Etiology
This syndrome results from irregular contractions of the abductory muscles of the larynx. It has a range of presentations from a severely breathy voice to a mild dropouts of certain consonants. It can be mixed with adductor SD. It may be very spasm like or it may have a very tonic quality. top
Diagnosis
History
Typical complaints
- instability
- unpredictability
- hate the phone
- “I can hear my own voice and its terrible”
- “I have to depend on my voice and it is not reliable”
- “I run out of air when I talk”
- wavering voice
- variability of voice
- glitches
- good days and horrible days
- people ask if I have laryngitis constantly
- I have seen several ENT doctors and they say nothing is wrong with me
- Stress makes it worse
- May be associated with previous head trauma
Character of a patient with abductor SD
- Patients are often frustrated because of the long period of time between the onset of their disorder and the correct diagnosis.
- They may have been told in the past that their problem was psychogenic.
- The disorder is highly variable and they may indeed present on a day when their spasms are almost nonexistent.
- Talkativeness scale: whole range top
Vocal capabilities
- Hear samples of ABductor spasmodic dyphonia
- Prolonged vowel phonation
- spasms interrupting voice are irregularly unsteady compared to tremor which is a regular 4 to 5 Hz fluctuation.
- Atypical spasmodic dysphonia may present with a tonic tightness to the voice without discrete spasms.
- Unsteadiness and quality tends to improve in falsetto register (tremor remains unchanged)
- Unsteadiness may improve with singing and distraction.
- pulling on the tongue during rigid laryngoscopy may eliminate the spasms) top
Laryngeal Exam
- rigid laryngoscope
- general unsteadiness with random contractions of supraglottis and glottis
- flexible laryngoscope
- during speech, spasms of the abductory muscles may be noted with inadvertent opening of the glottis
- The glottis may remain continuously open during steady phonation, but usually closes completely during intermittent closure such as a laugh.
- See a sample endoscopy of ABductor spasmodic dyphonia. top
Treatment
Medical
- botulinum toxin injections into posterior cricoarytenoid muscles (PCA)
- Our initial starting dose is 1.8 units divided unevenly between PCA muscles.
- Although patients seem to do well even with equivalent doses, it is hoped that a starting dose with one side slightly less paralyzed than the other will diminish the severity of the initial side effect of respiratory difficulty with exertion.
- Our average dose is 2.5 units total. Our range of dosing is .7 units to 10 units total dose.
- The dose does not seem to be related to body size, age or severity of dystonia.
- Thus the first two injections are typically trial doses to determine the ultimate dosing schedule.
- Duration of the effect is a median of 16 weeks with an approximate range of eight to twenty six weeks.
- There is no direct correlation between size of dose and duration of effect
- We inject translumen through the cricothyroid membrane, tracheal lumen and posterior cricoid cartilage into the PCA muscles like (Meleca et al).
- When the cartilage is calcified, I typically aim about 20 degrees inferior of perpendicular with the neck.
- EMG guidance is utilized for determination of placement into muscle.
- Patient information
- Meleca RJ; Hogikyan ND; Bastian RW, A comparison of methods of botulinum toxin injection for abductory spasmodic dysphonia. Otolaryngol Head Neck Surg 1997 Nov;117(5):487-92 top
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