Executive Profile of the Logopenic Variant of Primary Progressive Aphasia: Comparison with the Semantic and Non-Fluent Variants and Alzheimer's Disease.

The logopenic variant of primary progressive aphasia (lvPPA) shows different features from the non-fluent (nfvPPA) and semantic (svPPA) variants of PPA. Although language impairments remain the core symptoms, studies have highlighted the presence of executive disorders at the onset of the disease. Nevertheless, the results are contradictory, particularly in lvPPA. The aim of this study was to explore the executive profile of lvPPA. We compared executive functioning in lvPPA with the other two variants of PPA, Alzheimer's disease (AD) and a cognitively healthy group. In total, 70 patients with PPA, 32 patients with AD, and 41 healthy controls were included. They underwent a comprehensive executive battery assessing short-term and working memory, inhibition, flexibility, planning, and initiation. The analyses showed significant differences between the lvPPA group and the control group, except on visuospatial spans and the Stroop test, and between the lvPPA group and the other PPA groups and the AD group for several tasks. Thus, this research highlighted the existence of an executive dysfunction from the onset of the disease in lvPPA but also in the other two variants of PPA.

Biases in BCI experiments: Do we really need to balance stimulus properties across categories?

Brain Computer Interfaces (BCIs) consist of an interaction between humans and computers with a specific mean of communication, such as voice, gestures, or even brain signals that are usually recorded by an Electroencephalogram (EEG). To ensure an optimal interaction, the BCI algorithm typically involves the classification of the input signals into predefined task-specific categories. However, a recurrent problem is that the classifier can easily be biased by uncontrolled experimental conditions, namely covariates, that are unbalanced across the categories. This issue led to the current solution of forcing the balance of these covariates across the different categories which is time consuming and drastically decreases the dataset diversity. The purpose of this research is to evaluate the need for this forced balance in BCI experiments involving EEG data. A typical design of neural BCIs involves repeated experimental trials using visual stimuli to trigger the so-called Event-Related Potential (ERP). The classifier is expected to learn spatio-temporal patterns specific to categories rather than patterns related to uncontrolled stimulus properties, such as psycho-linguistic variables (e.g., phoneme number, familiarity, and age of acquisition) and image properties (e.g., contrast, compactness, and homogeneity). The challenges are then to know how biased the decision is, which features affect the classification the most, which part of the signal is impacted, and what is the probability to perform neural categorization per se. To address these problems, this research has two main objectives: (1) modeling and quantifying the covariate effects to identify spatio-temporal regions of the EEG allowing maximal classification performance while minimizing the biasing effect, and (2) evaluating the need to balance the covariates across categories when studying brain mechanisms. To solve the modeling problem, we propose using a linear parametric analysis applied to some observable and commonly studied covariates to them. The biasing effect is quantified by comparing the regions highly influenced by the covariates with the regions of high categorical contrast, i.e., parts of the ERP allowing a reliable classification. The need to balance the stimulus's inner properties across categories is evaluated by assessing the separability between category-related and covariate-related evoked responses. The procedure is applied to a visual priming experiment where the images represent items belonging to living or non-living entities. The observed covariates are the commonly controlled psycho-linguistic variables and some visual features of the images. As a result, we identified that the category of the stimulus mostly affects the late evoked response. The covariates, when not modeled, have a biasing effect on the classification, essentially in the early evoked response. This effect increases with the diversity of the dataset and the complexity of the algorithm used. As the effects of both psycho-linguistic variables and image features appear outside of the spatio-temporal regions of significant categorical contrast, the proper selection of the region of interest makes the classification reliable. Having proved that the covariate effects can be separated from the categorical effect, our framework can be further used to isolate the category-dependent evoked response from the rest of the EEG to study neural processes involved when seeing living vs. non-living entities.

Covert Attention to Gestures Is Sufficient for Information Uptake.

