My PN is a roller coaster, and when I have the spells you mention, I try hard to figure out if there was anything I can put my finger in that might have exacerbated it (diet? overuse from a recent strenuous event? fatigue/lack of proper sleep or rest? new medicine/temporary like an antibiotic?) I can’t pinpoint why hardly any of the time, but what comforts me is PT and home exercises that makes me feel good that I’m maintaining my strength all I can for these moments. My new home/HOA offers a stretch & tone class every week that is designed to be life style smart, simple exercises to help walk and work modestly on muscles we need for chores and basic activities. They even have an exercise to help prepare ourselves if we think we’re losing our balance and might fall, or if we are falling, how we might train our minds for the safest way to fall to reduce injury. I said it was a roller coaster for me; on days I’m feeling weak, my mind tells me to persevere because the good days come back.