Frontal Alpha Asymmetry Moderated by Suicidal Ideation in Patients with Major Depressive Disorder: A Comparison with Healthy Individuals.

OBJECTIVE: Frontal alpha asymmetry (FAA) of electroencephalography (EEG) has been studied to differentiate patients with major depressive disorder (MDD) from healthy controls (HC). However, inconsistent results have been obtained thus far. Suicidal ideation (SI) has been known to alter frontal lobe activity, and could be an important covariate in FAA studies. This study aimed to explore the influence of FAA on the relationship among MDD patients with SI and without SI, and HC. METHODS: Sixty-seven patients with MDD (44 without and 23 with SI) and 60 HCs were recruited. Resting state EEG was recorded with their eyes open, and FAA as a lateralized index of alpha power was calculated in the frontal brain region. Hamilton Rating Scale for Anxiety and Depression scores were estimated. RESULTS: FAA was higher (increased alpha power in the left frontal region) in the MDD group than in the HC group. The FAA was lower (reduced alpha power in the left frontal region) in MDD patients with SI than in MDD patients without SI. The severity of depression and anxiety symptoms were significantly correlated with FAA only in MDD patients with SI. SI moderated the effects of depressive symptom on FAA in the MDD group. CONCLUSION: Our results suggest that SI is a clinically important moderator of frontal alpha asymmetry in patients with MDD.

A Moderated Mediation Model of Self-Concept Clarity, Transformational Leadership, Perceived Work Meaningfulness, and Work Motivation.

The purpose of this study was to investigate the role of self-concept clarity in predicting employees' perceived work meaningfulness. We proposed a moderated mediation model in which perceived work meaningfulness could mediate the relationship between self-concept clarity and work motivation, and transformation leadership could moderate this mediating relationship. We tested our hypotheses using data collected from 488 employees in various companies. Results showed that individual differences in self-concept clarity were positively related to perceived work meaningfulness, and perceived work meaningfulness mediated the relationship between self-concept clarity and work motivation. Furthermore, the strength of indirect relationship between self-concept clarity and work motivation via perceptions of work meaningfulness was stronger when transformational leadership was low than when it was high. Implications of our findings along with limitations of this study and directions for future research are also discussed.

EEG beta and low gamma power correlates with inattention in patients with major depressive disorder.

BACKGROUND: Inattention is a common feature of major depressive disorder (MDD). The aim of this study was to explore the relationship between quantitative electroencephalography (qEEG) power of a specific band and inattention severity in patients with MDD. METHODS: EEG recordings of 73 patients with MDD were collected in during both eyes closed and eyes open conditions. Inattention was assessed by the inattention sub-scale of the Korean version of the Adult ADHD scale (K-AADHD). The severity of symptoms associated with depression and anxiety was assessed with the Hamilton Rating Scale for Anxiety (HAM-A), the Hamilton Rating Scale for Depression (HAM-D), and the Beck Depression Inventory (BDI). Multiple regression and Hayes mediation model were applied for the statistical analysis to verify the effects of clinical variables on inattention score. RESULTS: The beta (12-30Hz) and low gamma (30-50Hz) powers in fronto-central regions were negatively correlated with inattention scores. Symptom severity scores strongly predicted inattention scores; in particular, the BDI accounted for 23.9% of the variance. In mediation analysis, BDI fully mediated the path of anxiety to inattention. LIMITATIONS: The medication effect and comorbidity in our participants were not fully controlled. A subjective assessment tool was hired to measure inattention. CONCLUSIONS: Beta and low gamma power of the fronto-central regions might be a reliable measure of attention deficits in patients with MDD, which in turn, seems to be related to the severity of subjective depressive symptoms. Further work is needed to confirm this finding on larger, drug and comorbidity-free samples, and to test the clinical utility.

Quantitative Electroencephalography Reflects Inattention, Visual Error Responses, and Reaction Times in Male Patients with Attention Deficit Hyperactivity Disorder.

OBJECTIVE: Quantitative electroencephalography (qEEG) has been increasingly used to evaluate patients with attention deficit hyperactivity disorder (ADHD). The aim of this study was to assess the correlation between qEEG data and symptom severity in patients with ADHD. METHODS: Fifteen patients with ADHD and 20 healthy controls (HCs) were recruited. Electroencephalography was assessed in the resting-state, and qEEG data were obtained in the eyes-closed state. The Korean version of the ADHD Rating Scale (K-ARS) and continuous performance tests (CPTs) were used to assess all participants. RESULTS: Theta-band (4-7 Hz) power across the brain was significantly positively correlated with inattention scores on the K-ARS, reaction times and commission errors on the CPTs in ADHD patients. Gamma-band (31-50 Hz) power was significantly positively correlated with the results of the auditory CPTs in ADHD patients. The theta/alpha (8-12 Hz) and theta/beta (13-30 Hz) ratios were significantly negatively correlated with commission and omission errors on auditory CPTs in ADHD patients. No significant correlations between qEEG relative power and K-ARS and CPT scores were observed in HCs. CONCLUSION: Our results suggest that qEEG may be a useful adjunctive tool in patients with ADHD.