Biomedical subjects

Richard L Goode

Publications and source records attributed to Richard L Goode.

11 recordsLinked to original sources

PubMed2005

Outcomes of hyoid suspension for the treatment of obstructive sleep apnea.

OBJECTIVE: To examine the efficacy of hyoid myotomy and suspension as a treatment of hypopharyngeal obstruction in obstructive sleep apnea. DESIGN: Prospective, observational study. SETTING: Academic medical center. PATIENTS: Twenty-nine consecutive male patients with suspected hypopharyngeal obstruction INTERVENTIONS: Patients underwent hyoid suspension. Uvulopalatopharyngoplasty with or without tonsillectomy was performed at the same time for those patients who had not undergone this procedure previously. Patients underwent clinical examination and sleep study prior to surgery and approximately 1 year postoperatively. MAIN OUTCOME MEASURES: Primary outcome was a successful surgical result, defined as apnea-hypopnea index lower than 20, 50% or greater decline in apnea-hypopnea index, and no oxygen desaturations below 85% on the postoperative sleep study. Secondary outcomes included daytime sleepiness as determined by the Epworth Sleepiness Scale and the severity of snoring. Postoperative complications were also recorded. RESULTS: Only 5 (17%) of 29 patients achieved a successful outcome. The respiratory disturbance index did not change significantly for the group as a whole, although the lowest oxygen saturation did show some improvement. CONCLUSIONS: Hyoid suspension does not provide results equivalent to those reported for genioglossus advancement or multisession tongue radiofrequency. Hyoid suspension alone is not an efficacious treatment for hypopharyngeal airway obstruction in most patients with obstructive sleep apnea.

Adult↗

PubMed2005

Experimental study of an adjustable-length prosthesis in a temporal bone model.

CONCLUSIONS: This prosthesis has the advantage of rapid adjustment at the time of insertion in order to achieve optimal tension and, as a result, optimal sound transmission. OBJECTIVE: To test the acoustic performance of a new, adjustable incus replacement prosthesis in a human temporal bone model. MATERIAL AND METHODS: Experiments were performed in seven human temporal bones, before and after removal of the incus and insertion of the prosthesis. The input comprised 406 pure tones ranging in frequency between 0.1 and 10 kHz at an intensity of 80 dB SPL at the tympanic membrane. The output measurement was stapes footplate displacement, determined by means of a laser Doppler vibrometer. Three lengths of the prosthesis were investigated: optimal, optimal +0.2 mm and optimal +0.4 mm. RESULTS: The optimal-length prosthesis produced similar results to those of an intact middle ear. The slightly longer prostheses decreased middle ear sound transmission at all test frequencies, except those near 1.5 kHz.

Aged↗

PubMed2005

Bone-conducted sound: physiological and clinical aspects.

OBJECTIVE: The fact that vibration of the skull causes a hearing sensation has been known since the 19th century. This mode of hearing was termed hearing by bone conduction. Although there has been more than a century of research on hearing by bone conduction, its physiology is not completely understood. Lately, new insights into the physiology of hearing by bone conduction have been reported. Knowledge of the physiology, clinical aspects, and limitations of bone conduction sound is important for clinicians dealing with hearing loss and is the purpose of this review. DATA SOURCES: The data were compiled from the published literature in the areas of clinical bone conduction hearing, bone conduction hearing aids, basic research on bone conduction physiology, and recent research on bone conduction hearing from our laboratory. CONCLUSION: Five factors contributing to bone conduction hearing have been identified: 1) sound radiated into the external ear canal, 2) middle ear ossicle inertia, 3) inertia of the cochlear fluids, 4) compression of the cochlear walls, and 5) pressure transmission from the cerebrospinal fluid. Of these five, inertia of the cochlear fluid seems most important. Bone conduction sound is believed to reflect the true cochlear function; however, certain conditions such as middle ear diseases can affect bone conduction sensitivity, but less than for air conduction. The bone conduction route can also be used for hearing aids; since the bone conduction route is less efficient than the air conduction route, bone conduction hearing aids are primarily used for hearing losses where air conduction hearing aids are contraindicated.

Basilar Membrane↗

PubMed2005

Transmission properties of bone conducted sound: measurements in cadaver heads.

In the past, only a few investigations have measured vibration at the cochlea with bone conduction stimulation: dry skulls were used in those investigations. In this paper, the transmission properties of bone conducted sound in human head are presented, measured as the three-dimensional vibration at the cochlear promontory in six intact cadaver heads. The stimulation was provided at 27 positions on the skull surface and two close to the cochlea; mechanical point impedance was measured at all positions. Cochlear promontory vibration levels in the three perpendicular directions were normally within 5 dB. With the stimulation applied on the ipsilateral side, the response decreased, and the accumulated phase increased, with distance between the cochlea and the excitation position. No significant changes were obtained when the excitations were on the contralateral side. In terms of vibration level, the best stimulation position is on the mastoid close to the cochlea; the worst is at the midline of the skull. The transcranial transmission was close to 0 dB for frequencies up to 700 Hz; above it decreased at 12 dB/decade. Wave transmission at the skull-base was found to be nondispersive at frequencies above 2 kHz whereas it altered with frequency at the cranial vault.

