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WO1993008739A1 - Controleur de vigilance - Google Patents

Controleur de vigilance Download PDF

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Publication number
WO1993008739A1
WO1993008739A1 PCT/US1992/009231 US9209231W WO9308739A1 WO 1993008739 A1 WO1993008739 A1 WO 1993008739A1 US 9209231 W US9209231 W US 9209231W WO 9308739 A1 WO9308739 A1 WO 9308739A1
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WO
WIPO (PCT)
Prior art keywords
human subject
stimuli
series
stimulus
response
Prior art date
Application number
PCT/US1992/009231
Other languages
English (en)
Inventor
Charles A. Czeisler
William A. Ii Kennedy
Original Assignee
Brigham And Women's Hospital
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Brigham And Women's Hospital filed Critical Brigham And Women's Hospital
Publication of WO1993008739A1 publication Critical patent/WO1993008739A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/16—Devices for psychotechnics; Testing reaction times ; Devices for evaluating the psychological state
    • A61B5/162—Testing reaction times

Definitions

  • the present invention relates generally to a method and monitor for determining the alertness of a human subject and more particularly to a method and device for measuring and analyzing response latency to determine the alertness of a subject.
  • Dead-man's switches such as the one shown in the Slansky patent have been used extensively on a worldwide basis. However, it has been found that train operators, for example, can maintain trains equipped with a dead-man's switch at full throttle even though they are no longer sufficiently alert to external signals such as red stop lights. There is also evidence that an individual can maintain a dead-man's switch in a depressed position even when they are technically asleep.
  • Alerter devices typically require continuous performance of secondary tasks while performing primary tasks such as operating machinery.
  • Some alerter devices such as the one shown in U.S. Patent No. 4,679,648 to Johansen, require an operator to actively respond to a stimulus, such as an auditory or visual stimulus, by pressing a button. Failure to respond to the stimulus results in the signalling of an alarm. An affirmative response to the stimulus is assumed to indicate that the operator is fully alert Alerter devices have the advantage of demanding that an operator maintain a continual and anticipatory vigilant state in order to perform effectively.
  • Stage 1 sleep is a condition of waning consciousness, characterized by one's ability to partially respond to external stimuli. More specifically, Stage 1 sleep is defined by a relatively low voltage, mixed frequency EEG with a prominence of activity in the 2-7 cps range. Stage I sleep tends to be of short duration, ranging from about 1 to 7 minutes. Stage I sleep, especially following wakefulness, is characterized by the presence of slow eye movements.
  • Stage 2 sleep is a condition of altered consciousness with a greatly impaired to completely absent ability to respond to external stimuli. More specifically, Stage 2 sleep is defined by an EEG containing sleep spindles of frequency 12-14 cps and 0.5 seconds in duration and/or K-complexes also 0.5 seconds in duration.
  • Stage 2 is also characterized by a diminished muscle tone as measured by EMG. Therefore, alerter devices that rely exclusively on the lack of a subject's response to a stimulus cannot assure that an operator is alert or awake. It has also been found that operators tend to develop a spontaneous and rhythmic way of operating and monitoring alerter devices which permit correct operation even though the operator is at a low level of vigilance. In addition, experiments performed over fifty years ago (Loomis, Harvey and Hobart, "Electrical Potentials of the Human Brain,” Journal of Experimental Psychology, p. 249-279 (1936)) clearly demonstrated that there is no precise moment of sleep onset. Rather, it has been found that there is a gradual decline in alertness. Conventional alerter devices do not take this into account and thus also suffer the disadvantage of failing to differentiate different levels of alertness of the human subject.
  • the present invention is directed to a method of monitoring alertness in human subjects, comprising the steps of: calibrating a wake-time response latency of the human subject to a stimulus, generating a series of stimuli, providing the generated series of stimuli to a human subject, detecting the response of the human subject to each stimulus in the series of stimuli, measuring the time interval between the occurrence of each stimulus of the generated series and the detected response of the human subject and comparing the measured time interval to the calibrated wake-time response latency to determine a level of alertness of the human subject.
  • the method of the present invention may also comprise the step of determining the auditoiy threshold of the human subject in a working environment so that the stimulus provided to the human subject is an auditory stimulus slightly greater than the determined auditory threshold of the human subject in the working environment.
  • the method of the present invention may also comprise the step of determining the variance of response latencies during the wake-time calibration to determine whether the human subject is deliberately slowly responding to each of the stimuli.
  • the present invention may also be directed to an apparatus for monitoring alertness in a human subject comprising means for generating a series of stimuli, means for providing the generated series of stimuli to the human subject, means for detecting the response of the human subject to each stimulus of the generated series of stimuli and means for measuring the time interval between the occurrence of each stimulus of the generated series of stimuli and the detected responses of the human subject and for comparing the measured time interval to a calibrated wake-time response latency to determine the level of alertness of the human subject.
  • the present invention has a number of features and advantages not previously achieved with known methods and devices for monitoring alertness.
  • One feature and advantage is that the method and device of the present invention differentiates between different levels of alertness of the human subject.
  • the present invention may incorporate the additional feature and advantage of providing an auditory stimulus just above the measured wake-time auditory threshold of the human subject to assist in monitoring the alertness of the subject.
  • an additional feature and advantage of the present is found in the option of generating a random series of stimuli which prevents the development of a spontaneous and rhythmic response by the operator to a stimulus.
  • Yet another feature and advantage of the present invention is found in the individual calibration of the alertness monitor to the particular human subject.
  • Figure 1 is a flowchart depicting the steps of calibrating a wake-time response latency according to the present invention
  • Figure 2 is a flowchart depicting the method of monitoring alertness of the present invention.
  • the present invention comprises a method and apparatus for monitoring alertness of a human subject.
  • both the apparatus and its intended method of use are particularly useful in monitoring alertness of a human subject who is operating a piece of equipment or is performing some task by measuring and analyzing response latency to detect the alertness of the subject.
