Objective evaluation of TE substitute voice and speech

Three studies are presented which aim at rater-independent methods to evaluate voice quality, speech intelligibility and the benefit of rehabilitation of the patients: (1) real time endoscopy of the vibrating PE segment, (2) quantification of speech intelligibility by means of a computerized speech recognition system and (3) rating of the laryngectomees’ quality-of-life in relation to his substitute voice. 1. Real time endoscopy of the vibrating PE segment Objectives: Evaluation of the vibration pattern of the substitute voice generator of patients who have undergone laryngectomy. For automatic quantification of the oscillations of the pharyngoesophageal (PE) segments, image processing of digital high-speed video sequences is applied. Patients and methods: Endoscopic recordings were taken of 10 men who underwent laryngectomy (mean +/SD age, 61.5 +/5.2 years) during sustained phonation of a vowel using a 90 degree endoscope coupled to a high-speed camera. An image-processing algorithm was developed to automatically define the pseudoglottis in each recording and track its movements. Results: In a first step, the high-speed recordings of the substitute voice generator have been replayed in slow motion and visually categorized. The forms and oscillation characteristics of the pseudoglottides varied considerably: 3 pseudoglottides were circular, 6 were split shaped, and 1 was triangle shaped. Quasi-periodic openings and closings were observed and automatically detected by the described algorithm in each recording independently from quality of the recording and from morphologic and oscillation characteristics of the PE segment. The frequencies of the extracted oscillations of the pseudoglottides correspond to the structure of the acoustic signals. Conclusion: Automatic image processing of PE segments derived from highspeed endoscopic recordings enables the detection and quantification of the substitute voice generator's oscillations in high temporal resolution. These data directly prove that the detected pseudoglottis is the source of the substitute voice. Close relations between substitute voice and functional properties of the PE Evidence--based Voice and Speech Rehabilitation in Head and Neck Cancer (Invitational Round Table) Amsterdam, The Netherlands May 15--16, 2008 ISCAArchive http://www.isca-speech.org/archive