A pilot study of the safety and performance of the Otologics fully implantable hearing device: transducing sounds via the round window membrane to the inner ear.

OBJECTIVES: The safety and performance of the Otologics fully implantable hearing device were assessed in adult patients with mixed conductive and sensorineural hearing loss. METHODS: The subcutaneous microphone of this fully implantable device picks up ambient sounds, converts them into an electrical signal, amplifies the signal according to the user's needs, and sends it to an electromechanical transducer. The transducer tip is customized with a prosthesis in order to be in contact with the round window membrane and is protected by fascia; this translates the electrical signal into a mechanical motion that directly stimulates the round window membrane and enables the user to perceive sound. The implanted battery is recharged daily via an external charger and the user can turn the implant on and off as well as adjust the volume with a hand-held remote control. In this pilot study, 6 patients with mixed conductive and sensorineural hearing loss were implanted with the Otologics fully implantable hearing device. Pre- and postoperative air conduction, bone conduction, as well as aided and unaided thresholds and speech scores were measured. RESULTS: No significant differences between preoperative and postoperative pure-tone averages were noted. Average improvement ranged from 19.16 to 35.8 dB of functional gain across audiometric frequencies with a mean of 26.17 +/- 5.15 dB. Long-term average functional gain at 12 months was 20.83 +/- 6.22 dB. Word recognition scores demonstrated significant differences between unaided and implant-aided conditions. CONCLUSIONS: Preliminary results of this trial of the Otologics fully implantable hearing device provide evidence that this fully implantable device is capable of efficiently transferring the sound to the inner ear via the round window membrane in patients with mixed hearing loss.

The Otologics MET ossicular stimulator.

The advent of various technologies for middle ear implants (MEI) that directly stimulate the ossicles has created a new therapy for hearing loss and a new segment of the medical device industry. Benefits can be established when the MEI is compared with the best alternative currently available. Otologics, LLC, has developed an electromechanical MEI (middle ear transducer (MET) Ossicular Stimulator) designed to aid individuals with moderately severe to severe sensorineural hearing loss. The efficacy of the device is determined through a clinical comparison of the MET Ossicular Stimulator to that of a state-of-the-art digital hearing aid.

Treatment of acute mountain sickness: hyperbaric versus oxygen therapy.

STUDY OBJECTIVES: To compare the benefits of simulated descent in a hyperbaric chamber with those of supplementary oxygen for the treatment of acute mountain sickness. DESIGN: A prospective study. SETTING: The Snake River Health Clinic in Keystone, Colorado, which has an altitude of 2,850 m (9,300 ft). TYPE OF PARTICIPANTS: Twenty-four patients who presented with acute mountain sickness. INTERVENTIONS: A simulated descent of 1,432 m (4,600 ft) was attained by placing the patients in a fabric hyperbaric chamber and pressurizing the chamber to 120 mm Hg (2.3 PSI) above ambient pressure. Patients were randomly assigned to either the hyperbaric treatment or treatment with 4 L of oxygen given by facemask; both treatments lasted for two hours. MEASUREMENTS AND MAIN RESULTS: Mean arterial oxygen saturation (SaO2) increased 7% (84 +/- 2% to 91 +/- 1%) with pressurization and 14% (83 +/- 4% to 96 +/- 1%) with oxygen during treatment over pretreatment levels. Symptoms of acute mountain sickness decreased as rapidly with pressurization as with oxygen treatment, despite significantly higher SaO2 in the oxygen-treated group during treatment. Symptomatic improvement was retained in both groups at least one hour after treatment. CONCLUSION: Simulated descent in a fabric hyperbaric chamber is as effective as oxygen therapy for the immediate relief of acute mountain sickness.

A human breathing simulator designed to test the life support system of a hyperbaric tent.

A self contained life support system which can maintain a breathable atmosphere for up to eight hours was recently developed for use with a portable hyperbaric tent. To facilitate further life support system studies, the practicality of a human breathing simulator (HBS), which would remove oxygen and release carbon dioxide at the same rate as a human, was tested. The HBS consists of a cylinder of carbon dioxide bled into the chamber via a flow regulator and a Vanadous bubbler to chemically remove oxygen from the chamber. First experiments show that the HBS works, but that a larger chemical system is needed to remove oxygen at the desired rate. Scale up calculations have been completed.

A self-contained life support system designed for use with a portable hyperbaric chamber.

Recently, the Gamow Bag, a portable hyperbaric chamber, has been demonstrated to relieve the symptoms of acute mountain sickness (AMS). The patient is completely enclosed in the bag which is inflated and pressurized to simulate descent in altitude. CO2 produced by the patient is vented from the airtight bag by means of a pressure relief valve, while fresh air is brought in from the outside via a high volume foot pump. In order to eliminate the vigorous pumping that is necessary to maintain a suitable atmosphere in the bag, we have designed a completely portable, self-contained life support system that supplies oxygen as it is consumed and removes the waste CO2 as it is produced. The entire rebreathing unit, which maintains a homeostatic atmosphere in the chamber for six to eight hours weighs less than six pounds. The chamber with the self-contained life support system weights less than 18 pounds. It would find its greatest use in medical mountain clinics, isolated ski areas and should become standard equipment for mountain search and rescue units.