Aim
To date, there is a controversy regarding the effects of acute aerobic exercise of moderate intensity on executive function and prefrontal cortex activity in community‐dwelling older adults. This ...study aimed to investigate the effects of acute aerobic exercise of moderate intensity in healthy older adults.
Methods
Fifty‐six healthy older adults were randomly assigned to the experimental group (EG) that performed moderate‐intensity aerobic exercise or the wait‐list control group (CG) for a total of 15 sessions. To compare the two groups, the Stroop Color‐Word Task (SCWT) and the Trail‐Making Test Part B (TMT‐B) were implemented for executive function and prefrontal cortex activity during executive function testing.
Results
After the intervention, the EG achieved a significant improvement in the SCWT (P < 0.001; η2 = 0.196) and the TMT‐B (P < 0.001; η2 = 0.245) compared with the CG. In addition, the EG showed a lower HbO2 concentration in the prefrontal cortex than the CG during the SCWT (P < 0.05; η2 = 0.076) and the TMT‐B (P < 0.05; η2 = 0.090).
Conclusions
These findings shed new light on the clinical effectiveness of acute moderate‐intensity aerobic exercise on executive function and prefrontal cortex activity in healthy older adults. Geriatr Gerontol Int 2022; 22: 227–232.
The Rey-Osterrieth Complex Figure Test (RCFT) is a tool to evaluate cognitive function. Despite its usefulness, its scoring criteria are as complicated as its figure, leading to a low reliability. ...Therefore, this study aimed to determine the feasibility of using the convolutional neural network (CNN) model based on the RCFT as a screening tool for mild cognitive impairment (MCI) and investigate the non-equivalence of sub-tasks of the RCFT.
A total of 354 RCFT images (copy and recall conditions) were obtained from 103 healthy controls (HCs) and 74 patients with amnestic MCI (a-MCI). The CNN model was trained to predict MCI based on the RCFT-copy and RCFT-recall images. To evaluate the CNN model's performance, accuracy, sensitivity, specificity, and F1-score were measured. To compare discriminative power, the area under the curve (AUC) was calculated by the receiver operating characteristic (ROC) curve analysis.
The CNN model based on the RCFT-recall was the most accurate in discriminating a-MCI (accuracy: RCFT-copy = 0.846, RCFT-recall = 0.872, MoCA-K = 0.818). Furthermore, the CNN model based on the RCFT could better discriminate MCI than the MoCA-K (AUC: RCFT-copy = 0.851, RCFT-recall = 0.88, MoCA-K = 0.848). The CNN model based on the RCFT-recall was superior to the RCFT-copy.
These findings suggest the feasibility of using the CNN model based on the RCFT as a surrogate for a conventional screening tool for a-MCI and demonstrate the superiority of the CNN model based on the RCFT-recall to the RCFT-copy.
To date, there is a controversy on effects of cognitive intervention to maintain or improve hippocampal function for older adults with mild cognitive impairment (MCI).
The main objective of this ...study was to exam effects of virtual reality-based spatial cognitive training (VR-SCT) using VR on hippocampal function of older adults with MCI.
Fifty-six older adults with MCI were randomly allocated to the experimental group (EG) that received the VR-SCT or the waitlist control group (CG) for a total of 24 sessions. To investigate effects of the VR-SCT on spatial cognition and episodic memory, the Weschsler Adult Intelligence Scale-Revised Block Design Test (WAIS-BDT) and the Seoul Verbal Learning Test (SVLT) were used.
During the sessions, the training performances gradually increased (p < .001). After the intervention, the EG showed significant greater improvements in the WAIS-BDT (p < .001, η2 = .667) and recall of the SVLT (p < .05, η2 =.094) compared to the CG but in recognition of the SVLT (p > .05, η2 =.001).
These results suggest that the VR-SCT might be clinically beneficial to enhance spatial cognition and episodic memory of older adults with MCI.
Functional near-infrared spectroscopy (fNIRS) is a tool to assess brain activity during cognitive testing. Despite its usefulness, its feasibility in assessing mental workload remains unclear. This ...study was to investigate the potential use of convolutional neural networks (CNNs) based on functional near-infrared spectroscopy (fNIRS)-derived signals to classify mental workload in individuals with mild cognitive impairment.
