Treatment for Vocal Tremor

Vocal tremor is characterized by a rhythmic undulating vocal quality whenever talking, much akin to vibrato that can not be turned off. In the past, it was felt that use of botulinum toxin type A (botox) to treat vocal tremor was not possible nor realistic given the multiple muscle groups involved. This is in contrast to dystonias of the voice (i.e., spasmodic dysphonia) where only one muscle group is involved and is readily and easily treated with botox injections to the affected vocal cord muscle.

However over the past few years, several research papers have been produced that show that botox CAN alleviate (though not eliminate) vocal tremor both objectively and subjectively, though more than one site may need to be injected in order to produce vocal tremor relief. Such muscle sites include thyroarytenoid muscle, ventricularis muscle, lateral cricoarytenoid muscle, interarytenoid muscle, cricothyroid muscle, and strap muscles.

All these muscle sites are easily accessible either via, endoscopic guidance and/or EMG guidance alone. Indeed, physicians who already perform botox injections for spasmodic dysphonia should also be able to inject all the other muscle groups just as easily. [watch video]

Typically, "horizontal" vocal tremor is treated with thyroarytenoid, ventricularis, interarytenoid, and/or lateral cricoarytenoid muscle botox injections.

"Vertical" vocal tremor is treated with strap muscle botox injections.

Dosages are similar to that given to treat spasmodic dysphonia.

SO... for patients suffering from vocal tremor who do not respond well to oral medications (propranolol, primidone), consider botox injections!

Be aware that botox injections to treat vocal tremor may not be covered by insurance.

References:
A new paradigm for the management of essential vocal tremor with botulinum toxin. Laryngoscope. 2013 Apr 1. doi: 10.1002/lary.24073. [Epub ahead of print]

Botulinum toxin type A for treating voice tremor. Arch Neurol. 2004 Sep;61(9):1416-20.

Botulinum toxin for essential tremor of the voice with multiple anatomical sites of tremor: a crossover design study of unilateral versus bilateral injection. Laryngoscope. 2000 Aug;110(8):1366-74.

Tremor laryngeal dystonia: treatment of the lateral cricoarytenoid muscle. Ann Otol Rhinol Laryngol. 2004 May;113(5):349-55.

Read More

Compact EMG System for Targeted Muscle Injections

An EMG system (ElectroMyoGraphy) is a critical piece of equipment when it comes to targeted muscle injections in and around the neck, especially when you cannot see or feel the muscle.

This scenario is especially true when dealing with spasmodic dysphonia for which targeted botox injections are quite helpful. Given the muscles that need to be injected are contained inside the voicebox and not able to be seen and felt from outside the neck, accurate injection is quite difficult without EMG guidance.

Watch a video of this procedure using a traditional EMG system.

However, such traditional EMG systems are "overkill" in terms of technology and cost when all it is being used for is muscle placement.

It was with great excitement that a compact EMG device has been developed for just such a need when all that is required is needle localization for directed drug delivery.

Check out the MyoGuide made by Intronix Technologies based in Canada. The US supplier is Ambu.

I've been using MyoGuide for a few months now and am quite pleased with its performance. It pretty much does exactly what I want it to do... no more or less. There is both audio and display feedback, though I mainly depend on audio. It runs only on batteries.

For head and neck muscle injections, I find that a volume setting of 8 and vertical sensitivity of 6 works best.

My personal preference is using Ambu Inoject 35mm 27G needle for ADductor spasmodic dysphonia and the Allergan EMG needle for ABductor spasmodic dysphonia.

For those interested in trying out this device, there is a 2 week free trial.

Read More

Respiratory Spasmodic Dysphonia

Respiratory spasmodic dysphonia is one of the most rare subtypes of a class of laryngeal dystonia collectively known as spasmodic dysphonia. It is also known more accurately as laryngeal adductor breathing dystonia or respiratory spasmodic dystonia or respiratory laryngeal dystonia.

Introduction

Spasmodic dysphonia is a type of dystonia in which there are involuntary muscle spasms or contractions of the muscles involved in voice production. This disorder is similar to the involuntary eyelid twitches of blepharospasm. Spasmodic dysphonia should not be, but is often confused with muscle tension dysphonia or tremor. There are 2 main types of spasmodic dysphonia: ABductor and ADductor. Other much more rare types include mixed and respiratory.

ADductor dysphonia is when the vocal cords comes together suddenly while talking resulting in voice stops and effortful speech. Often, the voice chokes off. Counting from 80 to 89 is harder than counting from 60 to 69. Stressful situations often exacerbate the condition. ABductor dysphonia is when the vocal cords suddenly moves apart while talking resulting in loss of voice (breathy). These patients find counting from 60 to 69 harder than counting from 80 to 89. ABductor dysphonia is not as common as ADductor dysphonia.

Respiratory Spasmodic Dysphonia

Respiratory spasmodic dysphonia is when the vocal cords come together suddenly when inhaling. So the voice actually sounds quite normal... until the patient takes a breath in. During such inhalation, one can hear an audible choking sound.

A brief word about nomenclature. "Dysphonia" means hoarseness. As such, the term respiratory spasmodic dysphonia is not accurate. Rather, "dystonia" should be used instead which is defined as an abnormal muscle contraction.

In the video clip shown above, in the first half of the video, listen to the audio of a patient suffering from respiratory spasmodic dystonia talking. The latter half is a video of the patient's voicebox while vocalizing. Note that the vocal cords intermittently do not move apart when she is taking a breath in. Normally with breathing, the vocal cords should move apart to allow air to pass between the vocal cords.

Treatment

Treatment is the same as for ADductor spasmodic dysphonia. Botox is injected into the vocal cords which reduces the spasms when she takes a breath in.

Watch a video of botox being injected.

Click here to read more about spasmodic dysphonia.

Dr. Chang performs botox injections for this disorder every Friday afternoon.

Read More