Gender-Specific Influence of Education in Cognitive Subdomains in Alzheimer's Disease : A Clinical Research Center for Dementia of South Korea Study

OBJECTIVE: We aimed to find the sex differences of the way how educational attainment influence on cognitive function in patients with Alzheimer's disease (AD). METHODS: We recruited 424 patients with AD from a large hospital-based multi-center cohort. We evaluated cognitive subdomains using the Seoul Neuropsychological Screening Battery-Dementia version. We employed multiple linear regression analysis to compare the score of cognitive subdomains between the groups with high versus low educational attainment based on the high school graduate. Interaction between educational attainment and sex was also included in the analysis. RESULTS: High and low educational attainment group had 33.0% and 67.0% of patients in the study population. In the multiple regression analysis, score of all cognitive subdomains were significantly higher in the high educational attainment group. The score of attention was also significantly affected by interaction between educational attainment and sex. This result may be helpful to develop cognitive intervention therapy. CONCLUSION: In the female patients with AD, educational attainment showed higher influence on the attention score.

Extrapyramidal Signs and Risk of Progression from Mild Cognitive Impairment to Dementia: A Clinical Research Center for Dementia of South Korea Study

OBJECTIVE: Extrapyramidal signs (EPS) are common in patients with mild cognitive impairment (MCI). However, few studies have assessed the effect of EPS on the clinical course of MCI. We aimed to evaluate whether patients with EPS show more frequent progression from MCI to Alzheimer's disease (AD) and to other types of dementia. METHODS: Participants (n=882) with MCI were recruited, and were followed for up to 5 years. The EPS positive group was defined by the presence of at least one EPS based on a focused neurologic examination at baseline. RESULTS: A total of 234 converted to dementia during the follow-up period. The risk of progression to AD was lower in the patients with EPS after adjusting for potential confounders [hazard ratio (HR)=0.70, 95% confidence interval (CI)=0.53–0.93, p=0.01]. In contrast, the patients with EPS had a six-fold elevated risk of progression to dementia other than AD (HR=6.33, 95%CI=2.30–17.39, p < 0.001). CONCLUSION: EPS in patients with MCI is a strong risk factor for progression of MCI to non-Alzheimer dementia. The careful neurologic examination for EPS in patients with MCI can yield important clinical information for prognosis.

Extrapyramidal Signs and Impairment of Cognitive Subdomains in Mild Cognitive Impairment : A Clinical Research Center for Dementia of South Korea (CREDOS) Study

OBJECTIVES: This study investigated the association between extrapyramidal signs (EPS) and five cognitive sub-domains in a large number of patients with mild cognitive impairment (MCI). METHODS: Our analyses considered 1,943 patients with MCI drawn from the nationwide Clinical Research of Dementia of South Korea study. EPS were defined as presence in patients with at least 1 of 11 operationally specified features. We assessed five cognitive sub-domains : attention, language, visuospatial function, memory, and frontal/executive function using the Seoul Neuropsychological Screening Battery-Dementia version. The associations of EPS with each cognitive sub-domain were analyzed with a multiple linear regression model after controlling for confounding factors : sex, age, education years, diabetes, hypertension, severity of global function, depressive symptoms, and white matter hyperintensities (WMH). RESULTS: 138 MCI patients (7.1%%) had EPS. This group had more global cognitive deterioration and severe WMH. MCI patients with EPS showed lower performance compared to those without EPS in 3 cognitive sub-domains: attention (p=0.05), visuospatial function (p=0.02), and frontal/executive function (p<0.0001). The language sub-domain and the memory sub-domain did not differ between the EPS positive and the EPS negative groups. CONCLUSION: EPS in MCI are associated with greater cognitive impairment in specific functional sub-domains rather than with global greater cognitive deterioration.

