Changtae Hahn

Development and Validation of a Smartphone Addiction Scale (SAS)

Objective The aim of this study was to develop a self-diagnostic scale that could distinguish smartphone addicts based on the Korean self-diagnostic program for Internet addiction (K-scale) and the smartphones own features. In addition, the reliability and validity of the smartphone addiction scale (SAS) was demonstrated. Methods A total of 197 participants were selected from Nov. 2011 to Jan. 2012 to accomplish a set of questionnaires, including SAS, K-scale, modified Kimberly Young Internet addiction test (Y-scale), visual analogue scale (VAS), and substance dependence and abuse diagnosis of DSM-IV. There were 64 males and 133 females, with ages ranging from 18 to 53 years (M = 26.06; SD = 5.96). Factor analysis, internal-consistency test, t-test, ANOVA, and correlation analysis were conducted to verify the reliability and validity of SAS. Results Based on the factor analysis results, the subscale “disturbance of reality testing” was removed, and six factors were left. The internal consistency and concurrent validity of SAS were verified (Cronbachs alpha = 0.967). SAS and its subscales were significantly correlated with K-scale and Y-scale. The VAS of each factor also showed a significant correlation with each subscale. In addition, differences were found in the job (p<0.05), education (p<0.05), and self-reported smartphone addiction scores (p<0.001) in SAS. Conclusions This study developed the first scale of the smartphone addiction aspect of the diagnostic manual. This scale was proven to be relatively reliable and valid.

Regional Cortical Thickness and Subcortical Volume Changes Are Associated with Cognitive Impairments in the Drug-Naive Patients with Late-Onset Depression

Previous studies have shown an association between late-onset depression (LOD) and cognitive impairment in older adults. However, the neural correlates of this relationship are not yet clear. The aim of this study was to investigate the differences in both cortical thickness and subcortical volumes between drug-naive LOD patients and healthy controls and explore the relationship between LOD and cognitive impairments. A total of 48 elderly, drug-naive patients with LOD and 47 group-matched healthy control subjects underwent 3T MRI scanning, and the cortical thickness was compared between the groups in multiple locations, across the continuous cortical surface. The subcortical volumes were also compared on a structure-by-structure basis. Subjects with LOD exhibited significantly decreased cortical thickness in the rostral anterior cingulate cortex, the medial orbitofrontal cortex, dorsolateral prefrontal cortex, the superior and middle temporal cortex, and the posterior cingulate cortex when compared with healthy subjects (all p<0.05, false discovery rate corrected). Reduced volumes of the right hippocampus was also observed in LOD patients when compared with healthy controls (p<0.001). There were significant correlations between memory functions and cortical thickness of medial temporal, isthmus cingulate, and precuneus (p<0.001). This study was the first study to explore the relationships between the cortical thickness/subcortical volumes and cognitive impairments of drug-naive patients with LOD. These structural changes might explain the neurobiological mechanism of LOD as a risk factor of dementia.

Apathy and white matter integrity in Alzheimer's disease: a whole brain analysis with tract-based spatial statistics.

The aim of this study was to investigate the microstructural alterations of white matter (WM) in Alzheimer’s disease (AD) patients with apathy and to observe the relationships with the severity of apathy. Sixty drug-naïve subjects took part in this study (30 apathetic and 30 nonapathetic subjects with AD). The loss of integrity in WM was compared in AD patients with and without apathy through measurement of fractional anisotropy (FA) using by tract-based spatial statistics (TBSS). In addition, we explored the correlation pattern between FA values and the severity of apathy in AD patients with apathy. The apathy group had significantly reduced FA values (pcorrected<0.05) in the genu of the corpus callosum compared to the nonapathy group. The severity of apathy was negatively correlated with FA values of the left anterior and posterior cingulum, right superior longitudinal fasciculus, splenium, body and genu of the corpus callosum and bilateral uncinate fasciculusin the apathy group (pcorrected<0.05). This study was the first to explore FA values in whole brain WM in AD patients with apathy. The findings of these microstructural alterations of WM may be the key to the understanding of underlying neurobiological mechanism and clinical significances of apathy in AD.

