Use of the Clock Drawing Test and the Rey-Osterrieth Complex Figure Test-copy with convolutional neural networks to predict cognitive impairment.

BACKGROUND: The Clock Drawing Test (CDT) and Rey-Osterrieth Complex Figure Test (RCFT) are widely used as a part of neuropsychological test batteries to assess cognitive function. Our objective was to confirm the prediction accuracies of the RCFT-copy and CDT for cognitive impairment (CI) using convolutional neural network algorithms as a screening tool. METHODS: The CDT and RCFT-copy data were obtained from patients aged 60-80 years who had more than 6 years of education. In total, 747 CDT and 980 RCFT-copy figures were utilized. Convolutional neural network algorithms using TensorFlow (ver. 2.3.0) on the Colab cloud platform ( www.colab. RESEARCH: google.com ) were used for preprocessing and modeling. We measured the prediction accuracy of each drawing test 10 times using this dataset with the following classes: normal cognition (NC) vs. mildly impaired cognition (MI), NC vs. severely impaired cognition (SI), and NC vs. CI (MI + SI). RESULTS: The accuracy of the CDT was better for differentiating MI (CDT, 78.04 ± 2.75; RCFT-copy, not being trained) and SI from NC (CDT, 91.45 ± 0.83; RCFT-copy, 90.27 ± 1.52); however, the RCFT-copy was better at predicting CI (CDT, 77.37 ± 1.77; RCFT, 83.52 ± 1.41). The accuracy for a 3-way classification (NC vs. MI vs. SI) was approximately 71% for both tests; no significant difference was found between them. CONCLUSIONS: The two drawing tests showed good performance for predicting severe impairment of cognition; however, a drawing test alone is not enough to predict overall CI. There are some limitations to our study: the sample size was small, all the participants did not perform both the CDT and RCFT-copy, and only the copy condition of the RCFT was used. Algorithms involving memory performance and longitudinal changes are worth future exploration. These results may contribute to improved home-based healthcare delivery.

Coping with Dementia in the Middle of the COVID-19 Pandemic.

Multiple neurological complications have been associated with the coronavirus disease-19 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2. This is a narrative review to gather information on all aspects of COVID-19 in elderly patients with cognitive impairment. First, the following three mechanisms have been proposed to underlie the neurological complications associated with COVID-19: 1) direct invasion, 2) immune and inflammatory reaction, and 3) hypoxic brain damage by COVID-19. Next, because the elderly dementia patient population is particularly vulnerable to COVID-19, we discussed risk factors and difficulties associated with cognitive disorders in this vulnerable population. We also reviewed the effects of the patient living environment in COVID-19 cases that required intensive care unit (ICU) care. Furthermore, we analyzed the impact of stringent social restrictions and COVID-19 pandemic-mediated policies on dementia patients and care providers. Finally, we provided the following strategies for working with elderly dementia patients: general preventive methods; dementia care at home and nursing facilities according to the activities of daily living and dementia characteristics; ICU care after COVID-19 infection; and public health care system and government response. We propose that longitudinal follow-up studies are needed to fully examine COVID-19 associated neurological complications, such as dementia, and the efficacy of telemedicine/telehealth care programs.

Predictors of pre-operative cognitive impairment in meningioma patients over 60 years old.

BACKGROUND: The aim of this study was to assess the cognitive function of patients over 60 years old with meningioma using a domain-specific neuropsychological test and to investigate the relevant factors affecting pre-operative cognitive decline in different subdomains. METHODS: We retrospectively investigated 46 intracranial meningioma patients between the ages of 60 and 85 years. All patients underwent brain MRI and neuropsychological test. Tumor size, location, peritumoral edema, and medial temporal atrophy (MTA) were examined to determine the association with cognitive impairment. We performed a logistic regression analysis to examine the odds ratios (ORs) for cognitive decline of four subdomains: verbal memory, language, visuospatial, and executive functions. RESULTS: Tumor size and age were associated with executive dysfunction (OR 1.083, 95% confidence interval (CI) 1.006-1.166, and OR 1.209, 95% CI 1.018-1.436, respectively). There was no statistically significant association in other cognitive domains (language, verbal memory, and visuospatial function) with variables in regression analysis. CONCLUSIONS: We conclude that tumor size and age are positively related with executive function in pre-operative meningioma patients over 60 years old.

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.

The usefulness of visual rating of posterior atrophy in predicting rapid cognitive decline in Alzheimer disease: A preliminary study.

