Speech analysis apparatus for detection and measurement of low frequency amplitude and frequency modulations, tremor, of the fundamental frequency. A microphone signal of sustained phonation is input to the apparatus which demodulates and measures five parameters digitally displayed; fundamental frequency, amplitude demodulated frequency, amplitude demodulated level, frequency demodulated frequency, and frequency demodulated level. Demodulated outputs are provided for external analysis. A variable cutoff low pass filter maintains cutoff at 1.5 times the fundamental input frequency.

A speech analyzer is provided for determining the emotional state of a person by analyzing pitch or frequency perturbations in the speech pattern. The analyzer determines null points or "flat" spots in a FM demodulated speech signal and it produces an output indicative of the nulls. The output can be analyzed by the operator of the device to determine the emotional state of the person whose speech pattern is being monitored.

A method for electronically detecting human suicidal predisposition by analysis of an elicited series of vocal utterances from an emotionally disturbed or distraught person independently of linguistic content of the elicited vocal utterance includes converting the utterance into an electrical signal having time varying amplitude and frequency which are representative of the utterance, filtering frequency components of the signal above and below pre-selected frequencies to obtain a signal within the pre-selected frequencies, filtering non-repetitive components having amplitude above about 90 percent of average amplitude of the signal out of the signal, filtering repetitive signal components having frequency outside about 90 percent of frequency band width of the signal out of the signal and identifying as suicidally predisposed a person from whom the vocal utterance emanated if signal amplitude exhibits substantially non-instantaneous decays upon conclusion of each utterance or if amplitude of signal amplitude modulation is low or if frequency of signal amplitude modulation is low, relative to the decays of utterance signals or amplitude of signal amplitude modulation or frequency of signal amplitude modulation of depressed persons known otherwise to be in good mental health.

The present invention concerns an electronic device for processing a sound signal, said device being of the type comprising: means for receiving said sound signal and for transforming it into an electric signal, means for processing said electric signal, and means for restoring a modified sound signal from said processed electric signal. According to the invention, the device includes means (8) for selecting at least one band of frequencies of said signal, said means being disposed between said means (1) receiving the sound signal and said processing means (10) of the corresponding electric signal. In particular, the invention is applicable to hearing aids.

A method for detecting suicidal predisposition in a person by securing an utterance from the person, identifying the person as being suicidally predisposed if the utterance decays substantially non-instantaneously upon conclusion and identifying the person as being suicidally predisposed if signal amplitude modulation during the utterance is low. Low value of amplitude modulaation (of speech envelope waveform), as well as slow decay at the end of each utterance, are indicators of emotional disturbance, special filtering of repetitives and non-repetitive components enhanced the waveform for consideration.