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Biomedical subjects

I Honjo

Publications and source records attributed to I Honjo.

At least 55 records · Page 3Linked to original sources
PubMed1997

Application of parasagittal surface coil MRI to otoneurological diagnosis.

Parasagittal surface coil magnetic resonance imaging (MRI) of the internal auditory canal and the inner ear was performed in patients with otoneurological diseases. T2-weighted fast spin-echo sequences, plain and enhanced T1-weighted sequences were used to examine the inner ear and the individual nerves in the internal auditory canal. Normal parasagittal images of the inner ear and the internal auditory canal and 4 patients with otoneurological disorders are presented. Precise location of the acoustic tumor was visualized and postoperative status of the internal auditory canal and the inner ear was assessed by the present method. The cochlear nerve was not identified in a patient with long-standing unilateral deafness. A follow-up study with MRI was performed in a patient with Meniere's disease who underwent endolymphatic-mastoid shunt surgery, showing gradual postoperative shrinkage of the shunted endolymphatic sac. The present method provides a new approach to the assessment of otoneurological disorders.

Adolescent↗
PubMed1997

Usefulness of magnetic resonance imaging in diagnosing vertebro-basilar insufficiency.

To estimate the usefulness of magnetic resonance imaging (MRI) in diagnosing vertebro-basilar insufficiency (VBI), 41 VBI patients with vertigo or dizziness and 26 subjects without vertigo or dizziness (as control) were examined by MRI. Sixty-eight percent of the VBI group and 12% of the control group showed a large difference between the right and the left vertebral artery diameter, the incidence being significantly higher in the VBI group. Thirty-nine percent of the VBI group and 12% of the control group had lacunar infarction in the brain stem, of which the incidence was significantly higher in the VBI group, MRI can be recommended to diagnose VBI providing information on both blood vessel disorder and ischemic changes in the brain.

Aged↗
PubMed1996

Cortical speech processing mechanisms while vocalizing visually presented languages.

To elucidate cortical processing during vocalization, we used positron emission tomography to measure regional cerebral blood flow during vocalization in six Japanese subjects. During reading Japanese sentences used daily or short syllables aloud, the visual cortices, the left Heschl's gyrus, Broca's area, the primary motor area of the articulatory organs, the supplementary motor area and the cerebellum were significantly activated, compared with resting conditions. The superior temporal gyri were rarely activated. Significant activation of the cerebellum was observed by comparing cortical activity during reading sentences used daily with that during reading meaningless short syllables. These results suggest that vocalization of familiar materials is taken over by the cerebellum, rather than cortical speech areas, and without engagement of the superior temporal gyri.

Adult↗
PubMed1996

Magnetic resonance imaging of patients with large vestibular aqueducts.

The vestibular aqueduct (VA) and endolymphatic sac (ES) were examined by magnetic resonance imaging in eight patients (14 ears) with large VAs, and the results were compared with those obtained in five normal volunteers (10 ears). It was not possible to identify either the VA or ES in any of the control ears. However, in all the 14 ears with a large VA, the VA was detected as a fluid-filled structure. In 12 ears the ES was seen to be markedly enlarged and also filled with fluid. In one ear, the volume of the fluid-filled space within the VA and ES was measured as 912 mm3 on serial images. Five patients (ten ears) were observed to have a fluid-filled VA and enlarged ES without cochlear anomalies and reported frequent episodes of sudden hearing loss and vertigo following exercise, long exposure to sunshine, minor trauma and the like. Two other patients (three ears) also had enlarged VA and ES as well as cochlear anomalies, but did not have episodes of sudden hearing loss and vertigo. These findings suggest that direct transmission of intracranial pressure changes to the inner ear or subsequent movement of endolymph in patients with a large VA may adversely influence a seemingly normal cochlea and vestibule.

Adult↗
PubMed1996

Endoscopic findings at the pharyngeal orifice of the eustachian tube in otitis media with effusion.

