ALS and Dysphagia

Amyotrophic lateral sclerosis (ALS) is a motor neuron disease that is commonly referred to as Lou Gehrig disease. The disease usually presents first with changes in hands and feet ranging from cramps, to weakness and muscle atrophy. One telltale sign of the disease is asymmetry in these symptoms - the left limb may be heavily impacted while the right limp functions at nearly 100%. With progression the symptoms will become apparent at more proximal locations (closer to the trunk of the body, e.g. forearms or shoulder is this case). Next, one is likely to find more systemic issues like spasticity (stiffness or rigidity of the muscles), fasciculations (relatively small, involuntary contractions of muscles), clumsiness, altered gait, and issues controlling the expression and tongue. The most common cause of death for ALS patients is from respiratory failure with a prognosis as follows, quoted from the Merck Manual Professional Edition:

"50% of patients die within 3 yr of onset, 20% live 5 yr, and 10% live 10 yr. Survival for > 30 yr is rare. In progressive bulbar palsy with ALS (bulbar-variant ALS), deterioration and death occur more rapidly."

The bulbar-variant ALS refers to a combination of typical ALS pathophysiology and symptoms combined with those of progressive bulbar palsy. In progressive bulbar palsy there is a relative accelerated degradation of the nerves associated with chewing, speech, expression, tongue movement, and gag reflex. Many of these symptoms are interrelated and share roles in a number of functions. Dysphagia (difficulty swallowing) is one of these functions and is very dangerous - patients with bulbar symptoms are often at much higher risk of aspiration. Aspiration will often cause respiratory symptoms which is doubly dangerous for ALS patients who may be experiencing myogenic ventilation issues already.

I was curious about how dysphagia was characterized in ALS patients and I found a recent research article out of Kanazawa University detailing this topic. The study was able to asses fourteen different physiological parameters with videofluoroscopy (VF). VF is a simple procedure that uses an x-ray machine to examine the throat while swallowing barium-laced foods. The study found that dysphagia followed some fairly predictable patterns in terms of what parts of the swallowing process is affected by ALS and how the disease's severity correlated to the severity of the dysphagia.

Sources
Merck Manual Professional Edition: Amyotrophic Lateral Sclerosis
Wikipedia: Fasciculation
Wikipedia: Spasticity
Science Direct: Evaluation of dysphagia at the initial diagnosis of amyotrophic lateral sclerosis
American Speech-Language-Hearing Association: Videofluoroscopic Swallowing Study (VFSS)
Image: Magnetic resonance findings in amyotrophic lateral sclerosis using a spin echo magnetization transfer sequence