Either just by having developed their brains in a way that word facts just stick, or by constantly seeking out new word facts because that's what they love doing.
I believe that the gentleman in this case instantly saw the word 'cinematographer' hiding in 'megachiropteran' because his brain is a highly trained anagramming machine, and knew that it wasn't allowed because he knew all of the allowed 15-letter words, just in case he might get the opportunity to play one.
High-level players memorize staggering numbers of words. All 2- and 3- letter words is entry-level. All X-J-Q-Z, all Q-without-U, all words you ending in -MAN, all 70+ 7-letter words of the form SATINE+... top-level players know the 4000 4-letter words, the 5000 5's, and way, way more.
In a book release event for Stefan Fatsis's book on tournament Scrabble players, Word Freak, the host posed the "megachiropteran" anagram as a trivia question for a book giveaway.
One of the top players in my club _instantly_ replied "cinematographer," and added, "but megachiropteran isn't in the OSPD [Official Scrabble Players' Dictionary], so it doesn't really count."
Had to start researching this when a family member was recently diagnosed.
Parkinson's has many forms and many causes.
There's a big divide between Parkinson's _disease_ (idiopathic Parkinson's) and Parkinsonism from a variety of sources - stroke, drug-induced, and so on.
There are also other conditions, like progressive supranuclear palsy, that are considered either to masquerade as Parkinsonism or to constitute another cause of Parkinsonism.
Recommended treatments differ by the root cause of the symptoms. Some of the treatments that are recommended for one form may be contraindicated for other forms, or for different stages. For example, the recommended dopamine agonists are also the primary cause of Parkinson's hallucinations, so you have to trade back some strength and mobility if those start.
Something like 80% of Parkinsonism derives from idiopathic Parkinson's Disease.
Overall, it feels like we're really just getting started on these conditions. For decades, it's been thought to be primarily a motor disorder, but it turns out that there are scads of cognitive symptoms that develop years earlier than motor symptoms.