  • the alertness monitor is preferably self-contained and ambulatory and, for example, could be used by automobile drivers.
  • the output could also be attached to a recorder, such as a cockpit data logger on an airplane.
  • the method of monitoring alertness generally comprises four basic steps: calibrating a wake-time response latency, generating a series of stimuli, measuring a response time interval of a human subject to the series of stimuli and comparing the measured time interval to the calibrated wake-time response latency to detect a level of alertness of the human subject.
  • the wake-time response latency is preferably determined when the subject is fully alert A subject is considered to be fully alert when he/she is well- rested and is not under the influence of any drug.
  • the stimuli may be either auditory or visual. In generating auditory stimuli, the findings of Mullin and Kleitman ("Variations and
  • the series of stimuli in this step of the present invention are preferably auditory stimuli at the auditory threshold of the human subject as measured in the working environment. More specifically, the series of stimuli are preferably auditory stimuli which are within the range of
  • the auditory threshold of the subject is determined by a ⁇ diometric testing using any known technique.
  • One example is to use a Beltone Model 10D audiometer.
  • the working environment is defined as the environment in
  • the series of stimuli are generated in a random manner although a systematic series of stimuli having a predetermined time interval between individual stimuli may also be used.
  • the means for providing a series of auditory stimuli to the human subject is preferably
  • a loudspeaker or other auditory device a loudspeaker or other auditory device.
  • devices capable of providing visual stimuli such as a light bulb or other light source, may also be used alone or in combination with an auditory stimulus.
  • a soft tone followed by a visual flash may be used to alert the operator that the test is coming in the event that the operator is not
  • the tone provides warning of the impending arrival of the flash stimulus or test.
  • the human subject In response to the series of stimuli, the human subject is required to respond in an affirmative manner.
  • a microswitch is used to ⁇ elicit a response from the operator to each of the series of stimuli.
  • any type of switch or other device which can detect a response from a human subject may also be used.
  • a microswitch is defined as any switch that can be disposed adjacent the human subject so that there is a minimal time delay between the subject's perception of the stimulus and the affirmative response by the subject.
  • the switch could be integral with the equipment the operator is using such as a control panel or steering wheel.
  • the time interval between each stimulus of the generated series of stimuli and the affirmative response of the human subject to each stimulus is used to determine a response time interval.
  • the interval may be measured by a microcomputer or other time- measuring device such as a stop watch.
  • 12 response time intervals are measured to calibrate the average wake-time response latency although a greater or smaller number of responses could be measured.
  • a suitable range of intervals may be between 4 and 16.
  • a microcomputer can be used to perform multiple self- calibrations, accepting the wake-time calibration only if all of the responses are clustered in a narrow band. This is done because it is believed that individuals cannot deliberately be consistently slow (or fast) in responding to stimuli. If a subject fails this self-calibration, the calibration process is repeated.
  • the wake-time calibration can be stored in a computer memory device and used as a reference point to determine the level of alertness of the subject.
  • the second step involves generating a series of stimuli and exposing the generated series to the human subject in the working environment (i.e., when the subject is operating a piece of equipment or performing a task).
  • the series of stimuli are presented in a random rather than a systematic manner (a fixed time interval between stimuli).
  • the stimuli may be auditory, visual, or a combination of both as described above.
  • the third step of the method of the present invention requires an affirmative response from the human subject who is being monitored. Similar to step 1, a switch may be used to detect the response of the human subject to the generated series of stimuli. As described above, a non-intrusive microswitch provided adjacent a finger of the human subject is preferred. The time between the onset of the stimulus and the subject's affirmative response is defined as the response time interval of the human subject.
  • the fourth step of the present invention is to compare the measured response time interval of step three to the calibrated wake-time response latency of step one to determine a level of alertness of the human subject. Preferably, this comparison is performed by a computer. If the measured response time interval of step three exceeds the prior wake-time calibration of step one by a predetermined duration a loss of alertness is detected.
  • the computer may also be used to disable an apparatus under the control of the operator, to awaken the operator or to summon supervisory personnel if the human subject being monitored is determined to be incapable of implementing the task.
  • step four is a delay time during which no stimuli are generated, after which step one is repeated.
  • Table 1 shows experimental data collected by applicants. The data was accumulated by measuring the response latencies of six healthy human male subjects to sensory stimuli during various stages of alertness.
  • Each subject had a small microswitch taped to the index finger of his dominant hand such that it could be comfortably pressed by the thumb. The subject was instructed to press the switch when the subject detected the stimulus.
  • auditory stimuli were used, the auditory stimuli were delivered at the auditory threshold of the particular human subject determined in the working environment while the subject was fully awake.
  • Wakefulness and stages of sleep were determined by applying electrodes to the subject to measure the electroencephalogram, electromyogram and electroretinogram of the subject.
  • a total 675 visual stimuli were delivered to the subjects, of which 656 elicited responses.
  • Stage 1 sleep 684 visual stimuli were delivered of which 202 elicited responses.
  • Stage 2 sleep 1,388 visual stimuli were dehvered of which 11 elicited responses.
  • a total of 576 auditory stimuli were dehvered to all six subjects during wakefulness of which 526 elicited responses.
  • Stage 1 sleep 773 auditory stimuli were delivered or which 345 elicited responses.
  • 1261 auditory stimuli were delivered of which 26 elicited responses.
  • a comparison of the response latency of subject #2 to auditory stimulus during Stage 2 sleep is less than the response latency of subjects #4, #5 and #6 to a visual stimulus during wakefulness.
  • subject #2 completely failed to respond to visual stimuli during Stage 2 sleep.
  • subject #2 were operating a motor vehicle during Stage 2 sleep, he might respond to a honking horn, but not to a stop sign or red light.

