Method of and apparatus for evaluation and mitigation of microsleep events

• US 6,511,424 B1
• Filed: 03/03/2000
• Issued: 01/28/2003
• Est. Priority Date: 01/11/1997
• Status: Expired due to Term

• Current Assignee: Circadian Technolgies, Inc.
• Original Assignee: Circadian Technolgies, Inc.
• Inventors: Trutschel, Udo E., Heitmann, Anneke M., Moore-Ede, Martin C., Guttkuhn, Rainer
• Primary Examiner(s): Nasser, Robert L.
• Application Number:
  US09/519,050
• Time in Patent Office: 1,061 Days
• Field of Search: 600/544, 600/300, 340/575
• US Class Current: 600/300
• CPC Class Codes: A61B 3/113 for determining or recording eye movement
• CPC Class Codes: A61B 5/1103 Detecting eye twinkling
• CPC Class Codes: A61B 5/369 Electroencephalography [EEG] devices for psychotechnics A61B5/16
• CPC Class Codes: A61B 5/384 Recording apparatus or displays specially adapted therefor
• CPC Class Codes: A61B 5/398 Electrooculography [EOG], e.g. detecting nystagmus; Electroretinography [ERG]
• CPC Class Codes: A61B 5/6821 Eye
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61B 5/7267 involving training the classification device
• CPC Class Codes: G16H 50/70 for mining of medical data, e.g. analysing previous cases of other patients

Abstract

A method and apparatus for determining, monitoring and predicting levels of alertness by detecting microsleep episodes includes a plurality of channel processing units and a channel combining unit. Each of the channel processing units receives an information channel which conveys information associated with the mental state of the subject, such as an EEG channel, and classifies the information into a distinct category. Such categories may include microsleep, non-microsleep, one or more of a plurality of stages of sleep, one or more of a plurality of stages of wakefulness, or a transition state characterized by a transition from one of the aforementioned states to another. Each of the channel processing units includes a neural network which has been trained with a set of example input/result vector pairs. The example input/result vector pairs are generated by correlating actual information channel outputs with observed fatigue related events such as nodding off, head snapping, multiple blinks, blank stares, wide eyes, yawning, prolonged eyelid closures, and slow rolling eye movements.

Claims

1. A method of reducing microsleep events experienced by a subject while performing a primary task, comprising the steps of:

A. detecting at least one occurrence of said microsleep events associated with said subject via a detector based upon a neuro-fuzzy hybrid system; and

,

B. applying at least one fatigue countermeasure to said subject in response to said microsleep event occurrences;

wherein the step of applying at least one fatigue countermeasure further includes the step of evaluating a frequency and a time of said microsleep occurrences and selecting said countermeasure as a function of said frequency and time.

2. A method according to claim 1, further including the step of regulating an amount of said countermeasure applied to said subject as a function of said frequency and time.

3. A method according to claim 1, further including the step of applying a sequence of two or more said countermeasures, wherein said sequence is selected as a function of said frequency and time.

4. A method of reducing microsleep events experienced by a subject while performing a primary task, comprising the steps of:

A. detecting at least one occurrence of said microsleep events associated with said subject via a detector based upon a neuro-fuzzy hybrid system; and

,

B. applying at least one fatigue countermeasure to said subject in response to said microsleep event occurrences;

further including the steps of determining at least one characteristic of said microsleep related to said subject, and tailoring said at least one fatigue countermeasure according to said characteristic so as to maximize said efficacy of said countermeasure,

wherein said step of tailoring further includes the steps of determining a time of day that said subject is performing the task, and tailoring said countermeasure according said time of day.

5. A method of reducing microsleep events experienced by a subject while performing a primary task, comprising the steps of:

A. detecting at least one occurrence of said microsleep events associated with said subject via a detector based upon a neuro-fuzzy hybrid system; and

,

B. applying at least one fatigue countermeasure to said subject in response to said microsleep event occurrences;

further including the steps of applying a combination of two or more said countermeasures, and selecting said combination so as to maximize said efficacy of said countermeasure,

wherein said step of selecting said combination further includes the step of determining a time of day that said subject is performing the task, and tailoring said combination according said time of day.