Numerous studies have explored the benefit of iconic gestures in speech comprehension. However, only few studies have investigated how visual attention was allocated to these gestures in the context of clear versus degraded speech and the way information is extracted for enhancing comprehension. This study aimed to explore the effect of iconic gestures on comprehension and whether fixating the gesture is required for information extraction. Four types of gestures (i.e., semantically and syntactically incongruent iconic gestures, meaningless configurations, and congruent iconic gestures) were presented in a sentence context in three different listening conditions (i.e., clear, partly degraded or fully degraded speech). Using eye tracking technology, participants' gaze was recorded, while they watched video clips after which they were invited to answer simple comprehension questions. Results first showed that different types of gestures differently attract attention and that the more speech was degraded, the less participants would pay attention to gestures. Furthermore, semantically incongruent gestures appeared to particularly impair comprehension although not being fixated while congruent gestures appeared to improve comprehension despite also not being fixated. These results suggest that covert attention is sufficient to convey information that will be processed by the listener.

Late-Life Depression, Cognitive Impairment, and Relationship with Alzheimer's Disease.

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.

Perceptual and Interoceptive Strength Norms for 270 French Words.

Perceptual experience through the five modalities (i.e., vision, hearing, touch, taste, and smell) has demonstrated its key role in semantics. Researchers also highlighted the role of interoceptive information in the grounded representation of concepts. However, to this day, there is no available data across these modalities in the French language. Therefore, the aim of this study was to circumvent this caveat. Participants aged between 18 and 50 completed an online survey in which we recorded scores of perceptual strength (PS), interoceptive information, imageability, concreteness, conceptual familiarity, and age of acquisition of 270 words of the French language. We also analysed the relationships between perceptual modalities and psycholinguistic variables. Results showed that vast majority of concepts were visually-dominant. Correlation analyses revealed that the five PS variables were strongly correlated with imageability, concreteness, and conceptual familiarity and highlight that PS variables index one aspect of the semantic representations of a word. On the other hand, high interoceptive scores were highlighted only for the less imageable and less concrete words, emphasizing their importance for the grounding of abstract concepts. Future research could use these norms in the investigation of the role of perceptual experience in the representation of concepts and their impact on word processing.

The Role of Iconic Gestures in Speech Comprehension: An Overview of Various Methodologies.

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.

Affective Ratings of Pictures Related to Interpersonal Situations.

Many studies require standardized and replicable protocols composed of emotional stimuli. To this aim, several databases of emotional pictures are available. However, there are only few images directly depicting interpersonal violence, which is a specific emotion evocative stimulus for research on aggressive behavior or post-traumatic stress disorder. The objective of the current study is to provide a new set of standardized stimuli containing images depicting interpersonal situations (both positive and negative). This will allow a sensitive assessment of a wide range of cognitions linked to social interaction (empathy, perspective taking, traumatic experiences, etc.). To this aim, 240 participants rated the valence and arousal of 79 pictures collected from online sources in 2018. Results showed (1) a distinctive pattern of valence and arousal regarding the picture content and (2) specific associations between those two dimensions. Taken together, these results suggest a good reliability of the selected images. In conclusion, our study provides an open access set of recent pictures depicting interpersonal situations along with normative valence and arousal ratings, that are available for download from: https://osf.io/ak4m7/?view_only=None.

Do Alzheimer's Disease Patients Benefit From Prior-Knowledge in Associative Recognition Memory?

OBJECTIVES: Although the influence of prior knowledge on associative memory in healthy aging has received great attention, it has never been studied in Alzheimer's disease (AD). This study aimed at assessing whether AD patients could benefit from prior knowledge in associative memory and whether such benefit would be related to the integrity of their semantic memory. METHODS: Twenty-one AD patients and 21 healthy older adults took part in an associative memory task using semantically related and unrelated word pairs and were also submitted to an evaluation of their semantic memory. RESULTS: While participants of both groups benefited from semantic relatedness in associative discrimination, related pairs recognition was significantly predicted by semantic memory integrity in healthy older adults only. CONCLUSIONS: We suggest that patients benefitted from semantic knowledge to improve their performance in the associative memory task, but that such performance is not related to semantic knowledge integrity evaluation measures because the two tasks differ in the way semantic information is accessed: in an automatic manner for the associative memory task, with automatic processes thought to be relatively preserved in AD, and in a controlled manner for the semantic knowledge evaluation, with controlled processes thought to be impaired in AD. (JINS, 2019, 25, 443-452).

