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US-20260123876-A1 - Handheld or Wearable Device for Recording or Sonifying Brain Signals

US20260123876A1US 20260123876 A1US20260123876 A1US 20260123876A1US-20260123876-A1

Abstract

A handheld device for sonifying electrical signals obtained from a subject is provided. The device can utilize at least one of several operations including (but not limited) digitizing signals from electrodes, adjusting the signals based on accelerometer input, filtering the signals, conditioning the signals according to conditioning parameters, modulating the signal according to sound synthesis parameters, and generating sound from the representations of the signals to accomplish sonification. The device can include an analog-to-digital (A/D) converter to digitize the one or more electrical signals and a processor that receives the one or more digitized electrical signals and produces a representation of an acoustic signal. The device further includes a speaker system that sonifies the representation of the acoustic signal.

Inventors

  • Josef Parvizi
  • Christopher D. Chafe
  • Xingjuan Chao
  • Ronald C. Eddington, Jr.

Assignees

  • THE BOARD OF TRUSTEES OF THE LELAND STANFORD JUNIOR UNIVERSITY
  • CERIBELL

Dates

Publication Date
20260507
Application Date
20250611

Claims (20)

  1. 1 . (canceled)
  2. 2 . A system for sonifying electroencephalogram (EEG) signals comprising: a headband comprising a plurality of electrodes; and a portable device configured to receive at least one EEG signal from one or more of the plurality of electrodes, the portable device comprising: a speaker: an analog-to-digital converter configured to digitize the at least one EEG signal; and a processor configured to receive the at least one digitized EEG signal and produce a sonification of the at least one EEG signal by performing a set of operations in real time comprising: conditioning the at least one digitized EEG signal to produce at least one conditioned EEG signal, wherein conditioning comprises: boosting the at least one digitized EEG signal by taking the power-law exponent of the digitized EEG signal to enhance contrast of the digitized EEG signal; applying absolute value signal rectification to the at least one digitized EEG signal to double signal frequency; rejecting signals with an amplitude below a threshold as low-amplitude noise signals; scaling signals above the threshold to create a fixed range boosted signal; and compressing the fixed range boosted signal to raise the prominence of small features; and using the conditioned signal to modulate one or more sound synthesis parameters to produce a sonified signal, wherein the speaker is configured to output the sonified signal.
  3. 3 . The system of claim 2 , further comprising a filter, wherein the filter is configured to filter non-seizure-related brain wave features from the at least one digitized EEG signal.
  4. 4 . The system of claim 3 , wherein the filter filters the at least one digitized EEG signal using filter bandpass cutoffs as part of a dual-stage filter.
  5. 5 . The system of claim 4 , wherein the dual-stage filter comprises a first stage with a DC-blocking hi-pass filter and a second stage with a bandpass filter.
  6. 6 . The system of claim 5 , wherein the bandpass filter has a passband of 0.1-3.0 Hz to 5.0-15.0 Hz.
  7. 7 . The system of claim 4 , wherein the dual-stage filter is configured to reject at least one of DC-bias, AC line contamination, and non-seizure-related brain wave features.
  8. 8 . The system of claim 2 , wherein modulating one or more sound synthesis parameters comprises continuously modulating one or more vocal sound parameters.
  9. 9 . The system of claim 2 , wherein the one more sound synthesis parameters comprises pitch, loudness, or vowel quality.
  10. 10 . The system of claim 2 , further comprising performing a formant pitch mapping on the at least one EEG signal using a midi-to-frequency function.
  11. 11 . The system of claim 10 , further comprising performing an inverse pitch frequency mapping on the at least one EEG signal using an interpolated look-up table for the inverse of the pitch frequency.
  12. 12 . The system of claim 2 , wherein compressing the fixed range boosted signal comprises compressing the fixed range signal by a factor of between 1.5 and 3.0.
  13. 13 . The system of claim 2 , wherein modulating the one or more sound synthesis parameters comprises performing at least one of: applying a pitch offset in the range of 50-150 Hz; performing pitch scaling to a pitch scale in the range of 110-440 Hz; applying an amplitude offset in the range of 0.0001-0.01; performing amplitude scaling in the range of 0.05-2.0; applying a vowel offset in the range of 0.0-1.0; performing vowel scaling in the range of 0.05-2.0; or mapping the at least one digitized signal to a vowel lookup table comprising the sounds: “iii”, “ahh”, “ehh”, “eee”, “ohh”, and “000”.
  14. 14 . The system of claim 2 , wherein the processor is configured to apply the absolute value rectification to the at least one digitized EEG signal prior to taking the power-law exponent.
  15. 15 . A method for sonifying EEG signals comprising: receiving at least one EEG signal from a plurality of electrodes disposed on a headband; digitizing the at least one EEG signal to produce at least one digitized EEG signal; sonifying the at least one digitized EEG signal using a processor of a portable device to produce a sonified EEG signal, wherein the processor is configured to sonify the at least one digitized EEG signal by performing a set of operations in real time comprising: conditioning the at least one digitized EEG signal to produce at least one conditioned EEG signal, wherein conditioning comprises: boosting the at least one digitized EEG signal by taking the power-law exponent of the at least one digitized EEG signal to enhance contrast of the at least one digitized EEG signal; applying absolute value signal rectification to the at least one digitized EEG signal to double signal frequency; rejecting signals with an amplitude below a threshold as low-amplitude noise signals; scaling signals above the threshold to create a fixed range boosted signal; and compressing the fixed range boosted signal to raise the prominence of small features; and outputting the sonified signal using a speaker of the portable device.