6. A method of reducing microsleep events experienced by a subject while performing a primary task, comprising the steps of:

A. detecting at least one occurrence of said microsleep events associated with said subject via a detector based upon a neuro-fuzzy hybrid system; and

,

B. applying at least one fatigue countermeasure to said subject in response to said microsleep event occurrences;

further including the steps of determining at least one characteristic of said microsleep related to said subject, and identifying one or more countermeasures that are not effective, relative to said subject, for reducing occurrence of microsleep events.

7. A method of reducing microsleep events experienced by a subject while performing a primary task, comprising the steps of:

A. detecting at least one occurrence of said microsleep events associated with said subject via a detector based upon a neuro-fuzzy hybrid system; and

,

B. applying at least one fatigue countermeasure to said subject in response to said microsleep event occurrences;

further including the steps of determining a time of day that said subject is performing the task, and identifying one or more countermeasures that are not effective, relative to said time of day.

8. A method of reducing microsleep events experienced by a subject while performing a primary task, comprising the steps of:

A. detecting at least one fatigue-related parameter associated with said subject, indicative of occurrence of said microsleep events, via a detector based upon a neuro-fuzzy hybrid system; and

,

B. applying at least one fatigue countermeasure to said subject in response to said fatigue related parameter;

wherein the step of applying at least one fatigue countermeasure further includes the step of evaluating a frequency and a time of said microsleep occurrences and selecting said countermeasure as a function of said frequency and time.

9. A method according to claim 8, further including the step of regulating an amount of said countermeasure applied to said subject as a function of said frequency and time.

10. A method according to claim 8, further including the step of applying a sequence of two or more said countermeasures, wherein said sequence is selected as a function of said frequency and time.

11. A method of reducing microsleep events experienced by a subject while performing a primary task, comprising the steps of:

A. detecting at least one fatigue-related parameter associated with said subject, indicative of occurrence of said microsleep events, via a detector based upon a neuro-fuzzy hybrid system; and

,

B. applying at least one fatigue countermeasure to said subject in response to said fatigue related parameter;

further including the steps of determining at least one characteristic of said microsleep related to said subject, and tailoring said at least one fatigue countermeasure according to said characteristic so as to maximize said efficacy of said countermeasure,

wherein said step of tailoring further includes the steps of determining a time of day that said subject is performing the task, and tailoring said countermeasure according said time of day.

12. A method of reducing microsleep events experienced by a subject while performing a primary task, comprising the steps of:

A. detecting at least one fatigue-related parameter associated with said subject, indicative of occurrence of said microsleep events, via a detector based upon a neuro-fuzzy hybrid system; and

,

B. applying at least one fatigue countermeasure to said subject in response to said fatigue related parameter;

further including the steps of applying a combination of two or more said countermeasures, and selecting said combination so as to maximize said efficacy of said countermeasure,

wherein said step of selecting said combination further includes the step of determining a time of day that said subject is performing the task, and tailoring said combination according said time of day.

13. A method of reducing microsleep events experienced by a subject while performing a primary task, comprising the steps of:

A. detecting at least one fatigue-related parameter associated with said subject, indicative of occurrence of said microsleep events, via a detector based upon a neuro-fuzzy hybrid system; and

,

B. applying at least one fatigue countermeasure to said subject in response to said fatigue related parameter;

further including the steps of determining at least one characteristic of said at least one fatigue related parameter related to said subject, and identifying one or more countermeasures that are not effective, relative to said subject, for reducing occurrence of said fatigue related parameters.

14. A method of reducing microsleep events experienced by a subject while performing a primary task, comprising the steps of:

A. detecting at least one fatigue-related parameter associated with said subject, indicative of occurrence of said microsleep events, via a detector based upon a neuro-fuzzy hybrid system; and

,

B. applying at least one fatigue countermeasure to said subject in response to said fatigue related parameter;

further including the steps of determining a time of day that said subject is performing the task, and identifying one or more countermeasures that are not effective, relative to said time of day.