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Biomedical subjects

H Aritomo

Publications and source records attributed to H Aritomo.

10 recordsLinked to original sources
PubMed1996

[Clinical studies on acute otitis media in infants less than one year old].

Epidemiological and bacteriological studies were made on 164 infants less than 1 year old with acute otitis media (OMA) treated at the Department of Otorhinolaryngology, Matsuyama Red Cross Hospital between January 1991 and December 1993. The patients consisted of 101 males (61.6%) and 63 females (38.4%). Compared with the general population in Matsuyama city, the preponderance of male patients with OMA is statistically significant at the level of P = 0.05. In infants less than 1 year old males are likely to be more susceptible to OMA than females. One hundred and four patients among the 164 (63.4%) were referred by pediatricians. Fever was the most common symptom (57.9%) and the next was otorrhea (19.5%). Between the patients younger than 6 months (younger group) and those 6 months old or older (older group) there were epidemiological differences which were statistically significant at the level of P = 0.05. The older group contained 128 patients (78.0%) and the younger group 36 (22.0%). The difference in incidence between the two groups indicates that infants 6 months old or older are more susceptible to OMA than those younger than 6 months. In the older group 76.6% of the patients had bilateral OMA, while in 38.9% of those in the younger group the OMA was bilateral. In infants 6 months old or older bilateral involvement and, in contrast, in infants younger than 6 months unilateral involvement was more frequent. The period needed to cure OMA was confirmed for 179 ears of 106 patients. For 80 (44.7%) of the 179 ears the period extended beyond 4 weeks. Seventy-five of the 80 ears were those of patients in the older group. OMA in the older group tended to be more resistant to treatment. The middle ear secretion of 117 ears was examined bacteriologically. Specimens were collected from middle ear effusion of 99 ears following myringotomy and from otorrhea in 18 ears. Cultures of 68 specimens were positive for one species of bacteria and 13 cultures yielded two species. Streptococcus pneumoniae, Staphylococcus epidermidis and Haemophilus influenzae were the three most common microorganisms in middle ear effusion. But it was considered that S. spidermidis was not pathogenic and was a result of contamination. In otorrhea S. aureus was frequently found. No difference in the results of bacteriological study was noted between the two groups. Transplacental IgG1 and IgG2 antibodies to S. pneumoniae and H. influenzae are known to decrease after birth and their serum levels are lowest between ages 6 months and 1 year. Then the serum levels of the immunoglobulins increase gradually with active production until age 4 years. The incidence and period of restitution of OMA in infants less than 1 year old in the present study seem to reflect the above Change in the serum levels of IgG1 and IgG2 mentioned. Based on the above results emphasis is placed on close cooperation between the otolaryngologist and the pediatrician in the treatment of OMA in an infant less than 1 year old. Particularly careful follow-up is important in patients in the older age group because they tend to be more susceptible to OMA and the disease is more resistant to treatment.

Acute Disease↗
PubMed1993

Effect of changes in mass on middle ear function.

Vibrating systems such as the middle ear are affected by changes in mass. After disease or ear surgery, significant changes in mass may contribute positively or negatively to the postoperative hearing threshold. This article describes experiments in 15 human temporal bones of the addition or reduction of mass on the middle ear transfer function. Measurement of stapes and umbo vibration was performed using a Laser Doppler Vibrometer before and after the addition of different masses at several sites on the tympanic membrane (TM) and ossicular chain. The input was 61 pure tones swept from 147 to 19433 Hz at 80 dB SPL. The addition of mass onto the TM produced varying detrimental effects on sound transmission, depending on the location and amount of mass. The insertion of ventilation tubes, weighing 12 to 17 mg each, produced losses at 1.5 to 5.0 kHz compared with tympanotomy alone. Addition of mass to the umbo and malleus head produced a loss at mid and high frequencies, whereas addition of mass on the incus long process and stapes also produced a high-frequency decrease in stapes displacement. Reduction of TM mass by removal of the epithelium produced an increase, especially at 2.0 to 4.0 kHz.

Adult↗
PubMed1993

[Development of a cochlear input-impedance measuring device and its application in the temporal bones of dogs].

Cochlear input impedance was measured in 6 temporal bones taken from 3 dogs by use of a newly developed ceramic device. The device was composed of two ceramic bimorph elements, one for activation of the stapes and the other to pick-up vibration of the former element in the form of an electric output, which varies in accordance with the magnitude of cochlear impedance. Average impedance in the dogs was 2.3 Mohm at 2 kHz, 6.3 Mohm at 4 kHz and 17.8 Mohm at 6 kHz. Effect of closure of the round window was also investigated by placing dental cement on the window. In 3 ears, the impedance increased mainly below 4 kHz, while in the remaining 3 ears no such change occurred. This was probably because the closure was complete in the former but not in the latter.

Acoustic Impedance Tests↗
PubMed1989

Comments on "Acoustic Transfer Characteristics in Human Middle Ears Studied by a SQUID Magnetometer Method" [J. Acoust. Soc. Am. 82, 1646-1654 (1987)].

