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Objective: To compare the effect of superpulsed carbon dioxide (CO2) laser alone with that of cryotherapy in combination with CO2laser in treatment of facial rhytids. Design: A randomized prospective study. Setting: Facial Plastic Surgery Clinic at Stanford University Medical Center, Stanford, Calif. Patients: Twenty patients with perioral rhytids were randomized in the study, 11 in the laser group and 9 in the cryotherapy and laser group. Intervention: Patients in the laser group were treated with superpulsed CO2laser. Initially, the shoulders of rhytids were spot treated. The area was then wiped and rehydrated. The entire surface was then treated with a second pass. A third pass, if deemed necessary, was then used to treat the shoulders. Patients in the combined group underwent cryotherapy of the entire perioral region followed by CO2laser treatment similar to that previously described. Main Outcome Measure: Improvement in facial rhytids with laser treatment alone was compared with improvement using cryotherapy and laser. A skin wrinkle grading system was used and patients were graded by 3 independent observers. Close-up photographs were obtained preoperatively and postoperatively. A questionnaire was filled out by each patient 1 month following treatment and was used to rate overall patient satisfaction. Results: There was no statistically significant difference between the 2 groups regarding final outcome, amount of anesthetic agents required for each patient, or rate of complications. Conclusion: Superpulsed CO2skin resurfacing alone is as effective as combined cryotherapy and superpulsed CO2laser for treatment of perioral rhytids. Arch Otolaryngol Head Neck Surg. 1996;122:1169-1173

Routine incisions in the temporal area for rhytidectomy often remove hair-bearing skin anterior to the ear. This results in a cosmetic deformity, making the surgical intervention clearly visible. This is especially problematic for revision rhytidectomy or for patients with naturally high hairlines. This article describes a systematic approach to the temporal hairline and introduces a novel, hair-bearing, transposition flap that corrects iatrogenic loss of the preauricular tuft of hair.

The nasal cavity and paranasal sinuses are probably one of the last frontiers in the head and neck region where the use of topical antimicrobial agents is not yet established. Although the anatomy of the nasal cavity and the paranasal sinuses can theoretically be exploited for the administration of antimicrobials in rhinosinusitis, very few studies have been conducted to test the feasibility of this mode of therapy. We review the anatomical and physiological factors that should be considered in the use of topical nasal antimicrobial agents and the current status of topical nasal antimicrobial usage, and we make recommendations for the administration of topical nasal antimicrobial agents.

Many experts believe that a polysomnogram to screen for obstructive sleep apnea should be performed on every patient who has a history of loud snoring and sleepiness. In contrast, the author believes that with a careful history and physical examination, there is no need to study all such patients, at least not until home polysomnography units become as convenient and economical as pulse oximetry.

This study was designed to determine whether stapes movement is pistonlike or complex.The literature provides conflicting information on whether stapes footplate motion is only pistonlike or has other types of movement, such as hingelike or rocking.Using 10 freshly harvested human cadaver temporal bones, 3 targets were placed on the stapes footplate through an extended facial recess approach. The targets were 0.5-mm pieces of reflective adhesive material positioned on the long axis of the footplate at the anterior crus, central footplate, and posterior crus. Displacement and phase of the three targets were measured from 0.2 to 10 kHz at a 90dB sound pressure level input at the tympanic membrane. The measuring system was a sophisticated laser Doppler vibrometer (LDV). A computer program (Tymptest) calculated footplate displacement and relative phase at the three sites and the ratio of anterior-posterior rocking movement of the footplate long axis to displacement at the center.Below 2.0 kHz, stapes vibration is predominately pistonlike. Above 2.0 kHz, anterior-posterior rocking motion increases logarithmically with frequency, and, near 4.0 kHz, rocking and pistonlike motion are approximately equal.Stapes footplate vibration is primarily pistonlike up to 2.0 kHz but becomes more complex at higher frequencies because of an increase in anterior-posterior rocking motion. Hingelike movements were not observed. This information may be helpful in the design of ossicular replacement prostheses that mimic or improve upon normal stapes vibration.

