• Sleep Medicine and Psychophysiology
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• v.4 no.1
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• pp.29-38
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• 1997

Dementia is defined as a syndrome which is characterized by various impairments in cognitive functions, especially memory function. Most of the diagnostic criteria for dementia include memory impairment as on essential feature. Memory decline can be present as a consequence of the aging process. But it does not cause significant distress or impairment in social and occupational functionings while dementiadoes. Depression may also be associated with memory impairment. However, unlike dementia, depression dose not cause decrease in delayed verbal learning and recognition memory. In dementia, different features of memory impairment may be present depending on the involved area. Memory impairment in cortical dementia is affected by the disturbance of encoding of information and memory consolidation, while memory imparnene in subcortical denentiy is affected by the disturbance of retrieval in subcortical dementia.

• Development and Reproduction
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• v.21 no.4
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• pp.417-424
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• 2017

Alzheimer's disease (AD) is neurodegenerative disease, characterized by the progressive decline of memory, cognitive functions, and changes in personality. The major pathological features in postmortem brains are neurofibrillary tangles and amyloid beta ($A{\beta}$) deposits. The majority of AD cases are sporadic and age-related. Although AD pathogenesis has not been established, aging and declining mitochondrial function has been associated. Mitochondrial dysfunction has been observed in AD patients' brains and AD mice models, and the mice with a genetic defect in mitochondrial complex I showed enhanced $A{\beta}$ level in vivo. To elucidate the role of mitochondrial complex I in AD, we used SH-SY5Y cells transfected with DNA constructs expressing human amyloid precursor protein (APP) or human Swedish APP mutant (APP-swe). The expression of APP-swe increased the level of $A{\beta}$ protein in comparison with control. When complex I was inhibited by rotenone, the increase of ROS level was remarkably higher in the cells overexpressing APP-swe compared to control. The number of dead cell was significantly increased in APP-swe-expressing cells by complex I inhibition. We suggest that complex I dysfunction accelerate amyloid toxicity and mitochondrial complex I dysfunction in aging may contribute to the pathogenesis of sporadic AD.

• 한국노년학
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• v.40 no.4
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• pp.729-746
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• 2020

For the development and better use of information and communication technology(ICT) for promoting health and quality of life in older people, it is important to understand personal factors associated with ICT use. The aims of this study were to describe the pattern of ICT use according to health characteristics of elderly and to investigate significant factors related to ICT use among three age groups. The data of 2017 National Survey of Older Koreans was used for analysis and 10,058 of older adults aged 65 and over were included for study participants. As results, first, the young old(65~74) used more functions of ICT than the middle-old(75~84) and the old-old(85 and over). Second, ICT was more used among older people with good conditions in chronic disease, subjective health, cognition, depression, vision, hearing, walking and IADL. Third, higher prevalence of ICT use was significantly associated with age, education, household income, subjective health, depression, cognitive function, vision limitation and walking limitation. Fourth, factors influencing the use of ICT were a little different among three age groups. For the young-old(65~74), subjective health, depression, cognitive decline, walking limitation, and IADL disability were significant factors affecting on ICT use. For the middle-old(75-84), subjective health, depression, cognitive decline, vision, hearing, and walking limitation were related with their ICT use. For the old-old(85 and over), only cognitive function and depression were associated with their ICT use. Based on these results, this study suggested the need to consider multiple health conditions for developing and using ICT for older adults.

