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.

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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.

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Why Does EpiPen Have to be Injected into the Thigh?

As any severely food allergic patients know, when suffering from a potentially life-threatening anaphylactic reaction, they need to jab an epinephrine needle into the side of their thigh...

But... why the thigh? Why not the arm like most other shots?

Per AAAAI, there have been 3 anatomic sites investigated to determine which location offers the fastest systemic absorption of epinephrine when injected intramuscularly and/or subcutaneously.

• Intramuscular injection in the upper arm (deltoid muscle) just like a flu shot.
• Subcutaneous injection in the upper arm just like an allergy shot.
• Intramuscular injection in the lateral thigh (vastus lateralis muscle).

Of these sites, the intramuscular thigh injection demonstrated the fastest rise in blood epinephrine.

When dealing with a life-threatening anaphylaxis, you need the speed because if the drug is too slow, the person may die before adequate epinephrine levels are achieved... and the thigh muscle provides the speed whereas the other sites do not.

Why might that be?

It's probably because the thigh muscle is large with lots of blood vessels allowing for multiple points of access for the injected epinephrine to enter into the blood circulation.


References:
Epinephrine absorption in children with a history of anaphylaxis. J Allergy Clin Immunology 1998; 101(1):33-37.

Epinephrine absorption in adults: intramuscular versus subcutaneous injection. J Allergy Clin Immunol 2001; 108(5):871-873.

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Human Ear Contains a Built-In "Ear Plug"

According to one Australian researcher, by just chewing a gum or singing/talking loudly, one could be protecting your ears from noise-induced hearing damage. How???

It is not common knowledge that the human ear contains two muscles that attach to the middle ear bones called the stapedius and tensor tympani muscles.

The middle ear bones, composed of the malleus, incus, and stapes, are what transmits sounds from the eardrum to the cochlea which allows a person to hear. The stapedius muscle attaches to the stapes and the tensor tympani to the malleus.

If something prevents the middle ear bones from vibrating, that effectively dampens the sound transmission from the eardrum to the cochlea... just like an ear plug or a bad case or earwax dampens sound transmitted through the ear canal to the eardrum.

SO... if the middle ear muscles tighten which are attached to the middle ear bones preventing them from vibrating, less sound is transmitted to the cochlea... just like an ear plug, except it is built-in.

Just how effectively does this reduce sound?

According to the researcher who has been studying this phenomenon, by about 30 decibels (or 1000x fainter).

That's about the same as foam earplugs!

How does one "activate" the middle ear muscle contraction?

By chewing a gum or singing/talking loudly!

Some individuals can sense this contraction if they close their eyes and try to "pull the muscles around the ears together"... a fluttering sensation inside the ear may be heard/felt which is the contraction of the middle ear muscles. In rare patients, this contraction may occur involuntarily and continuously.

SO... if you happen to have forgotten your ear plugs and are attending a very loud rock concert, chew gum and/or sing along with the band loudly! This may actually protect your hearing!

Of course, it's better to wear hearing protection, or better yet, avoid such circumstances altogether.

Read more about this here.

Reference:
How do middle ear muscles protect the cochlea? Reconsideration of the intralabyrinthine pressure theory. Journal of Hearing Science 2011; 1(2): RA 9 - 23

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