Spatial images by constructing a statistical activation map from the prefrontal activity of 120 subjects with MCI performing three difficulty levels of the N-back task (0, 1, and 2-back) were used for CNNs. The CNNs were evaluated using a 5 and 10-fold cross-validation method.
As the difficulty level of the N-back task increased, the accuracy decreased and prefrontal activity increased. In addition, there was a significant difference in the accuracy and prefrontal activity across the three levels (p's < 0.05). The accuracy of the CNNs based on fNIRS-derived spatial images evaluated by 5 and 10-fold cross-validation in classifying the difficulty levels ranged from 0.83 to 0.96.
fNIRS could also be a promising tool for measuring mental workload in older adults with MCI despite their cognitive decline. In addition, this study demonstrated the feasibility of the classification performance of the CNNs based on fNIRS-derived signals from the prefrontal cortex.
Readily commercializable and cost‐effective next‐generation CsPbBr3 perovskite nanocrystals (PNCs) based X‐ray detectors are demonstrated. The PNCs‐based X‐ray detector exhibits higher spatial ...resolution (9.8 lp mm−1 at modulation transfer function (MTF) = 0.2 and 12.5–8.9 lp mm−1 for a linear line chart), faster response time (≈200 ns), and comparable stability (>40 Gyair s−1 of X‐ray exposure) compared with the commercialized terbium‐doped gadolinium oxysulfide (GOS)‐based detectors (spatial resolution = 6.2 lp mm−1 at MTF = 0.2 and 6.3 lp mm−1 for a linear line chart, response time = ≈1200 ns) because the PNCs‐based scintillator has ≈5.6‐fold faster average photoluminescence lifetime and stronger emission than the GOS‐based one.
A high‐performance next‐generation perovskite nanocrystal (PNC) scintillator is used for nondestructive X‐ray imaging. The high‐performance cheap CsPbBr3 PNCs scintillators are based on indirect X‐ray detectors with high‐resolution, sensitivity, and stability.
Soil erosion is a common land degradation problem and has disastrous impacts on natural ecosystems and human life. Therefore, researchers have focused on detection of land cover–land use changes ...(LCLUC) with respect to monitoring and mitigating the potential soil erosion. This article aims to appraise the relationship between LCLUC and soil erosion in the Cameron Highlands (Malaysia) by using multitemporal satellite images and ancillary data. Land clearing and heavy rainfall events in the study area has resulted in increased soil loss. Moreover, unsustainable development and agricultural practices, mismanagement, and lack of land use policies increase the soil erosion rate. Hence, the main contribution of this study lies in the application of appropriate land management practices in relation to water erosion through identification and prediction of the impacts of LCLUC on the spatial distribution of potential soil loss in a region susceptible to natural hazards such as landslide. The LCLUC distribution within the study area was mapped for 2005, 2010, and 2015 by using SPOT‐5 temporal satellite imagery and object‐based image classification. A projected land cover–land use map was also produced for 2025 through integration of Markov chain and cellular automata models. An empirical‐based approach (Revised Universal Soil Loss Equation) coupled with geographic information system was applied to measure soil loss and susceptibility to erosion over the study area for four periods (2005, 2010, 2015, and 2025). The model comprises five parameters, namely, rainfall factor, soil erodibility, topographical factor, conservation factor, and support practice factor. Results exhibited that the average amount of soil loss increased by 31.77 t ha−1 yr−1 from 2005 to 2015 and was predicted to dramatically increase in 2025. The results generated from this research recommends that awareness of spatial and temporal patterns of high soil loss risk areas can help deploy site‐specific soil conservation measures and erosion mitigation processes and prevent unsystematic deforestation and urbanization by the authorities.
Early detection of mild cognitive impairment (MCI), a pre-clinical stage of Alzheimer's disease (AD), has been highlighted as it could be beneficial to prevent progression to AD. Although prior ...studies on MCI screening have been conducted, the optimized detection way remain unclear yet. Recently, the potential of biomarker for MCI has gained a lot of attention due to a relatively low discriminant power of clinical screening tools.
This study evaluated biomarkers for screening MCI by performing a verbal digit span task (VDST) using functional near-infrared spectroscopy (fNIRS) to measure signals from the prefrontal cortex (PFC) from a group of 84 healthy controls and 52 subjects with MCI. The concentration changes of oxy-hemoglobin (HbO) were explored during the task in subject groups.
