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Biomedical subjects

K Kaga

Publications and source records attributed to K Kaga.

At least 163 records · Page 9Linked to original sources
PubMed1990

[A case report of ball variance of Smeloff-Cutter prosthetic valve].

A 37-year-old woman had undergone aortic valve replacement with Smeloff-Cutter prosthetic valve in 1967. She visited our hospital because of dyspnea and chest pain about 22 years after the operation. Severe aortic regurgitant murmur was audible and a chest X-ray demonstrated lung edema. A diagnosis was made of acute left heart failure due to prosthetic valve dysfunction, and emergency operation was performed. The Silastic ball was severely deformed and shrunken. Therefore, the ball was easily put off outside the cage. A St. Jude medical prosthetic valve was implanted. The postoperative course was uneventful.

Adult↗
PubMed1989

Analysis of optokinetic nystagmus in patients with localized lesions of unilateral visual cortices.

Optokinetic nystagmus (OKN) asymmetry in 4 patients with localized lesions of the unilateral visual cortices (2 in the right hemisphere and 2 in the left hemisphere), confirmed at autopsy or by CAT scan, was detected by computer analysis. The ENG recordings showed typical asymmetry of OKP: lower amplitude in the contralateral optokinetic pattern (OKP) than on the side with the visual cortex lesion. Analysis of this asymmetry revealed lower amplitude, remarkably impaired slow-phase velocity, and mildly impaired fast-phase velocity, with a slight difference in number of OKN. The findings suggested that asymmetry of OKP in patients with localized lesions of the unilateral visual cortices is primarily caused by the impaired slow-phase velocity of the contralateral OKN because of a slight change in number of OKN.

Adolescent↗
PubMed1989

Temporal bone pathology of a patient without hearing and caloric reaction, and with counter-rolling after chronic myelocytic leukemia.

The temporal bone pathology of a 36-year-old man who suffered from chronic myelocytic leukemia and sudden hearing loss of both ears, was studied from the viewpoint of neurotology. Neurotological examination showed bilaterally profound hearing loss and no caloric reaction but good counter-rolling reaction to the right and the left head tilt and no other abnormal neurological findings. He died of intracranial hemorrhage. A study of histopathology of the temporal bones revealed extensive destruction of the organ of Corti, dilatation of Reissner's membrane, leukemic infiltration in the cochlea but good preservation of sensory hair cells in the vestibular endorgans. Leukemic cell infiltration in perilymphatic and endolymphatic spaces, and leukemic hemorrhage in the perilymphatic spaces were observed. And also in the left internal auditory canal, obvious leukemic infiltration and marked hemorrhage were observed, but in the right internal auditory canal, no abnormal change was found. We discuss the correlation between neurotological findings and histopathological findings.

Adult↗
PubMed1989

[A case of auditory agnosia with the lesion of bilateral auditory radiation].

A 53-year-old man showed central auditory disturbance with recurrent cerebral hemorrhage. At his acute stage he had deafness and auditory anosognosia. Two or three months later, there was no deafness and auditory anosognosia, but he could not comprehend words, environmental sounds and music. Auditory brainstem responses showed no peripheral or brainstem damage, and the lesion of bilateral auditory radiation was detected by MRI. His auditory agnosia did not improve over one and a half year. There is no report like such permanent auditory agnosia with the lesion of bilateral subcortical temporal lobe.

Agnosia↗
PubMed1988

'Cat P300' disappears after septal lesions.

Endogenous responses were recorded from 9 awake cats with loud and soft clicks randomly presented as rare (P = 0.15) or frequent (P = 0.80) stimuli; a reinforced tone CS (P = 0.05) resulted in a conditioned eye blink response and focused the cat's attention on the auditory stimuli. Subsequent to 12 preoperative recording sessions the medial septal area was lesioned in 7 cats and similar but more rostral lesions were placed in 2 cats. Thereafter, 12 postoperative recording sessions were carried out, the animals were terminated, and the brains processed for AChE histochemistry and histology of the lesioned areas. Destruction of the medial septum and vertical limb of the diagonal band of Broca resulted in a transient postoperative 'cat P300' followed by reduction and disappearance of the response. The hippocampus of these animals was characterized by marked AChE depletion. In contrast, the animals with lesions rostral to the medial septal area showed no postoperative change in the P300 response and no depletion of hippocampal AChE. These data indicate an important role for the medial septal area as a modulator of 'cat P300' generation possibly through the cholinergic component of the septohippocampal projection system.

Acetylcholinesterase↗
PubMed1988

Excision of the lunate in Kienböck's disease. Results after long-term follow-up.

Excision of the lunate was performed for 18 patients with Kienböck's disease; 14 were followed up for an average of almost 12 years. Carpal collapse progressed with time, but rearrangement of the remaining carpal bones preserved a satisfactory range of movement and grip strength. Degenerative changes were not severe. All the patients had relief of pain, were able to carry out their normal activities, and all but two could perform strenuous activities.

