Detecting amyloid-ß positivity using regions of interest from structural magnetic resonance imaging.

BACKGROUND AND PURPOSE: Alzheimer disease (AD) is the most common type of dementia. Amyloid-ß (Aß) positivity is the main diagnostic marker for AD. Aß positron emission tomography and cerebrospinal fluid are widely used in the clinical diagnosis of AD. However, these methods only assess the concentrations of Aß, and the accessibility of these methods is thus relatively limited compared with structural magnetic resonance imaging (sMRI). METHODS: We investigated whether regions of interest (ROIs) in sMRIs can be used to predict Aß positivity for samples with normal cognition (NC), mild cognitive impairment (MCI), and dementia. We obtained 846 Aß negative (Aß-) and 865 Aß positive (Aß+) samples from the Alzheimer's Disease Neuroimaging Initiative database. To predict which samples are Aß+, we built five machine learning models using ROIs and apolipoprotein E (APOE) genotypes as features. To test the performance of the machine learning models, we constructed a new cohort containing 97 Aß- and 81 Aß+ samples. RESULTS: The best performing machine learning model combining ROIs and APOE had an accuracy of 0.798, indicating that it can help predict Aß+. Furthermore, we searched ROIs that could aid our prediction and discovered that an average left entorhinal cortical region (L-ERC) thickness is an important feature. We also noted significant differences in L-ERC thickness between the Aß- and Aß+ samples even in the same diagnosis of NC, MCI, and dementia. CONCLUSIONS: Our findings indicate that ROIs from sMRIs along with APOE can be used as an initial screening tool in the early diagnosis of AD.

Predicting superagers by machine learning classification based on the functional brain connectome using resting-state functional magnetic resonance imaging.

Superagers are defined as older adults who have youthful memory performance comparable to that of middle-aged adults. Classifying superagers based on the brain connectome using machine learning modeling can provide important insights on the physiology underlying successful aging. We aimed to investigate the unique patterns of functional brain connectome of superagers and develop predictive models to differentiate superagers from typical agers based on machine learning methods. We obtained resting-state functional magnetic resonance imaging (rsfMRI) data and cognitive measures from 32 superagers and 58 typical agers. The accuracies of three machine learning methods including the linear support vector machine classifier (SV), the random forest classifier (RF), and the logistic regression classifier (LR) in predicting superagers were comparable (SV = 0.944, RF = 0.944, LR = 0.944); however, RF achieved the highest area under the curve (AUC; 0.979). An ensemble learning method combining the three classifiers achieved the highest AUC (0.986). The most discriminative nodes for predicting superagers encompassed areas in the precuneus; posterior cingulate gyrus; insular cortex; and superior, middle, and inferior frontal gyrus, which were located in default, salient, and multiple-demand networks. Thus, rsfMRI data can provide high accuracy for predicting superagers, thereby capturing and describing the unique characteristics of their functional brain connectome.

Predicting cognitive stage transition using p-tau181, Centiloid, and other measures.

BACKGROUND: A combination of plasma phospho-tau (p-tau), amyloid beta (Aß)-positron emission tomography (PET), brain magnetic resonance imaging, cognitive function tests, and other biomarkers might predict future cognitive decline. This study aimed to investigate the efficacy of combining these biomarkers in predicting future cognitive stage transitions within 3 years. METHODS: Among the participants in the Korean Brain Aging Study for the Early Diagnosis and Prediction of Alzheimer's Disease (KBASE-V) study, 49 mild cognitive impairment (MCI) and 113 cognitively unimpaired (CU) participants with Aß-PET and brain imaging data were analyzed. RESULTS: Older age, increased plasma p-tau181, Aß-PET positivity, and decreased semantic fluency were independently associated with cognitive stage transitions. Combining age, p-tau181, the Centiloid scale, semantic fluency, and hippocampal volume produced high predictive value in predicting future cognitive stage transition (area under the curve = 0.879). CONCLUSIONS: Plasma p-tau181 and Centiloid scale alone or in combination with other biomarkers, might predict future cognitive stage transition in non-dementia patients. HIGHLIGHTS: -Plasma p-tau181 and Centiloid scale might predict future cognitive stage transition. -Combining them or adding other biomarkers increased the predictive value. -Factors that independently associated with cognitive stage transition were demonstrated.