Transnasal endoscopy of the pharyngeal orifice of the eustachian tube was performed on 155 ears with otitis media with effusion (77 ears of children, 78 ears of adults). In children, blockage of the orifice by mucopurulent nasal discharge was the most frequent finding (72.7%), followed by compression of the orifice by the adenoid tissue (52.0%), hypertrophy of the peritubal tonsil (16.9%), and edema around the orifice, especially at its posterior lip (10.4%). In adults, the most frequent abnormal finding was edema of the orifice (26.9%), followed by blockage of the orifice by mucopurulent nasal discharge (23.1%), and atrophy of the orifice (10.3%). In 39.7% of cases findings were normal. Thus, main pathological findings associated with tubal dysfunction involved inflammation in the nasopharynx.

Adult↗
PubMed1996

Cochlear implant efficiency in pre- and postlingually deaf subjects. A study with H2(15)O and PET.

We used 15O-labelled water in a PET study to test the efficiency of cochlear implants (CIs) in transmitting auditory information to the brain in 10 profoundly deaf subjects. Five were postlingually deaf, and five were prelingually deaf. All the subjects were right-handed. White noise and verbal stimuli, delivered through the CIs, were used for cortical activation. Similar tasks were performed by six right-handed hearing subjects as a control group. In the postlingually deaf subjects, verbal stimulation activated the transverse temporal gyri (primary auditory cortices) mainly on the side contralateral to the CI. The left posterior superior temporal gyrus (Wernicke's area), and the left inferior frontal gyrus (Broca's area) were also activated irrespective of stimulated side. The location of these activated foci was the same as that of the control group. White noise stimulation led to an increase of regional cerebral blood flow (rCBF) only in the primary auditory cortices of the postlingually deaf subjects, only on the side contralateral to the CI, and the intensity of activation was less than that obtained with verbal stimulation. In the prelingually deaf subjects, Wernicke's area and Broca's area were significantly activated by verbal stimulation, whereas there was no activation in the primary auditory cortices. White noise did not activate the primary auditory cortex in the prelingually subjects. These findings suggest that cortical representation of language is not dependent on early auditory experience, while processing in the primary auditory cortices is experience-dependent. The postlingually deaf subjects had a greater increase of rCBF in the Broca's and Wernicke's areas and better sentence comprehension than the prelingually deaf subjects, which suggest a parallel relation between rCBF increase and the ability to recognize spoken language. H2(15)O-PET with auditory stimulation is an effective means of objectively quantifying the response of auditory and association cortices after CIs in deaf subjects.

Adolescent↗
PubMed1996

Omohyoid muscle transposition for the treatment of bowed vocal fold.

Imperfect glottal closure is usually the most important factor causing dysphonia in patients with bowing of the vocal folds. We have performed laryngeal framework surgery, which allows the medialization of the vocal folds from the outside without creating any scar tissue on them. Over the past 6 years, however, we encountered three cases with marked bowing of the vocal folds that could not be cured by laryngeal framework surgery alone. We used an open laryngeal procedure in these cases, even though such procedures had been considered contraindicated in the treatment of hoarseness. After performing a laryngofissure, we made a small pocket beneath the vocal fold mucosa at the anterior commissure. The superiorly based omohyoid muscle flap was then transposed into the mucosal pocket and sutured to the vocal process. This procedure should be considered an option in treating highly bowed vocal folds.

Adult↗
PubMed1996

Cause of eustachian tube constriction during swallowing in patients with otitis media with effusion.

In order to clarify the cause of the constriction of the eustachian tube during swallowing that is often seen in patients with otitis media with effusion, video endoscopy of the pharyngeal orifice of the eustachian tube was performed and superimposed with videograms of the tubal airflow and resistance, which were simultaneously examined by the forced response test. In children with otitis media with effusion (17 ears), when the eustachian tube constricted on the videogram on swallowing, the tubal orifice was found to be squeezed between an elevated soft palate and a hypertrophied adenoid (7/17), squeezed between an elevated soft palate and edema of the posterior lip (7/17), or blocked by nasal discharge (5/17). In adults with otitis media with effusion (7 ears), edema of the posterior lip (5/7) was the main cause of the constriction of the tubal orifice during swallowing. Inflammation in the nasopharynx and the pharyngeal portion of the eustachian tube was considered to be closely related to the tubal constriction, which represents a considerable part of the cause of tubal ventilatory dysfunction in otitis media with effusion.

