Parietal.org--Presentations

Early Detection of MCI/Alzheimer's and Financing Care

Early detection

Parietal Lobe Activation During Rapid, Automatized Naming (RAN)

Background: The identification of neuropsychological tests sensitive enough to detect early brain abnormalities in subjects at risk for developing dementia, such as Alzheimer´s disease (AD), is of great interest in the light of modern pharmacological intervention. We here report on such a test for the assessment of parietal lobe function, and also report on its validation by means of regional cerebral blood flow measurements.

Objective: The purpose of this study was 1. to determine whether rapid automatized naming (RAN) functionally engages the parietal lobes in normal healthy subjects, 2. whether this task could be used to identify parietal lobe dysfunction in patients with AD.
Methods: The study population was 14 normal healthy subjects and 10 patients with AD (mild to moderate). Patients were diagnosed according to established criteria (DSM-IV, NINDS-ADRDA). Regional cerebral blood flow (rCBF) was assessed with the non-invasive xenon-133 inhalation method using the Cerebrograph Cortexplorer 64 ((Ceretronix, Randers, Denmark).Two rCBF-measurements were performed on each subject. After baseline rCBF (rest, eyes open), the subject was remeasured while performing the RAN-task, which involved the repeated reading of 40 different colour and form combinations, as rapidly as possible. The results were compared with normal reference data obtained during rest and during verbal fluency (n=92).

Results: Normal rCBF-values were significantly augmented in parietal areas during the RAN-task, when compared with rCBF obtained during rest and during verbal fluency (p<0.0001). In addition, a highly significant (p<0.0001) flow decrease was seen in frontal and frontotemporal areas bilaterally. In contrast, no parietal lobe activation was seen in the AD patients, who also had significantly longer reading times than the normal controls.

Conclusion: This is the first report on a sensitive neuropsychological test to detect parietal lobe dysfunction during brain imaging, and which can be readily performed by patients with AD.

of MCI and Alzheimer’s has become a global issue. This presentation introduces demographic data, differentiates Alzheimer’s from other dementias, delineates the disease progression from MCI to AD, and summarizes and compares current screening tests for MCI/AD. Screening methods, measurement objectivity, reliability and clinical utility are emphasized. Screening options are presented within a global perspective with involvement of SLPs. Family support systems, resources and financial realities are discussed. Sources of funding for long term care resulting from AD and other dementias (e.g., Medicare/Medicaid, personal assets) will be identified and resource guides provided. Care delivery systems emphasize quality of care.

The AQT© as a Useful Short Screening Test for Dementia. Evidence from Two European Cultures

Background: Alzheimer´s disease (AD) is the most common cause of dementia in the growing elderly population in many countries. The quests for symptomatic relief and prospects of pharmacological treatments of AD, call for sensitive and reliable screening tests which can be easily used by general practitioners in different countries and cultural settings. General criteria for such screening tests should include easy administration and unequivocal scoring, and independence of factors known to be related to cultural settings and educational level. The AQT is a novel screening test designed to assess cognitive processing speed. Three sets of universal stimuli are presented to patients in a fixed protocol. The administration takes 3 - 5 minutes and the clinical outcome measure is the time (seconds) it takes to perform the test. The AQT is standardized and validated in the USA and in Sweden. It is used by general practitioners and hospital staff throughout Sweden as a supplementary test to the MMSE in the assessment of dementia.

Objective(s): We performed a collaborative research study between two European countries, Sweden and Greece, in order to establish the validity and reliability of the AQT, and to further evaluate whether test results meet the criteria of being independent of language and educational level.

Methods: The Swedish participants were 97 patients with AD, and 59 healthy subjects, while the Greek participants were 75 patients with AD, and 29 healthy subjects, respectively. All patients met the NINCDS-ADRDA and the DSM-IV criteria for dementia. The patients’ educational level ranged from 2 to 17 years, MMSE: mean 22.6. The AQT and the MMSE were assessed in all subjects by experienced psychiatrists and neuropsychologists in routine clinical settings in both countries. The discriminatory values of the AQT and the MMSE in the two countries and languages are presented in the Table below.

	Sensitivity	Specificity	Predictive values (%)
AQT Sweden	93.1	99.9	99.9
AQT Greece	98.7	6.6	98.7
AQT Sweden	88.7	95.5	97.2
AQT Greece	93.3	69.0	88.6

Conclusions: The results demonstrate that cognitive processing speed is a general and very sensitive measure that clearly separates mild dementia from normal aging. The usefulness of the AQT in dementia assessment is suggested by the striking similarity of findings in different cultural settings.

Clinical Utility of AQT Color-Form Naming: Normal Aging and AD

Abstract: AQT Color-Form Naming and Mini Mental State Examination were administered to 38 adults with mild/moderate Alzheimer’s and 38 controls. Group means differed significantly (p < .001). AQT-CF specificity was 97%; sensitivity 97%. MMSE specificity was 100%, sensitivity 84%. AQT-CF is objective and highly reliable and differentiates AD-affected from non-AD subjects.