Radiological protection in human research ethics using a case study: toward update of the ICRP Publication 62.

The benefits of biomedical research involving humans are well recognised, along with the need for conformity to international standards of science and ethics. When human research involves radiation imaging procedures or radiotherapy, an extra level of expert review should be provided from the point of view of radiological protection. The relevant publication of the International Commission for Radiological Protection (ICRP) is now three decades old and is currently undergoing an update. This paper aims to provoke discussions on how the risks of radiation dose and the benefits of research should be assessed, using a case study of diagnostic radiology involving volunteers for whom there is no direct benefit. Further, the paper provides the current understanding of key concepts being considered for review and revision-such as the dose constraint and the novel research methods on the horizon, including radiation biology and epidemiology. The analysis revisits the perspectives described in the ICRP Publication 62, and considers the recent progress in both radiological protection ethics and medical research ethics.

Cilostazol Versus Aspirin on White Matter Changes in Cerebral Small Vessel Disease: A Randomized Controlled Trial.

BACKGROUND AND PURPOSE: Cerebral small vessel disease is characterized by progressive cerebral white matter changes (WMCs). This study aimed to compare the effects of cilostazol and aspirin on changes in WMC volume in patients with cerebral small vessel disease. METHODS: In a multicenter, double-blind, randomized controlled trial, participants with moderate or severe WMCs and at least one lacunar infarction detected on brain magnetic resonance imaging were randomly assigned to the cilostazol and aspirin groups in a 1:1 ratio. Cilostazol slow release (200 mg) or aspirin (100 mg) capsules were administered once daily for 2 years. The primary outcome was the change in WMC volume on magnetic resonance images from baseline to 2 years. Secondary imaging outcomes include changes in the number of lacunes or cerebral microbleeds, fractional anisotropy, and mean diffusivity on diffusion tensor images, and brain atrophy. Secondary clinical outcomes include all ischemic strokes, all ischemic vascular events, and changes in cognition, motor function, mood, urinary symptoms, and disability. RESULTS: Between July 2013 and August 2016, 256 participants were randomly assigned to the cilostazol (n=127) and aspirin (n=129) groups. Over 2 years, the percentage of WMC volume to total WM volume and the percentage of WMC volume to intracranial volume increased in both groups, but neither analysis showed significant differences between the groups. The peak height of the mean diffusivity histogram in normal-appearing WMs was significantly reduced in the aspirin group compared with the cilostazol group. Cilostazol significantly reduced the risk of ischemic vascular event compared with aspirin (0.5 versus 4.5 cases per 100 person-years; hazard ratio, 0.11 [95% CI, 0.02-0.89]). CONCLUSIONS: There was no significant difference between the effects of cilostazol and aspirin on WMC progression in patients with cerebral small vessel disease. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01932203.

Subtle Cognitive Deficits Are Associated with Amyloid-ß Positivity, but Not Severity of Self-Reported Decline: Results from the CoSCo Study.

INTRODUCTION: Subjective cognitive decline (SCD) can be considered as the preclinical manifestation of Alzheimer's disease (AD). The National Institute on Aging and the Alzheimer's Association criteria for preclinical AD proposed that subtle cognitive changes appear along with AD biomarkers in the late stage of preclinical AD. The objective of this study was to explore whether subtle cognitive impairment (SCI) in individuals with SCD is associated with brain amyloid-ß (Aß) status and SCD severity. METHODS: One hundred twenty individuals with SCD (mean age: 70.87 ± 6.10 years) were included in this study. SCI was defined as performance ≤ -1.0 SD on at least two neuropsychological tests. Participants underwent an amyloid positron emission tomography, which was assessed visually and quantitatively using standardized uptake value ratio (SUVR). The severity of SCD was assessed using two self-reported questionnaires: the SCD questionnaire based on the SCD-plus features and the Korean-Everyday Cognition (K-ECog) scale. RESULTS: SCD individuals with SCI (n = 25) had more Aß positivity than the SCD only group (n = 95) (44% vs. 15.79%; p = 0.002). In addition, the SCI group had a higher global SUVR than the SCD only group (p = 0.048). For self-reported questionnaires, there were no differences in SCD questionnaire total scores and K-ECog global and cognitive domain-specific scores between two groups. CONCLUSIONS: In SCD individuals, SCI was associated with higher Aß positivity, but not with the severity of self-reported cognitive decline, compared to the SCD only group. These results suggest that the recognition of objectively defined subtle cognitive deficits may contribute to the early identification of AD in SCD.

