Spectrographic differences between tracheal-esophageal and esophageal voice

In order to evaluate the results of voice and speech rehabilitation after total laryngectomy some acoustic parameters (fundamental frequency, waveform perturbation) were examined in 18 total laryngectomy patients. Eight of these subjects had previously been surgically rehabilitated with a tracheal-esophageal phonatory valve while 10 had been submitted to esophageal speech rehabilitation. Analysis of results has shown that tracheal-esophageal voices are more likely to provide a stable fundamental frequency; there is also a tendency toward more clearly defined harmonics; jitter and shimmer are more similar to the values of normal subjects compared with those observed in esophageal speech. Such results seem to depend on a more regular vibration pattern in the pharyngeal-esophageal segment, due to the more efficient expiratory flow in tracheal-esophageal speech. Moreover we were able to demonstrate a correlation between the objective parameters evaluated and the subjective score on speech acceptability.