Introduction -- In this study, we compared the discriminant ability of two single-dimension naming (color and form) and one dual-dimension naming (color-form) test from the AQT Assessment of Parietal Function (Wiig et al., 2002) and Mini Mental State Examination (MMSE) (Folstein et al., 1975) MMSE is an established screening test for Alzheimer’s disease (AD) for which extensive research exists (Molloy et al, 1991; Teng et al., 1998; Tombaugh & MacIntyre, 1992;). It uses formats for assessing cognitive impairments that probe cognitive content such as verbal memory and visual construction. AQT measures processing speed for naming single- and dual-dimension visual stimuli. Similar to other processing speed tests, it uses performance time, rather than content performance, as measures and the outcome measure includes reaction time and response time (Goetz et al., 1989; Teichner, 1975; Strauss et al., 1995; Stroop, 1935) AQT dual-dimension naming (color-form combinations) times allow evaluation of cognitive functions that underlie recognition, attention, working memory, automaticity and retrieval, each of which are adversely affected by dementia (Callahan et al., 1995; Baddeley et al., 1991).

Subjects -- There were 38 adults with mild to moderate Alzheimer’s disease (AD) in the age range from 59 to 87 years (M = 73·79 yrs.; SD = 7·42 yrs.) and 38 sex and age matched (within +/-12 mo.), normally functioning adults in the age range from 60 to 87 years (M = 73·89 yrs.; SD = 7·33 yrs.). All subjects underwent a thorough clinical evaluation, including physical, neurological, and psychiatric evaluation, screening laboratory tests, electro-cardiography (EEG), computerized tomography (CT) or magnetic resonance imagining (MRI), investigation of the regional cerebral blood flow (133Xenon inhalation technique) and CFS analysis. The diagnosis of a “probable AD” was made by exclusion in accordance with the NINCDS-ADRDA criteria (McKhann et al., 1984).

Materials -- The primary screening task, AQT Color-Form Naming (AQT-CF), consists of three tests. The first two feature 40 randomly repeated, single-dimension visual stimuli (colors: black, blue, green, red; forms: circle, line, square, triangle) and measure perceptual speed. The third features 40 repeated dual-dimension stimuli that require naming of first the color and then the form and measures cognitive speed (attention, working memory, retrieval and verbal automaticity). Test-retest reliability for color, form, and color-form naming is high (r = ·91, ·92, and ·95, respectively), and there is no evidence of habituation, learning, or fatigue in repeated trials over 10 minutes. The tests were preceded by three short, practice trials to establish adequacy in naming. The second measure, MMSE, is a standardized screening test for MCI and dementia. It has a score range from 0 to 30 points, with a normal range from 27 to 30 points. A range of test-retest reliability coefficients are reported with the highest coefficients suggesting a learning effect over short time periods (Tombaugh & McIntyre, 1992).

Results -- The mean AQT color, from and color-form combination naming times were 23.12, 29.19, and 53.72 seconds, respectively, for the controls, and 38.73, 51.99, and 90.18 seconds, respectively, for the AD subjects. All mean differences for naming times were highly significant (p < ·001). The mean MMSE score was 29·29 for the controls and 23·05 for the AD subjects, and the difference was highly significant (p < ·001). AQT single-dimension color naming time (sec.) correctly classified 100% of controls and 71% of AD subjects (predictive value 85.5%). Single-dimension form naming correctly identified 97% of the controls and 71% of the AD subjects (predictive value 79%). Dual-dimension color-form naming (AQT-CF) correctly identified 97% of the controls and 97% of the AD subjects (predictive value 97%). The relatively low sensitivity values (71%) for single-dimension color or form naming indicate that it is the combination of the two stimulus dimensions color and form that results in the high sensitivity of color-form naming (97%). By using a combination of AQT naming times (in seconds) for color (100% specificity), form (97% specificity) and color-form (97% specificity) false-positive identifications may be minimized. In comparison, MMSE correctly classified 100% of controls and 84% of AD patients (predictive value 87%). The high predictive value of the AQT-CF (a double task) agrees with findings that Alzheimer’s patients show marked deterioration of the ability to coordinate two tasks when compared to normally aging adults (Baddeley et al., 1991; Callahan et al., 1995).

Discussion -- An optimal screening test for Alzheimer’s disease would be expected to: (a) provide high reliability, sensitivity and specificity; (b) be objective and quick and easy to administer and score; (c) unaffected by education and cultural background; (d) not show habituation or effects of learning after repeated administrations; and (e) be relatively inexpensive for the patient (Burns et al., 2002; Crevel et al., 1999). AQT color-form naming responds positively to all of these criteria. AQT-CF has high reliability (r .95); specificity (97%) and sensitivity (97%). It is objective (timed) and the simple methodology allows administration by paraprofessionals after a short period of training. It is minimally affected by age (Jacobson et al., 2003) and exhibits features that are desirable in a culturally diverse society due to the simplicity and universality of the visual stimuli. Perhaps more importantly, AQT-CF can be administered anywhere with a minimum of materials required, provide for a wide range of finely separated measurement points (seconds) and results can be conveyed easily to professionals for judgment of outcomes AQT-CF has no ceiling, as it can measure total naming time to the infinite. In other words, when administered repeatedly, AQT-CF can catch minimal declines in performance even in high-performing adults. In combination these characteristics give AQT-CF several advantages over MMSE and other screening tests of cognitive content. It can be administered repeatedly, identify changes or drifts from a personal (baseline) or normal standard of performance, and monitor changes after medication. It therefore appears to be a candidate for an optimal primary screening test for evidence of decline in cognitive functions, including MCI and ‘probable Alzheimer’s.

Elisabeth H. Wiig, Ph.D. & Gail Steingold, M.S. 2005 Annual Convention of the American Speech-Language-Hearing Association, San Diego, CA.