This paper describes measurements of the vibratory modes of the middle ear ossicles made with a scanning laser Doppler vibrometer. Previous studies of the middle ear ossicles with single-point laser Doppler measurements have raised questions regarding the vibrational modes of the ossicular chain. Single-point analysis methods do not have the ability to measure multiple points on the ossicles and, consequently, have limited ability to simultaneously record relative phase information at these points. Using a Polytec Model PSV-100, detailed measurements of the ossicular chain have been completed in the human temporal bone model. This model, when driven with a middle ear transducer, provides detailed three-dimensional data of the vibrational patterns of the middle ear ossicles. Implications for middle ear implantable devices are discussed.

We describe a laser Doppler system (LDS) that can be used clinically for the measurement of tympanic membrane (TM), malleus and prosthesis head displacement in response to sound inputs of 80-to 100-dB sound-pressure level (SPL). It also has the potential for use in the operating room to perform measurements of prosthesis and stapes displacement. The information provided by such testing gives the otologist knowledge of TM and ossicular function that is unique in evaluating middle ear function; it should help select the best type of reconstruction in a given case and direct us toward new and better methods of TM and ossicular reconstruction. The results of umbo displacement measurements in 95 human ears are reported. Examples are provided of LDS measurements in representative ears and how they can be of help to the clinician. The potential of multisite TM-displacement testing is demonstrated in two temporal bones, including before and after partial ossicular replacement prosthesis (PORP) insertion.

We evaluate the metabolic inhibitory, antiproliferative, and antisecretory effects of LY300502, a benzoquinolinone human-specific type I-selective steroid 5alpha-reductase inhibitor in LNCaP human prostatic adenocarcinoma cell cultures. Reductive metabolism of [3H-T] in the LNCaP cells was inhibited in a concentration-dependent manner by LY300502 (IC50 approximately 5.77 nM). The proliferative responses of LNCaP cells to LY300502 were examined in the presence of 0.1 NM testosterone (T), a concentration that stimulates maximal LNCaP cell numbers 40% above control levels. LY300502 significantly anatagonized T-induced stimulation of LNCaP cellular proliferation at concentrations greater that 10 nM (P0.05), and at 1,000 nMcompletely blocked the mitogenic effects of T on LNCaP cells. In the absence of androgen, LY300502 had no effect on LNCaP cellular proliferation. In the presence of 100 nM T, an androgen concentration that maximally stimulates in vitro PSA production, LY300502 significantly antagonized T-induced PSA secretion at a concentration equal to or greater than 30 nM (P0.05). These studies provide the basis for additional investigations into the pathophysiologic significance of type I 5alpha-reductase to prostatic cancer and the potential utility of selective inhibitors as therapeutic agents.

Partially implantable electromagnetic hearing aids have several potential advantages over conventional hearing aids. As conventional hearing aids improve in the quality of sound they deliver, however, the role of implant aids must be redefined. One area where they may provide the most benefit is in patients with moderate to severe hearing loss.

Implantable hearing aids have an interesting and colorful history. These devices have usually been investigational, but this has changed. Currently, several implantable devices are available for ongoing clinical trials in humans. They have promise in providing improved hearing in certain cases of conductive, mixed, and sensorineural hearing loss.

Investigation of bulbourethral gland (BUG) development is useful to study genitourinary (GU) tract growth and differentiation. Understanding GU tract growth and differentiation is relevant to testing the hypothesis that the initial lesion of human benign prostatic hyperplasia involves focal re-expression of inductive processes in the periurethral region of the prostatic transitional zone. Prostaglandins play a role in regulating growth and morphogenesis of different organ systems. Previous reports have proposed that prostaglandin E2 (PgE2) mediates the masculinizing effects of testosterone in the developing neonatal male GU tract. We have previously shown that androgens lower rather than raise BUG PgE2 levels. Further studies led us to conclude that PgE2 does not play a major role in postnatal BUG growth and morphogenesis in vitro. In order to investigate the possible role of PgE2 in prenatal BUG development, indomethacin (INDO, 1.0 mg/kg- day, subcutaneously) was administered to pregnant BALB/c mice on gestational days 12-18. Control pregnant mice were either untreated or injected with dimethylsulfoxide vehicle. Anogenital distances were measured within 12 hours after birth in male and female offspring on day 19. In male neonatal mice, BUGs were examined histologically and PgE2 levels were measured by radioimmunoassay in BUGs and whole genital tracts. We observed no significant morphological differences in INDO-exposed BUGs compared to controls. No significant differences in mean anogenital distances of INDO-exposed male offspring or controls were detected. Mean anogenital distances of female offspring were similar in the three respective groups. Mean BUG PgE2 levels in INDO-exposed neonates were significantly lower (P0.05) than in untreated neonates.(ABSTRACT TRUNCATED AT 250 WORDS)

Measurement of the acoustic properties of middle ear prostheses in an appropriate model prior to insertion in humans should be part of the routine of the prosthesis development and testing process, but it is not. This article describes a human temporal bone model suitable for such testing and discusses the results of several commonly used prostheses evaluated in the model. By comparing existing and new experimental prostheses in such a model, we should be better able to develop prostheses capable of providing improved hearing results following middle ear reconstruction.