The Effect of Hearing Loss on Cognitive Function in Subjective Cognitive Decline.

INTRODUCTION: Subjective cognitive decline (SCD) is a self-reported cognitive decline without objective cognitive impairment. The relationship between audiometric hearing loss (HL) and cognitive function has not been reported in SCD. The purpose of this study was to investigate whether HL affects cognition-related indexes in SCD individuals. METHODS: This is a cross-sectional study that used the baseline data of a multicenter cohort study that monitors clinical progression from SCD to dementia. Individuals aged ≥60 years who reported cognitive decline but had no objective cognitive impairment on comprehensive neuropsychological tests were recruited. Participants were grouped into the normal-hearing (NH) and bilateral HL groups. The demographics, clinical characteristics, dementia biomarkers, global cognition, questionnaire scores, neuropsychological test scores, and segmental brain volumes from MRI were compared between the groups. RESULTS: Of a total of 120 participants, one hundred and two had NH (n = 57) or bilateral HL (n = 45). There were no group differences in the demographic and clinical data except the age. The biomarkers, global cognition, and questionnaire scores were not different between the groups. The HL group performed worse (the z-score of -0.06) in the Stroop Color Word Test than the NH group (0.27) (p = 0.025). Brain volumetric analysis revealed that the HL group had reduced gray matter volumes in four brain subregions: left temporal pole, left caudal middle frontal gyrus, left hippocampus, and right isthmus of the cingulate gyrus. CONCLUSION: In SCD, HL exerted an adverse effect on cognitive function, primarily frontal executive function tested in the Stroop task. HL was also related to gray matter volume reductions in brain subregions, although causality needs further investigation. This study may provide evidence for a potential link between hearing and cognition in SCD, an emerging clinical entity.

The Moderating Role of Sleep Quality on the Association between Neuroticism and Frontal Executive Function in Older Adults.

OBJECTIVE/BACKGROUND: Personality traits are regarded as risk factors for cognitive impairment in older adults, while sleep disturbance and physical inactivity are also considered as modifiable risk factors. Therefore, it could be beneficial to investigate the effects of those modifiable risk factors on the relationship between personality traits and cognitive functions, to prepare appropriate strategies for mitigating cognitive impairment. PARTICIPANTS: A total of 155 cognitively unimpaired older adults were included. METHODS: All participants underwent cognitive function tests using the Seoul Neuropsychological Screening Battery and examinations for personality traits using the Big Five Inventory. Individual physical activity and sleep quality were assessed using the International Physical Activity Questionnaire and Pittsburgh Sleep Quality Index, respectively. A hierarchical linear multiple regression analysis was performed to demonstrate the direct association between personality traits and cognitive functions, and the multiple moderator analysis was used to analyze the moderating effects of lifestyle factors on this association. RESULTS: Among the five personality traits, only neuroticism was negatively associated with the frontal executive and visuospatial functions after controlling age, sex, and years of education. Interestingly, the negative relationship between neuroticism and frontal executive function was alleviated in older adults with higher sleep quality. CONCLUSIONS: Our findings demonstrated that higher sleep quality has significant moderating effects on the negative association between neuroticism and frontal executive functions in older adults, which suggests intervention for improving sleep quality such as cognitive behavioral therapy can be considered in older adults who have personality traits associated with a high risk of cognitive impairment.

Language treatment effects on communicative abilities and working memory in Korean-speaking agrammatic Broca's aphasia caused by moyamoya disease: Phase II evidence from a case study.

The present study reports on the language treatment outcomes from sentence- and story-level linguistic facilitation and its generalization effect on communicative abilities, working memory, and sentence processing in the case of an adult with Moyamoya Disease (MMD). After treatment,the patient's overall performance, including the Aphasia Quotient, and sentence processing ability as measured by language testing, were improved. Furthermore, the treatment effects were generalizable to working memory abilities. Our case study conveys clinically meaningful implications since it is the first report on the effects of language treatment on linguistic and cognitive domains for an individual with MMD-induced agrammatic Broca's aphasia.

