During an electromyography, the electrical activity of a muscle is played through a loudspeaker. The electroneuromyographer listens as much as they look: a healthy muscle fills the room with a dense, even roar; a muscle failing from within crackles, small and high; a muscle abandoned by its nerve beats slowly, each motor unit a heavy, isolated thud.
You will hear six recordings. For each one, deliver the verdict: healthy, myopathic or neurogenic.
The observer does not hesitate. Neither should you.