# US 2025/0143589 A1 · Compact laser-powered speckle visibility spectroscopy devices

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- Number: US 2025/0143589 A1
- Document ID: US20250143589A1
- Status: Published application
- Kind: A1
- Application number: 18/935,159
- Filed: 2024-11-01
- Published: 2025-05-08
- Earliest claimed: 2023-11-03
- Assignees: California Institute of Technology
- Applicants: California Institute of Technology
- Inventors: Simon Mahler; Yu Xi Huang; Changhuei Yang
- Web page: https://patentgrep.com/patent/US20250143589A1

## CPC

- A61B 5/0205: Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
- A61B 5/02028: {Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction}
- A61B 5/0261: {using optical means, e.g. infrared light}
- A61B 5/4064: {Evaluating the brain (for intracranial pressure A61B5/031; for cerebral blood gases A61B5/14553; using EEG A61B5/369)}
- A61B 5/6803: {Head-worn items, e.g. helmets, masks, headphones or goggles}
- A61B 5/7271: {Specific aspects of physiological measurement analysis (specific diagnostics methods using bioelectric or biomagnetic signals A61B5/316)}
- A61B 5/0059: {using light, e.g. diagnosis by transillumination, diascopy, fluorescence (photoacoustic A61B5/0093; optical measurement of heart rate A61B5/02416; optical measurement of blood flow A61B5/0261; optical measurement of analytes A61B5/1455)}
- A61B 5/02438: {with portable devices, e.g. worn by the patient}
- A61B 5/02444: {Details of sensor (A61B5/02427 takes precedence)}
- A61B 5/0255: Recording instruments specially adapted therefor
- A61B 2560/0214: of power generation or supply
- A61B 2560/0462: Apparatus with built-in sensors
- A61B 2576/026: for the brain
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

Techniques for monitoring cerebral blood metrics such as cerebral blood flow, cerebral blood volume and/or heart rate are provided. In some embodiments, techniques involve a headset with at least one laser configured to emit light into the brain and one or more light detectors such as CMOS sensors that generate information indicative of light reflected from one or more structures within the brain, which can be used to determine the cerebral blood metrics. Each light detector may be positioned within 5 mm of the scalp in some cases.

## Claims

### Claim 1

A headband configured to be worn on a head; and
a laser coupled to the headband and configured to emit light into a brain within a skull of the head;
a light detector coupled to the headband and configured to generate information indicative of light reflected from one or more structures within the brain, wherein the light detector is configured to contact or be within 5 mm of a scalp of the skull; and
a power source coupled to the headband and in electrical communication with the laser.

### Claim 2 (depends on 1)

The headband of claim 1, wherein a distance between the laser and the light detector is adjustable by changing position of the laser and/or the light detector on the headband.

### Claim 3 (depends on 1)

The headband of claim 1, wherein the laser is a continuous laser and/or the laser is configured to emit light in a near-infrared or infrared wavelength.

### Claim 4

(canceled)

### Claim 5 (depends on 1)

The headband of claim 1, wherein the headband comprises one or more straps and/or is configured to encircle the head.

### Claim 6

(canceled)

### Claim 7 (depends on 1)

The headband of claim 1, wherein the headband is configured to place the light detector in contact with, and apply a pressure to, a region of the scalp of the head.

### Claim 8

(canceled)

### Claim 9 (depends on 1)

The headband of claim 1, further comprising one or more processors configured to:
cause, using the laser, light to be emitted into the brain;
obtain, using the light detector, the information indicative of the reflected light from one more structures within the brain; and
based on the obtained information, determine one or more cerebral blood metrics.

### Claim 10 (depends on 9)

The headband of claim 9, wherein the one or more cerebral blood metrics comprises one or more of a cerebral blood flow, a cerebral blood volume, or a heart rate.

