System and method for measuring coefficient variance of resonance frequency of musculoskeletal system

• US 20060229534A1
• Filed: 03/29/2005
• Published: 10/12/2006
• Est. Priority Date: 03/29/2005
• Status: Abandoned Application

• Current Assignee: Chung-Yuan Christian University
• Original Assignee: Chung-Yuan Christian University
• Inventors: Huang, Wen-Jui, Shih, Chun-Hsiung, Liu, Hwa-Chang, Chang, Walter Hong-Shong
• Application Number:
  US11/091,500
• Publication Number:
  US 20060229534A1
• Time in Patent Office: Days
• US Class Current: 600/587
• CPC Class Codes: A61B 5/1101 Detecting tremor
• CPC Class Codes: A61B 5/1104 induced by stimuli or drugs; A61B5/1102 takes precedence; investigating medicinal preparations G01N33/15
• CPC Class Codes: A61B 5/4519 Muscles A61B5/389, A61B5/224 take precedence
• CPC Class Codes: A61B 5/4528 Joints A61B5/4533, A61B5/4538 take precedence
• CPC Class Codes: A61B 5/726 using Wavelet transforms

Abstract

The present invention discloses system and method for measuring coefficient variance of resonance frequency of musculoskeletal system. In this regards, the system comprises a signal generation module, a signal retrieval module, and a signal analysis module. The purpose of the system is to measure resonance frequencies of a musculoskeletal system which implanted with an arthroplasty in order to form a statistical sampling space of resonance frequencies. Therefore a coefficient variance of the statistical sampling space of resonance frequencies can be derived. Consequently, the magnitude of this coefficient variance is used for determining whether the implated arthroplasty loose.

Claims

1. A measurement system for measuring a coefficient variance of resonant frequency of a musculoskeletal system, comprising:

a signal source generation module accepts instructions from a signal analysis module to generate vibration signals to said musculoskeletal system;

a signal sensor module senses vibration signals from said musculoskeletal system and feed into said signal analysis module; and

said signal analysis module calculates said coefficient variance of resonant frequency of said musculoskeletal system according to vibration signals fed by said signal sensor module.

2. A measurement system of claim 1, wherein said signal source generation module further comprises a source generator, an amplifier, and an oscillator attached on said musculoskeletal system, said source generator generates oscillatory signals according to instructions from said signal analysis module, generated oscillatory signals are amplified and outputted to said oscillator by said amplifier, said oscillator generates and conducts vibrations into said musculoskeletal system following the amplified oscillatory signals.

3. A measurement system of claim 1, wherein said signal sensor module further comprises an accelerometer attached on said musculoskeletal system and a charge amplifier, accelerations of said musculoskeletal system vibrations are sensed by said accelerometer, amplified by said charge amplifier, and be fed into said signal analysis module.

4. A measurement system of claim 1, wherein said signal analysis module applies a linear or non-linear spectrum transformation technique to transform temporal vibration signals from said signal sensor module into spectral resonant frequencies and store the spectral resonant frequencies in memorial media.

5. A measurement system of claim 4, wherein said linear spectrum transformation technique is fast Fourier transformation.

6. A measurement system of claim 4, wherein said non-linear spectrum transformation technique is wavelet transformation.

7. A measurement system of claim 4, said signal analysis module further comprises a comparison a quantity of resonant frequency samples in memorial media with a critical sample space size, continuing collecting resonant frequency samples whenever said quantity is insufficient.

8. A measurement system of claim 7, wherein said signal analysis module further comprises calculating said coefficient variance whenever said comparison indicated that said quantity is sufficient.

9. A measurement system of claim 8, wherein said signal analysis module further comprises calculating a standard deviation and a mean, said coefficient variance is a quotient of said standard deviation and said mean.

10. A measurement system of claim 9, wherein said mean is a quotient of a sum of resonant frequency samples divided by said quantity of resonant frequency samples.

