Brain activity and medical diagnosis: an EEG study

Abstract Background Despite new brain imaging techniques that have improved the study of the underlying processes of human decision-making, to the best of our knowledge, there have been very few studies that have attempted to investigate brain activity during medical diagnostic processing. We investigated brain electroencephalography (EEG) activity associated with diagnostic decision-making in the realm of veterinary medicine using X-rays as a fundamental auxiliary test. EEG signals were analysed using Principal Components (PCA) and Logistic Regression Analysis Results The principal component analysis revealed three patterns that accounted for 85% of the total variance in the EEG activity recorded while veterinary doctors read a clinical history, examined an X-ray image pertinent to a medical case, and selected among alternative diagnostic hypotheses. Two of these patterns are proposed to be associated with visual processing and the executive control of the task. The other two patterns are proposed to be related to the reasoning process that occurs during diagnostic decision-making. Conclusions PCA analysis was successful in disclosing the different patterns of brain activity associated with hypothesis triggering and handling (pattern P1); identification uncertainty and prevalence assessment (pattern P3), and hypothesis plausibility calculation (pattern P2); Logistic regression analysis was successful in disclosing the brain activity associated with clinical reasoning success, and together with regression analysis showed that clinical practice reorganizes the neural circuits supporting clinical reasoning.

Effects of acute physical exercise on executive functions: a comparison between aerobic and strength exercise

The aim of this study was to compare the effects of acute aerobic and strength exercises on selected executive functions. A counterbalanced, crossover, randomized trial was performed. Forty-two healthy women were randomly submitted to three different conditions: (1) aerobic exercise, (2) strength exercise, and (3) control condition. Before and after each condition, executive functions were measured by the Stroop Test and the Trail Making Test. Following the aerobic and strength sessions, the time to complete the Stroop "non-color word" and "color word" condition was lower when compared with that of the control session. The performance in the Trail Making Test was unchanged. In conclusion, both acute aerobic and strength exercises improve the executive functions. Nevertheless, this positive effect seems to be task and executive function dependent.

Juvenile myoclonic epilepsy: The impact of clinical variables and psychiatric disorders on executive profile assessed with a comprehensive neuropsychological battery

Executive dysfunction is reported in juvenile myoclonic epilepsy (JME). However, batteries employed in previous studies included no more than three tests of executive function. In this study, we aimed to assess executive and attentional functions in JME using a comprehensive battery of eight tests (encompassing fifteen subtests). We also evaluated neuropsychological profiles using a clinical criterion of severity and correlated these findings with epilepsy clinical variables and the presence of psychiatric disorders. We prospectively evaluated 42 patients with JME and a matched control group with Digit Span tests (forward and backward), Stroop Color-Word Test, Trail Making Test, Wisconsin Card-Sorting Test, Matching Familiar Figures Test and Word Fluency Test. We estimated IQ with the Matrix Reasoning and Vocabulary subtests of the Wechsler Abbreviated Intelligence Scale. The patients with JME showed specific deficits in working memory, inhibitory control, concept formation, goal maintenance, mental flexibility, and verbal fluency. We observed attentional deficits in processes such as alertness and attention span and those requiring sustained and divided attention. We found that 83.33% of the patients had moderate or severe executive dysfunction. In addition, attentional and executive impairment was correlated with higher frequency of seizures and the presence of psychiatric disorders. Furthermore, executive dysfunction correlated with a longer duration of epilepsy. Our findings indicate the need for comprehensive neuropsychological batteries in patients with JME, in order to provide a more extensive evaluation of attentional and executive functions and to show that some relevant deficits have been overlooked. (C) 2012 Elsevier Inc. All rights reserved.