Try this voice on for size.

The Stairmaster may do when the stomach sags or leg muscles turn to flab. But when the larynx loses its tone, a hydroxylapatite implant may be the best solution.

This rectangular, chalky white prosthesis represents one of the latest attempts to help people with paralyzed or weakened vocal cords, says Charles W Cummings, an otolaryngologist at Johns Hopkins University School of Medicine in Baltimore. The device pushes the vocal cords together.

Most of the time, surgeons carve these implants to fit a particular larynx while the patient lies on the operating table. But Cummings and his colleagues instead offer patients five sizes of preformed implants. The surgeon slips one into a slit cut into the anesthetized throat and then gets the recipient to sound out the alphabet. If the restored voice doesn't suit its owner, then the surgeon tries out another size, says Cummings.

Already, the group has restored the voices of 39 people - more than 80 percent of whom report signif icant improvements in their ability to talk, says Cummings. These results will appear in an upcoming ANNALS OF OTOLOGY, RHINOLOGY AND OTOLARYNGOLOGY. Meanwhile, the implant's designers plan a larger study of the new device that will involve three other research centers, he adds.