11. A measurement system of claim 9, wherein said standard deviation is a square root of a quotient minus one (1), the quotient is calculated as a differential, a sum of squares of samples minus a product of the mean and said quantity, divided by said quantity.

12. A measurement system of claim 8, wherein said signal analysis module further comprises comparing said coefficient variance with a cohesion threshold, said musculoskeletal system is determined as loosen whenever said coefficient variance is larger than said cohesion threshold, said musculoskeletal system is contrarily determined as cohesive well whenever said coefficient variance is not larger than said cohesion threshold.

13. A measurement system of claim 13, wherein said musculoskeletal system is a total hip anthroplasty implanted musculoskeletal system.

14. A measurement system of claim 14, wherein said cohesion threshold is 0.035.

15. A measurement method for measuring a coefficient variance of resonant frequency of a musculoskeletal system, comprising:

providing a measurement system, which further comprises a signal source generation module attached to said musculoskeletal system, a signal sensor module attached to said musculoskeletal system, and a signal analysis module;

performing a vibrating step, wherein said vibrating step let said signal source generation module accepts instructions from said signal analysis module to generate vibration signals to said musculoskeletal system;

performing a gathering step, wherein said gathering step let said signal sensor module senses vibration signals from said musculoskeletal system and feed into said signal analysis module; and

performing a analysis step, wherein said analysis step let said signal analysis module calculates said coefficient variance of resonant frequency of said musculoskeletal system according to vibration signals fed by said signal sensor module.

16. A measurement method of claim 15, wherein said signal source generation module further comprises a source generator, an amplifier, and an oscillator attached on said musculoskeletal system, said source generator generates oscillatory signals according to instructions from said signal analysis module, generated oscillatory signals are amplified and outputted to said oscillator by said amplifier, said oscillator generates and conducts vibrations into said musculoskeletal system following the amplified oscillatory signals.

17. A measurement method of claim 15, wherein said signal sensor module further comprises an accelerometer attached on said musculoskeletal system and a charge amplifier, accelerations of said musculoskeletal system vibrations are sensed by said accelerometer, amplified by said charge amplifier, and be fed into said signal analysis module.

18. A measurement method of claim 15, wherein said analysis step further comprises that said signal analysis module applies a linear or non-linear spectrum transformation technique to transform temporal vibration signals from said signal sensor module into spectral resonant frequencies and store the spectral resonant frequencies in memorial media.

19. A measurement method of claim 18, wherein said linear spectrum transformation technique is fast Fourier transformation.

20. A measurement method of claim 18, wherein said non-linear spectrum transformation technique is wavelet transformation.

21. A measurement method of claim 15, wherein said analysis step further comprises that said signal analysis module compares a quantity of resonant frequency samples in memorial media with a critical sample space size, continuing collecting resonant frequency samples whenever said quantity is insufficient.

22. A measurement method of claim 21, wherein said analysis step further comprises that said signal analysis module calculates said coefficient variance whenever said comparison indicated that said quantity is sufficient.

23. A measurement method of claim 22, wherein said analysis step further comprises that said signal analysis module calculates a standard deviation and a mean, said coefficient variance is a quotient of said standard deviation and said mean.

24. A measurement method of claim 23, wherein said mean is a quotient of a sum of resonant frequency samples divided by said quantity of resonant frequency samples.

25. A measurement method of claim 23, wherein said standard deviation is a square root of a quotient minus one (1), the quotient is calculated as a differential, a sum of squares of samples minus a product of the mean and said quantity, divided by said quantity.

26. A measurement method of claim 22, wherein said analysis step further comprises that said signal analysis module compares said coefficient variance with a cohesion threshold, said musculoskeletal system is determined as loosen whenever said coefficient variance is larger than said cohesion threshold, said musculoskeletal system is contrarily determined as cohesive well whenever said coefficient variance is not larger than said cohesion threshold.

27. A measurement method of claim 26, wherein said musculoskeletal system is a total hip anthroplasty implanted musculoskeletal system.

28. A measurement method of claim 27, wherein said cohesion threshold is 0.035.