Self- and informant-reported cognitive functioning and awareness in subjective cognitive decline, mild cognitive impairment, and very mild Alzheimer disease.

OBJECTIVES: The present study examined self-reports and informant reports of cognitive function and discrepancies between the two reporting methods in healthy controls (HC), subjective cognitive decline (SCD), mild cognitive impairment (MCI), and very mild Alzheimer disease (AD) using three questionnaires. METHODS: The study included a total of 300 individuals (mean age: 74.4 ± 5.7 y), including 130 HC, 70 SCD, 51 MCI, and 49 very mild AD patients. Self-ratings and informant ratings of cognitive function were assessed using the Korean Dementia Screening Questionnaire-Cognition (KDSQ-C), AD8, and Subjective Memory Complaints Questionnaire (SMCQ). Awareness of cognitive functioning was measured on the basis of the discrepancy scores between self-reports and informant reports. RESULTS: Group comparisons on questionnaire scores adjusting for age, education, and depressive symptoms showed that self-reports were lowest in HC than other groups, with no differences between SCD and MCI groups. Informant reports were lower in SCD than in MCI, while discrepancy scores were higher in SCD than in MCI (P < .001 for KDSQ-C and SMCQ; P = .076 for AD8). There were no differences in self-reports, informant reports, and discrepancy scores between MCI and AD groups. CONCLUSIONS: These results support the usefulness of informant-reported cognitive functioning to classify MCI among elderly with subjective cognitive complaints. In addition, discrepancies between self-reports and informant reports demonstrate that overestimation and underestimation of cognitive function may serve as a clinical indicator of SCD and MCI across the cognitive continuum, respectively.

A Comparative Evaluation of the KDSQ-C, AD8, and SMCQ as a Cognitive Screening Test to Be Used in National Medical Check-ups in Korea.

BACKGROUND: Korea has a periodic general health check-up program that uses the Korean Dementia Screening Questionnaire-Cognition (KDSQ-C) as a cognitive dysfunction screening tool. The Alzheimer Disease 8 (AD8) and Subjective Memory Complaints Questionnaire (SMCQ) are also used in clinical practice. We compared the diagnostic ability of these screening questionnaires for cognitive impairment when completed by participants and their caregivers. Hence, we aimed to evaluate whether the SMCQ or AD8 is superior to the KDSQ-C and can be used as its replacement. METHODS: A total of 420 participants over 65 years and their informants were recruited from 11 hospitals for this study. The patients were grouped into normal cognition, mild cognitive impairment, and dementia subgroups. The KDSQ-C, AD8, and SMCQ were completed separately by participants and their informants. RESULTS: A receiver operating characteristic analysis of questionnaire scores completed by participants showed that the areas under the curve (AUCs) for the KDSQ-C, AD8, and SMCQ for diagnosing dementia were 0.75, 0.8, and 0.73, respectively. Regarding informant-completed questionnaires, the AD8 (AUC of 0.93), KDSQ-C (AUC of 0.92), and SMCQ (AUC of 0.92) showed good discriminability for dementia, with no differences in discriminability between the questionnaires. CONCLUSION: When an informant-report is possible, we recommend that the KDSQ-C continues to be used in national medical check-ups as its discriminability for dementia is not different from that of the AD8 or SMCQ. Moreover, consistent data collection using the same questionnaire is important. When an informant is not available, either the KDSQ-C or AD8 may be used. However, in the cases of patient-reports, discriminability is lower than that for informant-completed questionnaires.

Prediction of cognitive impairment via deep learning trained with multi-center neuropsychological test data.

