Effects of Color Temperature and Brightness on Electroencephalogram Alpha Activity in a Polychromatic Light-emitting Diode

OBJECTIVE: It has been reported that working and learning efficiency might be increased through artificially controlling the color temperature and brightness of light. However, the neurological bases of these outcomes are not well established. Our study was designed to observe whether electroencephalogram (EEG) alpha frequency, as a candidate biological marker, demonstrates significant changes in response to alterations of specific light parameters. METHODS: Thirty-two healthy subjects performed cognitive tasks under four different polychromatic light conditions: a combination of two different levels of color temperature (2766K vs. 5918K) and brightness (300 lux vs. 600 lux). Spectrum analyses were performed on alpha frequency. RESULTS: Subjects reported that they felt more pleasant in bright conditions and more relaxed in warm color temperature conditions. Our findings indicate that alpha power increases in warm, low-light and cool, high-light conditions, and there is a significant interaction between color temperature and brightness. CONCLUSION: EEGs might serve as a useful biological marker for further research related to the effects of polychromatic light on cognitive function.

Pros and Cons of Various Research Designs in Clinical Psychiatry

An appropriate research design for hypotheses and purposes leads to a good quality of research results. In this review article, we summarized the types of research methods and described the characteristics of clinical trials. Research designs are categorized into observational studies and experimental ones, depending on data collecting methods. In an observational study, there are cross-sectional, cohort and case-control studies. Parallel groups design and crossover trial studies are representative designs in a randomized controlled trial study, a kind of experimental study. Clinical researchers should understand the characteristics of clinical research designs including advantages and disadvantages and choose the suitable design according to their study purposes and the nature of collected data or subjects.

Autobiographical Memory in Patients with Bipolar Disorder

OBJECTIVES: Autobiographical memory (ABM) is a special type of episodic memory, containing events that have occurred in a personal life. Overgeneral tendency of ABM refers to the retrieval of memory with only general and categorical descriptions rather than specific events. ABM specificity in depression and posttraumatic stress disorder is a robust finding with relation to cognitive vulnerability, affect regulation, problem-solving ability. It is also implicated in bipolar disorder with frequent relapses. In this study, we investigated whether ABM specificity was related to manic or euthymic mood states in patients with bipolar disorder. METHODS: Forty bipolar patients with manic and euthymic episodes and 25 healthy controls participated in this study. Prompted by 5 positively and 5 negatively valenced emotional cue words, each participant was instructed to recall positive or negative memories and describe them in detail. The one-way ANOVA was used to compare ABM scores and post-hoc analyses were done. RESULTS: Comapred to the healthy persons, the bipolar patients reported significantly more general than specific negative memories in both manic and euthymic episodes (p = 0.003). However, there was no significant difference between manic and euthymic patients (p = 0.074). CONCLUSIONS: These results suggest that overgeneral tendency of negative ABM may be a trait abnormality in bipolar disorder. Moreover, this phenomenon might be related to underlying cognitive deficits or affect regulation irrespective of the mood state.

Reward Learning in Euthymic Patients with Bipolar Disorder Using a Probabilistic Reward Task / 대한정신약물학회지

OBJECTIVE: Bipolar disorder patients often show excessive goal-directed and pleasure-seeking behavior during manic episodes and reduced hedonic capacity during depressive episodes, indicating that bipolar disorder might involve altered reward processing. As such, bipolar disorder subjects have been reported to show impaired reward learning in situations requiring integration of reinforcements over time. In this study, we examined characteristics of reward learning in euthymic patients with bipolar disorder using a probabilistic reward task. METHODS: We recruited 23 euthymic patients with bipolar disorder and 47 healthy subjects for the probabilistic reward task. This task is a reward-based paradigm to produce a response bias, in which correct identifications of two ambiguous stimuli are differently rewarded. The other dependent measures were the discriminability, hit rate and reaction time. RESULTS: Relative to comparison subjects, bipolar patients showed a reduced acquisition of response bias toward the more frequently rewarded stimulus (p<0.01). The overall reward learning was positively correlated with state and trait anxiety levels in bipolar patients (p<0.01). No significant differences of discriminability, hit rates, and reaction time were found between bipolar patients and controls. CONCLUSION: These findings suggest that euthymic patients with bipolar disorder may have deficits in reward learning related to anxiety.

Screening and Treating Wernicke's Encephalopathy among Alcoholic Patients in a University Hospital / 신경정신의학

OBJECTIVES: The purpose of this study was to investigate the prevalence and clinical characteristics of Wernicke's encephalopathy (WE) patients in alcoholics and to evaluate the utility of Caine's criteria as a screening test. METHODS: We made an admission note including Caine's criteria and applied it to patients who were admitted to an alcohol treatment unit. Demographic, clinical, and laboratory data were collected on 204 alcoholics. Our alcoholics who met more than one of Caine's criteria were considered at risk for WE and were given high-dose thiamine IV therapy. RESULTS: We was diagnosed in 15.2% of the alcoholic patients. Age and head trauma history were risk factors of WE. The sensitivity of Caine's criteria was 97% and specificity was 54%. High-dose thiamine IV therapy appeared to be a safe and cost-effective method to prevent the serious complications of WE. CONCLUSION: Caine's criteria is useful as a screening test for WE among alcoholic patients. High-dose thiamine IV therapy is cost-effective for alcoholic patients who are considered to be at risk for WE.

Clinical Case Conference / 신경정신의학

No abstract available.

Some Psychological Correlates Affecting Recognition of Neutral Facial Emotion in Young Adults / 신경정신의학

OBJECTIVES: Previous studies have shown the relationship between recognition of facial expressions and psychiatric symptoms. This study investigated how healthy young adults recognize neutral faces and which psychological distresses and symptoms relate to their recognition of neutral faces. METHODS: One hundred forty-three healthy volunteers participated in this study. We used neutral facial pictures, selected from the Japanese and Caucasian Facial Expressions of Emotion (JACFEE) photo set, to evaluate participants' facial expression recognition and the State-Trait Anxiety Inventory, Beck Depression Inventory, Toronto Alexithymia Scale, Conner-Davidson Resilience Scale, and Temperament and Character Inventory (TCI) to measure and examine their psychological characteristics. RESULTS: There were significant positive correlations between the recognition rate of neutral expressions as contempt and trait-anxiety level (r=0.21 ; p=0.01) and depression (r=0.20 ; p=0.02). This contempt-recognition was significantly negatively correlated with resilience score (r=-0.22 ; p=0.01) and the TCI self-directedness subscale (r=-0.29 ; p=0.00). Also, the TCI's harm avoidance subscale score was significantly positively correlated with the contempt recognition rate (r=0.21 ; p=0.01). CONCLUSION: These finding suggests recognition of neutral faces as contempt may be related to psychological distress, including trait and temperament characteristics. This negative bias toward neutral emotion (expressions) may affect interpersonal relations and social functioning in a healthy population.