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  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>BISEC'</journal-title>
      </journal-title-group>
    </journal-meta>
    <article-meta>
      <title-group>
        <article-title>Sleeping Disorder Diagnosis Methods - A Systematic Review</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>M. Nirubama</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>N. Arivazhagan</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>CINTEL Department, SRM Institute of Science and Technology</institution>
          ,
          <addr-line>Kattankulathur, Chengalpattu</addr-line>
          ,
          <country country="IN">India</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2024</year>
      </pub-date>
      <volume>15</volume>
      <fpage>28</fpage>
      <lpage>29</lpage>
      <abstract>
        <p>Significant advancements in the identification of sleep disorders, such as obstructive sleep apnea and insomnia, cardiovascular illnesses, diabetes, and mental health issues, have resulted from the combination of machine learning and deep learning approaches. These techniques leverage physiological signals and patient data to provide automated, accurate, and eficient diagnostic tools. Comparing these sophisticated computational techniques to conventional diagnostic procedures, there is potential for significant gains in eficiency and accuracy. This review examines current research (2021-2024) on applying ML and DL to diagnose distinct sleep disorders. It highlights approaches, datasets for important comparisons, performance measures, outcomes, potential future directions, and gaps in the field. With the incorporation of new technologies, the diagnosis of mental health illnesses, cardiovascular diseases, diabetes, and sleep disorders including obstructive sleep apnea and insomnia has changed dramatically.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;Deep learning</kwd>
        <kwd>Explainable AI</kwd>
        <kwd>Sleeping disorder</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>
        Sleep disorders such obstructive sleep apnea , insomnia, restless leg syndrome, narcolepsy, and comorbid
insomnia and sleep apnea , which can cause major health problems like neurological, metabolic, and
cardiovascular problems. Early detection and accurate diagnosis are essential for managing and treating
patients well. Polysomnography and clinical as- sessments, the conventional technique of identifying
these diseases, are labor-intensive, costly, time-consuming, and prone to human error. By using
massive datasets and complex algorithms to find patterns suggestive of diferent sleep disorders, recent
developments in machine learning and deep learning provide potential options for the efective, scalable
solutions and accurate diagnosis of sleep problem.Obstructive sleep apnea , insomnia, narcolepsy,
restless legs syndrome, and concomitant PhysioNet ECG Sleep Apnea v1.0.0 dataset for sleep apnea
detection. Achieved performance with the highest accuracy of 88.13%.SVM, logistic regression, Gaussian
naïve Bayes, discriminate analyses, nearest neighbor, decision tree, random forest, Ada- Boost, gradient
boosting, MLP, recurrent networks , and hybrid convolutional-recurrent networks are used with majority
voting. This method is more complex implementation [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ].
      </p>
      <p>
        For the detection of insomnia, the heart rate variability of ECG Signal Power spectral density. LDA
classifier achieves the finest insomnia detection accuracy with 99.0%. Fine-tuned and evaluated by the
free public PhysioNet dataset over fivefold trails cross-validation. This method is not generalized for
diferent data set [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ].
      </p>
    </sec>
    <sec id="sec-2">
      <title>2. Diagnosis Methods</title>
      <sec id="sec-2-1">
        <title>This section discusses various methods of sleeping disorders.</title>
        <sec id="sec-2-1-1">
          <title>2.1. Biomedical Signal Processing Methods</title>
          <p>
            Detecting bio-signals based-sleep stages .on Model Agnostic Meta-Learning achieved 5.4% to 17.7%
range upgrading with statistical diference in the mean. This method iis Computational Overhead.
Sensitivity to Hyperparameters. This method is limited when tasks are too dissimilar or when the task
distribution changes drastically [
            <xref ref-type="bibr" rid="ref3">3</xref>
            ].
          </p>
          <p>
            Detection of Insomnia presented with electroencephalogram (EEG) Demonstrated Gaussian
mixturehidden Markov model (GMM-HMM) achieves 86 accuracy. This method is having less accuracy
[
            <xref ref-type="bibr" rid="ref4">4</xref>
            ].