Acoustic Stimulation↗

PubMed2004

Round window membrane motion with air conduction and bone conduction stimulation.

The vibration patterns of the round window (RW) membrane in human cadaver temporal bone specimens were assessed by measurements of the velocity of reflective targets placed on the RW membrane with an approximate spacing of 0.2 mm. The velocity was measured in the frequency range 0.1-10 kHz by a laser Doppler vibrometer in four specimens with air conduction (AC) stimulation and in four specimens with bone conduction (BC) stimulation. The response pattern was investigated by analyzing the velocity response of all targets on the RW membrane, by making iso-amplitude and iso-phase contour plots of the membrane surface, and by creating animations of the surface vibration at several frequencies. Similar response pattern was found with AC and BC stimulations. At frequencies below 1.5 kHz, the RW membrane vibrates nearly as a whole in an in-and-out motion and above 1.5 kHz, the membrane moves primarily in two sections that vibrate with approximately 180 degrees difference. Indication of some traveling wave motion of the RW membrane at those frequencies was also found. At higher frequencies, above 3 kHz, the membrane motion is complex with a mixture of modal and traveling wave motion. An increase of the stimulation level did not alter the vibration pattern; it only gave an increase of the RW membrane vibration amplitude corresponding to the increase in stimulation. When the mode of stimulation at the oval window was altered, by the insertion of a 0.6 mm piston, the vibration pattern of the RW membrane changed.

Acoustic Stimulation↗

PubMed2004

Fluid volume displacement at the oval and round windows with air and bone conduction stimulation.

The fluids in the cochlea are normally considered incompressible, and the fluid volume displacement of the oval window (OW) and the round window (RW) should be equal and of opposite phase. However, other channels, such as the cochlear and vestibular aqueducts, may affect the fluid flow. To test if the OW and RW fluid flows are equal and of opposite phase, the volume displacement was assessed by multiple point measurement at the windows with a laser Doppler vibrometer. This was done during air conduction (AC) stimulation in seven fresh human temporal bones, and with bone conduction (BC) stimulation in eight temporal bones and one human cadaver head. With AC stimulation, the average volume displacement of the two windows is within 3 dB, and the phase difference is close to 180 degrees for the frequency range 0.1 to 10 kHz. With BC stimulation, the average volume displacement difference between the two windows is greater: below 2 kHz, the volume displacement at the RW is 5 to 15 dB greater than at the OW and above 2 kHz more fluid is displaced at the OW. With BC stimulation, lesions at the OW caused only minor changes of the fluid flow at the RW.

Acoustic Stimulation↗

PubMed2003

Basilar membrane and osseous spiral lamina motion in human cadavers with air and bone conduction stimuli.

It is generally accepted that bone conduction (BC) stimuli yield a traveling wave on the basilar membrane (BM) and hence stimulate the cochlea by the same mechanisms as normal air conduction (AC). The basis for this is the ability to cancel or mask a BC tone with an AC tone and the ability to generate two tone distortion products with a BC tone and an AC tone. The hypothesis is proposed that BC stimulates the BM not only through the hydrodynamics of the scala vestibuli and scala tympani, but also through osseous spiral lamina (OSL) vibrations. To test this hypothesis the BM and OSL response with AC as well as BC stimulation was measured with a laser Doppler vibrometer. Human temporal bones mounted on a shaker were used to record the velocities of the bone per se, the BM and the OSL. The measurements were then converted to relative BM and OSL velocities. The results from the basal turn of the cochlea show similar behavior with AC and BC stimulation. The motion of the OSL at the edge where it connects to the BM is in phase and is typically 6 dB lower than the BM motion. With BC stimulation, there is less phase accumulation in the OSL after the cochlea is drained; the OSL moves due to inertial forces and resonates at approximately 7 kHz. Inertial vibration of the OSL may partially contribute to the total response of BC sound, especially at the high frequencies, although current models of the cochlea assume a rigid OSL. The measurements reported here can be used to include a flexible OSL in cochlear models.

Acoustic Stimulation↗

PubMed2003

Airway management after maxillectomy: routine tracheostomy is unnecessary.