Findings revealed that significant reductions in HbO concentration were observed in the PFC in the MCI group. Specially, the mean of HbO (mHbO) in the left PFC showed the highest discriminant power for MCI, which was higher than that of the Korean version of montreal cognitive assessment (MoCA-K) widely used as a screening tool for MCI. Furthermore, the mHbO in the PFC during the VDST was identified to be significantly correlated to the MoCA-K scores.
These findings shed new light on the feasibility and superiority of fNIRS-derived neural biomarker for screening MCI.
Purpose: To date, the effects of dual-task training on balance underlying cognitive function remain unclear. Therefore, this study was to verify the effects of cognitive−physical dual-task training ...on balance and executive function in community-dwelling older adults with a history of falls. Method: Fifty-eight participants were randomly allocated to the experimental group (EG) receiving cognitive−physical dual-task training (n = 29) or to the control group (CG) receiving functional balance training (n = 29). After 12 sessions for 6 weeks, the One Leg Standing Test (OLST), the Timed UP and Go (TUG), and part B of the Trail-Making Test (TMT-B) were implemented to examine static and dynamic balance and executive function. Results: After the 12 sessions, the EG showed a greater improvement in the OLST (p < 0.001; η2 = 0.332), the TUG (p < 0.001; η2 = 0.375), and the TMT-B (p < 0.001; η2 = 0.224) compared to the CG. Conclusion: These results indicate that dual-task training is clinically beneficial to improving static and dynamic balance as well as executive function in older adults with a history of falls. These findings shed new light on a clinical implication that executive function should be considered in balance training for older adults.
To date, early detection of mild cognitive impairment (MCI) has mainly depended on paper-based neuropsychological assessments. Recently, biomarkers for MCI detection have gained a lot of attention ...because of the low sensitivity of neuropsychological assessments. This study proposed the functional near-infrared spectroscopy (fNIRS)-derived data with convolutional neural networks (CNNs) to identify MCI.
Eighty-two subjects with MCI and 148 healthy controls (HC) performed the 2-back task, and their oxygenated hemoglobin (HbO2) changes in the prefrontal cortex (PFC) were recorded during the task. The CNN model based on fNIRS-derived spatial features with HbO2 slope within time windows was trained to classify MCI. Thereafter, the 5-fold cross-validation approach was used to evaluate the performance of the CNN model.
Significant differences in averaged HbO2 values between MCI and HC groups were found, and the CNN model could better discriminate MCI with over 89.57% accuracy than the Korean version of the Montreal Cognitive Assessment (MoCA) (89.57%). Specifically, the CNN model based on HbO2 slope within the time window of 20-60 seconds from the left PFC (96.09%) achieved the highest accuracy.
These findings suggest that the fNIRS-derived spatial features with CNNs could be a promising way for early detection of MCI as a surrogate for a conventional screening tool and demonstrate the superiority of the fNIRS-derived spatial features with CNNs to the MoCA.
Landslide is one of the repeated geological hazards during rainy season, which causes fatalities, damage to property and economic losses in Korea. Landslides are responsible for at least 17% of all ...fatalities from natural hazards worldwide, and nearly 25% of annual casualties caused by natural hazards in Korea. Due to global climate change, the frequency of landslide occurrence has been increased and subsequently, the losses and damages associated with landslides also have been increased. Therefore, accurate prediction of landslide occurrence, and monitoring and early warning for ground movements are very important tasks to reduce the damages and losses caused by landslides. Various studies on landslide prediction and reduction in landslide damage have been performed and consequently, much of the recent progress has been in these areas. In particular, the application of information and geospatial technologies such as remote sensing and geographic information systems (GIS) has greatly contributed to landslide hazard assessment studies over recent years. In this paper, the recent advances and the state-of-the-art in the essential components of the landslide hazard assessment, such as landslide susceptibility analysis, runout modeling, landslide monitoring and early warning, were reviewed. Especially, this paper focused on the evaluation of the landslide susceptibility using probabilistic approach and physically based method, runout evaluation using volume based model and dynamic model, in situ ground based monitoring techniques, remote sensing techniques for landslide monitoring, and landslide early warning using rainfall and physical thresholds.
