Method and apparatus for detecting a tremor induced in a subject
A method and apparatus are provided for detecting tremors induced in a subject that are indicative of stress, emotion, fatigue, deception or other similar psychological states. The apparatus includes a signal source for directly applying an excitation signal having a predefined amplitude and frequency to the subject so as to induce the tremor. The apparatus also includes a Doppler system for irradiating the subject with electromagnetic radiation and for detecting the electromagnetic radiation returning from the subject following modulation by the induced tremor. The Doppler system also analyzes the returning electromagnetic radiation to determine at least one of an amplitude of the induced tremor and a phase shift of the induced tremor relative to the excitation signal provided by the signal source. The amplitude and/or phase shift of the modulated electromagnetic radiation provide information regarding the stress, emotion, fatigue, deception or other similar psychological states of the subject.
1. A method of detecting a tremor induced in a subject comprising:
applying electrical stimulus of a predefined frequency to the subject to thereby induce the tremor, wherein applying the electrical stimulus comprises selecting the predefined frequency based upon a frequency of tremors that otherwise occur naturally within a muscle group of the subject in response to stress or another psychological state and sweeping the predefined frequency of the electrical stimulus through a range of said predefined frequencies;
repeatedly irradiating the subject with electromagnetic radiation while the predefined frequency of the electrical stimulus that is applied to the subject is swept through the range of said predefined frequencies;
detecting the electromagnetic radiation returning from the subject following modulation by the induced tremor; and
analyzing the returning electromagnetic radiation to thereby monitor the induced tremor.
2. A method according to claim 1 wherein analyzing the returning electromagnetic radiation comprises determining a phase shift of the induced tremor relative to the electrical stimulus applied to the subject.
3. A method according to claim 1 wherein detecting the returning electromagnetic radiation comprises detecting an amplitude of the returning electromagnetic radiation.
4. A method according to claim 1 wherein applying the electrical stimulus comprises applying an electrical stimulus having a predefined amplitude and frequency.
5. A method according to claim 4 wherein applying the electrical stimulus further comprises applying an electrical stimulus having a frequency of no more than 100 Hz.
6. A method according to claim 1 wherein analyzing the returning electromagnetic radiation comprises comparing the returning electromagnetic radiation to a preestablished baseline.
7. A method according to claim 1 further comprising determining a galvanic skin response of the subject.