Conclusion: A perfectly normal ear is at a disadvantage when used alone. Similarly, a hard of hearing person wearing one excellent, well-fitted hearing aid will still experience hearing difficulties if the second ear is impaired and remains unaided. Think of hearing aids as you would eyewear. If you had vision problems in both eyes would you wear only one corrective lens? Or would you have proper prescriptions made for each side to achieve maximum clarity and focus? We were meant to hear with two ears-- that’s why we have two.
Sources: Walter Reed Army Medical Center: United States Government Study