Speech, Vision and ablitily to move issues?

Definitely get the sleep study if for no other reason than to rule out that problem. I've never heard of this but at least you've got tests etc by qualified physicians. My husband had the sleep study done and it was a royal pain trying to sleep with the electrodes etc but it was worth it, he's a different man because even when he was "sleeping" he really wasn't. It almost sounds like your husband is going catatonic for a short period. And it sounds like it is when he's extremely tired so the doctors are tying the episode to that. Once again, get the sleep study, at this point you have nothing to lose and God forbid if that happened when he was driving or something the results could be a disaster. Take care.