System an method for detecting tremors such as those which result from parkinson's disease

• US 5,293,879 A
• Filed: 09/23/1991
• Issued: 03/15/1994
• Est. Priority Date: 09/23/1991
• Status: Expired due to Term

• Current Assignee: Vitatron Medical BV
• Original Assignee: Vitatron Medical BV
• Inventors: Van Someren, Eugenio Johannes W., Vonk, B. F. M.
• Primary Examiner(s): Pellegrino, Stephen C.
• Assistant Examiner(s): Tucker, Guy V.
• Application Number:
  US07/763,621
• Time in Patent Office: 904 Days
• Field of Search: 128/782, 128/779, 128/784, 128/739, 364/508, 364/413.01, 364/413.02, 364/413.05, 604/50, 73/570, 73/579
• US Class Current: 600/595
• CPC Class Codes: A61B 5/1101 Detecting tremor
• CPC Class Codes: A61B 5/4082 Diagnosing or monitoring movement diseases, e.g. Parkinson, Huntington or Tourette
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00

Abstract

A system and method are provided for accurate determination of various tremors and movements derived from Parkinson'"'"'s Disease and other causes. Movement signals are generated by an accelerometer, the movement signals being analyzed to determine whether they are in a predetermined frequency range, and when there occurs an uninterrupted series of such movement signals that are within the frequency range. By determining when these two criteria are met, tremor signals are reliably discriminated from other activity signals. The system includes circuitry for collecting and storing data concerning the timing of tremor occurrences, the timing of other activity occurrences, and amplitude data concerning tremor occurrences.

Claims

1. A system for monitoring tremors in the limb of a patient, comprising

means for detecting limb movements and for generating signals representative of said limb movements,

analyzing means for analyzing said signals to determine signal periods,

storage means for storing signal period criteria, said criteria comprising data representing a range of signal periods within about 40-170 ms and characteristic of tremors, and a number greater than zero corresponding to a minimum number of consecutive signals with periods in said range which repeat uninterruptedly without intervening periods, and

determining means for determining when said signal periods of said signals are within said range and for determining when said signals with periods within said range repeat at least said minimum number of times without interruption, whereby tremor occurrences are detected.

2. The system as described in claim 1, wherein said number is eight.

3. The system as described in claim 1, comprising means for generating and storing tremor histogram data from said signals.

4. The system as described in claim 1, comprising amplitude means for determining the amplitude of said signals and for generating and storing amplitude data representative of said amplitudes.

5. The system as described in claim 4, wherein said amplitude means comprises means for generating peak amplitude data corresponding to said signals.

6. The system as described in claim 4, comprising treatment means for indicating treatment as a function of said signal amplitude data.

7. The system as described in claim 1, comprising time means for generating and storing time signals corresponding to the time of detected tremors.

8. The system as described in claim 7, comprising treatment means for indicating treatment as a function of said time signals.

9. The system as described in claim 8, wherein said treatment indicating means comprises means for determining data representative of normal patient activity and for indicating treatment as a function of the timing of tremors and the timing of normal activity.

10. The system as described in claim 1, further comprising marker interface means for enabling the patient to input time data into said system.

11. The system as described in claim 1, further comprising sound output means for outputting an audio signal representative of a detected condition of said system.

12. The system as described in claim 1, comprising storage means for storing tremor data representative of said tremor occurrences, a pump for introducing a medicinal liquid into said patient for treatment of tremors, and means responsive to said stored data for operating said pump.

13. The system as described in claim 1, comprising a programmable filter for filtering said generated representative signals so as to pass only signal frequencies within a programmable range.

14. The system as described in claim 1, wherein said detecting means comprises an accelerometer.

15. The system as described in claim 1, comprising storage means for storing tremor data representative of said tremor occurrences, computer means for processing said tremor data, and linking means for linking said stored tremor data to said computer means.

16. The system as described in claim 1, comprising threshold determining means for determining when signals being analyzed do not exceed a predetermined minimum amplitude, indicating a rest period.

17. The system as described in claim 1, wherein said determining means comprises rest means for determining when there is an interruption of signals having signal periods within said range, thereby indicating rest or inactivity.

18. A method of detecting a tremor of an ambulatory patient, comprising

establishing frequency and duration criteria applicable to the movements of a tremor to be detected,

continuously obtaining signals representative of limb movement of said patient,

determining when said signals meet said frequency criterion, and

determining when said signals meeting requirements of said frequency criterion continue substantially without any intervening periods over a time period corresponding to said duration criterion.

19. A system for detecting a tremor of a patient, said system having means for continuously obtaining and analyzing signals representative of limb movement of said patient, characterized by

means for storing frequency and duration criteria applicable to the movements of a tremor to be detected,

first means for determining when said signals meet requirements of said frequency criterion, and

second means for determining when said signals meeting requirements of said frequency criterion continue substantially without any intervening periods over a time period corresponding to said duration criterion.

20. The system as described in claim 19, comprising accumulating means for accumulating determined duration time.