睡眠紡錘波是透過腦電圖（EEG）測量, 主要是在睡眠期間非快速眼動（NREM）第二階段測量腦活動的短暫振動西格瑪頻率範圍（11-16Hz）。這些振動具有很大的生物和臨床意義，它們在各種學習與認知功能開發學習領域及複雜的神經系統中是重要的生物標記。通常，睡眠紡錘波由睡眠臨床專家目測腦電信號來辨識判定。這個過程非常耗時，而且不同專家之間的結果並不一致。為了解決這個問題，目前腦科學家已經發展了許多自動化睡眠紡錘波檢測方法。然而，在不同研究中, 這些自動睡眠紡錘波的檢測方法表現並不盡相同, 這主要有兩個原因：（1）缺乏共同的基準測試數據庫，（2）缺乏被腦科學界普遍接受的評估指標。在本研究中，我們專注於解決第二個問題，提出在多目標優化的環境中評估睡眠紡錘波檢測的效能。我們實驗假設，使用Pareto fronts來導出評估度量將提高自動睡眠紡錘波檢測。我們使用盛行於工程優化用用途的多目標演化演算法（MOEA），Strength Pareto Evolutionary Algorithm（SPEA2）來優化六種現有的以頻率為基準的睡眠紡錘波檢測演算法。它們包括三個傅立葉，一個連續小波變換（CWT）和兩個希爾伯特 - 黃變換（HHT）演算法。我們還探討了三種混合型方法。在使用公開取得的DREAMS和MASS數據庫進行了訓練和測試，兩種新的傅立葉與HHT演算法的混合型方法顯示出顯著的效能提升，F1分數達0.726-0.737的高準確度。

Sleep spindles are brief bursts of brain activity in the sigma frequency range (11–16 Hz) measured by electroencephalography (EEG) mostly during non-rapid eye movement (NREM) stage 2 sleep. These oscillations are of great biological and clinical interests because they potentially play an important role in identifying and characterizing the processes of various neurological disorders. Conventionally, sleep spindles are identified by expert sleep clinicians via visual inspection of EEG signals. The process is laborious and the results are inconsistent among different experts. To resolve the problem, numerous computerized methods have been developed to automate the process of sleep spindle identification. Still, the performance of these automated sleep spindle detection methods varies inconsistently from study to study. There are two reasons: (1) the lack of common benchmark databases, and (2) the lack of commonly accepted evaluation metrics. In this study, we focus on tackling the second problem by proposing to evaluate the performance of a spindle detector in a multi-objective optimization context and hypothesize that using the resultant Pareto fronts for deriving evaluation metrics will improve automatic sleep spindle detection. We use a popular multi-objective evolutionary algorithm (MOEA), the Strength Pareto Evolutionary Algorithm (SPEA2), to optimize six existing frequency-based sleep spindle detection algorithms. They include three Fourier, one continuous wavelet transform (CWT), and two Hilbert-Huang transform (HHT) based algorithms. We also explore three hybrid approaches. Trained and tested on open-access DREAMS and MASS databases, two new hybrid methods of combining Fourier with HHT algorithms show significant performance improvement with F1-scores of 0.726–0.737.

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