• Sleep Medicine and Psychophysiology
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• v.21 no.1
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• pp.5-13
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• 2014

Objectives: Depression, sleep complaints and cognitive impairments are commonly observed in the elderly. Elderly subjects with depressive symptoms have been found to show both poor cognitive performances and sleep disturbances. However, the relationship between sleep complaints and cognitive dysfunction in elderly depression is not clear. The aim of this study is to identify the association between sleep disturbances and cognitive decline in late-life depression. Methods: A total of 282 elderly people who underwent nocturnal polysomnography in a sleep laboratory were enrolled in the study. The Korean version of the Neuropsychological Assessment Battery developed by the Consortium to Establish a Registry for Alzheimer's Disease (CERAD-K) was applied to evaluate cognitive function. Depressive symptoms were assessed with the geriatric depression scale (GDS) and subjective sleep quality was measured using the Pittsburg sleep quality index (PSQI). Results: The control group ($GDS{\leq}9$) when compared with mild ($10{\leq}GDS{\leq}16$) and severe ($17{\leq}GDS$) depression groups, had significantly different scores in the Trail making test part B (TMT-B), Benton visual retention test part A (BVRT-A), and Stroop color and word test (SCWT)(all tests p<0.05). The PSQI score, REM sleep duration, apnea-hypopnea index and oxygen desaturation index were significantly different across the three groups (all indices, p<0.05). A stepwise multiple regression model showed that educational level, age and GDS score were predictive for both TMT-B time (adjusted $R^2$=35.6%, p<0.001) and BVRT-A score (adjusted $R^2$=28.3%, p<0.001). SCWT score was predicted by educational level, age, apnea-hypopnea index (AHI) and GDS score (adjusted $R^2$=20.6%, p<0.001). Poor sleep quality and sleep structure alterations observed in depression did not have any significant effects on cognitive deterioration. Conclusion: Older adults with depressive symptoms showed mild sleep alterations and poor cognitive performances. However, we found no association between sleep disturbances (except sleep apnea) and cognitive difficulties in elderly subjects with depressive symptoms. It is possible that the impact of sleep disruptions on cognitive abilities was hindered by the confounding effect of age, education and depressive symptoms.

• Sleep Medicine and Psychophysiology
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• v.3 no.1
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• pp.56-67
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• 1996

Objectives : This study was designed to find clinical factors that could be differentiated by the lateralization of lesion and also find clinical factors to predict the lateralization of lesion. Methods : The subjects were 65 cooperative inpatients and outpatients with non-traumatic subcortical cerebrovascular disease without neurologic and psychiatric history from January 1995 to September 1995 ; 48 patients in Kyung Hee University, Oriental Medicine Hospital, 35 patients in Anam Hospital, Korea University were examined as subjects, but authors excluded 20 patients whose data were incomplete or who had uncertain lesions on brain CT or MRI. The 65 patients were divided into three groups-group with left hemispheric lesion, group with right hemispheric lesion, group with both hemispheric lesion-according to the finding of brain imaging study. Their cognitive functions were evaluated by the Benton Neuropsychological Assessment(BNA), their subjective neurobehavioral symptoms by Symptom Check List-90-R(SCL-90-R), their objective neurobehavioral symptoms by Neurobehavioral Rating Scale, and their daily living functions by Geriatric Evaluation by Relative's Rating Instrument(GERRl) and Instrumental Activities of Daily Living Scale(IADLs). Results : The results were as follows : 1) The results of cognitive function test indicated that the group with right hemispheric lesion showed low functions in Tactile Form Perception(left), the group with left hemispheric lesion showed low functions in Finger localization(right), the group with right hemispheric lesion showed low functions in Finger Localization(left). 2) Though, there were little significant differences in subjective neurobehavioral symptoms, the group with right hemispheric lesion showed higher scores in all symptoms except hostility. 3) Though, there were little significant differences in objective neurobehavioral symptoms, the group with both hemispheric lesion showed higher scores in cognition, guilty/disinhibition, the group with left hemispheric lesion showed higher scores in lability of mood, the group with right hemispheric lesion showed highest scores in psychotism, neurotism, agitation-hostility and decreased motivation/emotional withdrawal. 4) There were little significant differences among three groups in Daily Living Functions, but the group with right hemispheric lesion showed the lowest functions in Instrumental Activities of Daily Living. 5) As a result of discriminant analysis on each factor's contribution to the prediction of lesion, Finger Localization(left), Phoneme Discrimination and Tactile Form Perception(right) showed that they had the potentiality to predict lesion. Conclusion : The results suggest that there are little significant differences among the groups of three non-traumatic subcortical cerebrovascular disease in cognitive functions, but the group with right hemispheric lesion showed more serious and various changes in subjective and objective neurobehavioral symptoms, and showed low functions in Instrumental Activities of Daily Living. This results suggest the possibility that the decline of the daily living function in the group with right hemispheric lesion were due to various symptoms, not due to cognitive dysfunction. The confirmation of the possibility should be worked out through the follow-up study of some groups containing cortical lesion. Apart from these findings, Finger Localization, Tactile Form Perception(right) and Phoneme Discrimination suggest that they can be used as clinically valuable cognitive parameters that predict the lateralization of lesion in non-traumatic cerebrovascular disease.