BACKGROUND: Approximately 10% to 30% of Alzheimer disease (AD) patients progress rapidly in severity and become more dependent on caregivers. Although several studies have investigated whether imaging biomarkers such as medial temporal atrophy (MTA) and posterior atrophy (PA) are useful for predicting the rapid progression of AD, their results have been inconsistent. OBJECTIVE: The study aims to investigate the association of visually rated MTA and PA with rapid disease progression in AD. METHODS: This was a retrospective cohort study of 159 AD patients who were initially diagnosed with mild AD and were followed for 1 year to determine whether they progressed rapidly (a decrease of three points or more on the Mini-Mental State Examination over 1 year). We used 5-point and 4-point visual rating scales to assess MTA and PA, respectively. MTA and PA scores for each patient were dichotomized as normal (without atrophy) or abnormal (atrophy). We performed a logistic regression analysis to determine the odds ratios (ORs) of MTA and PA for rapid disease progression with adjustment for covariates. RESULTS: Within the study population, 47 (29.6%) patients progressed rapidly. Visual assessment of the magnetic resonance imaging (MRI) scans revealed that 112 patients (70.4%) showed MTA, whereas 80 patients (50.3%) showed PA. The ORs with 95% confidence intervals for MTA and PA were 1.825 (0.819-4.070) and 2.844 (1.378-5.835), respectively. The association of visually assessed PA, but not MTA, with rapid progression was significant after adjustment for covariates. CONCLUSION: In patients with mild AD, visual assessment of PA exhibits independent predictive value for rapid disease progression.

Driving Cessation and Cognitive Dysfunction in Patients with Mild Cognitive Impairment.

Although driving by adults with cognitive impairment is an important public health concern, little is known about the indicators of driving cessation in patients with mild cognitive impairment (MCI). We aimed to investigate the prevalence of driving cessation in patients with MCI and the predictive value of cognitive performances for driving cessation. Patients with MCI were recruited in the Seoul National University Bundang Hospital; they met following inclusion criteria. Age range of 51⁻80 years, Clinical Dementia Rating scale score of 0.5, and ever car drivers including former and current drivers. All participants underwent comprehensive standardized cognitive assessments and information on driving status was obtained via an interview using a systematic questionnaire. The median age of the 135 participants was 72 years, and 54 participants (40%) were women; 93 patients (68.9%) were current drivers and 42 (31.1%) were former drivers. In univariate analysis, former drivers showed poorer performances in digit span backward and categorical fluency tests than current drivers. In multivariate logistic regression analysis, a poor digit span backward test score was significantly related with driving cessation (odds ratio: 0.493, 95% confidence interval: 0.258⁻0.939). In patients with MCI, poor performance in the digit span backward test, which represents impaired working memory capacity, was associated with a higher probability of driving cessation.

Multimodal Assessment of Neural Substrates in Computerized Cognitive Training: A Preliminary Study.

BACKGROUND AND PURPOSE: Several studies have validated the clinical efficacy of computerized cognitive training applications. However, few studies have investigated the neural substrates of these training applications using simultaneous multimodal neuroimaging modalities. We aimed to determine the effectiveness of computerized cognitive training and corresponding neural substrates through a multimodal approach. METHODS: Ten patients with mild cognitive impairment (MCI), six patients with subjective memory impairment (SMI), and 10 normal controls received custom-developed computerized cognitive training in the memory clinic of a university hospital. All of the participants completed 24 sessions of computerized cognitive training, each lasting 40 minutes and performed twice weekly. They were assessed using neuropsychological tests (both computerized and conventional), electroencephalography, fluorodeoxyglucose positron-emission tomography (FDG-PET), volumetric magnetic resonance imaging (MRI), and diffusion-tensor imaging (DTI) at pre- and posttraining. RESULTS: The patients with MCI exhibited significant improvements in the trail-making test-black & white-B, and memory domain of the computerized cognitive assessment. Subjects with normal cognition exhibited significant improvements in scores in the language and attention-/psychomotor-speed domains. There were no significant changes in subjects with SMI. In the pre- and posttraining evaluations of the MCI group, FDG-PET showed focal activation in the left anterior insula and anterior cingulate after training. Volumetric MRI showed a focal increase in the cortical thickness in the rostral anterior cingulate. DTI revealed increased fractional anisotropy in several regions, including the anterior cingulate. CONCLUSIONS: The anterior cingulate and anterior insula, which are parts of the salience network, may be substrates for the improvements in cognitive function induced by computerized cognitive training.

