Contrast echocardiography to assess left ventricular volume and function in Beagle dogs: comparison with 3-Tesla dual source parallel cardiac magnetic resonance imaging.

This study was performed to evaluate the effect and feasibility of contrast echocardiography (CE) compared with unenhanced echocardiography (UE) and cardiac magnetic resonance imaging (CMRI) to assess left ventricular (LV) volume and function, including end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), and ejection fraction (EF) in six healthy Beagles. When the dogs were conscious, LV measurements using CE were significantly higher than those obtained using UE, except for EF, and were similar to the values obtained using CMRI. Additionally, EDV, SV, and EF obtained using UE from anesthetized dogs were significantly lower than those obtained using CE or CMRI. Measurements of EDV, SV and EF using CE were not significantly different from the corresponding measurements obtained using CMRI (31.13±2.18 vs. 32.88±1.17 mL, 18.41±1.25 vs. 17.92±0.96 mL, 59.29±2.29% vs. 53.33±1.69%, respectively). Inter-observer agreements for UE (0.74±0.05) were lower than those for CE (0.80±0.04) and CMRI (0.92±0.03). In conclusion, LV function was assessed reproducibly using CE, and the measurements obtained were consistent with reference standard measurements obtained using CMRI. Measurements made using CE agreed more closely with CMRI than those made using UE.

Effectiveness of attention rehabilitation after an acquired brain injury: a meta-analysis.

The efficacy of attention rehabilitation after an acquired brain injury was examined meta-analytically. Thirty studies with a total of 359 participants met the authors' selection criteria. Studies were categorized according to whether training efficacy was evaluated by comparing pre- and posttraining scores only or included a control condition as well. Performance improved significantly (using the d+ statistic) after training in pre-post only studies but not in pre-post with control studies. Further analyses showed that specific-skills training significantly improved performance of tasks requiring attention but that the cognitive-retraining methods included in the meta-analysis did not significantly affect outcomes. These findings demonstrate that acquired deficits of attention are treatable using specific-skills training. Implications of these results for rehabilitation theory and future research are discussed.

Automatic activation of positive but not negative attitudes after traumatic brain injury.

This study investigated social judgment problems of an individual (AM) with bilateral frontal and temporal lobe damage including damage to the amygdala. We hypothesized that AM could automatically process positive, but not negative evaluative information and could process both types of evaluative information using controlled processing. In Phase 1 of Experiment 1 AM and controls were shown a series of words one at a time and were required to make good/bad judgments as quickly as possible. Results showed that AM was more likely than controls to rate words as good, and was significantly slower to make good/bad judgments of negatively, but not positively, evaluated words. In Phase 2 AM was shown a prime (positive or negative) then target (positive or negative) and instructed to evaluate whether the target word was good or bad. Results showed that AM responded more quickly when prime and target were both positive, but not when prime and target were both negative, whereas controls showed both types of priming. Experiment 2 determined whether AM's impaired processing of negative evaluative information could be abolished under controlled processing. AM was explicitly instructed to generate positive and negative connotations of a series of single words and given essentially unlimited time. Under these conditions, AM and controls did not differ significantly in their ability to generate positive versus negative connotations of words. In Experiment 3 AM and controls both showed normal semantic priming effects. The results are interpreted within the component process model of memory.

Divided attention impairments after traumatic brain injury.

This research investigated whether people with severe traumatic brain injury (TBI) are impaired on divided attention tasks requiring working memory. In experiment 1, a severe TBI and control group performed two tasks requiring working memory separately and concurrently. Results showed that the TBI group had impaired divided attention when performing the two tasks concurrently, although the two groups did not differ in performance when these tasks were performed separately. Experiment 2 showed that performance on the paced auditory serial addition task improved with increases in the intertrial interval for both TBI and control groups. A meta-analysis showed that TBIs are impaired on divided attention when the tasks require controlled processing, but not when the tasks can be carried out relatively automatically.