Selected acoustic characteristics of emerging esophageal speech: Case study

Abstract

The development of esophageal speech was examined in a laryngectomee subject to observe the emergence of selected acoustic characteristics, and their relation to listener intelligibility ratings. Over a two-and-a-half month period, the data from five recording sessions was used for spectrographic and perceptual (listener) analysis. There was evidence to suggest a fairly reliable correlation between emerging acoustic characteristics and increasing perceptual ratings. Acoustic factors coincident with increased intelligibility ratings appeared related to two dimensions: firstly, the increasing pseudoglottic control over esophageal air release; secondly the presence of a mechanism of pharyngeal compression. Increased pseudoglottic control manifested in a reduction of tracheo-esophageal turbulence, and a more efficient burping mode of vibration with clearer formant structure. Spectrographic evidence of a fundamental frequency did not emerge. These dimensions appeared to have potential diagnostic and therapeutic value, rendering an analysis of the patient's developing vocal performance more explicit for both clinician and patient.