Background: In addition to the cost and complexity of processing multiple signal channels, manual sleep staging is also tedious, time consuming, and error-prone. The aim of this paper is to propose an automatic slow wave sleep (SWS) detection method that uses only one channel of the electroencephalography (EEG) signal. New Method: The proposed approach distinguishes itself from previous automatic sleep staging methods by using three specially designed feature groups. The first feature group characterizes the waveform pattern of the EEG signal. The remaining two feature groups are developed to resolve the difficulties caused by interpersonal EEG signal differences. Results and comparison with existing methods: The proposed approach was tested with 1,003 subjects, and the SWS detection results show kappa coefficient at 0.66, an accuracy level of 0.973, a sensitivity score of 0.644 and a positive predictive value of 0.709. By excluding sleep apnea patients and persons whose age is older than 55, the SWS detection results improved to kappa coefficient, 0.76; accuracy, 0.963; sensitivity, 0.758; and positive predictive value, 0.812. Conclusions: With newly developed signal features, this study proposed and tested a single-channel EEG-based SWS detection method. The effectiveness of the proposed approach was demonstrated by applying it to detect the SWS of 1003 subjects. Our test results show that a low SWS ratio and sleep apnea can degrade the performance of SWS detection. The results also show that a large and accurately staged sleep dataset is of great importance when developing automatic sleep staging methods.
Abstract-This work develops a number of automatic slow wave sleep (SWS) detection methods that employ only one or two channels of EOG/EEG signals. In addition to the reduction of signal channels, a distinct feature of the proposed approach is the introduction of a new feature set that can make the proposed approach insensitive to interpersonal differences of the physiological signals. The tested subjects include 265 and 947 persons underwent full overnight polysomnography from two different sleep centers. With 265 subjects from one center as the training set and 147 subjects from the other center as the validation set, the first part of our experiments yields SWS detection results of Kappa coefficients 0.72-0.78, sensitivity 0.77-0.90 and positive predictive value 0.73-0.82. Using the 947 subject dataset, the second part of the experiments compares the relative merits of the tested methods and investigates the impacts of SWS ratio and severity of sleep apnea on the performances of the proposed methods. Finally, our results suggest that the quality of the training set is of great importance for the development of accurate SWS detection methods.
Background: A force plate is used to determine the ability to balance ability. However, only some medical centers or laboratories are equipped with force plates because they are costly so a low-cost force plate is required for home care or health care institutes. Few studies compare the reliability of postural sway measurements in terms of age. This study proposes a low-cost force plate to select reliable parameters to evaluate postural sway.Objectives: To determine the intra-rater reliability of a novel force plate and the effect of age difference on the intra-rater test-retest reliability for the center of pressure (COP).Methods: Forty participants were enrolled for this study: 20 youths and 20 older adults. Participants stood on a custom-made and low-cost force plate with eyes opened and eyes closed to measure COP-related parameters. The within-day test-retest reliability was measured at two sessions on the same day and the between-days reliability was measured on two different days. The COP-related parameters include the average velocity of COP, the average velocity in the antero-posterior and medio-lateral directions, the mean distance of COP and the mean distance in the antero-posterior and medio-lateral directions. An intra-class correlation coefficient test with one-way random model was performed to determine the reliability of different variables within-days and between-days. The results were presented in single measurement of intraclass correlation coefficient (ICC), the standard error of measurements, and the minimal detectable changes of each COP-related parameters.Results: The novel low-cost force plate demonstrates excellent reliability in terms of the COP velocity related parameters for within- and between-day measurements. The ICC of COP distance related parameters were good to excellent reliability for between-day measurements (range: 0.43–0.84). Older adults demonstrated excellent reliability in terms of the mean distance for antero-posterior and the results were better than those for younger participants for the eyes-opened and eyes-closed conditions. The reliability in terms of the mean distance for medio-lateral was poor to good for older adults (range: 0.38–0.55), and excellent for younger participants.Conclusion: The novel and low-cost force plate reliably measured balance and age affects the reliability of different COP variables, so the results of this study were pertinent to the selection of COP measures.
this paper first performs a comprehensive narration of the policy researches on non-state-owned museum, and confirmed that in the researches on non-state-owned museums at present, the research on supporting policy is insufficient. Then, according to the research on the supporting direction of the museum regulations, the paper summarizes six key problems that exist in the policy support for the non-state-owned museums. On this basis, the paper performs text analysis on the local policies for non-state museum in some areas of our country, and found the problems of talent guarantee and cooperation between museums are most important in the six problems. Finally, based on the previous findings, the author put forward some advice for improvement, and looks forward to making some contributions to the development of non-state museum.
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