Deterioration of Controlled Processes in the Preclinical Phase of Dementia: A Confirmatory Analysis

Abstract

Preclinical deficits in dementia have recently been investigated in the PAQUID cohort by means of a principal component analysis (PCA) performed from various test scores. According to the interpretation of the first PCA factor, which was found to be an independent predictor of dementia 2 years later, the authors suggested that cognitive deficits occurring in the preclinical phase of dementia may reflect the deterioration of controlled processes. Because this hypothesis relies essentially on the interpretation of PCA factors, the present study was designed to test it within the same cohort. The analyses were focused on one of the tests administered to the subjects, the Wechsler Paired Associate Test (WPAT) divided into two subscores in order to provide a measure of controlled processes of memory functioning (i.e. retrieval of unrelated pairs) as well as of more automatic processes (i.e. retrieval of related pairs). The results showed that the future demented subjects, although significantly impaired compared to elderly controls, were able to increase their performance across trials. More importantly, a new PCA including the subscores of the WPAT showed that the unrelated pair scores were strongly correlated to factor 1, which remained the only factor associated with subsequent dementia, whereas the related pair scores were rather correlated to factor 2. Therefore, these results confirm our previous PCA interpretation, lending more weight to our hypothesis of a preclinical impairment of controlled processes in dementia.

Annual Rate and Predictors of Conversion to Dementia in Subjects Presenting Mild Cognitive Impairment Criteria Defined according to a Population-Based Study

“…However, the test that was found to be the strongest predictor was the LCT, a test of visual selective attention. This result may be linked with previous studies evidencing an early deterioration of attentional executive processes in the course of dementia including in the preclinical stages of the disease [32,37] and underlies the need for clinical practice of systematic assessment of attentional functions in conjunction with other cognitive domains such as memory. Moreover, among the 3 subtasks of the LCT, the best prediction was obtained with the subtask involving a conjoined feature search, which proved to be a better predictor than the simple feature search (LCT1) and the multiple target search (LCT3) tasks.…”

Repetition-lag training to improve recollection memory in older people with amnestic mild cognitive impairment. A randomized controlled trial

“…The Verbal Paired Associates Test (from the Wechsler Memory Scale -Fourth Edition, Wechsler, 2009) contains both related ("sock-shoe") and unrelated word pairs ("laugh-stand"). This task is known to be sensitive to the kinds of memory impairment seen in aMCI (Perri, Carlesimo, Serra, & Caltagirone, 2005), and recall of unrelated word pairs may be a more sensitive measure of recollection than related word pairs (Amieva, Rouch-Leroyer, Fabrigoule, & Dartigues, 2000). (3) To extend findings by other researchers that RLT may improve working memory (measured here by Symbol Span) and cognitive flexibility (Trails B).…”

Cerebral metabolic correlates of four dementia scales in Alzheimer’s disease

“…This "controlled processes impairment " hypothesis has been explicitly explored in some recent studies [35][36][37][38][39]. In keeping with those data, attention (more precisely selective and divided attention) may be one of the earliest cognitive abilities to change in AD and progression of the illness is associated with attentional deterioration [40][41][42].…”