POST – LARYNGECTOMY SPEECH
Introduction:
The normal larynx produces an undifferentiated sound, which is moulded into intelligible speech by movements and positions of soft palate, tips, teeth and mandible. After total laryngectomy the patient is not able to speak using own vocal cords. Post laryngectomy speech is to enable the patient to speak after total laryngectomy.
Post laryngectomy patients can undergo 3 types of speech rehabilitation:
1) Using external voice prosthesis (artificial larynx).
2) Oesophageal speech.
3) Trachea-oesophageal fistula.
Normal larynx | Electrolarynx | Esophageal | Trachea-esophageal | |
Initiator | Pulmonary air | Battery | Esophageal air | Pulmonary air |
Voice Source | Glottis | Vibrating membrane | Neopharynx | Neopharynx |
Resonator | Vocal tract | Vocal tract | Vocal tract | Vocal tract |
Articulator | Oral cavity, oropharynx | Oral cavity, oropharynx | Oral cavity, oropharynx | Oral cavity, oropharynx |
I. The Artificial larynx:
Artificial larynx devices employ the use of either a new voice source (battery as in electrolarynx) or the use of an apparatus that utilises pulmonary air to produce voice (pneumatic larynx).
1. Pneumatic: Here air from the lungs is directed from the tracheostome via a device housing the vibrating reeds to the mouth.
Advantages of pneumatic larynx:
a) Can be used the day immediately after the surgery.
b) Vibrating membrane material can be selected according to the pitch and sound quality.
c) No battery, hence cheap.
Example:
Tokyo artificial larynx.
- Electronic voice box:
- The patient uses his normal articulatory mechanism to speak.
- The external vibrators have an adjustable pitch and intensity.
- The voice however has a metallic quality.
- The battery-operated device is placed at the corner of the mouth or against the skin of the neck. When button on the device is pressed, it makes a vibrating sound. By moving the mouth and tongue, one can form this sound into words. Training is needed with a speech therapist to learn how to use it properly.
Advantage:
- a) No speech therapy required.
- b) Good speech quality.
Disadvantage: Expensive.
II. Oesophageal Speech: This is a very simple and cheap method to develop speech.
Mechanism: Air is ingested into the oesophagus and expelled without allowing it to reach the stomach. Air escapes past the oesophageal sphincter causing vibrations
This can be done by 2 types:
a) Inhalation air method.
b) Ingested air method.
The quality of voice depends on the ability of the patient to control the air and produce sound.
III. Tracheo-oesophageal fistula:
A Surgical fistula is created between the trachea and pharynx. Air produces vibrations in the local tissues and audible speech can be generated.
Advantages:
a) Sound produced by exhalation of air hence there is better control.
b) Not much speech therapy is required.
Disadvantage:
a) Stenosis.
b) Aspiration.
Example: Blom-Singer prosthesis.