BACKGROUND: Neuropsychological tests (NPTs) are important tools for informing diagnoses of cognitive impairment (CI). However, interpreting NPTs requires specialists and is thus time-consuming. To streamline the application of NPTs in clinical settings, we developed and evaluated the accuracy of a machine learning algorithm using multi-center NPT data. METHODS: Multi-center data were obtained from 14,926 formal neuropsychological assessments (Seoul Neuropsychological Screening Battery), which were classified into normal cognition (NC), mild cognitive impairment (MCI) and Alzheimer's disease dementia (ADD). We trained a machine learning model with artificial neural network algorithm using TensorFlow (https://www.tensorflow.org) to distinguish cognitive state with the 46-variable data and measured prediction accuracies from 10 randomly selected datasets. The features of the NPT were listed in order of their contribution to the outcome using Recursive Feature Elimination. RESULTS: The ten times mean accuracies of identifying CI (MCI and ADD) achieved by 96.66 ± 0.52% of the balanced dataset and 97.23 ± 0.32% of the clinic-based dataset, and the accuracies for predicting cognitive states (NC, MCI or ADD) were 95.49 ± 0.53 and 96.34 ± 1.03%. The sensitivity to the detection CI and MCI in the balanced dataset were 96.0 and 96.0%, and the specificity were 96.8 and 97.4%, respectively. The 'time orientation' and '3-word recall' score of MMSE were highly ranked features in predicting CI and cognitive state. The twelve features reduced from 46 variable of NPTs with age and education had contributed to more than 90% accuracy in predicting cognitive impairment. CONCLUSIONS: The machine learning algorithm for NPTs has suggested potential use as a reference in differentiating cognitive impairment in the clinical setting.

PSEN1 p.Thr116Ile Variant in Two Korean Families with Young Onset Alzheimer's Disease.

An in depth study of PSEN1 mutation p.Thr116Ile (c.335C>T) is presented from two Korean families with autosomal dominant inheritance. Clinical manifestation of our patients included memory loss, attention deficits, visuospatial dysfunction, agnosia, aphasia, apraxia, and personality changes, which occurred in their 30s. PSEN1 Thr116Ile was initially discovered in an Italian patient and two French families with early onset Alzheimer's disease (EOAD) with similar age of onset. To verify the possible pathogenic mechanisms of mutation, in silico predictions and 3D modeling were performed. Structure predictions revealed significant aberrations in first hydrophilic loop (HL-I loop). The hydrophobic isoleucine could alter the loop orientation through increased hydrophobic contacts with the surrounding amino acids. Mutation could destroy a possible hydrogen bond between tyrosine 115 and threonine 116, which may affect the loop conformation. HL-I was confirmed as a conservative region of PSEN1, which may be critical in PSEN1 functions. An additional pathogenic mutation, PSEN1 Thr116Asn, was also found for the same residue, where the patient presented young onset AD (YOND). Other mutations in HL-I loop, such as Tyr115His and Glu120Asp, were described in patients with YOND, supporting the critical role of HL-I loop in PSEN1 activity.

Cerebrospinal Fluid Biomarkers for the Diagnosis of Alzheimer Disease in South Korea.

Laboratory-specific reference values for cerebrospinal fluid (CSF) Alzheimer disease (AD) biomarkers are necessary. Our objective was to apply well-known CSF biomarkers and redetermine their diagnostic cutoff values for AD in South Korea. CSF samples from matched control subjects (n=71), patients with AD dementia (ADD, n=76), and other neurological disorders with cognitive decline (OND, n=47) were obtained from 6 Korean dementia clinics according to a standardized protocol. CSF biomarker concentrations were measured using enzyme-linked immunosorbent assay. CSF biomarkers differed significantly between the ADD and control groups (P<0.001 for all), and between the ADD and OND groups (P<0.001 for all). The areas under the curve in differentiation of ADD from control subjects were 0.97 for Aß42, 0.93 for total tau (tTau), 0.86 for pTau, and 0.99 for both tTau/Aß42 and pTau/Aß42 ratios. Our revised cutoff value for Aß42 was higher than our previous one, whereas the values for the Tau proteins were similar. The tTau/Aß42 ratio had the highest accuracy, 97%. Our findings highlight the usefulness of CSF AD biomarkers in South Korea, and the necessity of continually testing the reliability of cutoff values.

Anosognosia and Its Relation to Psychiatric Symptoms in Early-Onset Alzheimer Disease.

