ABSTRACT
With the continued concern over the possible transmission of viral infections through homologous middle ear implants, there is increasing pressure to develop a truly biocompatible alloplastic middle ear prosthesis. The polymaleinate ionomer, which has been used in dentistry as a filling and luting material for more than 15 years, has recently been used to construct total and partial ossicular replacement prostheses. In an attempt to evaluate these new implants, a multicenter prospective clinical trial was initiated. To date, 92 patients have undergone implantation. The follow-up interval ranged from 3 months to 22 months. Although it is premature to discuss the long-term results, the preliminary surgical experience and audiometric data with these implants are reviewed. From a surgical perspective, the ionomeric prostheses were easily contoured with a diamond burr and were not prone to shattering. Preliminary follow-up audiometric data were available on 80 patients (59 partial ossicular replacement prostheses and 21 total ossicular replacement prostheses). Of the 59 partial ossicular replacement prostheses the air-bone gaps (average of 500 Hz, 1 kHz, 2 kHz and 3 kHz) were as follows: 0 dB to 10 dB, 15 (25%) of 59; 11 dB to 20 dB, 20 (34%) of 59; 21 dB to 30 dB, 11 (19%) of 59; and greater than 30 dB, 13 (22%) of 59. Of the 21 total ossicular replacement prostheses the air-bone gaps were as follows: 0 dB to 10 dB, 6 (29%) of 21; 11 dB to 20 dB, 6 (29%) of 21; 21 dB to 30 dB, 5 (24%) of 21; and greater than 30 dB, 4 (19%) of 21.
Subject(s)
Aluminum Silicates , Biocompatible Materials , Glass Ionomer Cements , Ossicular Prosthesis , Acoustic Stimulation , Aluminum Silicates/chemical synthesis , Aluminum Silicates/chemistry , Audiometry , Biocompatible Materials/chemical synthesis , Biocompatible Materials/chemistry , Bone Conduction , Doppler Effect , Evaluation Studies as Topic , Follow-Up Studies , Glass Ionomer Cements/chemical synthesis , Glass Ionomer Cements/chemistry , Hearing , Humans , Lasers , Ossicular Prosthesis/adverse effects , Postoperative Complications , Prospective Studies , Prosthesis Design , Stapes/physiology , Surface Properties , Tympanic Membrane/physiology , VibrationABSTRACT
The use of tone-burst stimuli for electrocochleography (ECochG) may offer certain advantages over conventional broad-band clicks. Namely, the summating potential (SP) component can be examined at different frequencies and may be easier to define and measure. To apply these findings clinically, it would first be necessary to establish SP amplitudes as a function of tone-burst frequency in normal listeners. The purpose of the present study was to do this using the tympanic membrane (TM) as the primary ECochG recording site. ECochG was recorded from 20 normal ears. Stimuli included 500-, 1000-, 2000-, 4000-, and 8000-Hz tone bursts presented randomly at 90 dB nHL. Mean SP amplitudes at these frequencies were +0.19, +0.17, +0.08, +0.10, and +0.22 microvolts, respectively. Although mean amplitudes were slightly positive regarding baseline, individual amplitudes varied between -0.41 and +0.73 microvolts. This study offers additional evidence that the SP to tone bursts can be recorded from the TM. The normative data provided should be useful for extended studies involving clinical populations.
Subject(s)
Action Potentials/physiology , Tympanic Membrane/physiology , Acoustic Stimulation , Adult , Audiometry, Evoked Response , Cochlea/physiology , Evoked Potentials, Auditory/physiology , Humans , Reference Values , Vestibulocochlear Nerve/physiologyABSTRACT
Electrocochleographic responses to tone bursts and clicks were recorded from the tympanic membranes (TMs) and promontories of six suspected Meniere's patients. Although the majority of ears had normal summating potentials (SPs), regardless of recording site and stimulus type, some displayed amplitude-enlarged SPs at both sites and to both types of stimuli. The following observations were made from these patients regarding the choice of recording approaches and stimuli for ECochG: (1) Although SP amplitudes at the promontory were approximately four times larger than corresponding TM values, response "patterns" leading to diagnostic interpretation were the same at both sites; (2) the majority of patients who displayed enlarged SP amplitudes to tone bursts also had enlarged SPs to clicks; and (3) with tone-burst stimuli, the amplitude of the SP alone was sufficient for diagnostic interpretation of the ECochG waveform.
Subject(s)
Ear, Middle/physiology , Membrane Potentials/physiology , Tympanic Membrane/physiology , Acoustic Stimulation , Audiometry, Evoked Response , Humans , Meniere Disease/physiopathologyABSTRACT
Several treatment forms exist for tinnitus. These multiple treatments speak to the elusive etiology of tinnitus. Many authors have reported tinnitus reduction or elimination with electrical stimulation. This study evaluates a new device (Audimax Theraband) which delivers inaudible, transdermal, mastoid electrical stimulation. Thirty patients suffering from chronic tinnitus were evaluated in a single-blind crossover fashion. Since the electrical stimulation is inaudible, each patient served as his or her own control. Patients received actual or placebo stimulation over a period of 2 weeks. They rated their tinnitus levels and the effectiveness of the device before and after using the Theraband. Only 2 subjects out of 30 (7%) obtained true positive results. Side effects were minimal and reversible.