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Hospice & Palliative Care (AREA)
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  • Developmental Disabilities (AREA)
  • Psychiatry (AREA)
  • Psychology (AREA)
  • Social Psychology (AREA)
  • Physics & Mathematics (AREA)
  • Child & Adolescent Psychology (AREA)
  • Biophysics (AREA)
  • Educational Technology (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Medical Informatics (AREA)
  • Molecular Biology (AREA)
  • Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
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  • Veterinary Medicine (AREA)
  • Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)

Abstract

La présente invention permet de contrôler la vigilance d'un sujet humain grâce à la mesure et à l'analyse de la latence du sujet en présence d'un stimulus. Le contrôleur de vigilance peut être constitué d'un micro-interrupteur qui doit être manipulé par le sujet lors d'un stimulus présenté selon des intervalles aléatoire. Le stimulus peut être soit visuel soit auditif. Le temps nécessaire au sujet pour appuyer sur le micro-interrupteur lors du stimulus détermine la latence dudit sujet. On analyse ensuite la latence du sujet de façon à déterminer si le sujet est suffisamment alerte pour continuer son activité. Les latences dépassant un temps d'éveil d'étalon prédéterminé indiquent une perte de vigilance.
PCT/US1992/009231 1991-10-29 1992-10-29 Controleur de vigilance WO1993008739A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US78367791A 1991-10-29 1991-10-29
US07/783,677 1991-10-29