Adult↗
PubMed1996

Influence of surface condition of mucosa of eustachian tube on tubal compliance.

To clarify the influence of the mucosal condition of the eustachian tube (ET) upon its collapsibility, three experimental studies were performed by using the forced response test. First, by washout of the mucous blanket of ET, the tubal compliance index (TCI), the ratio of passive tubal resistances at two different airflow rates, significantly increased in all the 6 ETs of 5 cats, and all returned to the baseline within 50 min. Second, the TCIs significantly decreased in all the 7 ETs of 5 cats after application of Triton X (surfactant) into the ET washed out by saline. Third, the increased TCIs of a tubal model by application of saline significantly decreased after application of Triton X. These results seem to support our hypothesis that compliance of the ET, which means its collapsibility, may depend upon the mucosal condition as well as on the property of the cartilaginous framework of ET.

Animals↗
PubMed1995

Orientation for cochlear implant surgery in cases with round window obstruction: a computer reconstruction study.

In order to improve cochlear implant surgery in patients with obstructed round windows, surgical orientations of the round window and scala tympani relative to the stapes footplate were examined in ten normal temporal bones using a computer-aided, three-dimensional reconstruction and measurement technique. The round window was found to be exactly inferior to the midpoint of the inferior margin of the stapes footplate in most cases. An optimal point on the promontory wall for drilling to reach the bottom of the scala tympani of the basal turn was found to lie approximately 1.5 mm anterolateral or anterolateral inferior to a point 3 mm inferior to the midpoint of the inferior margin of the stapes footplate. A combination of the transmeatal and facial recess approaches made it possible to consistently reach the scala tympani, and demonstrated that this approach was also applicable to patients with obstructed round windows.

Adolescent↗
PubMed1995

Effect of vestibular nerve section on cytochrome oxidase activity in the vestibular ganglion cells of the squirrel monkey.

Cytochrome oxidase (CO) activity of the vestibular ganglion cells of the squirrel monkey was demonstrated histochemically under normal and experimental conditions. Under general anesthesia, right vestibular nerve section was performed on adult squirrel monkeys between the vestibular ganglion and brain stem. The left side was left intact and was used as a within-animal normal control. One squirrel monkey that did not undergo vestibular nerve section was also included in the normal group. Following a survival period of seven months, neurons in the vestibular ganglion of both sides were examined. In the normal control sides, a significant negative correlation between the size of the neuron and its optical density for CO stain was observed. Many neurons in the vestibular ganglion survived after vestibular nerve section, but their cell sizes and optical densities of CO stain decreased compared with those of the control side.

Animals↗
PubMed1995

Cortical activation with sound stimulation in cochlear implant users demonstrated by positron emission tomography.

Six postlingually deaf patients using multi-channel cochlear implants were examined by positron emission tomography (PET) using 15O-labeled water. Changes in regional cerebral blood flow (rCBF) were measured during different sound stimuli. The stimulation paradigms employed consisted of two sets of three different conditions; (1) no sound stimulation with the speech processor of the cochlear implant system switched off, (2) hearing white noise and (3) hearing sequential Japanese sentences. In the primary auditory area, the mean rCBF increase during noise stimulation was significantly greater on the side contralateral to the implant than on the ipsilateral side. Speech stimulation caused significantly greater rCBF increase compared with noise stimulation in the left immediate auditory association area (P < 0.01), the bilateral auditory association areas (P < 0.01), the posterior part of the bilateral inferior frontal gyri; the Broca's area (P < 0.01) and its right hemisphere homologue (P < 0.05). Activation of cortices related to verbal and non-verbal sound recognition was clearly demonstrated in the current subjects probably because complete silence was attained in the control condition.

Acoustic Stimulation↗
PubMed1995

The influence of upper respiratory tract inflammation upon tubal function.

Eustachian tube function was examined in four patients (four ears) with a traumatic perforation of the tympanic membrane when they suffered from an upper respiratory tract (URT) infection or seasonal nasal allergy and after they had recovered. Although the tubal opening pressure did not show a distinct difference on the two occasions, the active ventilatory function was apparently impaired during the upper respiratory tract inflammation; particularly the negative middle ear pressure equalizing function, and was still impaired 2-3 weeks later after recovery from the upper respiratory tract inflammation. It is concluded that URT inflammation can affect tubal ventilatory function even in normal individuals.

