Patent No. 4926969 Sensory-driven controller

 

Patent No. 4926969  Sensory-driven controller (Wright, et al., May 22, 1990)

Abstract

A non-motive system for enabling a person to carry out a function includes circuitry designed to detect evoked-response potentials as a result of stimuli presented to the person. Each element of the stimulus corresponds to an external factor or function, so that the person attending to a particular element may communicate his desire that the external factor or function corresponding to that element be carried out merely through the detection of his brain wave response to the stimulus. The brain wave response is detected by electrodes, conditioned, and correlated with a precalibrated set of response template signals to derive the element attended by the subject, and thereby cause the indicated factor or function to be carried out.

Notes:  

Sensory driven controller. Filed November 1988, granted May 1990. Not on previous list/s. Another version of picking out a specific evoked potential from a group of evoked potentials in response to a plurality of stimuli and using it to control a device.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to brain-wave analysis and brain-based control, and, more specifically, to systems designed to perform various functions based upon evoked-response potentials.

2. Description of the Related Art

The present invention is designed to allow a subject to perform various controls and functions through the detection and analysis of electroencephalogram (EEG) response to stimuli. Prior art systems that attempt to enable a subject to carry out functions through non-motive means have been employed with a limited amount of success. Among those related to the operation of the present invention, the most successful have been eye-tracking systems that utilize laser beams to determine eye position of a person, to thereby enable the person to control various systems based upon the position of his eyes. Such systems, however, suffer from inaccuracies based primarily upon involuntary muscle activity, of which, for example, disabled persons are often afflicted. The basic theory and technology behind evoked-response potentials (ERPs), including their creation and detection, are well-established and widely discussed in the literature. ERPs are electrical potentials that occur in the human brain in response to an external physical event. By analyzing the ERP, or any or all of its components, data can be derived for analysis. Control techniques employing ERP technology are theoretically more accurate and predictable than the above-mentioned eye-tracking systems, and therefore promise more precise applications since the data is obtained directly from brain functions and mental processes rather than from gross muscular movements.

One system directed towards function control based upon EEG responses to stimuli is disclosed in U.S. Pat. No. 4,651,145 to Sutter, and in various publications by the same inventor but utilizes different algorithms for data presentation and analysis than does the present invention.

SUMMARY OF THE INVENTION

The present invention overcomes the problems of the prior art by providing a new system for detecting the point of attention of a person responding to a stimulus. The stimulus may be any sensory stimulus capable of producing a detectible EEG response, including visual or auditory. A sensory stimulus corresponding to a particular factor or function is provided to the subject to evoke an EEG response in the subject's brain. The EEG response is transmitted via electrodes or other known EEG-detecting devices to a system that amplifies and filters the EEG signal, and then converts it to digitized form for presentation to signal processing circuitry.

Preferably, a plurality of stimuli are provided simultaneously, each stimulus corresponding to an external factor or function. While the subject attends to a particular stimulus in order to thereby communicate a command to the signal processing circuitry and subsequent control system, the signal processor determines from the EEG responses which stimulus the subject is attending. The received EEG signals are conditioned to reduce noise and to suppress artifacts, and the subsequent signals are correlated with a precalibrated set of response template signals to determine the correlation between the EEG response and the template signals. This signal analysis algorithm enables the signal processor to determine which stimulus the subject attends, and thereby cause a control system to carry out a function corresponding to the attended stimulus.