Patent Document ID: 7565285
Application ID: 11600312
Patent Flag: 1

Claim One:
1. A method for using jitter variations in fundamental frequency of the voice of a person being evaluated for near-term suicidal risk, in determining such person to be at near-term risk for suicide based on measured difference between fundamental frequencies of two consecutive speech segments for such person as compared to speech fundamental frequency variations for persons known not to be at near-term suicidal risk comprising the steps of: A. setting an analysis window to a selected sample set length in excess of 3 where the particular sample is identified as the Kth sample; B. computing the wavelet transform for the sample set at scale 2 to the 4th power, with a scale factor defined by the quotient of the wavelet center frequency at level 0 and the desired center frequency; C. selecting two consecutive segments of the vocal signal of such person which are voiced segments and generating separate pulse trains in which the heights of the pulses correspond to amplitude of positive and negative peaks of the wavelet transformed speech signal; D. thresholding the segments of the vocal signal to discard peaks corresponding to possible unvoiced samples; E. computing a fundamental period over the entirety of each of the two segments by: i. finding the location of the first peak of the autocorrelation of the smoothed spectrum to the right of the zero lag component; ii. detecting a starting pulse exhibiting the property of being larger than both the pulse immediately preceding and immediately following such pulse and being greater than 50% of the global maximum of the pulse sequence; iii. locating following prominent pulses as detected in the neighborhood of expected locations determined by the peak of the autocorrelation sequence; iv. selecting, between two sequences of positive and negative peaks, the peak having the largest magnitude; and v. taking the difference between two consecutive prominent pulses as the duration for the glottal cycle; and F. determining period-to-period fluctuation of fundamental frequency by measuring the difference between fundamental frequencies of two consecutive segments; and G. comparing the measured difference between fundamental frequencies of two consecutive segments for such person to variations in fundamental frequency for persons known not to be at near-term suicidal risk and providing a signal to a clinician in the event such comparison finds the person to be at near-term risk for suicide.