"Stanic Rasin meets all requirements for coverage of hearing aids to treat her disabling hearing loss except that she is over age 21," according to the complaint, which was filed last week at the U.S. District for Nevada.

"Cigna has a standard policy of denying coverage of medically necessary prescription hearing aids to treat disabling hearing loss altogether and/or when the enrollee is over a certain age, such as the age of 21," according to the complaint. "As a direct result, Stanic Rasin and many class members have been forced to pay out-of-pocket for prescription hearing aids. Other members of the class have been forced to forgo needed hearing aids.

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Stanic-Rasin says setting an age limit on access to hearing aid benefits violates the anti-discrimination provisions in section 1557 of the Affordable Care Act.

She hopes to represent a class consisting of current or potential hearing aid users who are enrolled in health plans insured or administered by Cigna, other than Medicare Advantage plans, that set age limits on access to hearing aid benefits.

The proposed class would include participants in self-insured employer health plans as well as people with fully insured coverage.

One potential obstacle is that the Affordable Care Act itself calls for health insurers to provide some benefits aimed specifically at children. The ACA requires each state's "essential health benefits" package, or standard benefits package, to include basic dental and vision benefits for children. The EHB provisions do not require EHBs to include dental or vision benefits for adults.

The plaintiff acknowledges that the federal Age Discrimination Act lets affected organizations "reasonably take into account age as a factor necessary to the normal operation" of a health program, but the plaintiffs say Cigna would have to identify a clinical reason for not covering hearing aids for adults.

"Since hearing aids are medically necessary under the terms of Cigna's health plans — whether used by children or adults — Cigna cannot meet this narrow exception to the prohibition on facial age discrimination under the Age Discrimination Act and under [ACA] section 1557," the plaintiff says.

Cigna has not yet responded in court. Representatives for the company did not immediately respond to a request for comment.