Botulinum toxin, spasmodic dysphonia, dystonias

The conversation begins with presbyphonia, the age-related evolution of the vocal folds, covered on the page Menopause, andropause, presbyphonia. Adeline Toniutti asks whether, in some cases, something is injected into the vocal folds.

The principle of these augmentation injections is the exact opposite of that of the toxin. The aim is to fill the vocal fold in depth, to try to give it back the mass it has lost, with the most supple product possible: fat, hydroxyapatite or hyaluronic acid, whose uses are detailed on the presbyphonia page.

Before getting to spasmodic dysphonia, a detour via the vocal instabilities seen with age, because they give a very telling picture of the mechanism.

Dr Coulombeau takes the example of the arm. You hold your arm out horizontally, normally it holds. From time to time, there is a drop in tone, the arm falls a little, you catch it very quickly, and that makes an oscillation, an instability. The same thing can happen in the diaphragm, the muscles of the abdominal wall or the larynx, and produce an instability of the voice. It is recognised in singers whose speaking voice is almost normal and who, as soon as they sing, can no longer maintain a stable tone. It is also recognised in the vibrato that has become very wide in some seventy-five-year-olds who sing in choirs.

The dystonias proper form a wider family. Some people have their head turned to one side because the muscles contract unilaterally, and they cannot straighten it. This can occur in any muscle of the body.

In musicians, we speak of task-specific dystonias. Dr Coulombeau has seen them in violinists, guitarists and pianists, which does not mean that other instruments are spared. A hand can work perfectly in everyday life, and become incapable, as soon as the person is at the piano, of playing passages they used to play without difficulty. He cites the case of a pianist of a good standard forced to stop between the ages of twenty-five and thirty, her fingers no longer responding, while her hands worked normally in every standard activity.

Stuttering belongs to this family, in a slightly particular form. Rehabilitation helps, but every person who stutters says they are never cured, that they keep this unwanted muscle contraction ready to show up at any moment, even when others no longer hear it because they manage to control it.

On the origin, Dr Coulombeau is cautious. It is very probably neurological, and nobody knows which. A neurologist he worked with hypothesised that there are different circuits in the brain for the speaking voice and for the singing voice, and that some command circuits sometimes stop working in a consistent way. Functional MRI may provide explanations in the years to come.

This hypothesis of separate circuits sheds light on a case that struck him: a person whose speaking voice was very spastic, and whose singing voice was almost stable, without this contraction. This was not a professional singer, nobody was having them do high-level vocal exercises, and yet the disorder almost disappeared when singing.

Dr Mailly, who performs these injections, describes the procedure itself. Unlike an operation on the vocal folds, it requires no anaesthesia: it is done under electromyographic guidance.

The question of the cervical spine, which Adeline Toniutti had raised thinking that you needed to “see the vocal folds clearly” to inject, actually relates to another situation: surgery under general anaesthesia.

Adeline Toniutti knew that curare is injected with propofol during general anaesthesia, and wanted to understand what curare is for. Dr Mailly’s answer is of interest to every singer who has to undergo an operation.

For augmentation injections, on the other hand, the product decides the setting: fat requires putting the person to sleep, hydroxyapatite is done in the consulting room. Mentioning that you are a singer before any anaesthesia is one of the useful reflexes, including for an operation that has nothing to do with the voice.

This is the part that most directly concerns a singing lesson, and it gives rise to an exchange of views.

Dr Coulombeau begins with an observation: when vocal rehabilitation, vocal work and toxin injection are combined, the vocal work seems to prolong the effect of the toxin. He immediately adds that he does not believe this explanation, since the toxin is a molecule whose action is chemical and limited in time.

Adeline Toniutti suggests a reading: the body, once it has felt the area soothed, would develop a replacement gesture that takes over.

Dr Coulombeau suggests another, from a domestic image. You want to thread a needle, you cannot manage it, you tense up, and as you tense up it works less and less well. This is exactly what happens in dystonias: your muscular system responds poorly, you tense up, and you increase the dystonia. Stress, anxiety and fatigue increase dystonic manifestations, that is well known.

He adds that the two readings can perfectly well combine.

For a student, the practical consequence is clear. The months following an injection are a window for work. The muscle is temporarily less reactive, the vocal gesture becomes accessible again, and this is the time to put in place the support, the suppleness and the reference points that will prevent tensing up again when the molecule wears off. Work carried out during those months, with a teacher who knows the diagnosis and who talks with the phoniatrician, does not replace the treatment and gives it its best chance.

Dr Coulombeau gives a simple rule that is easy to remember: a dysphonia lasting more than a month warrants an examination. Most of the time, this examination will find normal vocal folds or classic features. That is precisely what makes it a good examination.

For the disorders covered in this article, a few reference points emerge.

This article is intended for information and prevention. It does not replace a consultation: any voice that changes lastingly must be examined by a phoniatrician or an ENT.