I have noticed with a lot of my students who seem to have additional learning problems, they switch hands frequently during signing. Whether the switching early in life caused the learning problem, or vice versa, or if they are completely unrelated, I’m not sure. I believe there was some research in the 1980s or 1990s about how changing hands doesn’t allow the correct hemisphere in the brain to retain the information. Can you help?
I don’t know of any research that links frequent hand switching with learning problems. There was some research in the early 1980s that examined when deaf signing children began to show a preference for linguistic handedness (i.e., for signing) and non-linguistic handedness (e.g., for reaching, handling objects, etc.). Sign handedness develops early and is relatively robust. Right hand dominance is linked to left hemisphere language (the typical pattern for both speakers and signers). Anecdotally, left-handers seem to switch hand dominance when signing more often than right-handers, but this doesn’t have anything to do with the brain retaining information. Note also that switching dominance is rule-governed and does not occur at random for fluent signers.