The mini-SKQ (semantic knowledge questionnaire): a quick screening tool to assess semantic memory impairment in Alzheimer's disease.

The breakdown of semantic memory appears early in Alzheimer's disease (AD). Lexico-semantic difficulties (e.g. difficulties in retrieving words and their meaning) are among the first symptoms of the disease. In order to screen this lexico-semantic decline, we propose the mini-SKQ, a semantic knowledge questionnaire. Mini-SKQ explores semantic impairment in AD patients with 12 questions. We administer mini-SKQ to 77 participants, 39 AD and 38 healthy old people. Results showed a significant difference between the groups: AD patients made significantly more errors than healthy old people. The Receiver operating characteristic (ROC) analysis established the optimal cut-off score of the mini-SKQ at 3 errors (sensitivity 61,5%, specificity 89,5%) in differentiating between AD patients and healthy old people. The mini-SKQ is a fast and easily administered questionnaire. Results indicated favorable indicators to screen semantic knowledge. These first observations underline that mini-SKQ could potentially be attractive for screening semantic memory deterioration.

The functional communication scale for patients with neurodegenerative disease: development and validation of a French test evaluating residual communication skills.

Verbal and nonverbal communication impairments are often observed in the context of neurodegenerative diseases. Identifying the most appropriate communication strategies for each patient, by a better understanding of his communicational difficulties, would help to maintain his autonomy and to improve his quality of life. OBJECTIVE: To propose a rapid and ecological tool specifically adapted for people with cognitive disorders in advanced stages of the diseases. METHODS: Two major steps were necessary, the development of the tool itself (A) and the evaluation of some of its psychometric properties (B). The first step (A) allowed the development of a tool aimed at the observation of communication skills during a situation of natural interaction and the analysis of communication according to various activities (production, recognition and comprehension of oral language acts, written and gestural, as well as figures, in different degrees of complexity). The second step (B) consisted to measure the validity of the content and the criterion of the test, as well as its fidelity between judges. The final version of the tool is composed of two grids, an examiner's guide and a patient's test sheet. The use of the tool has been standardized. RESULTS: At the end of the validation process, psychometric properties demonstrated good content validity and good criterion validity for the scale. Fidelity was subsequently measured and also judged to be good. After that, a pre-test with patients with neurodegenerative diseases has been carried out. CONCLUSION: This tool should address a significant clinical need to enable clinicians to rapidly describe communication skills in a patient with neurodegenerative disease and to recommend communication strategies for formal and informal caregivers.

Distinct progression of the deterioration of thematic and taxonomic links in natural and manufactured objects in Alzheimer's disease.

Taxonomic and thematic relationships are core elements of lexico-semantic networks. However, the weight of both links differs in semantic memory, with distinct support for natural and manufactured objects: natural objects tend to be more taxonomically identified while manufactured objects benefit more from the underlying thematic relationships. Alzheimer's disease (AD) causes early semantic memory impairment characterized by a category-specific deterioration, where natural objects are more sensitive to the disease than manufactured objects. However, relatively few studies have examined the progressive deterioration of specific thematic versus taxonomic relations in both categories of objects in AD. To better understand semantic memory disorganization in AD and analyze the potential interaction effect between the category (natural/manufactured), the condition (thematic/taxonomic) and AD, we will investigate the lexico-semantic network in 82 AD patients (divided into three groups depending on their global cognitive deterioration and their performance in a preliminary semantic knowledge questionnaire (mild (AD1), moderate (AD2) and advanced (AD3) stages of semantic knowledge alteration). The experimental protocol contains two tasks: an implicit semantic priming paradigm and an explicit card-sorting test that uses the same items, equally divided between natural and manufactured objects. Results show a distinct taxonomic and thematic evolution pattern with early taxonomic deterioration. Natural objects are also more vulnerable to the disease. Lastly, there is an interaction effect between the category and the condition in the priming task indicating that natural objects are more taxonomically organized and manufactured objects benefit more from both thematic and taxonomic organizations, reinforcing the idea of the robustness of this category. The theoretical accounts of these observations will be discussed in detail.

