Complex sentence: Studies have shown that people with acrophobia and/or an extreme fear of falling have higher scores of SMD, or space and motion discomfort-referring to physical symptoms elicited by visual or kinesthetic information that is inadequate for normal spatial orientation.
Split into simpler sentences: Studies have shown that people with acrophobia and/or an extreme fear of falling have higher scores of SMD, or space and motion discomfort. These are physical symptoms elicited by visual or kinesthetic information that is inadequate for normal spatial orientation.