Many middle ear prostheses are available for reconstruction of a missing or damaged incus. Little is known of the relative acoustic performance of these prostheses in vitro and the parameters (mass, shape, tension, angulation, area of head) that modify this performance. This report describes experiments in a human temporal bone model comparing the effect on stapes displacement of six commercially available incus replacement prostheses (IRP). Measurements were performed using a laser Doppler vibrometer before and after incus removal and IRP placement between the tympanic membrane (TM) and stapes head. In addition, experiments were performed on the effect of increasing prosthesis mass, varying the tension between TM and stapes head, changing the surface area in contact with the TM, and comparing different TM contact sites. All prostheses tested showed reasonable acoustic performance compared to the baseline condition. Optimum tension between the TM and stapes head produced the best overall sound transmission. The mid-malleus and umbo locations were the best malleus contact sites; however, the posterior TM contact site also worked well. Increased mass improved low frequency transmission and impaired higher frequency transmission, whereas a larger contact area with the TM contributed to increased gain in the mid frequencies.

A commercial laser doppler vibrometer (LDV) was used to evaluate umbo displacement at sound pressure levels of 60, 70, and 80 dB SPL at the tympanic membrane (TM) of six subjects. Thirty-five pure-tone test frequencies, five per octave, were tested from 140 to 19,433 Hz. A computer program (Tymptest) produced and controlled the tones as well as improved the signal-to-noise ratio of the LDV. The test took about an hour to perform and provided reproducible results in all subjects. In addition, measurement of umbo displacement using the same system was made in 15 fresh human temporal bones for comparison. Results in the humans revealed a relatively flat umbo displacement from 140 to 1000 Hz, with a gradually sloping roll-off of -8.25 dB per octave from 1000 to 7000 Hz. From 8000 to 14,000 Hz the roll-off increased to -12.5 dB per octave. At the mean resonant frequency of the middle ear, 1000 Hz, and an 80 dB SPL input, umbo displacement was 0.045 micron. The human temporal bones showed similar results. Possible future clinical applications of this measurement include the identification of ears with acoustically inefficient TMs (tin ears). By identifying and studying such ears we should be able to develop methods to improve their function and produce hearing threshold increases of 15 dB or more at key speech frequencies. In addition, analysis of umbo and TM vibration in reconstructed middle ears should help us achieve better postoperative hearing results.

The effects of hormonal ablation, estrogen, estrogen-derived cytotoxic agent, and estrogen antagonist therapies used clinically were evaluated on in vitro colony formation, in vivo growth, and lymphatic and pulmonary metastasis of the PAIII tumor. Ventral prostatic and seminal vesicle weights were evaluated in the same animals to assess androgen-related responses. Estradiol, estramustine phosphate, and testosterone had no effects on PAIII colony formation in vitro. Castration, hypophysectomy, estradiol benzoate, and estramustine phosphate treatment of PAIII-bearing Lobund Wistar rats produced significant (P less than 0.05) regression of male accessory sex organs. Of these treatments, only hypophysectomy had significant (P less than 0.05) inhibitory effects on primary PAIII growth and lymphatic and pulmonary metastasis. LY117018 [6-hydroxy-2-(p-hydroxyphenyl)benzo(b)thien-3-yl-p-2-(l-pyrrolidin yl)ethoxy phenyl ketone] has antiestrogenic activity but produces no significant agonist responses. LY117018 had no effect upon PAIII colony formation in vitro. Following s.c. implantation of PAIII cells, LY117018 (2.0, 10.0, or 20.0 mg/kg s.c.) had no effect on primary tumor growth in the tail. In vitro LY117018 administration produced marked antimetastatic effects. In a dose-dependent manner, LY117018 inhibited PAIII metastasis to the gluteal (97%) and iliac lymph nodes (88%) (P less than 0.05 for both). LY117018 also maximally inhibited pulmonary metastasis by 86% (P less than 0.05). Maximal regression of 42% for ventral prostatic and 35% for seminal vesicle weights were also seen after LY117018 administration (P less than 0.05 for both). Co-administration of estradiol benzoate had no antagonistic effect upon the antitumor responses produced by LY117018. The mechanism of action of LY117018 is not known. The failure of estradiol benzoate to affect PAIII growth and metastasis supports the contention that the responses to LY117018 are not attributable to simple antagonism of estrogen action. LY117018 may be exerting its antitumor effects through autocrine, paracrine, or endocrine mechanisms. LY117018 represents a class of agents with potential utility in treating metastatic cancer of the prostate.

