Microcomputer system for analysis of the verbal behavior of patients with neurological and laryngeal diseases

Abstract

The microcomputer system for verbal behavior analysis is built on the basis of the IBM-PC. It consists of two parts: hardware and software. The hardware is the condenser microphone and a two-channel ADC board, including: amplifiers with adjustable gain; two Bessel analog filters with cutoff frequencies of 800 Hz and 6 kHz; and two ADCs allowing sampling rate up to 40 kHz. The software is a program package which allows high precision pitch detection by means of the autocorrelaton function; finding the separate pitch periods by means of amplitude selection and parabolic interpolation; pitch period perturbation; number of subharmonic-to-fundamental frequency power; separation of segments where the signal is strictly periodic; realization of spectral analysis over these segments by means of fast Fourier and fast Walsh transforms; and evaluation of the degree of hoarseness from the spectra. Preliminary experimental research shows that the system may be very useful for analysis of the speech of patients with neurological and laryngeal diseases as well as the analysis for musical sounds. Results from analysis of pathologic voices agree with those of Kasuya et al. [“Preliminary Experiments on Voice Screening,” in Proceedings of the Symposium on Voice Acoustics and Dysphonia, Gotland, Sweden (August 1985)] and Laver et al. [“An Acoustic Screening System for the Detection of Laryngeal Pathology,” J. Phon. 14, 517–524 (1986)].