Respiratory muscle dystonia could involve the diaphragm and/or the accessory muscles used for breathing. Laryngeal dystonia is also called spasmodic dysphonia. This is a voice disorder caused by spasms of the muscles of the larynx or voice box. The abductor muscles, the adductor muscles or both may be affected.
Spasms of the abductor muscles cause the vocal cords to open. When the vocal cords are open they cannot vibrate to speak, but air can escape from the lungs while trying to speak. This causes the voice to be weak, quiet and breathy or whispery.
Spasms of the adductor muscles cause the vocal cords to close together and stiffen. When the vocal cords are closed it is difficult for them to vibrate to speak. This causes the voice to beak often with words being cut off or difficult to start similar to stuttering. The voice may have a tight, strained or strangled quality that is full of effort.
Speech therapy can help with breathing retraining so that you can once again resume diaphragmatic breathing and coordinate this with activity including speaking. Along with speech therapy periodic injections of Botox® (botulinum toxin) may be helpful to partially and temporarily paralyze these muscles of the voice box.