          </p>
          <p>Detection of Respiratory disturbances during sleep.A bed-integrated radio-frequency sensor through
near-field coherent sensing was applied. Apneic event detection attained a sensitivity up to 88.6% and
89.0% for -fold validation. For this method more controlled environment is required [5].</p>
          <p>Hybrid neural network with semi-supervised learning at the same time sleep arousal and sleep stage
ifnding with features of single-channel electroencephalography. On the Physio2018 dataset achieves an
overall accuracy of 0.78. This method is having less accuracy [6].</p>
          <p>1,111 characteristics were produced after several criteria were suggested in the literature. The
112 worthies tones for automated sleep grading were given by the actometer, respiratory inductance
plethysmography belts, pulse oximeter, PneaVoX sensor (which records tracheal sounds), nasal cannula,
and respiratory inductance plethysmography belts. The system gets substantial agreement with manual
scoring for classifications into two stages (wake vs. sleep: mean Cohen’s Kappa  of 0.63 and accuracy
rate Acc of 87.8%) and three stages (wake vs. R stage vs. NREM stage: mean  of 0.60 and Acc of 78.5%)
[7]. Finally, implemented a three-step model, consisting of category using a multi-layer perceptron,
sleep transition rules correction, and sequence corrections using a Viterbi hidden Markov model.</p>
          <p>Improved cardiovascular OSA phenotyping is required to rank treatment of high-risk individuals.
Methods: SpO 2 records from 1987 overnight polysomnography are included in the study. Of these,
974 come from patients who may have OSA, 931 from the Sleep Heart Health Study, which is based on
data from the general community, and 83 from healthy controls. For every oxygen desaturation, the
amplitude ratio of desaturation over resaturation, the minimum SpO 2 value, and the SpO 2 upslope
are retrieved and averaged per patient. Findings: The mICS performs 2.7% better when the SpO 2
parameters are included together with age and BMI. This results in a test area under the curve of 69.5%
for the identification of any cardiovascular comorbidity [ 8]. Although wearable sensor technology
has advanced dramatically over the past ten years, the absence of large and representative datasets
concurrently obtained with polysomnography (PSG) limits its clinical utility for the evaluation of
obstructive sleep apnea. Methods: respiratory efort and electrocardiogram data were used to create an
artificial neural network that would identify instances of sleep disturbed breathing. Findings: four-class
sleep staging distinguished between waking, combined N1-N2, N3, and REM with a  of 0.69 compared
to PSG. AHI estimate performed well in terms of diagnosis for various OSA severity thresholds, with an
intraclass correlation value of 0.91 [9].</p>
          <p>Although research on respiratory and metabolic issues has been the focus of central sleep apnea
(CSA), the neuronal dysfunction that underlies central sleep apnea is still largely understood. Here,
using hypnograms to analyze the sleep-wake dynamics, we explore the underlying neural mechanism of
central sleep apnea. Techniques: We reviewed the sleep records of seven subject groups: adults without
CSA ( = 25), adults with CSA ( = 29), adults with obstructive sleep apnea (OSA) ( = 28), strong
children ( = 40), children with OSA ( = 18), children with CSA ( = 73), and children with CSA
treated with CPAP ( = 10). We have discovered that, in difer to the scale-invariant (i.e., power-law)
distribution that has been documented for stimulations in healthy sleep, the sleep arousals of CSA
patients exhibit a distinctive temporal scale (i.e., exponential distribution) [10].</p>
          <p>The paper analyzes consumer sleep technology such as wearable sensors, bed sensors, smartphone
applications, ambient room sensors, and artificial intelligence, as well as sleep lab technologies like
polysomnography. The study also classifies the various learning approaches and gives an overview
of many clinical datasets for sleep staging. In conclusion, the paper provides our perspectives and
suggestions on the utilization of the examined sleep technologies [11].</p>
        </sec>
        <sec id="sec-2-1-2">
          <title>2.2. Deep Learning Methods</title>
          <p>Photoplethysmography (PPG) time series data used with residual convolutional network achieved
median Cohen’s Kappa ( ) score of 0.75 compare to 0.69 for existing method. This method is having less
accuracy [12, 13]. Single-channel EEG recording with long short-term memory along with convolutional
neural network for healthy-unhealthy, and disease grouping with an accuracy of 91.45% and 90.55%.This
method is having less accuracy [14].</p>
          <p>Pressure-sensor-based smart mattress to realize sleep status finding and quality evaluation. CNN
model for four various sleep postures archives accuracy of up to 96.987%.In this method Cross-validation
using medical data is not evaluated [15].</p>
          <p>Deep learning-based sleep staging was used to detect sleep phases by assessing the hypothesis,
overlap 30-second epochs with 15-, 5-, 1-, or 0.5-second epoch-to-epoch duration. With a period of
one second between epochs, the hazard ratio, which indicates the risk of fragmented sleep, was 1.14
( = 0.39) for mild OSA, 1.59 ( &lt; 0.01) for moderate OSA, and 4.13 ( &lt; 0.01) for severe OSA. The
ifndings show that, in order to properly diagnose sleep problems, a more thorough examination of sleep
architecture is required [16].</p>
          <p>Using wrist-worn consumer sleep technology (CST), categorization and detection of sleep apnea
