Neurology Motor Reflexes

Fasciculations

These are subtle, subcutaneous movements that represent contractions of a motor unit, seen in LMN disease (especially those involving anterior horn cells), but can be entirely benign.
In LMN lesions they are thought to represent the repetitive discharges of dying motor units.
Myokymia is the state of nearly continuous fasciculations causing a rippling appearance, associated with demyelinating diseases such as Guillain-Barre and MS.

Patient 1

This is a middle-aged man who presented with progressive weakness and paresthesias and was subsequently diagnosed with Guillain-Barré syndrome.