Time series analysis of glottal airflow in normal and pathological phonation.

Time series analysis of glottal airflow was carried out on 26 normal controls and 40 patients with voice disorders, using a modification of Isshiki's original technique which uses a hot-wire flowmeter, taking cycle-by-cycle fluctuations into consideration. The mean flow rate and mean AC/DC were shown to have significant differences among normal and patient groups. The standard deviations of AC/DC and AC/DC perturbation were calculated from the AC/DC value of 50 cycles and shown not to vary significantly among the normal and patient groups. The relationship between AC/DC and perceptual impression of voice was also studied among 20 selected patients with breathy voices. Using Spearman's rank correlation coefficient, this relationship was found to have statistical significance (P < .05).