At age 83, Effie Forte reported one year of effortful speaking. If she shouted for a while, she could continue to speak with effort. After resting her voice though, it was very difficult to get her voice started again. She spoke in short, tight bursts when describing her problem. On endoscopy, I noted that she squeezed her larynx tightly from each side every time she tried to produce a sound and that sound would be cut short by the squeeze. Except for the severe squeeze, her vocal cords appeared normal and using stroboscopic light, they vibrated normally for the brief period of each vocal effort.
I felt that her diagnosis was adductor spasmodic dystonia (also commonly called adductor spasmodic dysphonia). Adductor spasms of the vocal cords mean that the vocal cords over-contract, irregularly closing tightly when trying to phonate. It is a focal dystonia — spasms of a single muscle or a group of muscles. Spasms tend to be irregular and occur during intentional use. They usually do not occur at all when the muscle is at rest.
While a tremor is also an over-contraction often occurring during intentional movement, a tremor has a regularity about it — as one muscle over-contracts, the opposing muscle takes over and an oscillation starts, typically about 4 times per second. Spasms of dystonia also occur during intentional movement, but there is no counteracting muscle contraction. Spasms can be a nearly continuous contraction or a very intermittent and irregular contraction.
AD SD is one of the few laryngeal disorders that is often more easily visualized during speech than during a steady sound.
I recommended botulinum toxin injections to weaken the muscles closing her vocal cords. No one knows what causes a dystonia, though I suspect the problem is in the brain, not in the nerve endings. However, for now, the best available treatment seems to be partially blocking the nerve input to the spasming muscles. The wearing off of botulinum toxin is a downside — the beneficial effect wears off and the injection needs to be repeated in three to six months. Mrs. Forte was able to speak more freely after the treatments for three to nine months depending on the dose.
After three treatments she still sought a cure, not a treatment. She went to a general otolaryngologist who told her that she had Reinke’s edema. He had not taken any photos, but he took her to the operating room and had “stripped” her vocal cords to remove the edema. Her voice was worse after the surgery. Reinke’s edema is a condition also known as “smoker’s polyps,” which tobacco smokers who talk a lot develop. Mrs. Forte did not talk a lot, did not ever smoke tobacco, did not have a deep voice — and I had photos of her vocal cords from one-and-a-half years ago that were normal in terms of their structure.
She now had two problems: stiff vocal cords from the stripping, and spasmodic dysphonia. Botulinum toxin injections may not be the only treatment for some laryngeal dystonias. When the spasms involve the adductor branches of the recurrent laryngeal nerve, surgically cutting the adductor branch of the RLN and hooking up a sacrificial nerve from another neck muscle (ansa cervicalis) is also an option. This procedure is called a denervation-reinnervation surgery (DeRe) or selective laryngeal adductor denervation (SLAD). Many times I ask myself, what is the value to a patient and to society of a correct diagnosis?
Abductor Spasmodic Dystonia
In his mid-fifties, Bob Icon has had to reduce his preaching schedule to a minimum. For the past 15 years his voice has become progressively more undependable. His voice fades out, breaks up and sounds unsteady. It requires a great deal of effort to speak. The first ENT he saw diagnosed vocal polyps and sent him to speech therapy. However, the therapist told him that his voice sounded like he had abductor spasms. A second ENT tried injecting botulinum toxin using ultrasound guidance, but each time it made his voice breathy for a while without improving his voice. At one point, he had a cold and his voice improved temporarily during the infection.
Abductor laryngeal dystonias are spasms of the opening muscles of the larynx, the PCA muscle. The patient has “breathy breaks” in the voice while speaking. This type of dystonia may be treated with botulinum toxin injections into the PCA muscles. Based on Bob’s description of the injection, it sounds like the medication was placed in the TA muscle rather than the PCA — the resulting breathiness being a typical side effect of a TA injection, not a PCA injection.
I discussed with the patient that different physicians use different techniques for injecting the PCA muscles. I utilize an EMG and pass the needle straight through the front and out the back of the larynx so that I know when I am encountering the PCA muscle by the feel of the cartilage and the EMG signal. Part of my diagnostic process is to place the botulinum toxin and see the patient back in two weeks to confirm that the intended muscle is weakened. He was indeed improved and has resumed his preaching as well as continued with the injections.
Respiratory Dystonia – Inspiratory
For several years Mr. S. Tate Seller has noted pain in his shoulders and neck, and for two years he has noted difficulty talking and breathing. When he tries laying down to sleep, he struggles for about two hours before falling asleep because of difficulty breathing in. His breathing seems better in the morning, but as soon as he starts talking or moving, the difficult, noisy breathing returns. His voice is normal, but his breathing is very noticeable — gasping between words, especially on the phone. He is an estate broker, and when people hear him gasp he loses their confidence as well as the sale. He cannot even sell enough to pay for health insurance anymore.
