Movement artifact detector for sleep analysis

• US 4,550,736 A
• Filed: 10/10/1984
• Issued: 11/05/1985
• Est. Priority Date: 10/14/1983
• Status: Expired due to Fees

• Current Assignee: University of Ottawa
• Original Assignee: Canadian Patents and Development Limited
• Inventors: da Costa, Bernardo, Broughton, Roger
• Primary Examiner(s): Howell, Kyle L.
• Assistant Examiner(s): Jaworski, Francis J.
• Application Number:
  US06/659,295
• Time in Patent Office: 391 Days
• Field of Search: 128/731
• US Class Current: 600/544
• CPC Class Codes: A61B 5/369 Electroencephalography [EEG] devices for psychotechnics A61B5/16

Abstract

The movement detector monitors the electroencephalogram (EEG) signal in order to detect components having a real-time frequency greater than 30 Hz and an amplitude greater than 18 μV; a real-time frequency greater than 30 Hz and an amplitude between ±9 μV; or a real-time frequency less than 1.2 Hz and an amplitude greater than 200 μV. An output signal is provided when at least one of these components is detected.

Claims

1. A movement detector for a sleep analyser comprising:

means for receiving an electroencephalogram (EEG) signal;

first monitoring means for detecting only components in the EEG signal having a real-time frequency greater than approximately 30 Hz and greater than a first predetermined amplitude;

a second monitoring means for detecting only components in the EEG signal having a real-time frequency greater than approximately 30 Hz and a second predetermined amplitude smaller than the first predetermined amplitude;

third monitoring means for detecting only components in the EEG signal having a real-time frequency less than approximately 1.2 Hz and a third predetermined amplitude at least an order in magnitude greater than the first predetermined amplitude; and

means connected to the first, second and third monitoring means for providing an output only if at least one of the predetermined components are detected.

2. A movement detector as claimed in claim 1 wherein the first predetermined amplitude is approximately 18 μ

V, the second predetermined amplitude is between approximately ±

9 μ

V, and the third predetermined amplitude is approximately 200 μ

V.

3. A movement detector as claimed in claim 2 wherein the first monitoring means includes a high-pass filter, a first threshold discriminator connected to the high-pass filter, a first low-pass filter connected to the first discriminator and a second threshold discriminator connected to the first low-pass filter to provide an output when predetermined components are present in the EEG signal.

4. A movement detector as claimed in claim 3 wherein the second monitoring means includes a positive threshold discriminator and a negative threshold discriminator connected in parallel to the high-pass filter, a second low-pass filter for receiving the combined outputs of the negative and positive threshold discriminators and a threshold detector connected to the second low pass filter to provide an output when predetermined components are present in the EEG signal.

5. A movement detector as claimed in claim 4 wherein the output means includes an OR-gate.