Retired NFL players may be at risk for permanent hearing loss and tinnitus, according to Loyola University Medical Center ear surgeon John Leonetti, MD.

Many NFL players suffer one or more concussions during their careers. And Leonetti notes that such blunt head trauma has been associated with hearing loss and tinnitus (chronic ringing or buzzing in the ears).

Leonetti said there are two possible mechanisms by which blunt head trauma, such as a blow to the head, could damage hearing or cause tinnitus:

-- A blow to the head can cause the brain to wiggle like Jell-O, thereby damaging the nerves that connect the brain to the inner ear.

-- A blow to the head also can create a shock wave that damages the cochlea, the delicate auditory portion of the inner ear.

There is anecdotal evidence that athletes who play football and other contact sports may be at risk for hearing damage:

-- Leonetti recently spoke to retired players alongside EarQ at a meeting of the Chicago chapter of the NFL Players Association. When Leonetti asked how many players had experienced concussions during their career, they all raised their hands. When Leonetti asked how many have experienced hearing loss approximately 25 percent raised their hands. When he asked how many have tinnitus approximately 50 percent raised their hands.

-- Hall of Fame NFL lineman Joe DeLamielleure told USA Today that he experienced countless blows to the head during a 13-year career, and has suffered a 68 percent hearing loss in his left ear as a result.

-- Retired NHL hockey player Curt Bennett alleged in a class action lawsuit that he suffered from injuries associated with concussions and sub-concussive impacts, including tinnitus and hearing loss in both ears.

"To date, there is no proof that NFL players are suffering hearing loss and tinnitus at a rate higher than that of other men their ages," Leonetti said. "But based on what we already know about blunt head trauma, as well as anecdotal reports from retired athletes, we believe there are compelling reasons to conduct a scientifically rigorous study to quantify the risk of hearing loss and tinnitus among retired NFL players."

Leonetti is a professor in the departments of Otolaryngology and Neurological Surgery and program director of Cranial Base Surgery at Loyola University Chicago Stritch School of Medicine.