Reading and playing simutaneously on the hammered dulcimer is beyond the ken of most mere mortals such as myself. I don't read well enough to play and read on any instrument, though I do read well enough learn a tune from the paper. However, I must take it in phrases. That sort of "limitation" is actually a helpful device in dissecting and analyzing a tune. Once I start to learn a tune from the paper, the first step is "hearing" the phrase as I work it out initially, and then it's a process of stringing the phrases together. When I get to the end, I have the tune "by ear" but also carry a mental image of the paper around in my head. That's not a thing I do deliberately, but it seems to be a by-product of the method. I hasten to add that just because this method seems to work for me is no guarantee it would work for anybody else. The key words are "work" and "individuality".