Abstract/Text: OBJECTIVE: To design a brief cognitive screener with acceptable sensitivity and specificity for identifying subjects with cognitive impairment.
DESIGN: Cohort one is assembled from a community-based survey coupled with a second-stage diagnostic evaluation using formal diagnostic criteria for dementia. Cohort two is assembled from referrals to a specialty clinic for dementing disorders that completed the same diagnostic evaluation.
SETTING: Urban neighborhoods in Indianapolis, Indiana and the Indiana Alzheimer Disease Center.
PATIENTS: Cohort one consists of 344 community-dwelling black persons identified from a random sample of 2212 black persons aged 65 and older residing in Indianapolis; cohort two consists of 651 subject referrals to the Alzheimer Disease Center.
MEASUREMENTS: Formal diagnostic clinical assessments for dementia including scores on the Mini-mental state examination (MMSE), a six-item screener derived from the MMSE, the Blessed Dementia Rating Scale (BDRS), and the Word List Recall. Based on clinical evaluations, subjects were categorized as no cognitive impairment, cognitive impairment-not demented, or demented.
RESULTS: The mean age of the community-based sample was 74.4 years, 59.4% of the sample were women, and the mean years of education was 10.1. The prevalence of dementia in this sample was 4.3% and the prevalence of cognitive impairment was 24.6%. Using a cut-off of three or more errors, the sensitivity and specificity of the six-item screener for a diagnosis of dementia was 88.7 and 88.0, respectively. In the same sample, the corresponding sensitivity and specificity for the MMSE using a cut-off score of 23 was 95.2 and 86.7. The performance of the two scales was comparable across the two populations studied and using either cognitive impairment or dementia as the gold standard. An increasing number of errors on the six-item screener is highly correlated with poorer scores on longer measures of cognitive impairment.
CONCLUSIONS: The six-item screener is a brief and reliable instrument for identifying subjects with cognitive impairment and its diagnostic properties are comparable to the full MMSE. It can be administered by telephone or face-to-face interview and is easily scored by a simple summation of errors.

Abstract/Text: Patients with cognitive impairment can be divided into 2 broad groups: those with chronic cognitive decline (most likely diagnosable with a dementia) and those with acute cognitive changes (most likely experiencing a delirium). However, diagnosis in clinical practice is far more complicated than it is in textbooks. Perhaps the greatest hurdle in evaluating the cognitively impaired patient is the clarification of a cohesive history. Unfortunately, the cognitively impaired patient is most often unable to provide such a history, and in the absence of a reliable family member, friend, or caregiver to fill in the gaps, diagnostic clarity can be difficult to achieve. This article outlines the broad diagnostic spectra of delirium and dementia, reviews current understanding of their pathogenesis, and discusses useful diagnostic and therapeutic techniques.

Copyright © 2010 Elsevier Inc. All rights reserved.

Abstract/Text: We prospectively studied the evaluation of dementia in 107 unselected outpatients; 83 had so-called "irreversible" dementias, including 74 who had an Alzheimer-type dementia. Fifteen patients had potentially reversible dementias, of which hypothyroidism and drug toxicity were the commonest causes. Distinguishing features of reversible dementia were shorter duration, use of more prescription drugs, and less severe dementia. Almost half of the patients had other previously unrecognized treatable medical diseases. Most diagnoses were made from patient history and physical and mental status examination. Patients with reversible dementia improved but rarely reverted to normal. Objective improvement occurred in 25 patients after treating unrecognized coexistent medical and psychiatric diseases, or stopping unnecessary medication. Careful clinical observation is the most useful part of the evaluation and extensive testing may not be required for all patients. Overemphasis on distinguishing reversible from irreversible forms of dementia may detract from recognition of commoner, treatable causes of dysfunction and suffering.

Abstract/Text: Our objectives were to investigate the utility of the Hachinski Ischemic Score (HIS) in differentiating patients with pathologically verified Alzheimer's disease (AD), multi-infarct dementia (MID), and "mixed" (AD plus cerebrovascular disease) dementia, and to identify the specific items of the HIS that best discriminate those dementia subtypes. Investigators from six sites participated in a meta-analysis by contributing original clinical data, HIS, and pathologic diagnoses on 312 patients with dementia (AD, 191; MID, 80; and mixed, 41). Sensitivity and specificity of the HIS were calculated based on varied cutoffs using receiver-operator characteristic curves. Logistic regression analyses were performed to compare each pair of diagnostic groups to obtain the odds ratio (OR) for each HIS item. The mean HIS (+/- SD) was 5.4 +/- 4.5 and differed significantly among the groups (AD, 3.1 +/- 2.5; MID, 10.5 +/- 4.1; mixed, 7.7 +/- 4.3). Receiver-operator characteristic curves showed that the best cutoff was < or = 4 for AD and > or = 7 for MID, as originally proposed, with a sensitivity of 89.0% and a specificity of 89.3%. For the comparison of MID versus mixed the sensitivity was 93.1% and the specificity was 17.2%, whereas for AD versus mixed the sensitivity was 83.8% and the specificity was 29.4%. HIS items distinguishing MID from AD were stepwise deterioration (OR, 6.06), fluctuating course (OR, 7.60), hypertension (OR, 4.30), history of stroke (OR, 4.30), and focal neurologic symptoms (OR, 4.40). Only stepwise deterioration (OR, 3.97) and emotional incontinence (OR, 3.39) distinguished MID from mixed, and only fluctuating course (OR, 0.20) and history of stroke (OR, 0.08) distinguished AD from mixed. Our findings suggest that the HIS performed well in the differentiation between AD and MID, the purpose for which it was originally designed, but that the clinical diagnosis of mixed dementia remains difficult. Further prospective studies of the HIS should include additional clinical and neuroimaging variables to permit objective refinement of the scale and improve its ability to identify patients with mixed dementia.