Assessment of executive function impairments in adults with acquired brain injury across single-case experimental design: A scoping review of primary outcomes.

The use of single-case experimental design (SCED) to evaluate cognitive remediation is growing. SCEDs require rigorous methodology and appropriate choice of primary outcomes. To review primary outcomes that assess executive function impairments in patients with acquired brain injury (ABI). A scoping review was conducted using the Arksey and O'Malley framework and the PRISMA extension for scoping review (PRISMA-ScR). Five databases were searched resulting in the inclusion of twenty-one studies. Primary outcomes were extracted and classified according to the type of measure, ecological setting and sources of possible bias. A wide variety of primary outcomes were identified; the majority of which evaluated behavioural performance during a real-life activity or in a real-life simulated setting. The most frequent bias observed across outcomes was the coaching effect. The findings of this scoping review highlight the importance of selecting appropriate outcomes for repeated measures in SCED studies. Direct observation of the target behaviour is a potential gold standard for assessing the effectiveness of a cognitive intervention.

Inattentional deafness to auditory alarms: Inter-individual differences, electrophysiological signature and single trial classification.

Inattentional deafness can have deleterious consequences in complex real-life situations (e.g. healthcare, aviation) leading to miss critical auditory signals. Such failure of auditory attention is thought to rely on top-down biasing mechanisms at the central executive level. A complementary approach to account for this phenomenon is to consider the existence of visual dominance over hearing that could be implemented via direct visual-to-auditory pathways. To investigate this phenomenon, thirteen aircraft pilots, equipped with a 32-channel EEG system, faced a low and high workload scenarii along with an auditory oddball task in a motion flight simulator. Prior to the flying task, the pilots were screened to assess their working memory span and visual dominance susceptibility. The behavioral results disclosed that the volunteers missed 57.7% of the auditory alarms in the difficult condition. Among all evaluated capabilities, only the visual dominance index was predictive of the miss rate in the difficult scenario. These findings provide behavioral evidences that other early cross-modal competitive process than top down modulation process could account for inattentional deafness. The electrophysiological analyses showed that the miss over the hit alarms led to a significant amplitude reduction of early perceptual (N100) and late attentional (P3a and P3b) event-related potentials components. Eventually, we implemented an EEG-based processing pipeline to perform single-trial classification of inattentional deafness. The results indicate that this processing chain could be used in an ecological setting as it led to 72.2% mean accuracy to discriminate missed from hit auditory alarms.

"All that glitters is not alone". Congruity effects in highly and less predictable sentence contexts.

CONTEXT: Using natural connected speech, the aim of the present study was to examine the semantic congruity effect (i.e. the difference between semantically incongruous and congruous words) in sentence contexts that generate high or moderate final word expectancies. METHODS: We used sentences with two levels of word expectancy in the auditory modality: familiar proverbs (that generate high final word expectancy), and unfamiliar sentences (that generate only moderate final word expectancy). RESULTS: Results revealed an early congruity effect (0-200 ms) that developed across all scalp sites for familiar proverbs but not for unfamiliar sentences. By contrast, typical centro-parietal N400 and Late Positivity Component congruity effects developed later (200-500 ms and 600-900 ms ranges) for both familiar proverbs and unfamiliar sentences. DISCUSSION: We argue that the early congruity effect for proverbs comprises both a Phonological Mismatch Negativity, reflecting the processing of the acoustic/phonological mismatch between the expected (congruous) and unexpected (incongruous) sentence completions and a typical N400 semantic congruity effect with an unusual short latency because final words can be predicted from the unusually high contextual constraints of familiar proverbs. These results are considered in the light of current views of anticipation and prediction processes in sentence contexts.