Retrogenesis of semantic knowledge: Comparative approach of acquisition and deterioration of concepts in semantic memory.

OBJECTIVE: Semantic memory is the result of progressive development during childhood. During the construction of the lexico-semantic network, the features of the objects are progressively stored to build our knowledge. Alzheimer's disease (AD) disrupts conceptual links that support semantic memory. Individuals suffering from AD lose access to words as well as to meaning. Some researchers have made the assumption that cognitive retrogenesis leads to a cognitive decline that reverses acquisition steps in childhood. This study proposes to analyze the validity of this theory applied to semantic knowledge. METHOD: We administered a semantic knowledge questionnaire (SKQ) featuring 30 objects associated with 4 questions (2 superordinate questions; Q1 = general; Q2 = intracategorial; and 2 subordinate questions; Q3 = perceptual; Q4 = thematical/functional) to 93 children (30 5-year-old children; 30 7-year-old children; and 33 9-year-old children), 32 healthy elderly people, and 66 AD patients (20 in the initial stage of the disease, AD1; 16 in the intermediate stage, AD2; and 30 in the advanced stage, AD3). RESULTS: Our results show that the total number of errors in the SKQ evolved in a "u-shaped" curve: children made less and less errors at the SKQ during development while AD patients presented the reverse pattern. Moreover, the performance of 5-year-old children was identical to that of AD3 patients. Similar results were observed with 7-year-old children and AD2 patients, and with 9-year-old children and AD1 patients. CONCLUSION: These data are consistent with the idea of a lexico-semantic retrogenesis process. (PsycINFO Database Record

[The SQK: a semantic knowledge questionnaire to specify the severity of semantic deterioration in Alzheimer's disease patients]. / Le QCS : questionnaire de connaissances sémantiques pour déterminer le stade de détérioration sémantique chez les patients atteints de la maladie d'Alzheimer.

Lexico-semantic difficulties are common in Alzheimer's disease (AD). The bottom-up process theory is today well accepted: superordinate attributes tend to decline slower than subordinate ones. However, a specific issue in semantic memory investigation in AD is to determine the severity of the semantic impairment. Given that the regularity of the semantic disorder in early AD is uncertain, we argue that the constitution of experimental AD groups must consider the semantic deterioration stage. We thus propose a specific semantic knowledge questionnaire (SKQ), based on Laiacona et al.'s work (1993). SKQ was proposed to 49 AD patients and 33 healthy old people. Three experimental AD groups were created, based on the global cognitive deterioration. In a second study, we explore the possibility for early AD to display different semantic deterioration profile. Our results show a significant group effect, a significant type of question effect (superordinate vs subordinate) and a significant interaction effect. Moreover, a significant correlation between the total errors at the SKQ and the MMSE score is observed. Finally, we observe that early AD patients can show different semantic alteration, with mild or very mild semantic deterioration without any differences in the global cognitive alteration. The SKQ seems adapted to highlight the semantic deterioration and the bottom-up process in AD: superordinate information are better preserved than subordinate information. It can also distinguish different semantic deterioration in early AD. Our result clearly show that research on semantic deterioration in early stage of AD must take into account the severity of the semantic alteration.

Impact of auditory-visual bimodality on lexical retrieval in Alzheimer's disease patients.

The aim of this study was to generalize the positive impact of auditory-visual bimodality on lexical retrieval in Alzheimer's disease (AD) patients. In practice, the naming skills of healthy elderly persons improve when additional sensory signals are included. The hypothesis of this study was that the same influence would be observable in AD patients. Sixty elderly patients separated into three groups (healthy subjects, stage 1 AD patients, and stage 2 AD patients) were tested with a battery of naming tasks comprising three different modalities: a visual modality, an auditory modality, and a visual and auditory modality (bimodality). Our results reveal the positive influence of bimodality on the accuracy with which bimodal items are named (when compared with unimodal items) and their latency (when compared with unimodal auditory items). These results suggest that multisensory enrichment can improve lexical retrieval in AD patients.