5.3 for cerebrospinal fluid amyloid beta protein 1-42). The AD8 area under the curve for Pittsburgh compound B was 0.737 (95% confidence interval: 0.64-0.83) and for cerebrospinal fluid amyloid beta protein 1-42 was 0.685 (95% confidence interval: 0.60-0.77) suggesting good discrimination. The AD8 had superior sensitivity in detecting early stages of dementia compared with the Mini Mental State Examination. The AD8 had a likelihood ratio of a positive test of 5.8 (95% confidence interval: 5.4-6.3) and likelihood ratio of a negative test of 0.04 (95% confidence interval: 0.03-0.06), increasing the pre-test probability of an individual having symptomatic Alzheimer's disease. Individuals with AD8 scores of ≥2 had a biomarker phenotype consistent with Alzheimer's disease and lower performance on episodic memory tests, supporting a diagnosis of Alzheimer's disease. Informant-based assessments may be superior to performance-based screening measures such as the Mini Mental State Examination in corresponding to underlying Alzheimer's disease pathology, particularly at the earliest stages of decline. The use of a brief test such as the AD8 may improve strategies for detecting dementia in community settings where biomarkers may not be readily available, and may enrich clinical trial recruitment by increasing the likelihood that participants have underlying biomarker abnormalities.
[Show abstract][Hide abstract] ABSTRACT: Dementia is a global public health problem and detection in the primary care setting, particularly in developing countries, is challenging. The aim of this research was to produce the cross-cultural validation of the AD8 interview to the Brazilian Portuguese Language. The original version of the AD8 was submitted to translation, back-translation, and application of the questionnaire to 20 elderly informants for face validation. The AD8-Brazil was then evaluated in 109 community-dwelling elderly with a sociodemographic questionnaire, clinical examination, Mini Mental State Examination (MMSE), Katz Inventory of Activities of Daily Living (ADL), and Clinical Dementia Rating scale (CDR). The AD8-Brazil was compared with the other instruments and with the clinical diagnosis (DSM-IV) for criterion validation. There was significant agreement of AD8-Brazil with diagnosis of dementia (p < 0.001), MMSE (p = 0.047), and ADL (PFisher = 0.004). Also, the AD8-Brazil was able to differentiate the stages of dementia by CDR scale. The reliability was high (alpha = 0.818) and reproducibility analysis showed excellent inter-rater (kappa = 0.889) and test-retest consistency (kappa = 0.814). The AD8-Brazil showed excellent discrimination between CDR 0 and CDR > 0 (area under the curve 86.1%) and between CDR 0 and CDR 0.5 (area under the curve 76.9%). The administration of the questionnaire took 2.3 ± 0.1 minutes. The Brazilian version of the AD8 is a valid, reliable, quick, and easy screening instrument for dementia.
[Show abstract][Hide abstract] ABSTRACT: Many new therapies for dementia target a specific pathologic process and must be applied early. Selection of specific therapy is based on the clinical etiologic diagnosis. We sought to determine the stability of the clinical etiologic diagnosis over time and to identify factors associated with instability. We identified 4141 patients with dementia or mild cognitive impairment who made at least 2 visits approximately a year apart to a dementia research center, receiving a clinical etiologic diagnosis on each visit. We assessed concordance of etiologic diagnoses across visits, κ-statistics, and transition probabilities among diagnoses. The primary clinical etiologic diagnosis remained stable for 91% of patients but with a net shift toward dementia with Lewy bodies and Alzheimer's disease. Lower diagnostic stability was significantly associated with older age, nonwhite race, milder disease at presentation, more underlying conditions contributing to cognitive decline, lack of a consistent spouse/partner informant, and being evaluated by different clinicians on different visits. Multistate Markov modeling generally confirmed these associations. Clinical etiologic diagnoses were generally stable. However, several readily ascertained characteristics were associated with higher instability. These associations may be useful to clinicians for anticipating when an etiologic diagnosis may be more prone to future change.
American Journal of Alzheimer s Disease and Other Dementias 12/2013; 28(8):750-8. DOI:10.1177/1533317513504611 · 1.63 Impact Factor
Vincent Tse, Jennifer King, Caroline Dowling, Sharon English, Katherine Gray, Richard Millard, Helen O'Connell, Samantha Pillay, Jeffrey Thavaseelan
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