To determine how many patients diagnosed with motor neuron disease (MND) at a neuromuscular specialty clinic presented with fasciculations as an isolated symptom.

Benign fasciculations are a common phenomenon in the general population. However, some people seek out medical opinion regarding this phenomenon, often with concern for a motor neuron disease such as amyotrophic lateral sclerosis (ALS). A follow up study by Blexrud found that of 121 patients diagnosed with benign fasciculation syndrome, none developed MND. There are limited reports of patients with MND presenting with fasciculations, but often in combination with muscle cramps. There are only rare reports of patients with MND presenting with isolated fasciculations (Eisen, Carvalho).

A retrospective chart review of patients diagnosed with possible, probable or definite ALS, progressive muscular atrophy (PMA), and primary lateral sclerosis (PLS) seen at our neuromuscular center was done to determine how many patients diagnosed with MND presented initially with fasciculations. The primary endpoint was to assess the proportion of patients presenting with isolated fasciculations.

56 charts were reviewed. 23 patients reported muscle twitching consistent with fasciculations, which is a higher proportion than those reported in prior studies. However, only 5 patients reported fasciculations as one of their primary complaints. Weakness was reported as a concurrent symptom in 22 patients. 12 patients reported cramping as well as twitching. 3 patients reported concurrent paresthesias, however 2 of those patients had chronic paresthesias due to comorbid conditions.  20 patients had muscle atrophy on exam. Notably, 0 patients presented with isolated fasciculations.

Our review found that no patients with MND presented only with fasciculations. This provides a compelling argument to counsel patients that isolated fasciculations are unlikely to progress to MND.