(SA) is a deep transfer learning strategy for sleep stage. Methods: The model is based on a deep
convolutional neural network (DNN) that has been trained with information from accelerometers and
photoplethysmography recordings made at night. Using a hold-out test dataset containing raw data
from a wrist-worn CST, an external validation was performed. Using internal datasets that include
raw data from clinical and wrist-worn sensors, the DNN was trained and assessed. Findings: Training
on clinical data leads to a large improvement in performance, while feature enrichment using a sleep
stage stream only slightly improves performance. In CST datasets, raw data input performs better
than feature-based input. When comparing wearable device data to clinical data, the system performs
marginally worse, although it still generalizes well [17, 18].</p>
          <p>A new network called SwSleepNet is suggested that is capable of accurately ofline sleep staging
as well as online sleep stage prediction and calibration. In order to balance the network’s operational
eficiency and comprehensive feature extraction, For ofline analysis, the sequence consolidating module
(SCM), squeeze and excitation (SE) block, sequential CNN (SCNN), and sequence broadening module
(SBM) are coordinated by the suggested network. In the context of online analysis, the only models used
to predict the sleep state within a brief video clip are SCNN and SE.Two publicly accessible datasets,
The Sleep-EDF and the Montreal Archive of Sleep Studies Huashan Hospital Fudan University (HSFU),
as well as one clinical dataset, have been expanded. are used to validate SwSleepNet’s performance.
The result shows that SwSleepNet outperforms state-of-the-art ways with ofline accuracy of 84.5%,
86.7%, and 81.8%, respectively [19].</p>
          <p>To develop an accurate deep learning technique for the automatic classification of sleep phases and to
look into how the severity of OSA afects classification accuracy. Two distinct datasets’ worth of nightly
polysomnographic recordings were used to build a mixed convolutional and long short-term memory
neural network: one from a clinical dataset ( = 891) of patients with suspected OSA, and the other
from a public dataset of healthy persons (Sleep-EDF,  = 153). The model obtained an accuracy of 83.7%
( = 0.77) in sleep staging on the public dataset using a single frontal EEG channel, and 83.9% ( = 0.78)
when augmented with EOG. The model’s accuracy for the clinical dataset was 82.9% ( = 0.77) for a
single EEG channel and 83.8% ( = 0.78) for two channels (EEG+EOG) [20]. A deep learning model
was contructed to score respiratory events and sleep phases at the same time. Pulse oximetry data
alone should be suficient to accomplish the scoring and subsequent AHI computation, according to the
hypothesis. Methods: The deep learning models were trained using 877 polysomnography recordings
of people who may have had OSA. Three distinct input signal combinations were used to train the
same architecture: Photoplethysmogram and oxygen saturation (SpO2) were included in model 1; PPG,
SpO2, and nasal pressure were included in model 2; and respiratory belts, electroencephalogram, nasal
pressure, SpO2, and oronasal thermocouple were included in model 3. Results: Model 1 performed
comparably to models 2 and 3 in terms of REM- AHI and AHI estimation as well as REM-AHI [21, 22].</p>
        </sec>
        <sec id="sec-2-1-3">
          <title>2.3. Explainable AI in Sleep Diagnosis</title>
          <p>Using optical, diferential air pressure, and acceleration readings from a chest-worn sensor, five
somnographic-like signals are generated and fed into a deep network. To predict three patterns
related to breathing (normal, apnea, irregular), three patterns related to sleep (normal, snoring, loud),
and the overall signal quality (normal, corrupted),this solves a three-fold classification issue. Saliency
maps and confidence indices are two examples of qualitative and quantitative information that the
created architecture provides to enhance explainability and aid in prediction interpretation. The
accuracy of breathing rhythms was higher (0.93) than that of sleep patterns (0.76). Compared to apnea
(0.97), Using optical, diferential air pressure, and acceleration readings from a chest-worn sensor, five
somnographic-like signals are generated and fed into a deep network. To predict three patterns related
to breathing (normal, apnea, irregular), three patterns related to sleep (normal, snoring, loud), and the
overall signal quality (normal, corrupted), Consequently, this is a step in the direction of gradually
closer clinical translation of the usage of AI-based techniques for sleep problem detection [23].</p>
        </sec>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>3. Challenges and Future Directions</title>
      <p>Although ML and DL provide important improvements in the diagnosis of sleep disor- ders, there are
still a number of dificulties. These include the dificulty of integrating various physiological signals, the
requirement for sizable, annotated datasets for efi- cient model training, and the assurance of model
interpretability and clinical accepta- bility. In order to enable continuous monitoring and early action,
future research is probably going to concentrate on creating more reliable, understandable AI models
and incorporating these systems into wearable technology.</p>
      <p>1. Data Availability: To ensure the resilience of these models across various populations, larger and
more diverse datasets are required for both training and validation.
