Perhaps you should try some spelling variations:
significantly impaired » significantly improved (Expand Search), significantly improve (Expand Search), significantly improves (Expand Search)
significant effect » significant impact (Expand Search)
impaired decrease » marked decrease (Expand Search)
effect decrease » effects decreased (Expand Search)

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

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