Re-standardization of the Korean-Instrumental Activities of Daily Living (K-IADL): Clinical Usefulness for Various Neurodegenerative Diseases.

BACKGROUND AND PURPOSE: Evaluating instrumental activities of daily living (IADL) is an important part of procedure to diagnose dementia. The Korean-Instrumental Activities of Daily Living (K-IADL) has been used extensively in Korea. However, its cut-off score has not been reformulated since 2002. The purpose of this study was to yield a new optimal cut-off score for the K-IADL and confirm the validity of this new cut-off score with various dementia groups. METHODS: We retrospectively collected a total of 2,347 patients' K-IADL data from 6 general hospitals in Korea. These patients had mild cognitive impairment (MCI) or dementia with various etiologies for cognitive impairment. We also recruited a normal control group (n=254) from the community. Korean-Mini Mental State Examination, Short version of the Geriatric Depression Scale, Clinical Dementia Rating, and Global Deterioration Scale were administered to all participants. Caregivers completed K-IADL and Barthel Index. RESULTS: K-IADL scores were significantly different among dementia subgroups, but not significantly different among MCI subgroups. Based on internal consistency, correlations with other scales, and factor analysis, K-IADL showed excellent reliability and validity. The new optimal cut-off score to diagnose dementia was 0.40, which gave a sensitivity of 0.901 and a specificity of 0.916. Positive predictive value for dementia using the new cut-off score was 94.2% for Alzheimer's disease, 100% for vascular dementia, and 84% for Parkinson's disease. CONCLUSIONS: Our results illustrate that the new K-IADL cut-off score of 0.40 is reliable and valid for screening impairments of daily functioning resulting from various etiologies.

Visual Rating of Posterior Atrophy as a Marker of Progression to Dementia in Mild Cognitive Impairment Patients.

BACKGROUND: Although medial temporal atrophy (MTA) is a useful imaging marker of the progression to dementia in mild cognitive impairment (MCI), substantial numbers of MCI patients without MTA still progress to dementia. OBJECTIVE: We investigated whether visual ratings of posterior atrophy (PA) on magnetic resonance imaging show independent predictive value for the progression to dementia in MCI patients. METHODS: This was a retrospective cohort study of elderly patients who visited Seoul National University Bundang Hospital between 2004 and 2012. A total of 148 patients who were initially diagnosed with MCI were followed for up to 3 years (median 22 months) to determine whether they progressed to dementia. We used 4-point and 5-point visual rating scales to assess PA and MTA, respectively. PA and MTA scores were dichotomized into normal (no atrophy) or abnormal (atrophy) in each patient. We performed a Cox regression analysis to examine the hazard ratios (HRs) of PA and MTA for the progression to dementia with adjustment for age, APOEɛ4 allele status, and baseline Mini-Mental State Examination score. RESULTS: Among the study population, 47 patients progressed to dementia. Visual assessment of the MRI scans revealed that 67 patients (45.3%) showed PA, whereas 85 patients (57.3%) showed MTA. The HRs with 95% confidence intervals for PA and MTA were 2.516 (1.244-5.091) and 4.238 (1.680-10.687), respectively. The predictive values of visually assessed PA and MTA remained significant, independent of the covariates. CONCLUSION: Visual assessment of PA has independent predictive value for progression to dementia in MCI patients.

The Validity and Reliability of the Mini-Mental State Examination-2 for Detecting Mild Cognitive Impairment and Alzheimer's Disease in a Korean Population.