2. Integration into Clinical Practice: Further investigation is necessary to optimize the incorporation
of these sophisticated models into standard clinical procedures, tackling concerns pertaining to
interpretability of the models and their real-time implementation.
3. Cross-Disorder Applicability: The majority of current research focuses on certain illnesses, such
as sleep apnea. Increasing the application’s scope to cover more sleep disorders might improve
the overall efect.
4. Generalization Across Diverse Populations: The generalizability of the models across various
demographics and settings is impacted by dataset variety, which limits the majority of
investigations. Integration of Multimodal Data: While combining multichannel physiological signals
has increased accuracy, further study is required to successfully integrate various data sources,
including patient health records and wearable technology.</p>
    </sec>
    <sec id="sec-4">
      <title>4. Conclusion</title>
      <p>A potential area of medical technology is the combination of deep learning and machine learning for
the identification of sleep problems. An important development in sleep medicine is the use of ML and
DL in the diagnosis of sleep disorders. These cutting-edge techniques ofer efective, precise, and less
invasive substitutes for conventional diagnostic techniques, possibly revolutionizing the identification,
treatment, and successful integration of these technologies into clinical practice. These technologies
are anticipated to advance in sophistication, accessibility, and widespread clinical adoption as research
continues. These technologies will be further improved by ongoing research that focuses on various
datasets, multimodal integration, and useful deployment, ultimately leading to better patient outcomes
and more efective healthcare delivery. However, in order to integrate these technical advances into
clinical practice, it is imperative that the identified research gaps be addressed.</p>
    </sec>
    <sec id="sec-5">
      <title>Declaration on Generative AI</title>
      <sec id="sec-5-1">
        <title>The authors have not employed any Generative AI tools.</title>
        <p>[5] Z. Zhang, T. B. Conroy, A. C. Krieger, E. C. Kan, Detection and prediction of sleep disorders
by covert bed-integrated rf sensors, IEEE Transactions on Biomedical Engineering 70 (2022)
1208–1218.
[6] H. Liu, H. Zhang, B. Li, X. Yu, Y. Zhang, T. Penzel, Msleepnet: A semi-supervision based multi-view
hybrid neural network for simultaneous sleep arousal and sleep stage detection, IEEE Transactions
on Instrumentation and Measurement (2024).
[7] J. Vanbuis, M. Feuilloy, G. Bafet, N. Meslier, F. Gagnadoux, J.-M. Girault, A new sleep staging
system for type iii sleep studies equipped with a tracheal sound sensor, IEEE Transactions on
Biomedical Engineering 69 (2021) 1225–1236.
[8] M. Deviaene, P. Borzée, M. Van Gilst, J. van Dijk, S. Overeem, B. Buyse, D. Testelmans, S. Van Hufel,
C. Varon, Multilevel interval coded scoring to assess the cardiovascular status of sleep apnea
patients using oxygen saturation markers, IEEE Transactions on Biomedical Engineering 67 (2020)
2839–2848.
[9] P. Fonseca, M. Ross, A. Cerny, P. Anderer, F. Schipper, A. Grassi, M. van Gilst, S. Overeem,
Estimating the severity of obstructive sleep apnea using ecg, respiratory efort and neural networks,
IEEE Journal of Biomedical and Health Informatics (2024).