### Claim at position 11

11-12. (canceled)

### Claim 13 (depends on 1)

The headband of claim 1, wherein the laser, the light detector, and the power source form a first channel and further comprising one or more additional channels, wherein each additional channel comprises an additional light detector and wherein the light detectors of the first channel and the additional channels are configured to probe different regions of the brain.

### Claim at position 13

14-15. (canceled)

### Claim 16 (depends on 1)

The headband of claim 1, wherein the light detector comprises a plurality of sensor segments at different distances from the laser.

### Claim 17 (depends on 16)

The headband of claim 16, wherein the sensor segments are configured to probe different regions at different depths of the brain.

### Claim 18

(canceled)

### Claim 19

A multi-channel headset comprising:
a headband configured to be worn on a head during operation; and
a plurality of channels coupled to the headband, each channel comprising:
a laser configured to emit light into a brain within a skull of the head;
a light detector configured to generate information indicative of light emitted by the laser and reflected by one or more structures within the brain; and
a power source in electrical communication with the laser;
wherein the light detectors of the channels are configured to probe different regions of the brain.

### Claim 20 (depends on 19)

The multi-channel headset of claim 19, wherein at least two of the channels have light detectors configured to receive light from the same laser.

### Claim 21

An apparatus comprising:
a circuit board;
one or more processors attached to the circuit board;
a laser diode attached to the circuit board;
a light detector in electrical communication with the one or more processors; and
a light block located between the laser diode and the light detector.

### Claim 22 (depends on 21)

The apparatus of claim 21, further comprising (i) a power source in electrical communication with the laser diode and/or (ii) a wireless transmitter for transmitting wireless signals, the wireless transmitter in electrical communication with the one or more processors.

### Claim at position 21

23-24. (canceled)

### Claim 25 (depends on 21)

The apparatus of claim 21, wherein the one or more processors comprise one or both of an application-specific integrated circuit and a programmable logic device.

### Claim 26

(canceled)

### Claim 27 (depends on 21)

The apparatus of claim 21, wherein the circuit board and/or the light detector is made of a flexible material.

### Claim at position 25

28-29. (canceled)

### Claim 30 (depends on 21)

The apparatus of claim 21, wherein the light detector comprises a plurality of complementary metal-oxide-semiconductor sensors.

### Claim 31 (depends on 21)

The apparatus of claim 21, wherein the light detector comprises a plurality of sensor segments configured to probe different regions at different depths.

### Claim 32

(canceled)

### Claim 33 (depends on 21)

The apparatus of claim 21, wherein the one or more processors are configured to:
cause, using the laser diode, light to be emitted into a brain within a skull of a head of a user;
obtain, using the light detector, information indicative of light reflected from one more structures within the brain; and
based on the obtained information, determine one or more cerebral blood metrics.

### Claim at position 30

34-38. (canceled)

### Claim 39

A method of determining one or more cerebral blood metrics, the method comprising:
causing, using a laser, light to be emitted into a brain within a skull of a head of a user;
obtaining, using a light detector, information indicative of light reflected from one more structures within the brain; and
based on the obtained information, determining one or more cerebral blood metrics as a function of time.

### Claim 40

(canceled)

### Claim 41 (depends on 39)

The method of claim 39, wherein the obtained information comprises a plurality of speckle images.

### Claim 42 (depends on 41)

The method of claim 41, further comprising:
normalizing each speckle image based on a first set of the speckle images acquired during a first time period;
calculating a speckle contrast of each normalized speckle image; and
adjusting the speckle contrast to account for noise.

### Claim 43 (depends on 42)

The method of claim 42, further comprising calculating a cerebral blood flow from the adjusted speckle contrast of each image of a second set of the speckle images acquired during a second time period in which the user was holding their breath.

### Claim 44 (depends on 42)

The method of claim 42, further comprising:
calculating a plurality of cerebral blood flow values over time from the adjusted speckle contrast of a second set of the speckle images acquired during a second time period in which the user was holding their breath; and
calculating a heart rate from a period in the cerebral blood flow values over time.