Automated hippocampal subfields segmentation in late life depression

Although a few automated hippocampal subfields segmentation methods have been developed, there has been no in vivo Magnetic Resonance Imaging (MRI) study on the hippocampal subfields volumes of Late Life Depression (LLD). The aim of this study was to investigate the hippocampal subfields volume differences between LLD subjects and healthy elderly controls using an automated hippocampal subfields segmentation technique. Thirty subjects with LLD and 30 group-matched healthy control subjects underwent 3T MRI scanning, and hippocampal subfields volumes were measured and compared between the groups. Subjects with LLD exhibited significant hippocampal volume reductions in the total hippocampus, subiculum, and Cornu Ammonis (CA) 2-3 areas compared with healthy subjects (uncorrected, p<0.001). This study is the first to elaborate the subfields volume differences of both hippocampi between controls and LLD patients. These structural changes in the hippocampal presubiculum, subiculum, and CA2-3 areas might be at the core of the underlying neurobiological mechanisms of hippocampal dysfunction in LLD.

Neuroimaging Findings in Late-Onset Schizophrenia and Bipolar Disorder

In recent years, there has been an increasing interest in late-onset mental disorders. Among them, geriatric schizophrenia and bipolar disorder are significant health care risks and major causes of disability. We discussed whether late-onset schizophrenia (LOS) and late-onset bipolar (LOB) disorder can be a separate entity from early-onset schizophrenia (EOS) and early-onset bipolar (EOB) disorder in a subset of late-life schizophrenia or late-life bipolar disorder through neuroimaging studies. A literature search for imaging studies of LOS or LOB was performed in the PubMed database. Search terms used were “(imaging OR MRI OR CT OR SPECT OR DTI OR PET OR fMRI) AND (schizophrenia or bipolar disorder) AND late onset.” Articles that were published in English before October 2013 were included. There were a few neuroimaging studies assessing whether LOS and LOB had different disease-specific neural substrates compared with EOS and EOB. These researches mainly observed volumetric differences in specific brain regions, white matter hyperintensities, diffusion tensor imaging, or functional neuroimaging to explore the differences between LOS and LOB and EOS and EOB. The aim of this review was to highlight the neural substrates involved in LOS and LOB through neuroimaging studies. The exploration of neuroanatomical markers may be the key to the understanding of underlying neurobiology in LOS and LOB.

Relationships between hippocampal shape and cognitive performances in drug-naïve patients with Alzheimer's disease

Previous studies provided hippocampal shape analysis of Alzheimers disease (AD) patients using automated segmentation techniques. However, the relationships between the hippocampal deformations and various cognitive impairments were not clear. The aim of this study was to investigate hippocampal shape changes and their relationship to cognitive impairments. Fifty-one drug-naïve patients with AD and 50 group-matched healthy control subjects underwent 3T MRI scanning, and the hippocampal volumes and deformations were compared between the groups. Additionally, we explored the correlation pattern between the hippocampal deformations and the cognitive dysfunctions in AD using the Korean version of the Consortium to Establish a Registry for Alzheimers Disease (CERAD-K). AD subjects exhibited significant hippocampal deformations in the cornu ammnonis (CA1) and subiculum areas compared to those in healthy subjects (p<0.05, false discovery rate (FDR) corrected). Significant correlations were observed between hippocampal deformations in CA1 and subiculum areas and verbal immediate recall, verbal delayed recall, verbal recognition memory, and constructional recall scores (p<0.05, FDR corrected). This study was the first to explore the relationships between hippocampal deformations and various cognitive impairments of drug-naïve patients with AD. These structural changes in hippocampal CA1 and subiculum areas might be the core of the underlying neurobiological mechanisms of hippocampal dysfunction and their relevance to the various cognitive dysfunctions in AD.

Automated hippocampal subfield segmentation in amnestic mild cognitive impairments.

Although a few automated hippocampal subfield segmentation methods have been developed, the effects of amnestic mild cognitive impairment (aMCI) on the hippocampal subfield volumes on magnetic resonance imaging (MRI) are not clear. The aim of this study was to investigate the hippocampal subfield volume changes and their relationships with various neuropsychological tests in aMCI using an automated hippocampal subfield segmentation technique. Forty-five subjects with aMCI and 49 group-matched healthy control subjects underwent 3-tesla MRI scanning, and hippocampal subfield volumes were measured and compared. Additionally, we explored the correlation pattern between hippocampal subfield volumes and the Korean version of the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD-K) neuropsychological test scores in aMCI subjects. Subjects with aMCI exhibited significant hippocampal volume reductions in the presubiculum, subiculum and cornu ammonis 2–3 areas compared with healthy subjects. In addition, we also found significant positive correlations between presubiculum and subicular area volumes and the CERAD-K verbal and visuospatial delayed recall scores in aMCI. This study was the first to explore the relationships between hip-pocampal subfield volumes and various types of cognitive performances in aMCI. These structural changes might be at the core of the underlying neurobiological mechanisms of hippocampal dysfunction in aMCI.

