Method, system and device for sleep stage determination using frontal electrodes
Inventors
Wu, Jianping • Kurtz, Ronald Leon • Weinroth, Aaron Phillip
Assignees
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Publication Number
US-8244340-B2
Publication Date
2012-08-14
Expiration Date
Abstract
The described embodiments relate generally to methods, systems and devices for sleep stage determination using frontal electrodes. Certain embodiments relate to a system for sleep stage determination comprising a sensing unit and a processing unit. The sensing unit is positioned over a forehead area of a patient and has first, second and third electrodes for positioning at locations on or adjacent the forehead area for detecting electrical potentials of a human head. The processing unit is coupled to the sensing unit for receiving biological signals corresponding to the detected electrical potentials and processing the biological signals to determine a sleep stage of the patient. The processing of the biological signals is based on a plurality of rules.
Core Innovation
Embodiments provide a sleep-stage determination system and method in which a sensing unit receives electrical potentials corresponding to biological signals from an electrode assembly positioned over a head of a patient. The electrical potentials are processed to determine EEG signals, EOG signals and EMG signals, and a processor calculates a pre-score based on the EEG signals, the EOG signals, the EMG signals and a plurality of rules.
The processor uses the plurality of rules and the pre-score to determine whether the sleep stage can be categorized by the pre-score. The method includes checking whether a sleep stage has been categorized based on the pre-score, and when the checking step determines that the sleep stage could not be categorized based on the pre-score, the sleep stage is determined based on at least one epoch.
Embodiments further describe rules-based, epoch-based reasoning with single-epoch and multiple-epoch approaches, including handling of undecided epochs and previous undecided epochs and last determined epochs, using the plurality of rules and pre-scoring. A frontal sensing unit positioned on a patient’s forehead is described with an electrode assembly including at least three electrodes, positioned near nasion and lateral forehead areas, and signal conditioning and processing that support sleep-stage determination.
Claims Coverage
The independent claim(s) define a rules-based, pre-score driven sleep stage categorization from EEG, EOG, and EMG electrical potentials, with epoch-based determination when pre-score categorization fails. Dependent claims further specify aspects of the rules basis, forehead electrode placement, optional body-movement inputs, and temporal handling of undecided and last determined epochs. Number of inventive features for the independent claims: 1 (with multiple refinements in dependents).
Pre-score based sleep stage categorization with fallback to epoch-based determination
Receiving electrical potentials corresponding to biological signals from an electrode assembly positioned over a head of a patient; processing the biological signals to determine EEG signals, EOG signals and EMG signals; calculating, with a processor, a pre-score based on the EEG signals, the EOG signals and the EMG signals and a plurality of rules; using the processor for determining based on the plurality of rules and the pre-score whether the sleep stage can be categorized by the pre-score; checking whether a sleep stage has been categorized based on the pre-score using the processor; and when the checking step determines that the sleep stage could not be categorized based on the pre-score, determining the sleep stage based on at least one epoch.
Empirically derived rules correlating EEG, EOG, EMG signal activity to sleep stages
Calculating the pre-score based on the EEG signals, the EOG signals and the EMG signals and plurality of rules, wherein the plurality of rules are derived from empirically derived correlations between EEG, EOG and EMG signal activity and one or more stages of sleep.
Forehead electrode assembly with nasion-adjacent and laterally opposed electrodes
Providing the electrode assembly including first, second, and third electrodes placed on or near the forehead, with the first adjacent a nasion area and the second and third over laterally opposed forehead areas.
Second and third electrode placement relative to Fp1 and Fp2 positions
Positioning the second and third electrodes above and laterally beyond respective Fp1 and Fp2 positions.
Body-movement electrical potentials for determining sleep stage
Receiving additional electrical potentials corresponding to patient body movement, and determining based on the additional potentials.
Epoch-by-epoch determining using previous undecided epochs and last determined epochs
Performing the determining step using previous undecided epochs, last determined epochs, and the plurality of rules.
Across the independent claim and its refinements, the core inventive concept is a pre-score calculated from EEG, EOG and EMG using a plurality of rules to categorize sleep stages, with an explicit fallback to epoch-based determination when the sleep stage cannot be categorized by the pre-score. Dependent features narrow the basis of rules, specify a forehead electrode layout including nasion-adjacent and laterally opposed electrodes with placement relative to Fp1 and Fp2, optionally incorporate body-movement potentials, and refine temporal logic using previous undecided epochs and last determined epochs.
Stated Advantages
Documented Applications
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