A method for characterizing semantic and lexical properties of sentence completions in traumatic brain injury.

Clinical investigations of individuals with chronic stage traumatic brain injury (TBI) showing mild-to-moderate levels of residual impairment largely use standardized neuropsychological assessments to measure executive functioning. The Hayling Sentence Completion Test (HSCT) relies upon several executive functions but detects cognitive impairments across studies inconsistently. We sought to (a) further characterize sentence completions on the HSCT by quantifying their semantic and lexical properties and (b) investigate cognitive components important for HSCT performance. A sample of 108 mild-to-moderate participants with TBI underwent a comprehensive neuropsychological assessment that evaluated verbal ability, working memory, processing speed, task switching, and inhibitory control. Multiple regression analyses suggest that these 5 cognitive components differentially contribute to describing HSCT performance and measures of semantic and lexical properties of unconnected sentence completions. Across all 3 measures, verbal ability was most predictive of performance, while inhibitory control was the least predictive. Working memory capacity also predicted HSCT performance, while processing speed and task switching ability predicted lexical measures. We present a method for quantitatively measuring the semantic and lexical properties of generated words on the HSCT and how these additional measures relate to executive functions. (PsycINFO Database Record

Amygdala activation as a marker for selective attention toward neutral faces in a chronic traumatic brain injury population.

There has been great interest in characterizing the response of the amygdala to emotional faces, especially in the context of social cognition. Although amygdala activation is most often associated with fearful or angry stimuli, there is considerable evidence that the response of the amygdala to neutral faces is both robust and reliable. This characteristic of amygdala function is of particular interest in the context of assessing populations with executive function deficits, such as traumatic brain injuries, which can be evaluated using fMRI attention modulation tasks that evaluate prefrontal control over representations, notably faces. The current study tested the hypothesis that the amygdala may serve as a marker of selective attention to neutral faces. Using fMRI, we gathered data within a chronic traumatic brain injury population. Blood Oxygenation Level Dependent (BOLD) signal change within the left and right amygdalae and fusiform face areas was measured while participants viewed neutral faces and scenes, under conditions requiring participants to (1) categorize pictures of faces and scenes, (2) selectively attend to either faces or scenes, or (3) attend to both faces and scenes. Findings revealed that the amygdala is an effective marker for selective attention to neutral faces and, furthermore, it was more face-specific than the fusiform face area.