Adult↗
PubMed1988

Transplants and implants for major ear anomalies.

To accomplish two objectives, morphological and functional improvements, in plastic operation of major ear anomalies, the authors presented a surgical method utilizing exclusively auto materials and several pedicles of skin, fascia and periostium. A partially implantable middle ear implantable hearing aid (Partial-MEI) is also an indication to those anomalies. Incidentally, we implanted the first Partial-MEI to a patient with unilateral atresia-microtia. The case was presented and demonstrated Partial-MEI implantation as one of the approaches for major ear anomalies to improve hearing.

Ear, External↗
PubMed1986

Auditory brain stem responses and nonsense monosyllable perception test findings for patients with auditory nerve and brain stem lesions.

A nonsense monosyllable audiometric test was administered to 15 patients with eighth nerve or brain stem disorders caused by tumor, hemorrhage, encephalitis, and degenerative disease. Auditory brain stem responses (ABR) were abnormal in all patients. ABR abnormalities were defined by the absence of some or all waves or by prolongation of the wave V-I interval. The discrimination scores of the nonsense monosyllables were significantly lower in patients with completely absent ABR, with partial ABR series involving wave I, or with severely prolonged wave V-I intervals (over 3 SD). However, in patients with wave I only or with only moderately prolonged wave V-I intervals (less than 3 SD), test scores were within normal range. It is concluded that: 1. perception of nonsense monosyllables could be, though need not be, affected in patients with brain stem lesions; 2. eighth nerve lesions severely disrupt auditory comprehension as well as perception of nonsense monosyllables.

Adult↗
PubMed1986

Cat P300 present after primary auditory cortex ablation.

A long-latency (200-500 msec) endogenous potential with characteristics of the human P300 was recorded over 12 sessions in 4 adult cats. Principal components analysis with t tests showed that this potential was significantly larger in response to rare auditory stimuli than to the same stimuli presented frequently. The primary auditory cortex was ablated bilaterally. The preoperative tone-elicited conditioned eye blink response remained postoperatively. After 12 postoperative sessions, statistical analyses of these data demonstrated that the P300-like potential was still present. Thus, the primary auditory cortex is not necessary for generation of the P300-like response in cats.

Acoustic Stimulation↗
PubMed1986

Auditory brainstem responses in young children with Down's syndrome.

Auditory brainstem evoked responses (ABRs) were studied in 37 Japanese infants and children with Down's syndrome to determine the level of the lesion causing their unresponsiveness to sound stimuli. ABR thresholds, peak latencies of waves I and the peak interval latency of wave I-V were measured. For comparison with ABR thresholds, behavioral audiometry was performed. Thirty-two percent of the patients (12 cases) with Down's syndrome showed no responses by ABR as well as behavioral audiometry. The other ABR abnormalities with respect to age-matched controls were classified into 6 types: shorter wave I latencies (2 cases, 5%), shorter wave V latencies (7 cases, 19%), shorter wave I-V intervals (8 cases, 22%), wave I prolongation (13 cases, 35%), wave V prolongation (5 cases, 14%) and prolongation of wave I-V peak interval (no case, 0%). Our results demonstrate a high incidence of hearing loss at middle and inner ear levels, and suggest some anomaly within the auditory brainstem in Japanese cases of Down's syndrome.

Audiometry, Evoked Response↗
PubMed1986

Spontaneous downbeat nystagmus in two sisters with sudanophilic leukodystrophy.

Two sisters who manifested downbeat nystagmus at the early stage of leukodystrophy are reported. The younger sister whose onset was at the age of 20, deteriorated rapidly to the vegetative state, and died of acute pneumonia 7 years after. Her downbeat nystagmus was observed only during the early 2 years of the course of her disease. The histopathological study on her brain enabled a diagnosis of sudanophilic leukodystrophy which demonstrated overall gliosis of white matter in the cerebrum and severe depopulation of Purkinje cells in the cerebellum, particularly in the vermis. The elder sister's onset was at the age of 29 and deteriorated rapidly to akinetic mutism. Her downbeat nystagmus was observed only during the first year of the course of her disease. For over 10 years she has been at the vegetative state. CT-scan of her brain demonstrates low density areas in the white matter of the cerebrum and in the vermis of the cerebellum. These two cases showed similar clinical signs and courses of their diseases, which were spontaneous nystagmus, early changes of personality and intelligence, and extra-pyramidal sign and later rapid deterioration of the stage of akinetic mutism. Histopathologically these cases are suspected as having an identical hereditary etiology of sudanophilic leukodystrophy. In these cases it is noted that downbeat nystagmus was the early sign of the disease.

