Methods and device for determining a valid intrinsic frequency
Inventors
Phillips, James William • Jin, Yi
Assignees
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Publication Number
US-10588576-B2
Publication Date
2020-03-17
Expiration Date
Abstract
Described are methods and a device for determining a valid intrinsic alpha frequency. Described herein are methods and a device for determining the appropriate intrinsic alpha frequency (IAF) to be applied for neuro-EEG synchronization therapy using alternating magnetic fields to gently “tune” the brain and affect the mood, focus and cognition of subjects. Methods and a device described herein use an algorithm to quantitatively analyze EEG recordings to determine if recorded EEG frequencies are valid, and if necessary, requiring additional recordings and analysis until a valid EEG is found. Methods and devices described herein can be utilized to calculate the intrinsic frequency of other EEG bands, including the Theta, Beta Gamma and Delta bands.
Core Innovation
The invention determines a final intrinsic alpha frequency (fIAF) of a subject in a neuro-electroencephalogram (EEG) synchronization therapy by executing an EEG discrimination routine on one or more processors. The routine receives a first EEG recording from an EEG sensor in the time domain, segments the recording into a plurality of epochs, filters each epoch with a high-pass filter, and converts each filtered epoch into a frequency domain epoch. Each frequency domain epoch is further filtered using a smoothing filter.
For each frequency domain epoch, the routine calculates an epoch intrinsic alpha frequency (m_i) and then calculates a mean (M) intrinsic alpha frequency (IAF) from the epoch intrinsic alpha frequencies. The routine determines a farthest frequency domain epoch from the mean and, if the farthest epoch deviates from the mean by more than 0.5 hertz (Hz), removes the farthest epoch, decrements the total number of epochs, and repeats the mean and farthest-epoch determination.
If the deviation is within 0.5 Hz, the process continues and the routine sets the fIAF equal to M and outputs the fIAF to a therapy device. The therapy device delivers low amplitude stimulation at the fIAF as part of the neuro-EEG synchronization therapy, and the discrimination routine and its parameters are used to support validity checking concepts that can include an intrinsic alpha frequency validity assessment and multi-recording consistency checks.
Claims Coverage
The document contains one independent claim. It defines an EEG discrimination routine executed by one or more processors to compute a final intrinsic alpha frequency (fIAF) from EEG, and then uses that fIAF to drive a neuro-EEG synchronization therapy device delivering low amplitude stimulation; the core algorithm includes epoch-based intrinsic alpha frequency estimation and iterative outlier pruning based on a 0.5 Hz deviation criterion.
Final intrinsic alpha frequency from epoch intrinsic alpha frequencies with iterative outlier pruning
A method of determining a final intrinsic alpha frequency (fIAF) for neuro-EEG synchronization therapy by receiving a first time-domain EEG recording, segmenting it into a plurality of epochs, filtering each epoch using a high-pass filter, converting each epoch into a frequency domain epoch, filtering each frequency domain epoch using a smoothing filter, calculating an epoch intrinsic alpha frequency (m_i) for each frequency domain epoch, calculating a mean (M) intrinsic alpha frequency (IAF) from all epoch intrinsic alpha frequencies, determining a farthest frequency domain epoch from the mean, removing the farthest epoch and repeating while |m_I−M|>0.5 Hz, and continuing when |m_I−M|≤0.5 Hz, with fIAF set equal to M.
Using fIAF to deliver low amplitude stimulation with a therapy device
Outputting the fIAF to a therapy device and delivering, with the therapy device, low amplitude stimulation at the fIAF as part of the neuro-electroencephalogram synchronization therapy.
The independent claim covers computing fIAF from epoch intrinsic alpha frequencies via filtering, frequency-domain conversion, mean calculation, and iterative removal of the farthest epoch when it deviates by more than 0.5 Hz, and outputting the resulting fIAF to a therapy device for delivery of low amplitude stimulation at the fIAF.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Not explicitly described in patent.
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