METHOD OF SLUMBER DETECTION

Abstract: Method of slumber detection which includes the following steps. A hyper sensitive magnetometer is attached in the vicinity of and on detecting distance from an individual to be slumber detected. The signal pattern caused by feeble variations in the magnetic field of said individual is then continuously detected. The progress of said detected signal pattern is compared with a signal pattern progress characteristic of falling asleep/losing consciousness. A predetermined similarity between detected signal pattern progress and the signal pattern progress which is characteristic of falling asleep/losing consciousness is then caused to give rise to a warning signal.

Description: METHOD OF SLUMBER DETECTION The present invention relates to a method of slumber de- tection (sleep-onset), i.e. a method to be used for surveying an individual, preferably continuously, in order to establish the moment when said individual is about to fall asleep or is about to loose consciousness. The invention is particularly adapted for use within such technical areas in industry, transport or other technical areas in which individuals are engaged in surveying and/or control¬ ling functions having a monotonous character and in which the falling asleep or the loss of consciousness results in imminent danger or in a highly risky situation. Individuals who more frequently encounter such situations are e.g. car drivers, air¬ craft pilots, locomotive drivers, industrial process supervisors etc. The problem of finding a reliable method for slumber de¬ tection is old and has proven difficult to solve. Several kinds of detectors and detecting methods have been suggested, e.g. the so called "dead man's grip"; the method of attaching an accel erometer on the head of an individual (head drop); the detection of the eye movements of an individual ; the detection and analysis of the pattern of output signals produced by an individual (e.g. the movements of the steering wheel or of a control lever). For different reasons, e.g. due to the great variations with respect to the quality parameters between individuals combined with the fact that individuals still usually are more intelligent than surveying apparatuses, the reliability and precision of known slumber detecting systems are far from being satisfactory. Since it is obvious that a reliable and simple slumber detection system would involve great benefits and save lives and money, it is still highly desirable to provide a solution to the problem of slumber detection and to make available a reliable, simple and cheap slumber detection system for use in the technical areas mentioned intinially. The object of the present invention is to provide a 5 : method of slumber detection which is highly reliable and which opens up for the possibility of designing a slumber detection system which is simple, reliable and which, at least in the near future, will be well suited for mass production. TCT In accordance with the present invention this object is obtained by a method including the measures specified in the appended claims. The invention is based on the knowledge of the possi¬ bility of detecting immediately from EEG-signals (Electro 15 Encephalogram-signals) the moment when an individual falls asleep/looses consciousness. In practising this previously known method it is necessary to attach EEG-el ectrodes on the individual to be detected. However, practising this method on e.g. car drivers or industrial process super- ZQ visors etc. would be highly unpractical and would probably not be accepted by the intended users. Magnetometers having such a sensitivity and such in¬ terference suppression which renders possible the detec¬ tion of magnetic fields generated by the v ery small nerv 25 signal currents of the body, are already available today and are in clinical use. The type of detector used is called SQUID and is based on a so called "Josephson Junction", which is a "poor" electric connection point which a cryogenic temperature conditions obtains exceptional pro- 3.0 perties. Use of SQUID in contact-free measurement of magneto cardiogram (MKG) and magneto encephalogram (MEG) is practised today. Thanks to the interference suppression through i.e. a differential measuring method, it is also possible to 15 ; having such measurements carried out in common indoor en- vironment with 50/60 Hz field etc. A SQUID thus provides a possibility of directly inter¬ linking an individual and an apparatus via magnetic fields. In accordance with the present invention it is possible, 5 by applying previously known technique, viz. hyper sentitive magnetometers (type SQUID) together with established EEG technique, to the classical problem of slumber detection, e.g. by attaching such a detector in the ceiling of a car above the driver's seat, to provide a new type of slumber 10 detector which is practical to the user and which provides a direct and exact detection result. The price of a SQUID is, at least today, probably to high for mass application. There is, however, at present an intense research and 15 developement work being carried out in the field of sensor technology which also includes magnetometers. As a result of this research and development there are already avail¬ able, although only as prototypes, magnetometers which are based on a combination of fibre optics and new magneto- 2.G strictive alloys, having sensivities approaching 10 -12 to -13 10 Tesla. New magnetometers based on Faraday rotation could also be possible. This sensivity will in principle be sufficient for use in slumber detection, and the probable price for this type of magnetometers is very low. It seems 2.5 thus reasonable to believe that a slumber detector of the type described above within short might be made available for mass application. The method according to the present invention discussed above thus includes the following characteristic steps: ΪQ - attaching a hyper sensitive magnetometer in the vi¬ cinity of and on detecting distance from an individual to be slumber detected, and continuously detecting the signal pattern caused by feeble variations in the magnetic field of said individual; 35 - comparing the progress of said detected signal pattern with a signal pattern progress which is characteristic of falling asleep/loosing consciousness; and - causing a predetermined similarity between detected signal pattern progress and the signal pattern progress characterestic of falling asleep/loosing consciousness, to give rise to a warning signal. Preferably said hyper sensitive magnetometer is attached in a position for continuously detecting the signal pattern caused by feeble variations in the magnetic field of the brain of said individual. In a preferred embodiment according to the invention the magnetometers used are magnetometers based on a combina¬ tion of fibre optics and magnetostrict ve alloys having a sensitivity of 10 "12 to lO -13 Tesla.

Claims: CLAIMS 1. Method of slumber detection, c h a r a c t e r i z e d by the following measures: 5 - attaching a hyper sensitive magnetometer in the vi¬ cinity of and on detecting distance from an individual to be slumber detected, and continuously detecting the signal pattern caused by feeble variations in the magnetic field of said individual; 1Q - comparing the progress of said detected signal pattern with a signal pattern progress which is characteristic of falling asleep/loosing consciousness; and - causing a predetermined similarity between detected signal pattern progress and the signal pattern progress 15 characteristic of falling asleep/loosing consciousness, to give rise to a warning signal . 2. Method as claimed in claim 1 , c h a r a c t e r i z e d in that said hyper sensitive magnetometer is positioned so as to continously detecting the signal pattern caused by feeble 2.0. variations in the magnetic field of the brain of said indi¬ vidual . 3. Method as claimed in any of claims 1 or 2, c h a r a c ¬ t e r i z e d in that the detection of said signal pattern is carried out by means of magnetometers based on a combination 2.5 of fibre optics and magnetostrictive alloys having a sensivity of 10 '12 to 10 "13 Tesla. 4. Method as claimed in any of claims. 1 or 2, c h a r a c ¬ t e r i z e d in that the detection of said signal pattern is carried out by means of magnetometers based on Faraday rota- 3Q tion. 5. Method as claimed in any of claims 1 or 2, c h a r a c ¬ t e r i z e d in that the detection of said signal pattern is carried out by means of magnetometers based on the Josephson Junction (SQUID). 35

Inventors: TYREN CARL H, TYREN, CARL, H.
Applicants: TYREN CARL, TYREN, CARL, H.
Application year: 1986
Main classification: G08B21
IPC codes: A61B5, B60K28, G08B21