Fatigue monitoring device and method

• US 6,352,516 B1
• Filed: 03/27/2000
• Issued: 03/05/2002
• Est. Priority Date: 03/27/2000
• Status: Expired due to Fees

• Current Assignee: San Diego State University Foundation
• Original Assignee: San Diego State University Foundation
• Inventors: Agraz, Jose L., Pozos, Robert S.
• Primary Examiner(s): Winakur, Eric F.
• Assistant Examiner(s): WINGOOD, PAMELA LYNN
• Application Number:
  US09/536,834
• Time in Patent Office: 708 Days
• Field of Search: 600/592, 600/587, 600/595-597, 482/79, 482/34
• US Class Current: 600/587
• CPC Class Codes: A61B 2560/0228 using calibration standards
• CPC Class Codes: A61B 2560/0406 specially shaped apparatus housings
• CPC Class Codes: A61B 5/1107 Measuring contraction of parts of the body, e.g. organ, muscle apparatus for measuring work or force in general G01L
• CPC Class Codes: A61B 5/225 of the fingers, e.g. by monitoring hand-grip force
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6897 Computer input devices, e.g. mice or keyboards
• CPC Class Codes: G06F 3/0219 Special purpose keyboards
• CPC Class Codes: G06F 3/03543 Mice or pucks G06F3/03541 takes precedence
• CPC Class Codes: G06F 3/0383 Signal control means within the pointing device
• CPC Class Codes: H01H 2217/044 Repetitive strain injury [RSI] considerations

Abstract

The present invention relates to a device and method for monitoring fatigue. In one embodiment, a sequential finger fatigue measuring system is provided which measures the force output from fingers while the fingers are sequentially generating forces as they strike a keyboard. Force profiles of the fingers are generated from the measurements and evaluated for fatigue. The system can be used clinically to evaluate patients, to ascertain the effectiveness of clinical intervention, pre-employment screening, to assist in minimizing the incidence of repetitive stress injuries at the keyboard, mouse, joystick, and to monitor effectiveness of various finger strengthening systems.

Claims

1. A method of monitoring fatigue in at least one body part of a person performing repetitive motions, said method comprising the steps of:

measuring forces generated by the body part during performance of the repetitive motions in the form of force data; and

evaluating the force data for fatigue.

2. The method according to claim 1, further comprising the step of generating measurable signals in proportion to the forces.

3. The method according to claim 2, further comprising the step of converting the signals into a sequence of discrete force data representative of the forces generated by the body part.

4. The method according to claim 1, further comprising the step of measuring EMG signals from one or more muscles of the person.

5. The method according to claim 4, further comprising the step evaluating the EMG signals for fatigue.

6. The method according to claim 1, wherein the body part is a finger and the repetitive motions are repeatedly pressing a button with the finger.

7. The method according to claim 6, further comprising the step of generating signals in proportion to the forces generated by the finger pressing the button.

8. The method according to claim 7, further comprising the step of converting the signals into a sequence of discrete force data representative of the forces generated by the finger.

9. The method according to claim 1, wherein the body part is a hand having a plurality of fingers and a hand base.

10. The method according to claim 9, wherein the series of repetitive motions is repeatedly pressing buttons with the fingers.

11. The method according to claim 10, further comprising the step of measuring a baseline force output of each of the fingers.

12. The method of claim 11, further comprising the step of normalizing the force data with the baseline force output to produce a normalized set of discrete force data representative of the forces generated by the fingers.

13. The method according to claim 12, further comprising the step of calculating a rate of amplitude change from the normalized set of discrete force data.

14. The method according to claim 13, further comprising the step of converting the rate of amplitude change into a value representative of fatigue.

15. The method according to claim 10, further comprising the step of measuring forces generated by the hand base and the fingers as the buttons are repeatedly pressed with the fingers.

16. The method according to claim 15, further comprising the steps of generating a first set of signals in proportion to the forces generated by the handbase and a second set of signals in proportion to the forces generated by the fingers.

17. The method according to claim 16, further comprising the steps of converting the first set of signals into a first set of discrete force data representative of the forces generated by the handbase and converting the second set of signals into a second set of discrete force data representative of the forces generated by the fingers.

18. The method according to claim 17, further comprising the steps of calculating a first rate of amplitude change from the first set of discrete force data and a second rate of amplitude change from the second set of force data.

19. The method according to claim 18, further comprising the step of converting the first rate of amplitude change, the second rate of amplitude change or the relationship between the first rate of amplitude change and the second rate of amplitude change into a value representative of fatigue.

20. An apparatus for monitoring fatigue in at least one body part of a subject performing a series of repetitive motions, comprising:

an input device having a force sensor for generating signals in proportion to a force transmitted to the input device by the body part during performance of the repetitive motions;

a processor connected to the force sensor, wherein the processor is programmed to receive the signals and produce a sequence of discrete force data representative of the forces transmitted to the input device; and

a plurality of EMG preamps for collecting EMG signals representative of an activity from one or more muscles of the subject.

21. The apparatus according to claim 20, wherein the processor is connected to the preamps, and wherein the processor is programmed to receive the EMG signals to produce EMG data representative of the activity of the muscle or muscles.