The study by Brenkman et al. [J. Acoust. Soc. Am. 82, 1646-1654 (1987)] of malleus umbo and anterior crus of stapes displacement in 14 human temporal bones shows a mean -7.3-dB/oct slope above 1.0 kHz for stapes displacement in response to a 80-dB SPL input at the eardrum. The slope they obtained for midfrequency (1.0-4.0 kHz) stapes displacement is significantly flatter than what was found previously [Gyo et al., Acta Otolaryngol. 103, 87-95 (1987); Gundersen, Prostheses in the Ossicular Chain (University Park, Baltimore, MD, 1971); Kringlebotn and Gundersen, J. Acoust. Soc. Am. 77, 159-164 (1985); Vlaming and Feenstra, Clin. Otolaryngol. 11, 353-363 (1986a)]; in these studies, stapes displacement rolled off at -12.0 to -14.9 dB/oct above 1.0 kHz. It appears that their mean midfrequency stapes displacement slope has been flattened by some unusual results in a small number of ears. Possible reasons for these results are discussed.

Acoustic Stimulation↗
PubMed1989

[Ossicular vibration in human temporal bones].

Vibration mode of the ossicles was investigated in twelve fresh human temporal bones using a video measuring system (VMS, Technical Instrument). This system allows one to observe the ossicular vibration and to measure its vibration amplitude (up to 0.2 micron) and phase angle. In this study the inner and middle ear was kept intact except for two small holes in the tympanic tegmen. These holes were for the observation of ossicular movement and were covered with a thin cover glass during the experiment. The vibration amplitude and phase angle of the umbo, malleus head, lenticular process and stapes head were measured at 19 frequencies between 0.1 kHz and 4.5 kHz. The umbo moved piston-like at 0.1-0.8 kHz and 2.6-4.5 kHz but in an ellipse at 1.0-2.4 kHz. The malleus head showed elliptical movement with its long axis anteriorly tilted around 45 degrees from the direction of the umbo vibration at 0.1 kHz. Both the lenticular process and stapes head showed similar movement; piston-like in lower frequencies and elliptical in higher frequencies. The umbo, lenticular process and stapes head vibrated parallel at lower frequencies. The position, displacement and phase angle of the rotation axis of the ossicles was calculated based on the displacement and phase angle of the umbo, malleus head and lenticular process. The axis was around the level of the neck of the malleus in frequencies lower than the resonant frequency, beneath the level of the short process near the resonant frequency and at the top of the malleus head in higher frequencies. The average axis displacement was 0.9 microns at 1 kHz but much smaller at frequencies lower than 0.8 kHz or higher than 2 kHz. This suggests that such axis movement may reduce the efficiency of the middle ear sound transmission.

Aged↗
PubMed1988

The role of pars flaccida in human middle ear sound transmission.

The role of the pars flaccida in middle ear sound transmission was studied with the use of twelve otoscopically normal, fresh, human temporal bones. Peak-to-peak umbo displacement in response to a constant sound pressure level at the tympanic membrane was measured with a noncontacting video measuring system capable of repeatable measurements down to 0.2 micron. Measurements were made before and after pars flaccida modifications at 18 frequencies between 100 and 4000 Hz. Four pars flaccida modifications were studied: (1) acoustic insulation of the pars flaccida to the ear canal with a silicone rubber baffle, (2) stiffening the pars flaccida with cyanoacrylate cement, (3) decreasing the tension of the pars flaccida with a nonperforating incision, and (4) perforation of the pars flaccida. All of the modifications (except the perforation) had a minimal effect on umbo displacement; this seems to imply that the pars flaccida has a minor acoustic role in human beings.

Acoustic Stimulation↗
PubMed1987

Implantable hearing aid. Report of the first human applications.

To our knowledge, this is the first report of human application of the partial implantable hearing aid. Direct driving of the stapes by an ossicular vibrator of piezoelectric ceramic bimorph is the fundamental mechanism of this device. Acoustic signals received by a microphone were transmitted to the external link coil after amplification. By means of electromagnetic induction, the internal coil placed under the retroauricular skin excited electroacoustic energy, which is transmitted to the vibrator directly coupled with the stapes. The device used in this first patient has been functioning for longer than one year. Excellent frequency response of the vibrator and highly efficient direct transmission of electroacoustic signals to the inner ear gave rise to acoustic perception of superior quality that could not be obtained by other surgical or rehabilitative measures.

Deafness↗
PubMedDate not supplied

Measurement of the ossicular vibration ratio in human temporal bones by use of a video measuring system.

Vibration modes of the ossicles and the lever function were studied in human cadaver temporal bones with an intact cochlea. After placing tiny steel spheres on the ossicles, ossicular vibration to a sound stimulus was measured by observing the displacements of the spheres under a microscope with strobe illumination by means of a video measuring system. The lever ratio varied from 1.9 at 0.6 kHz (minimum) to a peak of 6 near 2 kHz. This relatively high lever ratio at higher frequencies was considered to be caused by a shift of the malleus-incus rotation axis secondary to the loading of the cochlear fluid on the ossicular system. Dependence of the lever ratio on frequency indicated that the rotation axis of the ossicles was not fixed, but variable according to frequency due to a relative increase in the translational movements of the rotation axis of the malleus and incus with frequency.

Aged↗