A Systematic Review of Cognition in Chiari I Malformation

Displacement of the cerebellar tonsils in Chiari type I malformation (CMI) can affect functions controlled by the cerebellum and brainstem. While playing an integral role in the control of movement, the cerebellum also has widespread cortical connections, influencing a range of cognitive process. A systematic literature review was conducted to examine the relationship between cognition and CMI, assessing evidence for general or domain-specific cognitive change. The search protocol examined the AMED, CINAHL, Cochrane Library, EMBASE, MEDLINE, PsycINFO, and Scopus databases. Articles meeting the following criteria were included in this review (i) examined children or adults with a clinically defined diagnosis of CMI, (ii) assessed cognitive function with a prospective examination, (iii) included at least one standardized instrument designed to measure general or specific domains of cognitive function, and (iv) were published in English in a peer-reviewed journal. Twelve articles were identified, including 783 cases aged 3 months to 64 years. General cognition, processing speed, and learning and memory appeared less affected, while language deficits appeared to diminish with age. Executive dysfunction was the most commonly reported cognitive impairment, while attention and working memory, and visuospatial and perceptual skills also appeared vulnerable. Numerous methodological limitations were identified that should be considered in interpreting the impact of CMI and planning future investigations. Overall, there is currently insufficient evidence to describe a valid and reliable profile of cognitive impairment in CMI. Further research is required to confirm these preliminary psychometric results and integrate them with pathophysiological models     

Response-retrieval and negative priming

The existence of across-notation automatic numerical processing of two-digit (2D) numbers was explored using size comparisons tasks. Participants were Arabic speakers, who use two sets of numerical symbols—Arabic and Indian. They were presented with pairs of 2D numbers in the same or in mixed notations. Responses for a numerical comparison task were affected by decade difference and unit-decade compatibility and global distance in both conditions, extending previous findings with Arabic digits (Nuerk, Weger, & Willmes, 2001). Responses for a physical comparison task were affected by congruency with the numerical size, as indicated by the size congruency effect (SiCE). The SiCE was affected by unit-decade compatibility but not by global distance, thus suggesting that the units and decades digits of the 2D numbers, but not the whole number value were automatically translated into a common representation of magnitude. The presence of similar results for same- and mixed-notation pairs supports the idea of an abstract representation of magnitude.     

Person perception informs understanding of cognition during visual search

Does person perception—the impressions we form from watching others—hold clues to the mental states of people engaged in cognitive tasks? We investigated this with a two-phase method: In Phase 1, participants searched on a computer screen (Experiment 1) or in an office (Experiment 2); in Phase 2, other participants rated the searchers’ video-recorded behavior. The results showed that blind raters are sensitive to individual differences in search proficiency and search strategy, as well as to environmental factors affecting search difficulty. Also, different behaviors were linked to search success in each setting: Eye movement frequency predicted successful search on a computer screen; head movement frequency predicted search success in an office. In both settings, an active search strategy and positive emotional expressions were linked to search success. These data indicate that person perception informs cognition beyond the scope of performance measures, offering the potential for new measurements of cognition that are both rich and unobtrusive.     

Similarity-based interference during language comprehension: Evidence from eye tracking during reading

The nature of working memory operation during complex sentence comprehension was studied by means of eye-tracking methodology. Readers had difficulty when the syntax of a sentence required them to hold 2 similar noun phrases (NPs) in working memory before syntactically and semantically integrating either of the NPs with a verb. In sentence structures that placed these NPs at the same linear distances from one another but allowed integration with a verb for 1 of the NPs, the comprehension difficulty was not seen. These results are interpreted as indicating that similarity-based interference occurs online during the comprehension of complex sentences and that the degree of memory accessibility conventionally associated with different types of NPs does not have a strong effect on sentence processing.