Association between Cognitive Subdomains and Insight in Alzheimer Disease: A Clinical Research Center for Dementia of South Korea Study

OBJECTIVE: The aim of this study was to investigate the association between cognitive subdomains and insight into one's cognitive impairment in patients with Alzheimer disease (AD). METHODS: We recruited 1,722 patients with AD from the Clinical Research of Dementia of South Korea study and designed a cross-sectional study. Each patient's cognitive subdomain was assessed by using the Seoul Neuropsychological Screening Battery-Dementia version. Severity of dementia was evaluated by Korean version of Mini-Mental Status Examination (K-MMSE) and Clinical Dementia Rating Sum of Boxes (CDR-SB). Insight into one's cognitive impairment was categorized as 'with insight' and 'without insight' through interview with patient's caregivers. RESULTS: Among the 1,722 patients with AD, 1,475 patients were included in the 'with insight' group and the remaining 247 patients were included in the 'without insight' group. Subjects in the 'without insight' group had lower K-MMSE and CDR-SB scores than those in the 'with insight' group. After controlling for demographic data and dementia severity, higher scores on both attention function (odds ratio=1.12, 95% confidence interval : 1.03-1.21) and frontal-executive function (odds ratio=1.03, 95% confidence interval : 1.01-1.05) significantly predicted the membership to 'with insight' group. CONCLUSION: In patients with AD, attention and frontal-executive function were associated with insight into one's cognitive impairment.

Association between Cognitive Subdomains and Extrapyramidal Signs in Alzheimer Disease: A Clinical Research Center for Dementia of South Korea (CREDOS) Study

OBJECTIVES: We aimed to investigate the prevalence of Extrapyramidal signs (EPS) and the associations between EPS and cognitive subdomains in patients with Alzheimer disease (AD). METHODS: We recruited 1,324 patients with AD from the Clinical Research of Dementia of South Korea (CREDOS), a hospital based cohort study with fifty-six participating hospitals. We estimated cognitive subdomain using the Seoul Neuropsychological Screening Battery-Dementia version (SNSB-D). Dementia severity was measured by Clinical Dementia Rating Sum of Boxes (CDR-SB) and Korean version of Mini-Mental Status Examination (K-MMSE). The EPS group was defined by the presence of at least one EPS based on a focused neurologic examination. RESULTS: The prevalence of patients with EPS was 11%. These had higher CDR-SB scores than non-EPS group. After controlling for demographic, radiological, and dementia severity (CDR-SB) factors, EPS group showed lower cognitive ability in the subdomains for visuospatial and frontal-executive function than non-EPS group. The patients with EPS were showed significantly higher scores in the subdomain for memory function. CONCLUSION: The presence of EPSs in patients with AD was associated with lower visuospatial, frontal-executive function and higher memory function.

Association between Depression and Education Level in Alzheimer's Dementia : A CREDOS (Clinical Research Center for Dementia of South Korea) Study

OBJECTIVES: We aimed to identify the association depression with education level in patients with Alzheimer's dementia (AD). METHODS: We examined 911 patients with AD in CREDOS (Clinical Research Center for Dementia of South Korea) study and designed cross-sectional study. Each patient underwent psychiatrical, neurological and medical examination, interview for caregivers, laboratory tests, neuropsychological tests, and brain MRI. Cognitive function was measured using Korean version of Mini-Mental State Examination, Global Deterioration Scale and Clinical Dementia Rating. Psycho-Behavioral symptom was measured using Caregiver-Administered Neuropsychiatric Inventory. Daily Living was measured using Barthel Index for daily living activities and Seoul-Instrumental Activities of Daily Living. Depressive symptoms using the Korean version of the Short form on Geriatric Depression Scale were measured. Education was classified into low, intermediate, and high levels. 621 patients were performed APOE genotyping among the 911 patients. RESULTS: Out of the 911 patients, 477 were low education, 287 were intermediate education, and 147 were high education. 341 patients had depression. In logistic regression model we confirmed low education was the risk factor of depression (OR 2.26, 95% CI 1.66-3.07). CONCLUSION: This study confirmed that low education was associated with depression in Alzheimer's dementia.