Tissue oxygen saturation detection and related apparatus and methods
A wearable optical device is described for optically detecting parameters of interest within muscle, such as during physical activity or when at rest. The parameters of interest include oxygenation level and/or hemoglobin concentrations in some situations. The detected parameters, such as oxygenation level, may be used to assess physical performance, such as the extent to which the muscle is utilizing aerobic or anaerobic processes. Methods for determining the parameters of interest, such as oxygenation level, from the detected optical signals are also described, and feedback may be provided to a user.
1. A narrow-band optical device for determining muscle oxygenation level, comprising:
a wearable housing;
an optical source array in the wearable housing including a plurality of narrow-band optical sources;
a plurality of optical detectors in the wearable housing including at least three optical detectors arranged substantially in a linear arrangement on a same side of the optical source array, wherein the at least three optical detectors include a first optical detector of a first size disposed a first distance from the optical source array, a second optical detector of a second size larger than the first size disposed a second distance greater than the first distance from the optical source array, and a third optical detector disposed a third distance greater than the second distance from the optical source array,
wherein the first optical detector, the second optical detector, and the third optical detector are configured to detect an optical signal emitted from the optical source array; and
a processor coupled to outputs of the plurality of optical detectors and configured to process output signals from the plurality of optical detectors and determine the muscle oxygenation level.
2. The narrow band optical device of claim 1 , wherein the plurality of narrow band optical sources are arranged substantially in a linear arrangement with respect to each other, and wherein the linear arrangement of the plurality of optical sources is substantially perpendicular to the linear arrangement of the at least three optical detectors.
3. The narrow band optical device of claim 1 , wherein the plurality of narrow band optical sources occupy a single position within the wearable housing.
4. The narrow band optical device of claim 1 , wherein the third optical detector is larger than the second optical detector.
5. The narrow band optical device of claim 1 , wherein the wearable housing includes a raised ring forming a perimeter surrounding the optical source array and the plurality of optical detectors.
6. The narrow band optical device of claim 1 , further comprising a coil disposed on or within the optical housing and configured to receive wireless charging signals.
7. The narrow band optical device of claim 1 , wherein the wearable housing includes a recess in which the optical source array is disposed such that the optical source array lies beneath a surface of the wearable housing.
8. The narrow band optical device of claim 1 , wherein the wearable housing includes respective recesses in which the plurality of optical sources are disposed such that the plurality of optical sources lie beneath a surface of the wearable housing.
9. The narrow band optical device of claim 1 , wherein the wearable housing includes respective recesses in which the plurality of optical detectors are disposed such that the plurality of optical detectors lie beneath a surface of the wearable housing.
10. The narrow band optical device of claim 1 , further comprising an adjustable strap to which the wearable housing is affixed.
11. The narrow band optical device of claim 1 , wherein the plurality of narrow band optical sources are arranged substantially in a linear arrangement with respect to each other, and wherein the linear arrangement of the plurality of narrow band optical sources is substantially perpendicular to the linear arrangement of the at least three optical detectors, and wherein the first optical detector is smaller than the third optical detector.
12. The optical device of claim 1 , wherein the processor is disposed within the wearable housing.
13. The narrow band optical device of claim 12 , further comprising wireless communication circuitry configured to wirelessly transmit data indicative of signals produced by the plurality of optical detectors.
14. The narrow band optical device of claim 1 , wherein the third optical detector is larger than the first optical detector.
15. The narrow band optical device of claim 1 , wherein the third optical detector is configured to detect an optical signal emitted only from optical sources that are disposed on the same side of the optical source array.
16. The narrow band optical device of claim 1 , wherein the plurality of narrow band optical sources occupy a single position within the wearable housing and wherein the third optical detector is larger than the first optical detector.