Adult↗
PubMed1986

Auditory brainstem responses and behavioural responses in pre-term infants.

Auditory brainstem responses (ABRs) and behavioural thresholds were studied in 25 pre-term infants with post-conceptional ages of approximately 40 weeks to ascertain whether there were differences in the ABR between normal preterm and full-term new born infants to compare behavioural thresholds around 40 weeks of post-conceptional age and to follow changes of their behavioural thresholds in the first year of life. ABR thresholds, peak latencies of Waves I and V and the I-V peak interwave latency were measured. Behavioural audiometric thresholds to pure tones were determined through behavioural observation audiometry and conditioned orientation-reflex audiometry. The ABR thresholds of the pre-term infants, whether they were small for date (SFD) or appropriate for date (AFD), were in the normal ranges of the controls. Moreover, there were no significant differences between either the SFD or the AFD group and controls, as far as Wave I or V latency or I-V interval are concerned. Thus, the ABR was apparently unaffected by the infant being small-for dates. Behavioural audiometry disclosed that all normal full-term infants responded to pure tone stimuli, with mean thresholds of 85 dB, while only 42% of AFD and 30% of SFD would respond to pure tone stimuli at 90 dB or less. Behavioural thresholds caught up with the normal range by 12 months of age, except for a few infants.

Audiometry↗
PubMed1985

The auditory pathology of brain death as revealed by auditory evoked potentials.

A case of brain death is reported in which the auditory brainstem response, middle latency component, and slow vertex response were recorded before and after the cessation of cortical activity, and in which histological examination of the temporal bone and central auditory pathways was performed post mortem. Brain death of at least 48 hours' duration was demonstrated by neurological examination, flat electroencephalographic recording, and persistent absence of auditory evoked responses. The postmortem examination was performed 3 hours after death. The pathological studies of the whole length of the auditory pathway revealed total autolysis of the organ of Corti, marked cell loss in the dorsal cochlear nucleus, and moderate cell loss in other nuclei of the central auditory pathway. It should be considered that total autolysis of the organ of Corti and severe cell loss of the cochlear nucleus may occur if the auditory brainstem response becomes absent in comatose patients.

Adult↗
PubMed1985

Recovery of vestibulospinal balance function after unilateral labyrinthectomy in patients with Ménière's disease.

The influence of unilateral labyrinthectomy on vestibulospinal balance function in patients with Ménière's disease is studied with a gravicorder. Our data disclosed that vestibulospinal balance recovery was better when tested in the light, including the total length and area. Moreover, this quantitative test which measures changes in the center of gravity in standing subjects revealed that total length recovery was almost achieved within 5 weeks when measured in the light but required 12 months when measured in the dark; total area was almost in the normal range within 1 week when measured in the light but required 5 weeks when measured in the dark.

Adult↗
PubMed1985

Auditory short, middle, and long latency responses in acutely comatose patients.

For assessing comatose patients, the combination of auditory short, middle, and long latency evoked potentials (auditory brain stem response [ABR], middle latency component [MLC], and slow vertex response [SVR] ) is more comprehensive than auditory brain stem response (ABR) only or ABR with slow vertex response (SVR). Fifty-four acutely comatose patients were studied. Thirty-four of the patients had severe head injury and others had coma of varied etiology. Within two months after admission, 25 patients survived, while 29 patients died. Auditory evoked response measurements were conducted usually within 48 to 72 hours after admission. For patients with normal SVR, MLC, and ABR, there was 100% survival; with absent SVR but normal MLC and ABR, survival was 91%; with absent SVR and MLC and normal ABR, it was 60%; with abnormal ABR, it was 10%; no patient survived whose ABR was absent. It is emphasized that a normal MLC is clearly a predictor of survival of comatose patients, but a normal ABR is not always a reliable indicator of survival.

Adolescent↗
PubMed1984

Normalization of poor auditory brainstem response in infants and children.

In these past 10 years, the usefulness of auditory brainstem response (ABR) has been demonstrated in the clinical evaluation of audiological or neurological disorders, and the absence of an ABR is commonly accepted as consistent with a peripheral hearing loss caused by middle or inner ear diseases. In this article, the authors report nine infants and children who had an absent or difficult to detect ABR at the first examination with subsequent normalization of ABR. Repeated otological examinations were always normal in these patients. The final diagnoses were delayed development, Waardenburg syndrome with congenital heart disease and epilepsy, healthy infant, infantile convulsion, mental retardation with history of low birth weight, in each case, and chromosomal aberration in four patients. The reason for normalization of ABR in our patients is not clear and is yet to be ascertained. However, the authors believe that neurological maturation rather than an improved primary peripheral disorder is responsible for the noted normalization of the ABR, because of the high incidence of neurological abnormalities in these patients.

Audiometry, Evoked Response↗