OBJECTIVES/HYPOTHESIS: There is a paucity of data to guide the optimal management of the airway in patients after maxillectomy. The decision on whether a concomitant tracheostomy is needed is often dictated by the surgeon's training and experience. We reviewed our experience with maxillectomy to assess the need for tracheostomy in postoperative airway management. STUDY DESIGN: Retrospective analysis at a university hospital. METHODS: We identified 121 patients who underwent 130 maxillectomies between October 1990 and September 2001. Twenty-four of these were total (all six walls removed), 45 were subtotal (two or more walls removed), and 61 were limited (only one wall removed). Reconstruction ranged from none to microvascular free flap, with split-thickness skin graft being the most common reconstructive option. RESULTS: Only 10 tracheostomies (7.7%) were performed at the time of maxillectomy. These included four tracheostomies in patients who underwent bulky flap reconstruction, two tracheostomies in patients who underwent both flap reconstruction and mandibulectomy, one tracheostomy in a patient who underwent mandibulectomy, one tracheostomy in a patient with mucormycosis in anticipation of prolonged ventilatory support postoperatively, and two tracheostomies at the surgeons' discretion because of concern for upper airway edema. Among the 111 patients who underwent 120 maxillectomies without concomitant tracheostomy, 1 patient (0.9%), a 74 year-old man with oxygen-dependent chronic obstructive pulmonary disease, required repeat intubation on day 3 and again on day 10 after the surgery, because of respiratory failure; fiberoptic examination confirmed the absence of upper airway compromise. CONCLUSIONS: The routine performance of tracheostomy in patients undergoing maxillectomy is unnecessary. Selective use of tracheostomy may be indicated in situations in which mandibulectomy or bulky flap reconstruction is performed or a concern for postoperative oropharyngeal airway obstruction because of edema or packing exists.

Adult↗

PubMed2003

Factors contributing to bone conduction: the outer ear.

The ear canal sound pressure and the malleus umbo velocity with bone conduction (BC) stimulation were measured in nine ears from five cadaver heads in the frequency range 0.1 to 10 kHz. The measurements were conducted with both open and occluded ear canals, before and after resection of the lower jaw, in a canal with the cartilage and soft tissues removed, and with the tympanic membrane (TM) removed. The sound pressure was about 10 dB greater in an intact ear canal than when the cartilage part of the canal had been removed. The occlusion effect was close to 20 dB for the low frequencies in an intact ear canal; this effect diminished with sectioning of the canal. At higher frequencies, the resonance properties of the ear canal determined the effect of occluding the ear canal. Sectioning of the lower jaw did not significantly alter the sound pressure in the ear canal. The sound radiated from the TM into the ear canal was investigated in four temporal bone specimens; this sound is significantly lower than the sound pressure in an intact ear canal with BC stimulation. The malleus umbo velocity with air conduction stimulation was investigated in nine temporal bone specimens and compared with the umbo velocity obtained with BC stimulation in the cadaver heads. The results show that for a normal open ear canal, the sound pressure in the ear canal with BC stimulation is not significant for BC hearing. At threshold levels and for frequencies below 2 kHz, the sound in the ear canal caused by BC stimulation is about 10 dB lower than air conduction hearing thresholds; this difference increases at higher frequencies. However, with the ear canal occluded, BC hearing is dominated by the sound pressure in the outer ear canal for frequencies between 0.4 and 1.2 kHz.

Auditory Threshold↗

PubMed2002

Factors contributing to bone conduction: the middle ear.

Measurement of the motion of the malleus umbo and stapes footplate during bone conduction (BC) stimulation was conducted in vitro in 26 temporal bones using a laser Doppler vibrometer over the frequency range 0.1 to 10 kHz. For lower frequencies, both ossicular sites followed the motion of the temporal bone. The differential motion between the malleus and the surrounding bone was greater than the differential motion of the stapes footplate; both resonated near 1.5 kHz. Different lesions were shown to affect the response: (1) a mass attached to the umbo lowered the resonance frequency of the ossicular vibration; (2) fixation of either the malleus or stapes increased the stiffness and shifted the resonance frequency upward; and (3) dislocation of the incudo-stapedial joint did not significantly affect the ossicular vibration. The sound radiated from the tympanic membrane was approximately 85 dB SPL at an umbo differential velocity of 1 mm/s for low frequencies in an open ear canal and about 10 dB higher for an occluded one; at higher frequencies (above 2 kHz) resonances of the canal determine the response. It was also found that the motion between the footplate and promontory was within 5 dB when the specimen was stimulated orthogonal to the vibration direction of the ossicles than in line with the same. Measurement of the differential motion of the umbo in one live human skull gave similar response as the average result from the temporal bone specimens.

Bone Conduction↗

PubMedDate not supplied

Three-dimensional stapes footplate motion in human temporal bones.

The literature provides conflicting information on whether the motion of the stapes footplate is piston-like or some other type of motion, such as rotational or rocking. Examination of the three-dimensional (3D) motion of the stapes footplate appears to be an excellent way to understand this complicated motion. Five microsphere reflective targets were placed on the stapes footplate in ten fresh human cadaver temporal bone preparations, and their vibration measured through an extended facial recess approach using a laser Doppler vibrometer. The five target sites on the stapes footplate were center, anterior, posterior, superior and inferior. The stimulus was a sound input of 80-120 dB SPL at the tympanic membrane over a frequency range of 0.1 to 10 kHz. The 3D motion of the stapes footplate was calculated using the velocity amplitude and phase obtained for each target. For frequencies up to 1.0 kHz the vibration of the stapes footplate was primarily piston-like; this motion became complex at higher frequencies, with rotary motion along both the long and short axis of the footplate. When the cochlea was drained, stapes footplate motion became essentially piston-like for all frequencies.

Aged↗