Adult↗
PubMed1995

Surface-coil magnetic resonance imaging of the internal auditory canal and the inner ear. Preliminary report.

Parasagittal surface-coil magnetic resonance imaging of the internal auditory canal and the inner ear was performed. We used T2-weighted fast spin-echo sequences to visualize the inner ear and the individual nerves in the internal auditory canal with high contrast in a short acquisition time. Computer-assisted quantitative measurement of the nerves was performed to estimate the cross-sectional areas and the diameters of the nerves. The average diameters of the facial nerve, the cochlear nerve, and the vestibular nerve of normal-hearing individuals were, respectively, 1.1 +/- 0.2 mm (mean +/- SD), 1.2 +/- 0.2 mm, and 1.5 +/- 0.2 mm. In the cerebellopontine angle, the average diameter of the eighth nerve was 1.8 +/- 0.2 mm. Two patients with unilateral and bilateral hearing loss were also presented. In the patient with unilateral deafness, the cochlear nerve of the diseased side was not identified and the eighth cranial nerve diameter was smaller than that of the normal side. In the patient with bilateral deafness, fibrosis of the inner ear and atrophy of the eight nerve were demonstrated in the ear with posttraumatic deafness. The present method may represent a new approach to the assessment of pathologic processes involving the inner ear and the nerves in the internal auditory canal.

Adult↗
PubMed1995

Sensorineural hearing loss in patients with large vestibular aqueduct.

In examining 181 patients (327 ears) with sensorineural hearing loss of unknown etiology and 25 people (50 ears) with normal hearing by high-resolution computed tomography (CT), the image of the large vestibular aqueduct (VA) was defined as being a visible large aperture (> or = 4 mm), and small distance between vestibule and traceable part of the VA nearest to the vestibule (> or = 1 mm). The large VA was found in 13 patients (23 ears, 7.0%); it was relatively frequent following hypoplastic cochlea (33 ears, 10.1%) in all the inner ear anomalies detected. In patients with large VA, high-frequency hearing was affected more than low frequency, and history of sudden hearing loss was observed frequently (61% of ears with large VA), which was found to be triggered by characteristic episodes such as minor head trauma, etc. Those clinical features were observed more in those without cochlear anomaly than in those accompanying cochlear anomaly. Pathogenesis of sensorineural hearing loss and characteristic fluctuation of hearing in those patients are discussed.

Adult↗
PubMed1995

Vestibular function in patients with a large vestibular aqueduct.

Four patients (7 ears) with a large vestibular aqueduct (VA) were examined for history of vertigo and vestibular function. Vertigo was observed in all the 4 patients. The caloric responses were significantly poorer in ears with a large VA than in the controls. On a patient with a large VA who had several attacks of sudden hearing loss and vertigo following minor head trauma, long-time exposure to sunshine, common cold, and exercise, vestibular function tests were performed several times; the caloric responses were found to fluctuate and direction changing apogeotropic positional nystagmus was observed. These findings suggest that in patients with a large VA, not only hearing but also the vestibular function are generally impaired. We believe than direct transmission of intracranial pressure changes to the inner ear or subsequent inner ear fluid movement through the large endolymphatic sac and duct have an influence on the cochlea and vestibule.

Adolescent↗
PubMed1995

Studies of currently used and experimental cochlear implants.

Since 1987 we have inserted multichannel cochlear implants in 60 patients with severe hearing impairment. The surgical procedures were not very difficult, and few postoperative complications were encountered. Postoperative speech recognition by every patients was satisfactory. Nevertheless, some patients complained about their hearing in a noisy environment, or while listening to either TV or music. Consequently, cochlear implants needs further improvement. To improve speech recognition ability, a newly developed experimental system was constructed. Judging from the electrode activation pattern, the new system extracted the features of consonants more successfully than the present system. However, when this new system was installed in cochlear implant patients, no significant improvement in consonant recognition was obtained.

Adult↗