It's an easy question, but it can be surprisingly difficult to answer. Insurances and governments all have their own definitions. Ego has a different agenda. Which is all to say that the answer may vary depending on the purpose it is being asked. If you haven't already, catch HypoPP and Me for some background.
Image from spinlife.com
There are times when I can confidently say "I'm not disabled" and feel truthful in that statement. Those times rarely last for more than a few hours. This is a common struggle for people with hypokalemic periodic paralysis - sometimes, we are definitely not disabled. Other times.... we are very disabled. When laying on the floor, unable to move and struggling to breathe, I feel very disabled. When I was younger, I'd just lose mobility in my arms and legs for 20-30 minutes. Didn't seem like a big deal.
Screen capture from Merriam Webster
The U.S. government has it's own definitions of disabled depending on diagnosed illnesses. Seriously, they have a big book with all the diseases/issues they consider possibly disabling and criteria within each for defining when "disability" is reached. PP falls under muscular dystrophy in the blue book. Basically, if I can't use my hands or require a wheel chair, then the U.S. government considers me disabled. In order to qualify for assistance, it must last at least one year and be expected to continue. You can guess how murky things get for PP there.
So, am I disabled? Depends on who's asking, why they're asking, and when they're asking. Periodic paralysis is obviously a defining feature of my existence, and I'm limited in many ways.... for now. It is possible if we get medications dialed in just so that I become more functional. It's also possible that the presentation suddenly changes. The degree and duration of disability simply cannot be guessed.
I survive with a few mantras. They show up here and there. Today, I leave you with this:
Do what you can with what you have when you have it.