Detection of clinical Alzheimer's disease in diverse populations: Contribution of a delayed recall to the TNI-93.

Abstract

Faced with increasing diversity in Europe, a large body of research in neuropsychology has emerged to develop tools for the reliable detection of cognitive disorders in diverse older adults. Following this perspective, few tools have been validated, particularly for assessing episodic memory, such as the Nine Images Test (TNI-93). The aim of the present study was to test the interest of adding a delayed recall to the classic TNI-93 procedure for the detection of clinical Alzheimer's disease (AD) in diverse populations. A French retrospective analysis was conducted based on the clinical and neuropsychological data of 281 patients (111 who received a clinical diagnosis of AD; 101 with a cognitive profile not suggestive of AD and 70 patients with a subjective cognitive decline). The sample was mostly composed of people with a low level of education and non-French speakers. The TNI-93 data from the neuropsychological assessment, including a free and a cued recall after a 20 min delay, were analysed. First, AD patients performed more poorly than both other groups on all scores. However, performance decreased more significantly after a 20 min delay in AD patients than in the other groups. Second, the Receiver-Operating-Characteristic analysis showed that the higher diagnostic accuracy for the detection of AD patients was obtained for the 20 min free recall. These results confirm the relevance of the TNI-93 for the clinical detection of AD in diverse populations. The added delayed recall condition seems relevant to highlight the accelerated forgetting of AD patients in a 20 min time window following learning.