BACKGROUND: We investigated differences in the prevalence of anosognosia and neuropsychiatric symptoms (NPSs) characteristics according to disease severity in patients with early-onset Alzheimer disease (EOAD). METHODS: We recruited 616 patients with EOAD. We subdivided participants into 2 groups based on the presence or absence of anosognosia and then again by Clinical Dementia Rating (CDR) scale. We compared the differences in the Neuropsychiatric Inventory (NPI) scores according to anosognosia and disease severity. RESULTS: The percentage of patients with anosognosia in each CDR group steadily increased as the CDR rating increased (CDR 0.5 8.6% vs CDR 1 13.6% vs CDR 2 26.2%). The NPI total score was significantly higher in patients with anosognosia in the CDR 0.5 and 1 groups; by contrast, it had no association in the CDR 2 group. Frontal lobe functions were associated with anosognosia only in the CDR 0.5 and 1 groups. After stratification by CDR, in the CDR 0.5 group, the prevalence of agitation ( P = .040) and appetite ( P = .013) was significantly higher in patients with anosognosia. In the CDR 1 group, patients with anosognosia had a significantly higher prevalence of delusions ( P = .032), hallucinations ( P = .048), and sleep disturbances ( P = .047). In the CDR 2 group, we found no statistical difference in the frequency of symptoms between patients with and without anosognosia. CONCLUSION: These results confirm that the prevalence of anosognosia as well as the individual NPS and cognitive functions associated with it differ according to EOAD severity.

Effect of Individual and District-level Socioeconomic Disparities on Cognitive Decline in Community-dwelling Elderly in Seoul.

This study was to investigate the effects of individual and district-level socioeconomic status (SES) on the development of cognitive impairment among the elderly. A 3-year retrospective observational analysis (2010-2013) was conducted which included 136,217 community-dwelling healthy elderly who participated in the Seoul Dementia Management Project. Cognitive impairment was defined as 1.5 standard deviations below the norms on the Mini-mental status examination. In the individual lower SES group, the cumulative incidence rate (CIR) of cognitive impairment was 8.7% (95% confidence interval [CI], 8.64-8.70), whereas the CIR in the individual higher SES group was 4.1% (95% CI, 4.08-4.10). The CIR for lower district-level SES was 4.7% (95% CI, 4.52-4.86), while that in the higher district-level SES was 4.3% (95% CI, 4.06-4.44). There were no additive or synergistic effects between individual and district-level SES. From this study, the individual SES contributed 1.9 times greater to the development of cognitive impairment than the district-level SES, which suggests that individual SES disparities could be considered as one of the important factors in public health related to cognitive impairment in the elderly.

Group- and Home-Based Cognitive Intervention for Patients with Mild Cognitive Impairment: A Randomized Controlled Trial.

BACKGROUND: We examined the efficacy of group-based cognitive intervention (GCI) and home-based cognitive intervention (HCI) in amnestic mild cognitive impairment (aMCI) and intervention effects on serum brain-derived neurotrophic factor (BDNF). METHODS: In this randomized and rater-blinded trial, 293 patients with aMCI from 18 nationwide hospitals were randomized: 96 to the GCI group, 98 to the HCI group and 99 to the control group. For 12 weeks, subjects receiving GCI participated twice per week in group sessions led by trained instructors, and those receiving HCI completed homework materials 5 days per week. They were assessed at baseline, postintervention (PI) and at the 6-month follow-up after the intervention. The primary endpoint was the change from baseline to PI in the modified Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-Cog). RESULTS: In comparison to the controls (a 0.8-point decrease), the subjects receiving GCI (a 2.3-point decrease, p = 0.01) or HCI (a 2.5-point decrease, p = 0.02) showed significant improvements in the modified ADAS-Cog at PI, respectively. By the 6-month follow-up, those receiving GCI or HCI had better scores in the modified ADAS-Cog than the controls. The changes in BDNF levels significantly correlated with the changes in the modified ADAS-Cog in the GCI (r = -0.29, p = 0.02 at PI) and HCI (r = -0.27, p = 0.03 at 6-month follow-up) groups, respectively. CONCLUSIONS: The GCI and HCI resulted in cognitive improvements in aMCI. An enhanced brain plasticity may be a component of the mechanism underpinning the cognitive improvements associated with the cognitive interventions.

Factors related to prevalence, persistence, and incidence of depressive symptoms in mild cognitive impairment: vascular depression construct.