Between 1975 and 1982, 38 patients with locally advanced head and neck cancer attached to the carotid artery underwent surgical excision followed by iodine 125 vicryl suture implant in the neck. Most patients had neck masses that were greater than 6 cm and stage IV disease without clinically evident distant metastases. Twelve patients had received no previous therapy while 26 underwent an implant for recurrent disease. The local control rate in the implant volume was 79%. The local and regional control rate in all head and neck sites was 53%. The mean survival was 11 months. The overall complication rate was 26%. There was no significant correlation of local control or complications with the minimum total dose, volume implanted, individual 125I seed strength, or total seed strength. In patients with large masses attached to the carotid artery, surgical resection followed by a 125I implant for residual disease is a viable alternative to resection of the carotid artery.

The surgical therapy for velopharyngeal incompetence has always been a challenging problem. In spite of the surgical choices of palatal pushback, pharyngeal flap, pharyngoplasty, muscle transfers, and pharyngeal wall implants, the reported failure rate has varied from 10% to 50%. A group of ten patients with velopharyngeal insufficiency is presented, two posttonsillectomy and adenoidectomy, three secondary to congenital deficiencies, and five following palatal and pharyngeal paralysis secondary to severe closed head injuries. The technique and experience with the lateral port control pharyngeal flap is discussed.

It appears that a variety of surgical techniques are available to safely decrease the size of hyperplastic inferior turbinates; when used properly in appropriate patients they can provide significant improvement in the symptoms of chronic nasal obstruction.

The carcinogenicity of benzo[a]pyrene (BP) and its widespread occurrence as an environmental pollutant have prompted numerous studies on the metabolic fate and biological activity of this hydrocarbon. Our laboratories in Nutley and Bethesda have jointly undertaken a systematic study of the metabolic fate and biological activity of BP and its many metabolites. The goal of this research program is to elucidate the molecular events that result in the metabolic activation of BP and to identify the proximate and ultimate carcinogenic forms of this environmental carcinogen. This chapter is a progress report that describes (1) a high-pressure liquid chromatography system for the separation of BP dihydrodiols, BP phenols, and BP quinones; (2) the metabolism of BP by a solubilized and reconstituted cytochrome P448 monooxygenase system in the presence and absence of purified epoxide hydrase; (3) the metabolic activation of BP to mutagenic metabolites by a cytochrome P448 or cytochrome P450 reconstituted monooxygenase system; (4) the effect of epoxide hydrase on the cytochrome P448-mediated activation of BP to mutagenic metabolites; (5) the mutagenic activity of 28 synthetic derivatives of BP; and (6) the carcinogenicity of three BP oxides on mouse skin.

Colposcopic evaluation of patients with abnormal Papanicolaou smears permits the physician to visualize cervical lesions and determine the extent of intraepithelial neoplasia. Through the use of colposcopy with cryotherapy, many patients with cervical intraepithelial neoplasia may avoid a more invasive form of treatment. Family physicians should become familiar with colposcopic technique so that they can select patients who are suitable for local treatment with cryotherapy.

Isolates of Bacillus subtilis that had been presumed to carry the cysA14 lesion have been studied. Our data indicate that these strains contain four mutations, all of which are linked by transformation and lie in the region of the ribosomal markers. The requirement for cysteine results from a defective serine transacetylase that is coded for by the cysA locus. Therefore, these mutants grow only in the presence of cysteine but not with sulfate, sulfite, or sulfide as the sole source of sulfur. A second genetic lesion (css) can be recognized by an increased sensitivity to the amino acid L-cysteine. The inhibited enzyme(s) has not been determined but inhibition is overcome by a mixture of eight amino acids. The third mutation (hts) results in the overproduction and excretion of hydrogen sulfide. This compound appears to be produced from cysteine by the enzyme cysteine desulfhydrylase and not by an increased activity of the sulfate-reductive pathway. This locus presumably codes for a regulatory element involved in the control of cysteine desulfhydrylase. The fourth mutation (cym) is not well characterized biochemically but results in a requirement for cysteine or methionine. The following order of these mutations has been established by transformation studies: hts, cysA, css, cym. The generally poor growth of these mutants in minimal-salts glucose media supplemented with cysteine can now be explained by these observations. The cysA14 mutants not only require an amino acid that is itself inhibitory to growth but they also overproduce the highly toxic compound hydrogen sulfide.

