My voice does not fit the MG description I´ve usually come across on the internet. But it definitely changes and fluctuates.

Mine goes from being quite a sing-songy voice to sounding completely monotone. It sounds almost pinched, as if someone were upset or just been crying. I noticed that it happens especially whilst taking antibiotics or comes along with other muscle weakness. The SFEMG practitioner noticed it kept fluctuating into a lower resonance whilst we were chatting.

If you have voice fluctuations, does yours become nasal?

Anacrusis