Publications (1)

Publication Number Publication Date
WO1993008739A1 true WO1993008739A1 (fr) 1993-05-13

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Application Number Title Priority Date Filing Date
PCT/US1992/009231 WO1993008739A1 (fr) 1991-10-29 1992-10-29 Controleur de vigilance

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AU (1) AU2921392A (fr)
WO (1) WO1993008739A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996016830A1 (fr) * 1994-11-28 1996-06-06 The Driver Alert Technology Company Limited Moniteur de surveillance de la vigilance d'un conducteur
EP1226780A3 (fr) * 2001-01-25 2002-10-23 Siemens Aktiengesellschaft Procédé, système et dispositif portable de détermination des capacités de psychomotricité
US6743022B1 (en) * 1998-12-03 2004-06-01 Oded Sarel System and method for automated self measurement of alertness equilibrium and coordination and for ventification of the identify of the person performing tasks
US7170994B2 (en) 2003-10-15 2007-01-30 Motorola, Inc. Method and apparatus for selecting an alert mode based on user biometrics
EP3012701A1 (fr) * 2014-10-21 2016-04-27 Honeywell International Inc. Appareil et procédé permettant de gérer la vigilance d'un opérateur et d'améliorer l'efficacité d'un opérateur pour des systèmes de commande industriels
WO2019122533A1 (fr) * 2017-12-22 2019-06-27 Ocuspecto Oy Procédé et système d'évaluation de la fiabilité de résultats dans un test de réaction visuelle

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3761921A (en) * 1968-08-29 1973-09-25 Biviator Sa Vigilance testing and warning apparatus
US3922665A (en) * 1974-10-04 1975-11-25 Whittaker Corp Apparatus and method for maintaining operator alertness
US4201225A (en) * 1977-09-02 1980-05-06 Bethea James W Iii Method and apparatus for measuring stimulated acoustic reflex latency time

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3761921A (en) * 1968-08-29 1973-09-25 Biviator Sa Vigilance testing and warning apparatus
US3922665A (en) * 1974-10-04 1975-11-25 Whittaker Corp Apparatus and method for maintaining operator alertness
US4201225A (en) * 1977-09-02 1980-05-06 Bethea James W Iii Method and apparatus for measuring stimulated acoustic reflex latency time

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996016830A1 (fr) * 1994-11-28 1996-06-06 The Driver Alert Technology Company Limited Moniteur de surveillance de la vigilance d'un conducteur
US6743022B1 (en) * 1998-12-03 2004-06-01 Oded Sarel System and method for automated self measurement of alertness equilibrium and coordination and for ventification of the identify of the person performing tasks
EP1226780A3 (fr) * 2001-01-25 2002-10-23 Siemens Aktiengesellschaft Procédé, système et dispositif portable de détermination des capacités de psychomotricité
US7170994B2 (en) 2003-10-15 2007-01-30 Motorola, Inc. Method and apparatus for selecting an alert mode based on user biometrics
EP3012701A1 (fr) * 2014-10-21 2016-04-27 Honeywell International Inc. Appareil et procédé permettant de gérer la vigilance d'un opérateur et d'améliorer l'efficacité d'un opérateur pour des systèmes de commande industriels
US9396639B2 (en) 2014-10-21 2016-07-19 Honeywell International Inc. Apparatus and method for managing operator alertness and enhancing operator effectiveness for industrial control systems
WO2019122533A1 (fr) * 2017-12-22 2019-06-27 Ocuspecto Oy Procédé et système d'évaluation de la fiabilité de résultats dans un test de réaction visuelle
CN111565640A (zh) * 2017-12-22 2020-08-21 奥斯派克特公司 用于评估视觉反应测试中的结果的可靠性的方法和系统
US10898072B2 (en) 2017-12-22 2021-01-26 Ocuspecto Oy Method and system for evaluating reliability of results in a visual reaction test

Also Published As

Publication number Publication date
AU2921392A (en) 1993-06-07

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