Twenty-eight patients with squamous carcinomas of the base tongue were seen and evaluated in a conjoint Head and Neck Tumor Board at Stanford between 1976 and 1982. Fourteen patients were treated by combined external beam and interstitial irradiation, 11 of whom had Stage III and IV carcinomas (American Joint Committee). An initial dose of 5000 to 5500 rad was first delivered by external beam irradiation in 5 to 5.5 weeks, followed approximately 3 weeks later by an iridium 192 (192Ir) interstitial implant boost by the trocar and loop technique. The key to successful treatment of these neoplasms was found to be the use of a lateral percutaneous cervical technique, which placed horizontal loops through the oropharyngeal wall above and below the hyoid bone; the superior loop included the pharyngoepiglottic fold and the tonsilloglossal groove. Standard multiple loop implants (submentally inserted) of the base tongue from the vallecula anteriorly to the circumvallate papillae were also used routinely. This approach has been successful, since 10 of the 14 patients (71%) remain without evidence of disease (mean follow-up, 32 months). There have been only two local recurrences, both on the pharyngoepiglottic fold in patients who did not receive the now standard pharyngoepiglottic fold/lateral pharyngeal wall implants. No patients have relapsed after 18 months. The other 14 patients were treated prospectively during the same period by combining initial resection, radical neck dissection, and postoperative irradiation. In this group, there were more locoregional failures compared to the group treated with radiation therapy alone (5 tongue recurrences and 7 neck relapses); in addition, more severe complications were noted in these 14 patients who received surgery and postoperative irradiation. The authors believe that combined external beam and interstitial irradiation is effective treatment for base tongue carcinomas, especially when the high-dose distribution includes the adjacent tonsilloglossal groove, pharyngoepiglottic fold, and oropharyngeal wall to and below the level of the hyoid bone, in addition to treating an adequate base tongue volume.

The indications for use of implantable hearing aids are presented. Features of the devices that are currently available are presented. Comparisons with conventional hearing aids are also made.

Eighteen patients with advanced squamous cell cancer of the head and neck were treated with cis-diamminedichloroplatinum in a 24-hour infusion. The most frequent dose used was 80 mg/m2 repeated every three weeks. Six were treated preoperatively for Stage III or IV disease, and twelve were treated for recurrent disease. The overall response rate was 72% with one complete remission, greater than 50% regression in six patients, and 25--50% regression in six patients. Toxicity was minimal: creatinine greater than 2 in 6% of courses, leukopenia in 9%, anemia in 29%, vomiting in 76%, and documented minimal hearing loss in one patient. Plasma and urine platinum levels during infusion are presented. The dosage of 80 mg/m2 administered over 24 hours gives a response rate in head and neck cancers equivalent to that reported with higher doses given by rapid infusion, and toxicity is minimal.

Indium-111 BLEDTA, a bleomycin analog containing an EDTA group, was used for tumor imaging in 110 patients with cancer. Scans with In-111 BLEDTA agreed with biopsy results in 75 of 95 patients (79% accuracy). A positive scan was obtained in 71 of 88 patients with a positive biopsy (81% sensitivity). In 21 of 95 patients (22%), the scan revealed tumor sites that had not been detected. The main limitation of visualization was the size of the tumor (1.5--2.0 cm diameter was the smallest size seen). Background radioactivity in the liver, spleen, and bone marrow also made tumor detection in these areas more difficult. The cause of this background, and of false-positive uptake in sites of inflammation, is correlated with specific radiolabeling of polymorphonuclear leukocytes by In-111 BLEDTA. Means of eliminating this background are discussed.

