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Biomedical subjects

F Ohta

Publications and source records attributed to F Ohta.

At least 55 records · Page 3Linked to original sources
PubMed1989

Hearing aid evaluation using psychoacoustical proximity between Japanese monosyllables.

To facilitate hearing aid selection, a new method was developed to assess the qualitative changes in speech perception with and without a hearing aid. This method utilizes maps of the Japanese monosyllables where the degrees of confusion are represented by distances between the monosyllables. On these maps, perceptual failures of the monosyllables can be simply analyzed by connecting confused stimuli and the corresponding wrong responses. The qualitative characteristics of monosyllable confusion for 53 patients with hearing impairment were comparatively analyzed with and without hearing aids. Results show that this method is useful for describing the qualitative effects of hearing aids on speech perception, and that it thus provides important information for hearing aid selection.

Adolescent↗
PubMed1989

[The onset of sudden deafness and Bell's palsy--statistical analysis].

Existing studies on sudden deafness and Bell's palsy have shown no statistically significant differences in the numbers of patients by the times of the onsets, namely, days of the week, weeks of the month, months of the year and seasons of the year. However, accumulation of collective data in various areas and years may produce averaged data. Correlation between the occurrence of sudden deafness and that of Bell's palsy has not been studied so far. The yearly differences in the onsets of these diseases for the past 10 years were investigated using the Kendall's coefficient of concordance. In sudden deafness, very slight but statistically significant differences were found, when the numbers of patients and the onsets were analyzed by monthly basis, trimonthly basis (Nov-Jan, Feb-Apr, May-July and Aug-Oct) and quarterly basis. In Bell's palsy, no statistically significant differences were found in the times of onset of Bell's palsy and that of sudden deafness.

Facial Paralysis↗
PubMed1989

[Multiple spinal neurinomas without von Recklinghausen's disease: report of three cases].

Multiple spinal tumors are relatively rare and account for from only 1.2 to 9.5% of all spinal tumors. Half of the multiple spinal tumors are accompanied with von Recklinghausen's disease. Since March 1983, we have encountered 31 spinal tumors including 11 neurinomas, three of which were multiple and showed no manifestations of von Recklinghausen's disease. The incidence of multiple spinal tumors was 9.7% in our series. Altogether, 40 cases of multiple spinal neurinomas without von Recklinghausen's disease have been reported including our three cases. According to those 40 cases, much neurinomas occur 5 times more frequently in men than in women, and they are found predominantly in the lumbosacral region. In the present paper, we describe three cases of multiple spinal neurinomas, and compare the results of several neuroradiological examinations. Myelography was the most reliable method to determine whether or not the tumors were multiple. However, in cases where myelography was completely blocked out, other neuroradiological methods such as metrizamide-CT scan or MRI with Gd-DTPA intravenous injection were able to bring us information concerning multiplicity.

Adult↗
PubMed1989

[Carpal tunnel syndrome associated with long-term hemodialysis: case report].

Since Warren and Otieno reported carpal tunnel syndrome in patients on intermittent hemodialysis in 1975, a number of related reports have been published. However, there are few reports associated with neurosurgery about carpal tunnel syndrome in patients on long term hemodialysis. We reviewed this disease and reported our case. We treated a patient who complained of bilateral hand numbness and atrophy of the right thenar muscle. He had been suffering from chronic renal failure and had been treated with hemodialysis for ten years. We diagnosed carpal tunnel syndrome based on the findings concerning Tinel's sign, Phalen test, and the conduction velocity of the median nerve. We performed decompression surgery of the median nerve. However, although there was no recovery from thenar muscle atrophy, there was improvement of hand numbness. Histologically, amyloid deposits within the hypertrophic transverse carpal ligament on the right side, could be found but on the left side where the internal shunt had been made amyloid deposits were absent. The reason why patients receiving long term hemodialysis develop carpal tunnel syndrome is controversial, but it seems that beta 2 microglobulin may play an important role in developing carpal tunnel syndrome in hemodialysis patients. This was reported by Gejyo in 1985. There may be uremic and/or diabetic neuropathy in these patients, and these neuropathies may be responsible for the more rapid deterioration and poorer surgical results in carpal tunnel syndrome associated with hemodialysis than in idiopathic cases. It is most important that carpal tunnel syndrome has to be diagnosed early and that surgical decompression is performed while the disease is in its early stage.

Carpal Tunnel Syndrome↗
PubMed1989

[Usefulness and limitations of neuroradiological examinations in lumbar canal stenosis].

Since 1983, we have performed 434 spinal surgery operations. Among them are included 51 cases of lumbar canal stenosis. For these 51 cases, we performed several neuroradiological examinations, such as lumbar plain X-ray, myelography, metrizamide-CT scan (Met-CT) and magnetic resonance imaging (MRI). We discussed and examined the usefulness and limitations of such neuroradiological methods for diagnosis of lumbar canal stenosis. On myelography, these 51 patients were divided into three types; a complete block type with 29 patients, soy-beans type with 7 patients and strangulation type with 15 patients. Myelography could show the level of stenosis, but could give little information about the compressing factors, particularly in complete-block type. Met CT was performed in 37 cases. In both strangulation type and soy-beans type which had been shown through myelography, Met-CT could clearly demonstrate the subarachnoid space, and several structures around the lumbar spinal canal could be clearly identified. In cases which myelography revealed as complete-block type, we identified two subtypes. In the first type subarachnoid space was clearly demonstrated by Met-CT. The second type was comprised of those cases where Met-CT scan could not demonstrate subarachnoid space at all. In the former group, useful information about lumbar canal stenosis could be obtained, but, in the latter, information was scarce. MRI was performed on 21 patients. MRI clearly showed the anatomical relationship of disc, subarachnoid space, yellow ligament and hypertrophied bony structure.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

[Transthoracic approaches to the lesions of thoracic cord and thoracic vertebrae].