OBJECTIVE: To examine the validity and reliability of the MMSE-2 for assessing patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD) in a Korean population. Specifically, the usefulness of the MMSE-2 as a screening measure for detecting early cognitive change, which has not been detectable through the MMSE, was examined. METHODS: Two-hundred and twenty-six patients with MCI, 97 patients with AD, and 91 healthy older adults were recruited. All participants consented to examination with the MMSE-2, the MMSE, and other detailed neuropsychological assessments. RESULTS: The MMSE-2 performed well in discriminating participants across Clinical Dementia Rating (CDR) stages and CDR-Sum of Boxes (CDR-SOB), and it showed excellent internal consistency, high test-retest reliability, high interrater reliability, and good concurrent validity with the MMSE and other detailed neuropsychological assessments. The MMSE-2 was divided into two factors (tests that are sensitive to decline in cognitive functions vs. tests that are not sensitive to decline in cognitive functions) in normal cognitive aging. Moreover, the MMSE-2 was divided into two factors (tests related overall cognitive functioning other than memory vs. tests related to episodic memory) in patients with AD. Finally, the MMSE-2 was divided into three factors (tests related to working memory and frontal lobe functioning vs. tests related to verbal memory vs. tests related to orientation and immediate recall) in patients with MCI. The sensitivity and specificity of the three versions of the MMSE-2 were relatively high in discriminating participants with normal cognitive aging from patients with MCI and AD. CONCLUSION: The MMSE-2 is a valid and reliable cognitive screening instrument for assessing cognitive impairment in a Korean population, but its ability to distinguish patients with MCI from those with normal cognitive aging may not be as highly sensitive as expected.

A Comparison of Five Types of Trail Making Test in Korean Elderly.

BACKGROUND AND PURPOSE: Previously developed Korean versions of the Trail Making Test (TMT) that replaced the English in part B, has been unsuccessful in Korea. The current study identifies the type of TMT tasks from the among multiple TMT versions, which practically and accurately detects the stage of cognitive decline. METHODS: We applied five TMT versions, which include the original TMT, TMT-Korean letter (TMT-KL), TMT-Korean consonant (TMT-KC), TMT-black and white (TMT-B&W), and TMT-square and circle (TMT-S&C). A total of 168 participants were enrolled: 42 cognitively normal controls (NC), 72 patients with mild cognitive impairment (MCI), and 54 patients with Alzheimer's disease (AD). Two sets of TMT (set "A" including TMT, TMT-KL and TMT-B&W, and set "B" including TMT, TMT-KC, and TMT-S&C) were randomly administered to subjects within the contact of a fixed neuropsychological battery. RESULTS: The completion times of TMT-B and TMT-B&W successfully distinguished NC from MCI and AD. TMT-B&W also showed a high correlation with other neuropsychological tests, and correlated well with the original TMT. The other TMT were frequently not successfully completed, nor could they differentiate the clinical groups. CONCLUSIONS: Among the five TMT tasks, the original TMT and the TMT-B&W appeared to be most sensitive to the degree of cognitive impairment. TMT-B&W showed a pattern consistent with the original TMT; thus, this measure may be optimal in Korean older adults, where familiarity with the English alphabet is questionable.

Abstract Word Definition in Patients with Amnestic Mild Cognitive Impairment.

The aims of this study were to investigate concrete and abstract word definition ability (1) between patients with amnestic mild cognitive impairment (aMCI) and normal adults and (2) between the aMCI subtypes (i.e., amnestic single-domain MCI and amnestic multidomain MCI; asMCI and amMCI) and normal controls. The 68 patients with aMCI (29 asMCI and 39 amMCI) and 93 age- and education-matched normal adults performed word definition tasks composed of five concrete (e.g., train) and five abstract nouns (e.g., jealousy). Task performances were analyzed on total score, number of core meanings, and number of supplementary meanings. The results were as follows. First, the aMCI patients scored significantly poorer than the normal controls in only abstract word definition. Second, both subtypes of aMCI performed worse than the controls in only abstract word definition. In conclusion, a definition task of abstract rather than concrete concepts may provide richer information to show semantic impairment of aMCI.

A comprehensive visual rating scale of brain magnetic resonance imaging: application in elderly subjects with Alzheimer's disease, mild cognitive impairment, and normal cognition.

BACKGROUND: Brain magnetic resonance imaging (MRI) shows cerebral structural changes. However, a unified comprehensive visual rating scale (CVRS) has seldom been studied. Thus, we combined brain atrophy and small vessel disease scales and used an MRI template as a CVRS. OBJECTIVE: The aims of this study were to design a simple and reliable CVRS, validate it by investigating cerebral structural changes in clinical groups, and made comparison to the volumetric measurements. METHODS: Elderly subjects (n = 260) with normal cognition (NC, n = 65), mild cognitive impairment (MCI, n = 101), or Alzheimer's disease (AD, n = 94) were evaluated with brain MRI according to the CVRS of brain atrophy and small vessel disease. Validation of the CVRS with structural changes, neuropsychological tests, and volumetric analyses was performed. RESULTS: The CVRS revealed a high intra-rater and inter-rater agreement and it reflected the structural changes of subjects with NC, MCI, and AD better than volumetric measures (CVRS-coronal: F = 13.5, p < 0.001; CVRS-axial: F = 19.9, p < 0.001). The area under the receiver operation curve (aROC) of the CVRS showed higher accuracy than volumetric analyses. (NC versus MCI aROC: CVRS-coronal, 0.777; CVRS-axial, 0.773; MCI versus AD aROC: CVRS-coronal, 0.680; CVRS-axial, 0.681). CONCLUSION: The CVRS can be used clinically to conveniently measure structural changes of brain. It reflected cerebral structural changes of clinical groups and correlated with the age better than volumetric measures.

