Female-pitched sound-producing voice prostheses - initial experimental andclinical results

In order to improve voice quality in female laryngectomees and/or laryngect omees with a hypotonic pharyngo-oesophageal segment, a sound-producing voic e prosthesis was designed. The new source of voice consists of either one o r two bent silicone lips which perform an oscillatory movement driven by th e expired pulmonary air that flows along the outward-striking lips through the tracheo-oesophageal shunt valve. Four different prototypes of this pneu matic sound source were evaluated in vitro and in two female laryngectomees , testing the feasibility and characteristics of this new mechanism for alt ernative alaryngeal voice production. In vivo evaluation included acoustic analyses of both sustained vowels and read-aloud prose, videofluoroscopy, s peech rate, and registration of tracheal phonatory pressure and vocal inten sity. The mechanism proved feasible and did not result in unacceptable airf low resistance. The average pitch of voice increased and clarity improved i n female laryngectomees. Pitch regulation of this prosthetic voice is possi ble with sufficient modulation to avoid monotony. The quality of voice atta ined through the sound-producing voice prostheses depends on a patient's ab ility to let pulmonary air flow easily through the pharyngo-oesophageal seg ment without evoking the low-frequency mucosal vibrations that form the reg ular tracheo-oesophageal shunt voice. These initial experimental and clinic al results provide directions for the future development of sound-producing voice prostheses. A single relatively long lip in a container with a recta ngular lumen that hardly protrudes from the voice prosthesis may have the m ost promising characteristics.