[10] H. Dvir, S. Guo, S. Havlin, N. Xin, T. Jun, D. Li, X. Zhifei, R. Kang, R. P. Bartsch, Central sleep
apnea alters neuronal excitability and increases the randomness in sleep-wake transitions, IEEE
Transactions on Biomedical Engineering 67 (2020) 3185–3194.
[11] G. Cay, V. Ravichandran, S. Sadhu, A. H. Zisk, A. L. Salisbury, D. Solanki, K. Mankodiya, Recent
advancement in sleep technologies: A literature review on clinical standards, sensors, apps, and ai
methods, IEEE Access 10 (2022) 104737–104756.
[12] K. Kotzen, P. H. Charlton, S. Salabi, L. Amar, A. Landesberg, J. A. Behar, Sleepppg-net: A deep
learning algorithm for robust sleep staging from continuous photoplethysmography, IEEE Journal
of Biomedical and Health Informatics 27 (2022) 924–932.
[13] D. Marzorati, A. Dorizza, D. Bovio, C. Salito, L. Mainardi, P. Cerveri, Hybrid convolutional networks
for end-to-end event detection in concurrent ppg and pcg signals afected by motion artifacts,
IEEE Transactions on Biomedical Engineering 69 (2022) 2512–2523.
[14] A. Wadichar, S. Murarka, D. Shah, A. Bhurane, M. Sharma, H. S. Mir, U. R. Acharya, A hierarchical
approach for the diagnosis of sleep disorders using convolutional recurrent neural network, IEEE
Access (2023).
[15] L.-J. Kau, M.-Y. Wang, H. Zhou, Pressure-sensor-based sleep status and quality evaluation system,</p>
        <p>IEEE Sensors Journal 23 (2023) 9739–9754.
[16] H. Korkalainen, T. Leppänen, B. Duce, S. Kainulainen, J. Aakko, A. Leino, L. Kalevo, I. O. Afara,
S. Myllymaa, J. Töyräs, Detailed assessment of sleep architecture with deep learning and shorter
epoch-to-epoch duration reveals sleep fragmentation of patients with obstructive sleep apnea,
IEEE journal of biomedical and health informatics 25 (2020) 2567–2574.
[17] M. Olsen, J. M. Zeitzer, R. N. Richardson, V. H. Musgrave, H. B. Sørensen, E. Mignot, P. J. Jennum,
A deep transfer learning approach for sleep stage classification and sleep apnea detection using
wrist-worn consumer sleep technologies, IEEE Transactions on Biomedical Engineering (2024).
[18] K. McClure, B. Erdreich, J. H. Bates, R. S. McGinnis, A. Masquelin, S. Wshah, Classification and
detection of breathing patterns with wearable sensors and deep learning, Sensors 20 (2020) 6481.
[19] H. Zhu, Y. Wu, Y. Guo, C. Fu, F. Shu, H. Yu, W. Chen, C. Chen, Towards real-time sleep stage
prediction and online calibration based on architecturally switchable deep learning models, IEEE
Journal of Biomedical and Health Informatics 28 (2023) 470–481.
[20] H. Korkalainen, J. Aakko, S. Nikkonen, S. Kainulainen, A. Leino, B. Duce, I. O. Afara, S. Myllymaa,
J. Töyräs, T. Leppänen, Accurate deep learning-based sleep staging in a clinical population with
suspected obstructive sleep apnea, IEEE journal of biomedical and health informatics 24 (2019)
2073–2081.
[21] R. Huttunen, T. Leppänen, B. Duce, E. S. Arnardottir, S. Nikkonen, S. Myllymaa, J. Töyräs, H.
Korkalainen, A comparison of signal combinations for deep learning-based simultaneous sleep
staging and respiratory event detection, IEEE Transactions on Biomedical Engineering 70 (2022)
1704–1714.
[22] R. Lazazzera, M. Deviaene, C. Varon, B. Buyse, D. Testelmans, P. Laguna, E. Gil, G. Carrault,
Detection and classification of sleep apnea and hypopnea using ppg and spo _2 signals, IEEE
Transactions on Biomedical Engineering 68 (2020) 1496–1506.
