Apparatus, method and computer program product for determining respiratory condition

• US 20070010722A1
• Filed: 07/05/2006
• Published: 01/11/2007
• Est. Priority Date: 07/06/2005
• Status: Active Grant

• Current Assignee: TDK Corporation
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Sugahara, Atsushi, Suzuki, Takuji
• Granted Patent: US 7,981,045 B2
• Time in Patent Office: Days
• US Class Current: 600/300
• CPC Class Codes: A61B 7/003 Detecting lung or respiration noise

Abstract

An apparatus for determining a respiratory condition includes a breath sound measuring unit 111 measuring a breath sound passing through a subject'"'"'s airway by a breathing; a frequency converting unit 132 converting a frequency on the breath sound to obtain a frequency spectrum; a respiratory synchronous component extracting unit 134 extracting a respiratory synchronous component, which varies depending on the breathing, from the frequency spectrum; a frequency distribution detecting unit 136 detecting a frequency distribution of the respiratory synchronous component; and a respiratory condition determining unit 138 determining a subject'"'"'s respiratory condition based on the frequency distribution. According to the apparatus, various symptoms, such as airway occlusion, respiratory obstruction and the like in relation to breathing during sleep can be determined.

Claims

1. An apparatus for determining a respiratory condition comprising:

a breath sound measuring unit measuring a breath sound passing through a subject'"'"'s airway by a breathing;

a frequency converting unit converting a frequency on the breath sound to obtain a frequency spectrum;

a respiratory synchronous component extracting unit extracting a respiratory synchronous component, which varies depending on the breathing, from the frequency spectrum;

a frequency distribution detecting unit detecting a frequency distribution of the respiratory synchronous component; and

a respiratory condition determining unit determining a subject'"'"'s respiratory condition based on the frequency distribution.

2. The apparatus according to claim 1 further comprising:

a normal frequency distribution maintaining unit maintaining a normal frequency distribution that is a frequency distribution of the respiratory synchronous component when the subject is in a normal state,

wherein the respiratory condition determining unit determines the subject'"'"'s respiratory condition when the subject is sleeping based on the normal frequency distribution and a frequency distribution during sleep that is the frequency distribution detected with respect to a breath sound measured from the sleeping subject.

3. The apparatus according to claim 2, wherein the respiratory condition determining unit determines that the respiratory condition becomes worse when a frequency shift of the frequency distribution during sleep with respect to the normal frequency distribution is equal to or greater than a predetermined value.

4. The apparatus according to claim 3, wherein the respiratory condition determining unit determines that the respiratory condition becomes worse when the frequency shift in a predetermined frequency band of the frequency distribution during sleep is equal to or greater than a predetermined value.

5. The apparatus according to claim 2, wherein the normal frequency distribution maintaining unit maintains, as the normal frequency distribution, a frequency distribution before falling asleep that is the frequency distribution of the respiratory synchronous component before the subject falls asleep.

6. The apparatus according to claim 5, wherein the breath sound measuring unit measures a breath sound before falling asleep in the condition before the subject falls asleep, and the normal frequency distribution maintaining unit maintains the frequency distribution before falling asleep, which is detected by the frequency distribution detecting unit, based on the breath sound before falling asleep.

7. The apparatus according to claim 1, wherein the breath sound measuring unit is embedded in a bed.

8. The apparatus according to claim 7, wherein the breath sound measuring unit is embedded in a pillow.

9. The apparatus according to claim 1 further comprising:

a plurality of the breath sound measuring units measuring breath sound passing through the subject'"'"'s airway, in a state where the plurality of breath sound measuring units are in contact with the subject'"'"'s skin at different positions; and

a selecting unit of the breath sound measuring unit selecting the breath sound measuring unit utilized for the determination of a respiratory condition among the plurality of breath sound measuring units based on the plurality of respiratory synchronous components obtained from the breath sound measured by the plurality of the breath sound measuring units,

wherein the respiratory condition determining unit determines the respiratory condition based on the breath sound measured by the breath sound measuring unit selected by the selecting unit of the breath sound measuring unit.

10. The apparatus according to claim 9, wherein the selecting unit of the breath sound measuring unit selects the breath sound measuring unit which exhibits greatest amplitude of the respiratory synchronous component.

11. The apparatus according to claim 9 further comprising:

an impedance change detecting unit detecting changes in impedance between neighboring two electrodes,

wherein the respective breath sound measuring units are disposed adjacent to each other, and

the selecting unit of the breath sound measuring unit selects the breath sound measuring unit utilized for the determination of a respiratory condition based on the changes in impedance between the electrodes, which are detected by the impedance change detecting unit.

12. The apparatus according to claim 9 further comprising:

at least three of the breath sound measuring units disposed adjacent to each other; and

an impedance change detecting unit detecting changes in impedance between two neighboring electrodes,

wherein the selecting unit of the breath sound measuring unit selects the plurality of breath sound measuring units as candidate breath sound measuring units based on the changes in impedance between the electrodes, and selects the breath sound measuring unit which exhibits the greatest amplitude of the breath sound synchronous component, among the plurality of the candidate breath sound measuring units.

13. The apparatus according to claim 9 further comprising:

a first pressing member that presses a first breath sound measuring unit among the plurality of breath sound measuring units against the subject;

a second pressing member that presses a second breath sound measuring unit among the plurality of breath sound measuring units against the subject; and

a pressure controlling unit controlling pressure of the first pressing member, when the selecting unit of the breath sound measuring unit selects the first breath sound measuring unit.

14. The apparatus according to claim 13, wherein the first pressing member is an air bag, and the pressure controlling unit controls an amount of air in the air bag.

15. The apparatus according to claim 14 further comprising:

a respiratory signal measuring unit measuring a subject'"'"'s respiratory signal based on the pressure transmitted to the air bag,

wherein the respiratory condition determining unit further determines the subject'"'"'s respiratory condition based on the respiratory signal measured by the respiratory signal measuring unit.

16. A method of determining respiratory condition comprising:

measuring a breath sound passing through a subject'"'"'s airway by a breathing;

converting a frequency on the breath sound to obtain a frequency spectrum;

extracting a respiratory synchronous component, which varies depending on the breathing, from the frequency spectrum;

detecting a frequency distribution of the respiratory synchronous component; and

determining a subject'"'"'s respiratory condition based on the frequency distribution.

17. A computer program product having a computer readable medium including programmed instructions for determining respiratory condition, wherein the instructions, when executed by a computer, cause the computer to perform:

measuring a breath sound passing through a subject'"'"'s airway by a breathing;

converting a frequency on the breath sound to obtain a frequency spectrum;

extracting a respiratory synchronous component, which varies depending on the breathing, from the frequency spectrum;

detecting a frequency distribution of the respiratory synchronous component; and

determining a subject'"'"'s respiratory condition based on the frequency distribution.