Hippocampal shape and cognitive performance in amnestic mild cognitive impairment.

Previous studies have carried out hippocampal shape analysis of amnestic mild cognitive impairment (aMCI) patients using automated segmentation techniques. However, the relationships between hippocampal deformations and various episodic memory impairments were not clear. The aim of this study was to investigate hippocampal shape changes and their relationships with various episodic memory impairments in aMCI. Hippocampal volumes and deformations were compared between the aMCI and the controls. In addition, we explored the correlation pattern between hippocampal deformations and cognitive dysfunctions in aMCI using a comprehensive neuropsychological battery. Patients with aMCI exhibited significant hippocampal deformations in the right cornu ammonis 1 (CA1) and subiculum areas compared with healthy individuals. Significant correlations were observed between constructional recall scores and the right CA1 and subiculum areas in aMCI. Verbal delayed recall scores were also significantly correlated with the left CA1 and subiculum areas in aMCI. This study was the first to explore the relationships between hippocampal deformations and various types of cognitive performances in aMCI. These structural changes in the hippocampal CA1 and subiculum areas might be at the core of underlying neurobiological mechanisms of hippocampal dysfunction and their relevance to verbal and visuospatial delayed recall in aMCI.

Reliability and Validity of the Korean Version of the Cornell Scale for Depression in Dementia

Objective The aim of this study was to explore the reliability and validity of the Korean version of the Cornell Scale for Depression in Dementia (CSDD-K), a scale for assessment of depression in dementia. Methods The original CSDD was translated into Korean and the content was verified through back-translation procedures. This study included 59 depressive patients with Alzheimers disease (AD), 62 non-depressive patients with AD and 36 healthy elderly controls. The subjects were assessed using CSDD-K, the 17-item Hamilton Depression Rating Scale (HAM-D17), the 15-item Korean version of Geriatric Depression Scale (GDS15) and the Korean version of Mini-mental Status Examination (MMSE-K). Results In the reliability test, Cronbachs α coefficient and test-retest reliabilities were 0.92 and 0.91, respectively, indicating that the CSDD-K has good internal consistency. There were significant differences in CSDD-K total scores between AD patients with depression and AD patients without depression (p<0.001). In the analysis of the concurrent validity of the CSDD-K, there were significant correlations between the CSDD-K and HAM-D17 (r=0.91, p<0.001) and between the CSDD-K and GDS15 (r=0.75, p<0.001). ROC curve analysis identified a cut-off score of 7 for the CSDD-K, where the sensitivity was 87.5% and the specificity was 100%. Factor analysis resulted in a four-factor solution accounting for 63.8% of the common variance. Conclusion The CSDD-K showed good reliability and validity for the assessment of depressive symptom severity in AD patients. The CSDD-K is a useful instrument for assessing AD patients with depressive symptoms in Korean ethnic population.

Sub-regional volumes changes of the corpus callosum in the drug naive patients with late-onset depression.

Although sub-regional analysis methods of the corpus callosum (CC) have been developed, there has been no in vivo magnetic resonance imaging (MRI) study on a sub-regional volume analysis of the CC of late-onset depression (LOD). The aim of this study was to investigate the CC volume differences between LOD subjects and healthy elderly controls using a sub-regional analysis technique. Forty subjects with LOD and thirty nine group-matched healthy control subjects underwent 3T MRI scanning, and sub-regional volumes of the CC were measured and compared between the groups. The volumes of total (F=5.8, p=0.001), the anterior (F=5.2, p=0.001) and the posterior CC (F=5.1, p=0.001) were significantly reduced in the LOD group as compared to the control group. We measured cognitive functions in several different domains (language functions, verbal learning, visuospatial functions, delayed recall, memory consolidation, recognition memory, and executive functions) through the Korean version of the Consortium to Establish a Registry for Alzheimers Disease. The anterior CC volume in the LOD group showed significant positive correlation with the Verbal Fluency scores. The posterior CC volume in the LOD group was positively correlated significantly with the Word List Memory, the Word List Recall and the Constructional Praxis scores. This study is the first to elaborate the sub-regional volume differences of the CC between controls and LOD patients. These structural changes in the CC might be at the core of the underlying neurobiological mechanisms in LOD.