• Molecules and Cells
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• v.37 no.11
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• pp.767-776
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• 2014

Alzheimer's disease (AD) is clinically characterized with progressive memory loss and cognitive decline. Synaptic dysfunction is an early pathological feature that occurs prior to neurodegeneration and memory dysfunction. Mounting evidence suggests that aggregation of amyloid-${\alpha}$ ($A{\alpha}$) and hyperphosphorylated tau leads to synaptic deficits and neurodegeneration, thereby to memory loss. Among the established genetic risk factors for AD, the ${\varepsilon}4$ allele of apolipoprotein E (APOE) is the strongest genetic risk factor. We and others previously demonstrated that apoE regulates $A{\alpha}$ aggregation and clearance in an isoform-dependent manner. While the effect of apoE on $A{\alpha}$ may explain how apoE isoforms differentially affect AD pathogenesis, there are also other underexplored pathogenic mechanisms. They include differential effects of apoE on cerebral energy metabolism, neuroinflammation, neurovascular function, neurogenesis, and synaptic plasticity. ApoE is a major carrier of cholesterols that are required for neuronal activity and injury repair in the brain. Although there are a few conflicting findings and the underlying mechanism is still unclear, several lines of studies demonstrated that apoE4 leads to synaptic deficits and impairment in long-term potentiation, memory and cognition. In this review, we summarize current understanding of apoE function in the brain, with a particular emphasis on its role in synaptic plasticity and the underlying cellular and molecular mechanisms, involving low-density lipoprotein receptor-related protein 1 (LRP1), syndecan, and LRP8/ApoER2.

• Journal of Life Science
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• v.21 no.5
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• pp.647-655
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• 2011

The neurotoxicity of aggregated amyloid ${\beta}$ ($A{\beta}$) has been implicated as a critical cause in the pathogenesis of Alzheimer's disease (AD). It can cause neurotoxicity in AD by evoking a cascade of apoptosis to neuron. Here, we investigated the neuroprotective effects of cilostazol, which acts as a phosphodiesterase III inhibitor, on $A{\beta}_{25-35}$-induced cytotoxicity in mouse neuronal cells and cognitive decline in the C57BL/6J AD mouse model via peroxisome proliferator-activated receptor (PPAR)-${\gamma}$ activation. $A{\beta}_{25-35}$ significantly reduced cell viability and increased the number of apoptotic-like cells. Cilostazol treatment recovered cells from $A{\beta}$-induced cell death as well as rosiglitazone, a PPAR-${\gamma}$ activator. These effects were suppressed by GW9662, an antagonist of PPAR-${\gamma}$ activity, indicative of a PPAR-${\gamma}$-mediated signaling. In addition, cilostazol and rosiglitazone also restored PPAR-${\gamma}$ activity levels that had been altered as a result of $A{\beta}_{25-35}$ treatment, which were antagonized by GW9662. Furthermore, cilostazol also markedly decreased the number of apoptotic-like cells and decreased the Bax/Bcl-2 ratio. Intracerebroventricular injection of $A{\beta}_{25-35}$ in C57BL/6J mice resulted in impaired cognitive function. Oral administration of cilostazol (20 mg/kg) for 2 weeks before $A{\beta}_{25-35}$ injection and once a day for 4 weeks post-surgery almost completely prevented the $A{\beta}_{25-35}$-induced cognitive deficits, as did rosiglitazone. Taken together, our findings suggest that cilostazol could attenuate $A{\beta}_{25-35}$-induced neuronal cell injury and apoptosis as well as promote the survival of neuronal cells, subsequently improving cognitive decline in AD, partly because of PPAR-${\gamma}$ activation. The phosphodiesterase III inhibitor cilostazol may be the basis of a novel strategy for the therapy of AD.