Executive function as a strong predictor of recovery from disability in patients with acute stroke: a preliminary study.

BACKGROUND: Cognitive impairment impedes stroke rehabilitation. However, it is unclear whether cognitive impairment of specific domains or the degree of severity is more critical to functional recovery in patients with poststroke disability. METHODS: We identified 182 patients who were disabled at 3 months after acute stroke, as defined by a modified Rankin Scale score of 2-5. At a single time point between 3 months and 1 year after onset, the following 4 cognitive domains were assessed: executive function, visuospatial ability, language, and memory. With respect to the severity of cognitive impairment, the patients were classified as having vascular dementia (VD), vascular cognitive impairment no dementia (VCIND), or normal cognition. The primary outcome was functional recovery between 3 months and 1 year after onset. To examine the association between cognitive status and functional recovery, multiple logistic regression with backward stepwise analysis was performed. RESULTS: A total of 74 (40.7% of 182) patients demonstrated functional improvement at 1 year compared with 3 months. Patients with executive impairment demonstrated significantly less improvement in functional outcomes, with an adjusted odds ratio (OR) of .472 (95% confidence interval [CI], .245-.910). Patients with VD also demonstrated less functional recovery, with an adjusted OR of .289 (95% CI, .120-.700). The remaining 3 cognitive domains and VCIND were not significantly associated with functional recovery. CONCLUSIONS: Executive function is a strong predictor of recovery from disability in patients with acute stroke. In addition, functional recovery is significantly hampered by cognitive impairment due to VD, but not VCIND.

Cortical hubs and subcortical cholinergic pathways as neural substrates of poststroke dementia.

BACKGROUND AND PURPOSE: A role of neural networks in the development of poststroke dementia has not been clearly established. We hypothesized that stroke-mediated disruption of subcortical cholinergic pathway or large-scale neural networks contributes to poststroke dementia. METHODS: A matched case-control study was conducted in a predetermined cohort with acute ischemic stroke. Cases were defined as newly developed dementia diagnosed >3 months after stroke using the Korean Vascular Cognitive Impairment Harmonization Standards. Each case was matched to 2 controls for age, education, and initial stroke severity. The Cholinergic Pathways HyperIntensities Scale was applied with some modifications to characterize disruption of cholinergic pathways by acute stroke lesions. Involvement of major cortical hub locations of the default mode network, central executive network, and salience network was also investigated. RESULTS: After matching, 38 cases and 66 matched controls were included. Cholinergic Pathways HyperIntensities Scale scores were significantly higher in cases than in controls (2.2±2.9 versus 0.9±1.4). Acute ischemic lesions affecting the default mode and central executive networks were more frequently observed in cases compared with controls (36.8% versus 7.6% and 26.3% versus 6.1%, respectively). These findings remained significant in the multiple logistic regression models adjusted for various sets of potential confounders. Lesion location analysis revealed that cases were more likely to have acute lesions in the left corona radiata, hippocampal formation, and posterior parietal cortex. CONCLUSIONS: Disruption of cholinergic pathways and major hubs of large-scale neural networks might contribute to newly developed dementia after acute ischemic stroke.

Alternative type of the trail making test in nonnative English-speakers: the trail making test-black & white.

