Alterations of Structural Network Efficiency in Early-Onset and Late-Onset Alzheimer’s Disease

Background@#and Purpose Early- and late-onset Alzheimer’s disease (EOAD and LOAD, respectively) share the same neuropathological hallmarks of amyloid and neurofibrillary tangles but have distinct cognitive features. We compared structural brain connectivity between the EOAD and LOAD groups using structural network efficiency and evaluated the association of structural network efficiency with the cognitive profile and pathological markers of Alzheimer’s disease (AD). @*Methods@#The structural brain connectivity networks of 80 AD patients (47 with EOAD and 33 with LOAD) and 57 healthy controls were reconstructed using diffusion-tensor imaging.Graph-theoretic indices were calculated and intergroup differences were evaluated. Correlations between network parameters and neuropsychological test results were analyzed. The correlations of the amyloid and tau burdens with network parameters were evaluated for the patients and controls. @*Results@#Compared with the age-matched control group, the EOAD patients had increased global path length and decreased global efficiency, averaged local efficiency, and averaged clustering coefficient. In contrast, no significant differences were found in the LOAD patients. Locally, the EOAD patients showed decreases in local efficiency and the clustering coefficient over a wide area compared with the control group, whereas LOAD patients showed such decreases only within a limited area. Changes in network parameters were significantly correlated with multiple cognitive domains in EOAD patients, but only with Clinical Dementia Rating Sum-of-Boxes scores in LOAD patients. Finally, the tau burden was correlated with changes in network parameters in AD signature areas in both patient groups, while there was no correlation with the amyloid burden. @*Conclusions@#The impairment of structural network efficiency and its effects on cognition may differ between EOAD and LOAD.

Academic Stress and Its Influencing Factors among Medical and Non‐Medical Students / 의학교육논단

This study examined the relationships among personality traits, coping efficacy, and academic stress in medical and non-medical students in South Korea, and investigated the mediating effect of coping efficacy in the relationship between personality traits and academic stress. The study group comprised 210 medical students and 175 non-medical students. They were asked to rate their personality traits, coping efficacy, and academic stress. The data were analyzed using IBM SPSS ver. 26.0 (IBM Corp., Armonk, NY, USA) and AMOS ver. 26.0 (IBM Corp.). Medical students scored higher for examination stress and lower for extroversion than non-medical students. In both groups, extroversion and conscientiousness positively affected coping efficacy, while neuroticism influenced it negatively. Neuroticism directly influenced all types of academic stress in both groups, while extroversion and conscientiousness only had direct effects on examination stress among medical students. Coping efficacy mediated the associations between personality traits and academic stress, except for the relationship between neuroticism and grade stress among medical students. The study indicates that coping efficacy had a significant effect on relieving academic stress among students with higher scores for extroversion and conscientiousness. Efforts should be made to decrease neuroticism to lower academic stress, as the relationship between neuroticism and academic stress is not directly influenced by coping efficacy. The implications of these results are discussed regarding a consultation system for students, especially those in medical school.

Academic Stress and Its Influencing Factors among Medical and Non‐Medical Students / 의학교육논단

This study examined the relationships among personality traits, coping efficacy, and academic stress in medical and non-medical students in South Korea, and investigated the mediating effect of coping efficacy in the relationship between personality traits and academic stress. The study group comprised 210 medical students and 175 non-medical students. They were asked to rate their personality traits, coping efficacy, and academic stress. The data were analyzed using IBM SPSS ver. 26.0 (IBM Corp., Armonk, NY, USA) and AMOS ver. 26.0 (IBM Corp.). Medical students scored higher for examination stress and lower for extroversion than non-medical students. In both groups, extroversion and conscientiousness positively affected coping efficacy, while neuroticism influenced it negatively. Neuroticism directly influenced all types of academic stress in both groups, while extroversion and conscientiousness only had direct effects on examination stress among medical students. Coping efficacy mediated the associations between personality traits and academic stress, except for the relationship between neuroticism and grade stress among medical students. The study indicates that coping efficacy had a significant effect on relieving academic stress among students with higher scores for extroversion and conscientiousness. Efforts should be made to decrease neuroticism to lower academic stress, as the relationship between neuroticism and academic stress is not directly influenced by coping efficacy. The implications of these results are discussed regarding a consultation system for students, especially those in medical school.