I agree with Fitzi. I think it's a sensory integration issue. I sometimes bump into things when I am walking (people, corners, furniture, etc). I notice I generally don't realize I am going to collide until it is too late to correct my course. It's like the visual part of my brain that is calculating the trajectory I need to take is miscalibrated.
I also think it happens to me because if I am really "in" to what I am thinking, I don't think I pay close enough attention to what's going on around me. I am vaguely aware of the people, corners, and furniture, but not to the degree necessary to avoid "clipping" them. I say clipping because I don't fully collide with things like "head on." It's more than I'm in inch away from where I need to be (an inch to close), so I clip the thing I could have avoided.
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Mom to 2 exceptional atypical kids
Long BAP lineage