OBJECTIVE: The Trail Making Test (TMT) has its limitations when applied to Eastern cultures due to its reliance on the alphabet. We looked for an alternative tool that is reliable and distinguishable like the TMT and devised the Trail Making Test Black & White (TMT-B&W) as a new variant. This study identifies the applicability of the TMT-B&W as a useful neuropsychological tool and determines whether the TMT-B&W could play an equivalent role as the TMT. METHODS: The TMT-B&W uses numbers encircled by black or white circles as stimuli, instead of using the alphabet. A total of 138 participants were including containing groups of 31 cognitively normal controls (NC), 55 mild cognitive impairment (MCI), and 52 people with Alzheimer's disease (AD). Along with the TMT-B&W, the TMT and other neuropsychological tests were administered to all subjects. RESULTS: A considerably low dropout rate for TMT B&W demonstrates that all participants were more willingly engaged in the TMT B&W than the TMT. In particular, subjects with cognitive impairments or lower levels of education performed better on the TMT-B&W than the TMT. The difference in time-to-completion of the TMT-B&W was significant according to the level of cognitive impairment. The TMT-B&W revealed a high correlation with the TMT and frontal lobe function test. CONCLUSION: The TMT-B&W is as reliable and effective as the TMT. It is worth developing a new variant of the TMT.

Comparison between the story recall test and the word-list learning test in Korean patients with mild cognitive impairment and early stage of Alzheimer's disease.

Among verbal memory tests, two that are commonly used to measure the ability of verbal memory function in cognitive impairment are story recall tests and word-list learning tests. However, research is limited regarding which test might be more sensitive in discriminating between normal cognitive aging and patients with Alzheimer's disease (AD) in the Korean population. The purpose of the current study was to compare the word-list learning test (Seoul Verbal Learning Test; SVLT) and the story recall test (Korean Story Recall Test; KSRT) to determine which test is more sensitive in discriminating between individuals with normal cognitive aging and patients with mild cognitive impairment (MCI) and early stage of AD in Korea. A total of 53 healthy adults, 127 patients with MCI, and 72 patients with early stage of AD participated in this study. The receiver-operating characteristic (ROC) curve and area under the curve (AUC) were evaluated to compare these two tests. The results showed that the AUC of the SVLT was significantly larger than the AUC of the KSRT in all three groups (healthy adults vs. MCI and early stage of AD; healthy adults vs. MCI; healthy adults vs. early stage of AD). However, in comparison of patients with MCI and early stage of AD, the AUC of SVLT and the AUC of KSRT were not significant. The word-list learning test is a more useful tool for examining verbal memory function for older adults in Korea than the story recall test.

Line quadrisection errors in patients with hemispatial neglect.

Patients with left unilateral neglect misbisect lines toward the right. To discriminate between contralesional unawareness and ipsilesional hyperattention hypotheses for this ipsilesional bias, we performed the line quadrisection test on 18 patients with and 25 without neglect, and 24 normal controls. Overall the patients with neglect were unbiased when performing the left quadrisection task, but erred rightward on the right quadrisection task. These results suggest that the ipsilesional bisection errors produced by patients with neglect are primarily influenced by ipsilesional hyperattention rather than contralesional unawareness. However, further analyses showed heterogeneity of performance in left quadrisection, which can be explained by multiple factors that include the top down attention to left space associated with left quadrisection, the orienting to the salience of the line's left end, and distorted mental representation, in addition to ipsilesional hyperattention.

Non-invasive cortical stimulation improves post-stroke attention decline.

PURPOSE: Attention decline after stroke is common and hampers the rehabilitation process, and non-invasive transcranial direct current stimulation (tDCS) has the potential to elicit behavioral changes by modulating cortical excitability. The authors tested the hypothesis that a single session of non-invasive cortical stimulation with excitatory anodal tDCS applied to the left dorsolateral prefrontal cortex (DLPFC) can improve attention in stroke patients. METHODS: Ten patients with post-stroke cognitive decline (MMSE 25) and 10 age-matched healthy controls participated in this double blind, sham-controlled, crossover study involving the administration of real (2 mA for 20 min) or sham stimulation (2 mA for 1 min) to the left DLPFC. Attention was measured using a computerized Go/No-Go test before and after intervention. Improvements in accuracy and speed after stimulation relative to baseline were compared for real and sham stimulations. RESULTS: In healthy controls, no significant improvement in Go/No-Go test was observed after either real or sham stimulation. However, in stroke patients, tDCS led to a significant improvement in response accuracy at 1 hour post-stimulation relative to baseline, and this improvement was maintained until 3 hours post-stimulation (P< 0.05), whereas sham stimulation did not lead to a significant improvement in response accuracy (P> 0.05). Changes in reaction times were comparable for the two stimulations (P> 0.05). CONCLUSION: Non invasive anodal tDCS applied to the left DLPFC was found to improve attention versus sham stimulation in stroke patients, which suggests that non-invasive cortical intervention could potentially be used during rehabilitative training to improve attention.