Deficits in Analogical Reasoning in Adolescents with Traumatic Brain Injury

Individuals with traumatic brain injury (TBI) exhibit deficits in executive control, which may impact their reasoning abilities. Analogical reasoning requires working memory and inhibitory abilities. In this study, we tested adolescents with moderate to severe TBI and typically developing (TD) controls on a set of picture analogy problems. Three factors were varied: complexity (number of relations in the problems), distraction (distractor item present or absent), and animacy (living or non-living items in the problems). We found that TD adolescents performed significantly better overall than TBI adolescents. There was also an age effect present in the TBI group where older participants performed better than younger ones. This age effect was not observed in the TD group. Performance was affected by complexity and distraction. Further, TBI participants exhibited lower performance with distractors present than TD participants. The reasoning deficits exhibited by the TBI participants were correlated with measures of executive function that required working memory updating, attention, and attentional screening. Using MRI-derived measures of cortical thickness, correlations were carried out between task accuracy and cortical thickness. The TD adolescents showed negative correlations between thickness and task accuracy in frontal and temporal regions consistent with cortical maturation in these regions. This study demonstrates that adolescent TBI results in impairments in analogical reasoning ability. Further, TBI youth have difficulty effectively screening out distraction, which may lead to failures in comprehension of the relations among items in visual scenes. Lastly, TBI youth fail to show robust cortical–behavior correlations as observed in TD individuals

Contributions of phonological and semantic short-term memory to sentence comprehension in normal and head injured children

The relation of short-term memory to sentence comprehension was investigated in 4 children who had sustained severe closed head injury. Two of the patients showed dissociation in performance on short term memory tasks. One of the patients, CS showed a pattern of performance on short term memory tasks consistent with a phonological short term memory deficit. Another patient, CB, showed a pattern of performance which suggests a deficit in semantic memory. The dissociations in short term memory tasks exhibited by these patients corresponded to a dissociation in their performance on sentence processing tasks. On a sentence anomaly judgment task in which the memory load had to be maintained before the judgment could be made CS performed similarly to the Control subjects, while CB showed a deficit which was related to memory load. The opposite pattern was observed for a verbatim sentence repetition task on which CB's performance was within the normal range, but CS was very impaired. The results support models of short term memory that postulate separable components of semantic and phonological short term memory and the differential contribution of the two components to sentence comprehension

A phonological short-term deficit: A case study

The performance of a highly literate subject, BS, was assessed on tests of short-term memory. He demonstrated a pattern of performance similar to that of patients having a phonological short-term memory deficit. His profile included an exaggerated phonological similarity effect for auditorily, but not visually presented materials, the absence of a recency effect, a reversed modality effect, and difficulty repeating non-words. In contrast to previously described phonological short-term memory patients, BS performed fairly normally in a foreign language learning task, though his acquisition rate was slower than that of control subjects. This finding is counter to current theory which suggests intact phonological short-term memory is necessary to learning of new phonological forms. Further investigation of BS's deficit suggested that his areas of preserved performance were the result of strategic reliance upon semantic, lexical or orthographic factors. Thus support is demonstrated for theories of short-term memory that propose multiple components contributing to short-term memory