This patient is a 73 year old with a 6 month history of strider and a 25 pack year history of smoking.  Her voice was good but the airway was compromised.   CT Scan of the chest and lower neck was unremarkable.  The cause of the paralysis was unknown.  A year and a half later she required a tracheotomy.
  
This video shows the function of a larynx with Bilateral abductor true vocal cord paralysis.  The patient has a good voice but cannot fully open the vocal cords.  The vocal cords can still fully adduct (close).  However, they did not abduct (open) even on coughing.