The T-tube has several advantages that should be considered when selecting a ventilation tube. First, it remains in place much longer than the average tube; thus allowing the physician, rather than chance, to determine when the tube should be removed. Second, it can be removed painlessly without an anesthetic when indicated. Third, it does not have the problem of a high post-removal perforation rate such as seen with other long term tubes. Fourth, it can be easily modified to suit the needs of the patient and the physician.

These modifications minimize flap loss, fistulae, and stenosis, and make the final stage easier to perform. The need for periodic dilation with Maloney dilators may be required; however, we do not consider this a significant complication. The goal is a predictable result with a low complication rate so that oral feedings can begin 5 weeks after laryngopharyngectomy, and postoperative radiotherapy may be started at 6 weeks. The need for three stages may appear excessive; however, three planned stages are better than three or more unplanned stages that result in flap loss or dehiscence.

Mesenchyme (UGM) and epithelium (UGE) isolated from the urogenital sinuses (UGS) of 17-day male and female rat embryos were separated by using a trypsinization procedure, grown on soft agar, transplanted into syngeneic pubertal male hosts as subcapsular renal grafts, and then collected after 29-30 days. Neither UGM nor UGE underwent prostatic morphogenesis when grown under these conditions. However, tissue recombinants composed of UGM + UGE grew and produced prostatic glands with acinar secretory material. Further, UGM + UGE recombinants were made by varying the proportions of mesenchymal and epithelial tissues. The size of the implants was a function of the absolute amount of mesenchyme; increasing the absolute amount of UGM produced larger specimens whereas varying the UGE had no effect. The UGM was also found to be essential for supporting the growth of small glandular elements derived from the ventral prostate of pubescent rats. Segments isolated from the terminal vesicles (TIPs) and from prostatic tissue adjacent to the urethra (PDCT) regressed when implanted alone under the kidney capsule. However, combination of the prostatic segments with UGM produced prostatic glands with relative wet weight and DNA content responses of the following order: UGM + TIP greater than UGM + PDCT = UGM + UGE. Two-dimensional gel electrophoretic protein patterns from UGM + PDCT and UGM + TIP specimens had differential expression of three protein regions unique to the ventral prostate Quantitative and qualitative responses of the TIP and PDCT segments to UGM inductive influences indicate that differences exist between the epithelia of the TIP and PDCT regions of the ventral lobes of the rat prostate.

Mediastinoscopy is a safe and simple endoscopic procedure for the exploration of the superior mediastinum. It provides useful information as to the possible resectability of bronchogenic carcinoma, or for establishing the diagnosis of primary tumors of the mediastinum, metastatic disease and a variety of chronic granulomata.

A UNIVERSALLY ideal tracheal replacement has been a challenging but as yet unsolved surgical problem. Defects involving a portion of the tracheal circumference may satisfactorily be repaired with grafts of autogenous fascia or cartilage 1 and longitudinal defects may be repaired with skin grafts supported with wire sutures. 2,3 In the past, circumferential cervical tracheal defects of not more than 2 cm were repaired by mobilization and end-to-end anastomosis 4,5 ; however, recent work 6 has demonstrated that as much as 4 cm of cervical trachea may be excised and the end-to-end anastomosis accomplished. Still longer segments of trachea may be excised, but in order to accomplish an end-to-end anastomosis a thoracotomy must be performed to free the tracheobronchial tree. Circumferential defects greater than 4 cm usually require a staged reconstructive procedure utilizing skin flaps 7,8 if a thoracotomy is to be avoided. As previously noted, 9 very limited success has

Conventional teaching regarding the acoustic function of the human middle ear is that it serves as an impedance matching system to offset the loss that occurs when sound passes from the low-impedance sound field to the high-impedance cochlear fluid. A transformer analogy is often used with the pressure transformation produced by the eardrum; footplate area ratio and the lever ratio considered to be approximately 27 dB. Recent data on middle ear function has shown this to be only partially correct. A transformer analogy is not appropriate since the pressure gain of the middle ear decreases above 1000 Hz and does not depend on the cochlear load at all frequencies. Experiments are described of umbo, malleus short process, and stapes displacement in human temporal bones using a laser Doppler measuring system (LDS). The measurements support previous studies that indicate that in addition to a roll-off in tympanic membrane function above 1000 Hz, there is slippage in the ossicular lever system that causes an increasing "lever ratio" above 1000 Hz, thought to be caused by translational movement of the ossicular rotation axis near the short process. An improved analog circuit model of the external and middle ear has been developed that produces results equivalent to those found in the temporal bones.