When a patient comes to you with complaints of hoarseness, the first thing you do is probably perform your evaluation. Check. You make sure the patient has been seen by an ENT, and then you perform a videostroboscopy. You'll most likely follow with a behavioral voice evaluation and/or a laryngeal function study. You have an idea in your head of what the diagnosis might be before the patient even steps in the room. Case history can lead you in the right direction, but sometimes it is important to be aware of all possible causes of symptoms, even the very rare. You patient comes in:
1. The voice is strained, pressed and sounds strangled. Hoarseness is present, as well as a mild hypernasal quality and vocal fry.
2. The patient has a low pitch, it's lower than normal for gender and age.
3. Voice onset for vowels is difficult, and the patient speaks softer than normal.
Initially, you think there is a strong possibility that the patient has Muscle Tension Dysphonia because of the strain. You want to make sure and rule out Adductor Spasmodic Dysphonia, however. You have your patient count from 80-89 to listen for laryngeal spasms. Your videostroboscopy reveals some vestibular fold hyperfunction paired with hypoadduction of the true vocal folds. Your patient is also complaining of some mild dysphagia.
You're still uncertain of what your diagnosis is. There are just some missing pieces. Something is just not adding up. How can you explain the low pitch and low intensity? It might be MTD, but what if it is something else...
Amytrophic Lateral Sclerosis (ALS) has been all over social media lately with the viral Ice Bucket Challenges. It usually presents with extremity weakness, atrophy, and decreased muscle tone. Sometimes, however, it begins with voice quality changes before anything else. A person can develop a voice that sounds strained, strangled, harsh or breathy. The voice might waver with tremor or have unsteady pitch. A patient might also have some hypernasality to boot. A certain kind of ALS onset, called bulbar (affecting the lower motor neurons), can be the culprit. It affects the lower motor neurons in the brain stem, and your videostroboscopy might show some hypoadduction. A patient with this bulbar onset might show signs of mild dysphagia and dysarthria early on, and quite possibly have hyperfunction of false vocal folds and ventricular compression to compensate for that hypofunction.
So how do you determine if it is ALS? ALS has a very rapid onset time, and within months you start to see the degenerative progression in multiple areas. One case study (to be taken with a grain of salt) showed that after 4 months, with the usual treatment for vocal fold atrophy/bowing, there was no improvement. Dysphagia worsened as well as the dysarthria. So, time might be a deciding factor here.
Knowing that ALS is a possible cause for hyperfunction and hypofunction in the larynx is something to hold in your back pocket. It will not happen often as a diagnosis, but it is worth being aware of. Just treat the symptoms you see, and if your patient's condition gets progressively worse despite intervention, there's a good chance you might be dealing with a progressive neurological disease. You should always refer back to the neurologist if you suspect this component.
But with what type of treatment can help you with this differential diagnosis? For bowing or atrophy of the TVF's, you might find success with Lee Silverman Voice Treatment (LSVT) as it has helped improve individuals suffering from age related bowing or Parkinson's disease. You might try to improve the hyperfunction by trying Lessac-Madsen Resonant Voice Therapy (LMRVT) or Casper-Stone Confidential Flow Therapy (CS-CFT) or a variation of Stone & Casteel's Stretch-and-Flow. With whatever is appropriate for your patient, pay close attention to whether there is benefit, or whether quality worsens despite your best efforts.
References: Watts, Christopher R, and Martine Vanryckeghem. “Laryngeal Dysfunction in Amyotrophic Lateral Sclerosis: a Review and Case Report.” BMC Ear, Nose, and Throat Disorders 1 (2001): 1. PMC. Web. 10 Jan. 2015.
Check out our Mobile Videostroboscopy and FEES Clinic: Voice Diagnostix.