That communication is incredibly important.
That the higher up the org chart someone is the busier they are. So what you spend 40 hours a week thinking about they might not spend 45 minutes thinking about. So over-communicate and remind them of important information about the project. Because they will forget lots of important details, and things that are glaringly obvious to you won't even show up on their radar.
How to sell.
Something related that I wish I had learned much earlier: Just because that person forgets the details doesn't mean they don't care or that they're just stupid. Expecting someone several levels removed from day-to-day development to remember the exact structure of that table or how exactly we do dependency injection makes me the unreasonable one.
Respectfully, that's a proverbial crock of trite bullshit perpetuated to game the naive/inexperienced.
If the next level above me couldn't spend at least 45 minutes thinking about the general problem I've been trying to solve in the past week, then that person:
a.) is stretched way too thin (which should be pretty obvious); or
b.) seriously needs to GTFO for the sake of the rest of the team.
P.S. As a de facto (not even official) technical lead on a US$3mil+ project that I've been assigned to, I spend at least 45 minutes a week sitting on a toilet bowl thinking of ways to improve the performance of my team while literally taking a shit. What's your project manager's excuse?
Grandparent comment did not say "next level" above. People are often talking to people in different parts of a company, or more than one level up/down.
On the other hand, maybe this explains why upper management is always so disconnected.