Aphonia means "no voice." In other words, a person with this disorder has "lost" his/her voice.
In this case, the patient's history and the observed unilateral immobility rules out functional aphonia.
Basically, any injury or condition that prevents the vocal cords, the paired bands of muscle tissue positioned over the trachea, from coming together and vibrating will have the potential to make a person unable to speak. When a person prepares to speak, the vocal folds come together over the trachea and vibrate due to the airflow from the lungs. This mechanism produces the sound of the voice. If the vocal folds cannot meet together to vibrate, sound will not be produced. Fear also is often a concomitant and a contributor.
Botulinum toxin A: Various toxicities (first reports for aphonia, migraine, peripheral vascular disorders and transverse myelitis): 13 case reports
Oct 18, 2008; Health Canada received 13 reports of patients experiencing adverse effects after receiving botulinum toxin A [Botox or Botox...