[23] M. Rossi, D. Sala, D. Bovio, C. Salito, G. Alessandrelli, C. Lombardi, L. Mainardi, P. Cerveri,
Sleepsee-through: Explainable deep learning for sleep event detection and quantification from wearable
somnography, IEEE journal of biomedical and health informatics 27 (2023) 3129–3140.</p>
      </sec>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          [1]
          <string-name>
            <given-names>M.</given-names>
            <surname>Bahrami</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Forouzanfar</surname>
          </string-name>
          ,
          <article-title>Sleep apnea detection from single-lead ecg: A comprehensive analysis of machine learning and deep learning algorithms</article-title>
          ,
          <source>IEEE Transactions on Instrumentation and Measurement</source>
          <volume>71</volume>
          (
          <year>2022</year>
          )
          <fpage>1</fpage>
          -
          <lpage>11</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          [2]
          <string-name>
            <given-names>P.</given-names>
            <surname>Tripathi</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Ansari</surname>
          </string-name>
          ,
          <string-name>
            <given-names>T. K.</given-names>
            <surname>Gandhi</surname>
          </string-name>
          ,
          <string-name>
            <given-names>R.</given-names>
            <surname>Mehrotra</surname>
          </string-name>
          ,
          <string-name>
            <surname>M. B. B. Heyat</surname>
            ,
            <given-names>F.</given-names>
          </string-name>
          <string-name>
            <surname>Akhtar</surname>
            ,
            <given-names>C. C.</given-names>
          </string-name>
          <string-name>
            <surname>Ukwuoma</surname>
            ,
            <given-names>A. Y.</given-names>
          </string-name>
          <string-name>
            <surname>Muaad</surname>
            ,
            <given-names>Y. M.</given-names>
          </string-name>
          <string-name>
            <surname>Kadah</surname>
            ,
            <given-names>M. A.</given-names>
          </string-name>
          <string-name>
            <surname>Al-Antari</surname>
          </string-name>
          , et al.,
          <article-title>Ensemble computational intelligent for insomnia sleep stage detection via the sleep ecg signal</article-title>
          ,
          <source>IEEE Access 10</source>
          (
          <year>2022</year>
          )
          <fpage>108710</fpage>
          -
          <lpage>108721</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          [3]
          <string-name>
            <given-names>N.</given-names>
            <surname>Banluesombatkul</surname>
          </string-name>
          ,
          <string-name>
            <given-names>P.</given-names>
            <surname>Ouppaphan</surname>
          </string-name>
          ,
          <string-name>
            <given-names>P.</given-names>
            <surname>Leelaarporn</surname>
          </string-name>
          ,
          <string-name>
            <given-names>P.</given-names>
            <surname>Lakhan</surname>
          </string-name>
          ,
          <string-name>
            <given-names>B.</given-names>
            <surname>Chaitusaney</surname>
          </string-name>
          ,
          <string-name>
            <given-names>N.</given-names>
            <surname>Jaimchariyatam</surname>
          </string-name>
          ,
          <string-name>
            <given-names>E.</given-names>
            <surname>Chuangsuwanich</surname>
          </string-name>
          ,
          <string-name>
            <given-names>W.</given-names>
            <surname>Chen</surname>
          </string-name>
          ,
          <string-name>
            <given-names>H.</given-names>
            <surname>Phan</surname>
          </string-name>
          ,
          <string-name>
            <given-names>N.</given-names>
            <surname>Dilokthanakul</surname>
          </string-name>
          , et al.,
          <article-title>Metasleeplearner: A pilot study on fast adaptation of bio-signals-based sleep stage classifier to new individual subject using meta-learning</article-title>
          ,
          <source>IEEE Journal of Biomedical and Health Informatics</source>
          <volume>25</volume>
          (
          <year>2020</year>
          )
          <fpage>1949</fpage>
          -
          <lpage>1963</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          [4]
          <string-name>
            <given-names>J.</given-names>
            <surname>Huang</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Ren</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Feng</surname>
          </string-name>
          ,
          <string-name>
            <given-names>F.</given-names>
            <surname>Yang</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Yang</surname>
          </string-name>
          ,
          <string-name>
            <given-names>K.</given-names>
            <surname>Yan</surname>
          </string-name>
          ,
          <article-title>Ai empowered virtual reality integrated systems for sleep stage classification and quality enhancement</article-title>
          ,
          <source>IEEE Transactions on Neural Systems and Rehabilitation Engineering</source>
          <volume>30</volume>
          (
          <year>2022</year>
          )
          <fpage>1494</fpage>
          -
          <lpage>1503</lpage>
          .
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>