Perhaps you should try some spelling variations:
significantly impaired » significantly improved (Expand Search), significantly improve (Expand Search), significantly improves (Expand Search)
significantly changed » significantly enhanced (Expand Search), significant changes (Expand Search), significant change (Expand Search)
impaired decrease » marked decrease (Expand Search)
changed decrease » marked decrease (Expand Search), larger decrease (Expand Search), change increases (Expand Search)

You may be able to get more results by adjusting your search query.

• Removing quotes may allow a broader search: (( significantly impaired decrease ) OR ( significantly changed decrease )).