OBJECTIVE: Depression is prevalent among elders with cognitive impairment. Cerebral white matter hyperintensities (WMH) have consistently been implicated in late-life depression and in cognitive impairment. This study aims to clarify the factors related to prevalence, persistence, and new onset of depressive symptoms in subjects with mild cognitive impairment (MCI). METHODS: As part of a multicenter prospective study, the Clinical Research Center for Dementia of South Korea (CREDOS) Study, we enrolled 590 subjects diagnosed with MCI and with no prior history of depression. Depressive symptoms were assessed by the Korean version of the Geriatric Depression Scale short form (SGDS-K) at baseline and at follow-up visits. Brain magnetic resonance imaging was performed at baseline to quantify WMH using a visual rating scale. RESULTS: The baseline prevalence of clinically significant depressive symptoms (SGDS-K ≥5) was 51.4%, and this feature was associated with younger age, lower educational achievement, and higher Clinical Dementia Rating Sum of Boxes (CDR-SB) scores. Persistence of depressive symptoms across the study period was significantly associated with baseline CDR-SB and depression scores. New onset of depression (SGDS-K ≥8; incidence 15.7%) among subjects free of depressive symptoms (SGDS-K <5) at baseline was associated with severe deep subcortical, but not periventricular, WMH. CONCLUSIONS: In patients with MCI aged 50 years or older, depressive symptoms were highly prevalent. Cognitive status was closely related to both prevalence and persistence of depressive symptoms, while new onset of depression was associated with deep subcortical WMH severity in this MCI cohort. Our findings provide prospective evidence consistent with the vascular depression hypothesis. Copyright © 2015 John Wiley & Sons, Ltd.

Predictors of Clinical Progression of Subjective Memory Impairment in Elderly Subjects: Data from the Clinical Research Centers for Dementia of South Korea (CREDOS).

BACKGROUND/AIMS: The aims of this study were to determine baseline factors related to the progression of subjective memory impairment (SMI) in elderly subjects and to develop a new modeling scale to predict progression. METHODS: Elderly subjects with SMI were recruited from the nationwide Clinical Research Centers for Dementia of South Korea (CREDOS) multicenter cohort and divided into two groups: (1) progressed to mild cognitive impairment or Alzheimer's disease or (2) stable without progression. Baseline clinical characteristics were compared between the groups, and the most relevant predictors of progression were assessed. A new modeling scale combining the predictors was developed. RESULTS: In total, 129 subjects with SMI were analyzed. The follow-up duration was 0.5-4.7 years, and the median time to event was 3.64 years. The progressing group (n = 29) differed from the stable group (n = 100) in terms of baseline age, apolipoprotein E4 (APOE4) status, and some cognitive domains. Older age, a lower Mini-Mental State Examination recall score, APOE4 carrier, and a lower verbal delayed recall score were the most relevant predictors of progression, and a new modeling scale with these 4 predictors provided a better explanation of progression. CONCLUSION: SMI subjects with a higher risk of progression can be identified using a new modeling scale and might need further evaluations and more frequent follow-up.

Gender differences in risk factors for transition from mild cognitive impairment to Alzheimer's disease: A CREDOS study.

BACKGROUND: Women are subject to a disproportionate burden from Alzheimer's disease (AD) and sex differences exist in treatment response and prognosis of the disease. Yet gender-specific risk factors have not been widely studied. We aimed to investigate gender-specific risk factors for AD in subjects with mild cognitive impairment (MCI). METHODS: Participants (n=294) with MCI were recruited from a nationwide, prospective cohort study of dementia and were followed for a median (range) of 13.8 (6.0-36.0) months. Sex-stratified associations of progression to AD with baseline characteristics were explored. RESULTS: Seventy-four individuals (25.2%) developed incident dementia (67 AD) during follow-up. Significant risk factors for probable AD differed by sex. In men, the significant risk factors were severe periventricular white matter hyperintensities, and poorer global cognitive function. In women, older age, clinically significant depressive symptoms at baseline, and positive APOE ε4 alleles were the significant risk factors. CONCLUSIONS: Risk factors for progression from MCI to probable AD differed in men and women. These results may translate to gender-specific preventative or therapeutic strategies for patients with MCI.