What you're referring to is called 'active listening'.
It's demonstrating via body language and/or vocalising that the speaker has your attention. It can go further to demonstrating you understand what's being said but that's not always the case.
No one is ND in my household as far as I'm aware, but I did have a similar issue with my partner. When he speaks to me, I put down my phone or book, or pause/mute the TV, look at him and make eye contact and at the very least make 'mm' noises, or 'really?' 'wow' 'huh' 'ok' or paraphrase what he's said to either confirm or demonstrate I understand him. It's how I was brought up. It's how I function at work.
He does none of those things and will get annoyed if I stop taking and ask if he's listening. He always says he is, but gives absolutely no visual or audible signs that he is.
So it became a point of contention in our relationship. For me what he was doing was rude. I felt stupid talking into the void with no response. Whereas he said he didn't feel that responding was necessary.
My first approach was passive aggression, I'm not proud to say. I started doing exactly what he was doing when I spoke to him. He haaaaaated it. Kept pausing to ask if I was listening. Got to the point where he'd pick up the remote and pause what I was watching before he started talking to me. It was ridiculous on both our parts and caused a tonne of fights. But the one positive was that I could say to him 'do you know how rude I felt behaving that way? Did it feel rude to you? Why? Surely you're not knowingly being rude to me?'
Anyway, the penny dropped. Now he knows he has to give me a perfunctory grunt when I start speaking to indicate he's listening. And honestly that's enough for me. If it's a serious issue or I need his input (so I'm not just rambling about something funny I read or venting about work), I'll pause, he'll notice and he'll drop whatever he's doing to give me attention.
So that's all to say, if the person genuinely is listening, they may just need to be told that they're creating frustration for both of you, and it's perceived as rude. That all they have to do is make a sound of acknowledgment. That more will be expected from them in the workplace and now might be a good time to start practicing. YMMV with ND but it's a worthwhile conversation.
Off topic but why the fuck is there an X on the ad box if it doesn't actually close the ad window