This narrative review aimed to explore the existing knowledge in order to examine the multiple forms of late-life depression (LLD) within a non-neurodegenerative or a neurodegenerative context, in particular Alzheimer’s disease (AD). This review will first provide information about different pathogenic hypotheses proposed to describe LLD when it is not linked to a neurodegenerative context. Within the presentation of these syndromes, the literature reports thymic and cognitive specific features and highlights a common preponderance of cognitive impairment, and particularly executive. This review will also report data from research works that have addressed the role of depressive symptoms (DSs) in incidence of AD and mild cognitive impairment (MCI) conversion to AD. These findings support the claim that the relationship between DS (or LLD) and the cognitive decline encountered in AD can be of 2 types: (1) risk factor or (2) prodrome. They also support the hypothesis that the effect of DS on the incidence of AD can be identified between specific characteristics of these symptoms such as a very first apparition late in life, an increasing severity of DS, and a poor response to medical treatment. Finally, longitudinal and cross-sectional research will be presented, aiming to identify the predictive value of DS (or LLD) on AD incidence and/or conversion of MCI (and specifically amnestic MCI). This final section shows that specific features of LLD, such as being of early- or late-onset, can be considered as indices of AD incidence.

The Brief Irritability Test (BITe, Holtzman et al., 2014 ) is a brief, reliable, and valid self-report measure of irritability. Despite the growing interest to understand the underlying causes and consequences of irritability, this questionnaire has not been developed and validated for a French-speaking population yet. In the present study, 413 participants completed our French adaptation of the BITe (i.e., TCI; Test Court d’Irritabilité) and measures of associated constructs (depression, anger, hostility, and aggression) and well-being (life satisfaction and social support). Descriptive, psychometric (i.e., Cronbach alpha and Spearman correlation coefficients), and factor analyses were conducted. An exploratory factor analysis in sample 1 (n = 209), yielded one single factor. The confirmatory factor analysis in sample 2 (n = 204) showed a reasonable fit of this single factor model explaining 55.5% of the variance and presenting a strong internal consistency (α = .80). Compared to the original English questionnaire, the TCI shares similar unidimensional factor organization and correlations with other constructs, although a gender bias was identified, with women scoring higher than men. Irritability was higher among respondents in the age range 17–25, compared to older adults. A hierarchical regression analysis showed that TCI scores significantly predict depressive symptoms when demographics were controlled for. In summary, the TCI presents good psychometric properties and could constitute a valuable tool to evaluate irritability in clinical and research contexts.

Iconic gesture-speech integration is a relatively recent field of investigation with numerous researchers studying its various aspects. The results obtained are just as diverse. The definition of iconic gestures is often overlooked in the interpretations of results. Furthermore, while most behavioral studies have demonstrated an advantage of bimodal presentation, brain activity studies show a diversity of results regarding the brain regions involved in the processing of this integration. Clinical studies also yield mixed results, some suggesting parallel processing channels, others a unique and integrated channel. This review aims to draw attention to the methodological variations in research on iconic gesture-speech integration and how they impact conclusions regarding the underlying phenomena. It will also attempt to draw together the findings from other relevant research and suggest potential areas for further investigation in order to better understand processes at play during speech integration process.

While previous studies have shown the importance of visuo-spatial working memory in the processing of co-speech iconic gestures, clear evidence for a potential involvement of the verbal working memory (vWM) is currently lacking. To address this issue, participants in the present study were presented with a dual task paradigm. The main outcome variable was the performance on a Stroop-like gesture task which provides a behavioural index of gesture-speech integration. Participants performed this task under conditions of either high or low concurrent vWM load. Unlike in previous studies, the number of words to remember in the high load condition was determined by their individual verbal span rather than being fixed. Results showed reaction time costs in the form of longer reaction times for semantically incongruent gesture-speech combinations as compared to congruent combinations. However, this semantic congruency effect disappeared when the vWM load increased. This result suggests a causal involvement of verbal working memory capacity in gesture-speech integration.

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