Experiences of transthoracic approaches to the thoracic cord lesions were reported. Since 1983, we have performed six transthoracic approaches to the thoracic lesions; one thoracic OPLL, one dumbbell-shaped neurinoma, two thoracic soft disc, one epidural metastatic tumor to thoracic vertebrae. From the viewpoint of surgical anatomy, the thoracic vertebrae show a physiological kyphosis and the subarachnoid space of the ventral site is narrower than that of the dorsal site. Due to such anatomical characteristics, the thoracic laminectomy for decompression is not so effective as in the cervical or lumbar region and a relatively small mass lesion can bring a paraplegic state. The lesion of the ventral site of the thoracic cord has been regarded as no man's land because of poor results of posterior approaches. Instead of posterior approaches, anterior or anterolateral approaches with transthoracic route have been adopted. In the present paper, we used transthoracic anterolateral approaches for four patients and anterior sternum-splitting approach for two patients. The operative procedures of the approaches were described in detail. By these approaches, we could treat four patients with favourable results but the result of thoracic OPLL was poor. The cause of this poor result seemed to depend upon the intraoperative compression of the thoracic cord. For the troublesome complication, we described the postoperative cerebrospinal fluid leakage into thoracic cavity with respiratory disturbance. Several devices to prevent such troublesome complication were discussed.

Adult↗
PubMed1987

Quantitative analysis of inner ear anomalies by high resolution CT scanning of the temporal bone.

High resolution CT-scanning of the temporal bone revealed malformations of the labyrinthine capsule in 50 ears in our clinic from November 1980, to the end of 1984. Detailed assessment of the nature and extent of the abnormality allowed each ear to be awarded a mathematical score. Using statistical methods, the score was then correlated with the patient's hearing in that ear. By this method it was possible, with an 80% chance of being correct, to allocate a patient into one of two groups, i.e. partial deafness or total deafness.

Adolescent↗
PubMed1985

Reconstruction of the Eustachian tube and the anterior tympanum: planned staged tubo-tympanoplasty.

A new technique is demonstrated in the management of chronic otitis media with inflammatory stenosis of the Eustachian tube. Bone exposure of the Eustachian tubal orifice and peritubal air cells was followed by placement of a long T-shaped solid silicone plate in this area. Postoperative care was taken to ensure wound healing in the same way as after radical mastoidectomy. At the second stage surgery the Eustachian tube and pretympanum were found to have developed with an intact mucous membrane. A middle ear space with or without reconstruction of the posterior meatal wall and obliteration of mastoidectomy cavity could easily be rebuilt. A sound pressure transformer mechanism could be established at the second stage surgery.

Adolescent↗
PubMed1984

Reconstruction of the middle ear with tragal cartilage.

A surgical technique for reconstruction of a well-ventilated middle ear space using tragal cartilage has been developed. Our technique was designed so as to secure an atticoantrum cavity and a complement of posterior tympanic annulus with a cartilage. This technique can be utilized in a radical mastoidectomy cavity at an original surgery and at a revision.

Adolescent↗
PubMed1984

[Gangliocytoma of the pineal body. A case report and general review].

A case of pineal gangliocytoma in a 51 year-old man is presented. He was admitted to the hospital on February 2, 1982, with complaints of headache, nuchal pain, blurred vision, nausea and vomiting of three years' duration. Neurological examination did not show any neurological deficits but bilateral choked disc. Preoperative CT scan disclosed a sharp by circumscribed high density lesion in the pineal region with moderate hydrocephalus. Preoperative 99m Tc-DTPA brain scan revealed a warm activity in the pineal region, and changes of its activity were only little in the course of time. Preoperative Amipaque ventriculogram showed dilation of the lateral ventricles and a shadow of the tumor bulging into the posterior half of the distended third ventricle. A diagnosis of tumor of the pineal region was made and removal of the tumor was performed by biparieto-occipital interhemispheric approach in "sea lion" position. The tumor was a dark reddish solid mass which replaced the pineal body and extended under the cerebellar tentorium. The patient made an uneventful recovery without any neurological deficits. By light microscopy, the neoplasm was composed mostly of mature and immature ganglion cells and small round cells with moderate cellularity and multiform cytologic features. Ganglion cells with large nuclei and prominent nucleoli had characteristic Nissl substance in various amounts. Oligodendrocytes and astrocytes appeared around the tumor but did not show neoplastic growth. GFAP stain did not show glial component in the tumor. According these findings, the tumor was diagnosed as gangliocytoma originated from the pineal body, and this was the first case in Japan.

Brain Neoplasms↗
PubMed1983

Evaluation of alaryngeal voice quality by nonparametric procedures.

Alaryngeal voice quality was evaluated based on nonparametric statistics. Twenty voice samples of the vowel /e/ were recorded from sixteen alaryngeal and four normal speakers, and were randomized and presented to twenty normal listeners. The listeners rated the voices using seven-point scales consisting of twelve pairs of polar-opposite adjectives. By means of nonparametric procedures such as the Wilcoxon signed rank test, significant differences in the rating scores were detected for certain combinations of the voice samples, the classes of voicing methods, the listeners and the rating scales. Quality of the alaryngeal voices differed significantly from that of the normal voices on some of the rating scales. The results suggest the nonparametric procedures are useful to evaluate alaryngeal voice quality.

Adult↗