• The Korean Journal of Nuclear Medicine
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• v.36 no.2
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• pp.91-101
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• 2002

Purpose : The aim of this study was to identify the brain areas in which reductions of regional cerebral blood flow (rCBF) were correlated with decline of general mental function, measured by Mini-Mental State Examination (MMSE). Materials and Methods : Tc-99m HMPAO brain SPECT was peformed in 9 probable AD patients at the initial and follow-up periods of 1.8 years (average) after the first study. MMSE scores were also measured in both occasions. The mean MMSE score of the initial study 16.4 (range: 5 - 24) and the mean MMSE score of the follow-up was 8.1 (range: 0 - 17). Each SPECT image was normalized to the cerebellar activity and a correlation analysis was peformed between the level of rCBF in AD patients and the MMSE scores by voxel-based analysis using SPM99 software. Results : Significant correlation was found between the blood-flow decrease in left inferior prefrontal region (BA 47) and left middle temporal legion (BA 21) and the MMSE score changes. Additional areas such as anterior and posterior cingulate cortices, precuneus, and bilateral superior and middle prefrontal regions showed the similar trends. Conclusions : A relationship was found between reduction of regional cerebral blood flow in left prefrontal and temporal areas and decline of cognitive function in Alzheimer's disease(AD) patients. This voxel-based analysis is useful in evaluating the progress of cognitive function in Alzheimer's disease.

• The Journal of the Korea Contents Association
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• v.19 no.9
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• pp.308-320
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• 2019

This study aims at investigating the major symptoms that help family carers detect mental illness in elderly patients. Another purpose of this study is to empirically verify the major factors determining the utilization of mental health services with a focus on family carers. The results of this study are as follows. First, the most commonly detected symptoms that caused the family carers to suspect mental illness in the elderly patients were memory decline and other forms of cognitive function decline. Second, the determinants of the elderly's utilization of mental health services included the patient's long-term care insurance level, the age of the family carer, the period of care, the level stress associated with the provision of care felt by the carer, his understanding of geriatric mental illness, and the level of perception about community mental health services. Based on these findings, this study suggests policies and practical implications for the early detection of and response to elderly mental health problems and the utilization of related services from the viewpoint of the family carers of the elderly.

• Journal of Korea Multimedia Society
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• v.20 no.12
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• pp.1980-1991
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• 2017

Many stroke patients undergoing rehabilitation therapy require a quantitative indicator for the evaluation of body function in paretic and non-paretic regions. In this study, the impedance parameters were acquired to assess the physical status in the upper extremity of thirty six stroke patients with hemiplegia caused by cerebral hemorrhage (10 patients) and cerebral infarction (26 patients), using bioelectrical impedance. Prediction marker (PM), phase angle (PA), PM/PA, and resistance (R) versus reactance ($X_c$) were utilized to evaluate the functional status of the paretic and non-paretic regions. In addition, the hand grip strength (HGS) and the pinch strength (lateral, palmer, tip) were measured on the upper extremity of hemiplegic stroke patients. PM was distributed in inversely proportional to HGS, but PA was distributed in proportional to HGS. However, there were a number of patients with HGS of 0, regardless of the impedance parameters (PM, PA, R vs. $X_c$). Paretic and non-paretic status in upper extremity of these patients could not be analyzed using impedance parameters. At the rehabilitation therapist's instructions, they were unable to move the hand and fingers of the paretic upper extremity by cranial nerve damage, motor nerve damage, and severe cognitive decline.