On endoscopy, I note that he can speak easily and that his larynx is smooth and stable during phonation. However, when he attempts to breathe in, instead of opening, both vocal cords appear very unsteady as he tries to breathe in, spasm closed and create quite a bit of noise during inspiration. The vocal cords never really open anywhere near normal except briefly during a cough. While the more common dystonia of the adductor muscles occurs during attempts to speak, his spasms occur during attempts to breathe.
Mr. Seller’s LCA muscle is spasming when he tries to breathe in, an exhausting condition. By the time I see him, he has to sit up in bed struggling for every breath until pure fatigue renders him asleep. I inject botulinum toxin into the closing muscles of his vocal cords and one month later he has stopped all of his nasal inhalers and all of his allergy medications because they were unneeded. Speaking is easier, breathing is easier, though he still audibly gasps between words. After a number of treatments, between injections he never returned to as severe a condition as when I first saw him, even if he goes for a long period between injections. There seems to be some partial permanent improvement after several injections. Mr. Seller receives injections about every six months.
Respiratory Dystonia – Expiratory
Mrs. Tock complains that she has too much phlegm, a rather common complaint in an ENT office. During endoscopy, there is no excess of secretions but there is an unusual movement of her vocal cords during breathing. Her vocal cords open to take in air, but then close prematurely and sit against each other shortly after she breathes in. Normally, vocal cords close slightly during expiration to provide some resistance and keep the lungs from collapsing. Hers are closing most of the way together, such that the flexible part of the vocal cords are completely together.
I find that many times the sensation of excessive mucous production relates to only a small amount of mucous which ends up sticking to the vocal cords. For Mrs. Tock, with the membranous vocal cords sitting against each other she senses the touching as phlegm build up, but it is actually each vocal cord touching the other that she is sensing. There is no extra mucous. She has spasms of her LCA muscles occurring during expiration — a respiratory dystonia of expiration. An injection of botulinum toxin into the adductor muscles softens her voice, but also allows the vocal cords to rest apart during breathing and relieves her sensation of phlegm build-up for several months.
Other Dystonias and Summary
Muscles surrounding the larynx, muscles supporting the larynx and muscles involving the speech tract above the speech line (pharynx, tongue, lips, jaw) may spasm and impair airflow and thus impair voice and speech. Some regional dystonias respond well to botulinum toxin injections, particularly in the supraglottis. With muscles more closely involved in swallowing, side effects from botulinum toxin weakening swallowing can make treatment of the muscle spasms not worthwhile for the patient.
Dystonias can involve a single muscle or a local group of muscles. They occur as a spasm during attempted voluntary movement — effectively an inappropriately strong movement when not desired. Whether the spasm occurs during breathing or speaking, they also may involve some of the nearby muscles in the neck which are recruited to help move air through the tightening vocal cords. This caused Mr. Seller to have neck pain from chronic muscle tightness. This neck pain also improved after each laryngeal treatment.
Dystonias of the larynx most frequently occur with phonation, typically the TA or LCA muscles, interrupting and cutting off the voice and consequently interrupting speech. Spasms of the PCA muscle during phonation cause inappropriate opening, which in turn causes breathy breaks in sound production. Depending on the timing of spasms of the TA or the LCA muscles or both, interruptions can also occur with breathing in, cutting off the airway as with Mr. Seller, or with breathing out as with Mrs. Tock.
What you learned
- Laryngeal dystonia is a focal dystonia — irregular, involuntary spasms of a laryngeal muscle during intentional use; unlike tremor, it has no regularity.
- Adductor spasmodic dysphonia (AD SD) causes the voice to cut off mid-sentence as the TA/LCA muscles clamp shut during phonation; it is often more visible during connected speech than during a sustained vowel.
- Abductor spasmodic dysphonia (AB SD) causes breathy breaks as the PCA muscle inappropriately opens the cords during phonation; the PCA is a different target for botulinum toxin injection than the TA/LCA.
- Respiratory dystonias can affect either inspiration (LCA spasming on breath-in) or expiration (LCA closing prematurely on breath-out); both respond to botulinum toxin into the adductor muscles.
- No one knows what causes focal laryngeal dystonia; the best current treatment is repeated botulinum toxin injections every three to six months, or surgically re-routing the nerve supply (DeRe surgery) for a more lasting result.