  16. 16 . The method of claim 15 , further comprising filtering non-seizure-related brain wave features from the at least one digitized EEG signal.
  17. 17 . The method of claim 15 , further comprising performing a formant pitch mapping on the at least one EEG signal using a midi-to-frequency function.
  18. 18 . The method of claim 17 , further comprising performing an inverse pitch frequency mapping on the at least one EEG signal using an interpolated look-up table for the inverse of the pitch frequency.
  19. 19 . The method of claim 15 , further comprising using the conditioned signal to modulate one or more sound synthesis parameters, wherein modulating comprises performing at least one of: applying a pitch offset in the range of 50-150 Hz; performing pitch scaling to a pitch scale in the range of 110-440 Hz; applying an amplitude offset in the range of 0.0001-0.01; performing amplitude scaling in the range of 0.05-2.0; applying a vowel offset in the range of 0.0-1.0; performing vowel scaling in the range of 0.05-2.0; or mapping the at least one digitized signal to a vowel lookup table comprising the sounds: “iii”, “ahh”, “ehh”, “cee”, “ohh”, and “000”.
  20. 20 . The method of claim 15 , further comprising detecting occurrence of a seizure by ear based upon the sonified signal output by the speaker of the portable device.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. patent application Ser. No. 18/416,030 filed Jan. 18, 2024, which is incorporated herein by reference. U.S. patent application Ser. No. 18/416,030 is a continuation of U.S. patent application Ser. No. 16/700,578 filed Dec. 2, 2019, which is incorporated herein by reference.U.S. patent application Ser. No. 16/700,578 is a continuation of U.S. patent application Ser. No. 15/159,759 filed May 19, 2016, which is incorporated herein by reference.U.S. patent application Ser. No. 15/159,759 claims priority from US Provisional Patent Application 62/163,637 filed May 19, 2015, which is incorporated herein by reference. FIELD OF THE INVENTION The disclosed embodiments relate generally to the field of sonifying signals detected from a living subject (e.g., electrical signals indicative of brain activity and/or heart activity), and in particular, to a handheld or wearable device for sonifying signals from a living subject. BACKGROUND OF THE INVENTION The ability to measure signals from a living subject (e.g., relating to the living subject's bodily functions) is beneficial for medical and diagnostic applications. For example, from a diagnostic point of view, measuring brain signals helps to ascertain brain activity related to abnormal brain function, to monitor spatial and/or temporal progression of brain disease, to aid surgical or nonsurgical intervention by localizing disease-sites in the brain, and to monitor brain activity of a healthy subject or a subject of unknown health status when the subject experiences a variety of stimuli and lack of stimuli. However, the use of electrical signals received from, for example, the brain (e.g., electroencephalography (EEG) signals) often requires a great deal of resources. Conventional EEG tests are typically performed at specialized centers (e.g., tertiary care centers), by specialized technicians, and the results are interpreted by specialized doctors (e.g., neurologists). Thus, conventional EEG is not typically available to, e.g., first responders in an acute emergency. Instead, the first responders must rely on external signs (e.g., level of consciousness or shaking) when deciding whether a patient may have a neurological problem. Because conventional EEG is beyond the resources of even some hospitals, a patient with suspected neurological problems will often be taken to a specialized center. Even at a specialized center, it may take hours to obtain EEG results and have the results interpreted by a neurologist. Every year in the United States alone, about 10 million people are seen in emergency departments (ED) for evaluation of altered mental state (AMS). Additionally, 5 million patients with critical conditions are admitted to intensive care units (ICU). Some of these are admitted through EDs but a majority of the patients are either transferred directly from other hospitals or are cases with postsurgical complications. In these patients, electroencephalography (EEG) is the gold-standard test for detecting seizures. While there are many causes of AMS, seizures are one of the most frequently suspected. About 10-20% of ICU patients are subject to seizures, and 90% of seizures in ICUs are non-convulsive. Where EEG is available, physicians order it to rule in/out ongoing non-convulse status epilepticus (NCSE). If the diagnosis of NCSE is made quickly, it will precipitate appropriate acute management, and will reduce unnecessary diagnostic procedures, length of hospitalization, and morbidity. In the US alone, about 20,000 patients die of NCSE. These patients have other severe co-morbidities but ongoing non-convulsive seizures will be a significant contributing factor to their extremely high mortality rate. In fact, NCSE has a mortality rate higher than the mortality rate of convulsive status epilepticus partly because of lack of obvious behavioral signs of seizures (e.g., convulsions), which delays detection and treatment. EEG is the only way to detect ongoing seizures. Early diagnosis of NCSE is life-saving for these patients and every hour of delay in diagnosis counts. Mortality of patients with NCSE treated with a delay of 20 hours is twice as high as those treated within 30 minutes. Because EEG is one of the oldest diagnostic tools in neurology, and because it has shown promise in saving lives, one would assume that it is widely integrated into medical practice everywhere and one might think that it is equally available to all populations at risk. This is unfortunately not the case. Inequality of access exists even in the United States, and at a wider scale on the global stage. Many hospitals in the US cannot offer an EEG platform. In addition to purchasing expensive EEG platforms, a given hospital has to hire certified EEG techs and neurologists with training in clinical electrophysiology and maintain an on-call schedule leading to a substantial management cost. For hospitals without a la