Apraxia testing to distinguish early Alzheimer's disease from psychiatric causes of cognitive impairment.

Objective: Mood- and stress-related disorders commonly cause attentional and memory impairments in middle-aged individuals. In memory testing, these impairments can be mistakenly interpreted as symptoms of dementia; thus, more reliable diagnostic approaches are needed. The present work defines the discriminant accuracy of the Dementia Apraxia Test (DATE) between psychiatric conditions and early-onset Alzheimer's disease (AD) on its own and in combination with memory tests. Method: The consecutive sample included 50-70-year-old patients referred to dementia investigations for recent cognitive and/or affective symptoms. The DATE was administered and scored as a blinded measurement, and a receiver operating curve analysis was used to define the optimal diagnostic cut-off score. Results: A total of 24 patients were diagnosed with probable AD (mean age 61 ± 4) and 23 with a psychiatric condition (mean age 57 ± 4). The AD patients showed remarkable limb apraxia, but the psychiatric patients mainly performed at a healthy level on the DATE. The test showed a total discriminant accuracy of 87% for a total sum cut-off of 47 (sensitivity 79% and specificity 96%). The limb subscale alone reached an accuracy of 91% for a cut-off of 20 (sensitivity 83% and specificity 100%). All memory tests were diagnostically less accurate, while the combination of the limb praxis subscale and a verbal episodic memory test suggested a correct diagnosis in all but one patient. Conclusions: Apraxia testing may improve the accuracy of differentiation between AD and psychiatric aetiologies. Its potential in severe and chronic psychiatric conditions should be examined in the future.

The dementia apraxia test can detect early-onset Alzheimer's disease.

OBJECTIVE: Limb apraxia is a common early sign of Alzheimer's disease (AD) and is thought to occur specifically in early-onset (before the age of 65) AD. The Dementia Apraxia Test (DATE), a test of limb and face praxis developed to support the differential diagnosis of dementia, has shown good diagnostic accuracy in detecting AD in older patients, but it has not been validated for younger age groups. We investigated how accurately DATE can detect AD in middle-aged individuals and whether apraxia is a distinctive feature in early-onset AD. METHOD: A sample of mild-stage AD patients (n = 24; Mage = 61, SD = 4) was drawn from a prospective consecutive series of individuals referred to our neurology clinic for dementia investigations. A healthy comparison group (HC) of comparable age (n = 22; Mage = 61, SD = 7), sex distribution, and education was recruited. DATE was administered as a blinded experimental measure, and a receiver operating characteristic (ROC) analysis was used to define the optimal diagnostic cutoff point. RESULTS: The DATE classified 93% of the participants correctly as AD or HC (sensitivity 0.88, specificity 1.00, area under curve 0.968). The optimal diagnostic cutoff point was higher (49 points) than in a previous sample of older patients (45 points). Early onset did not seem to be associated with worse praxis performance in AD. CONCLUSIONS: DATE is an accurate tool for detecting early-onset AD within 2 years of symptom onset. The diagnostic cutoff point should be higher for middle-aged populations than for late-onset AD. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Attentional bias towards interpersonal aggression in depression - an eye movement study.

Depressed individuals exhibit an attentional bias towards mood-congruent stimuli, yet evidence for biased processing of threat-related information in human interaction remains scarce. Here, we tested whether an attentional bias towards interpersonally aggressive pictures over interpersonally neutral pictures could be observed to a greater extent in depressed participants than in control participants. Eye movements were recorded while the participants freely viewed visually matched interpersonally aggressive and neutral pictures, which were presented in pairs. Across the groups, participants spent more time looking at neutral pictures than at aggressive pictures, probably reflecting avoidance behavior. When the participants could anticipate the stimulus valence, depressed participants - but not controls - showed an early attentional bias towards interpersonally aggressive pictures, as indexed by their longer first fixation durations on aggressive pictures than on neutral pictures. Our results thus preliminarily suggest both an early attentional bias towards interpersonal aggression, which is present, in depressed participants, also when aggression contents are anticipated, and a later attentional avoidance of aggression. The early depression-related bias in information processing may have maladaptive effects on the way depressed individuals perceive and function in social interaction and can, therefore, maintain depressed mood.