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Biomedical subjects

E Adachi-Usami

Publications and source records attributed to E Adachi-Usami.

At least 109 records · Page 6Linked to original sources
PubMed1987

Pattern electroretinogram and visual evoked cortical potential in ethambutol optic neuropathy.

Forty-one eyes in 21 cases of ethambutol optic neuropathy were investigated for the pattern visual evoked cortical potential (VECP) and the pattern electroretinogram (ERG). In 21 of the eyes the disappearance VECP responses were not detectable. In the other 20 eyes the peak latency and amplitude of the disappearance VECP were delayed and decreased significantly compared with normal eyes. The recovery of the peak latency of the disappearance VECP in ethambutol optic neuropathy was faster than that of the amplitude. Twelve eyes in six patients were studied by pattern reversal ERG. Though the mean peak latency of the pattern ERG was within normal limits, the mean amplitude was decreased significantly. Our investigations indicated that ethambutol optic neuropathy disturbed not only the optic nerve but also the retina.

Adult↗
PubMed1987

Evaluation of pattern visual evoked cortical potentials for prescribing spectacles in mentally retarded infants and children.

We found that refractive errors were present in about 80% of 650 mentally retarded infants and children. The appropriate spectacles were prescribed for 75%. Evaluation of the effectiveness of wearing spectacles was based on the observation of their daily behavior and visually evoked cortical potentials to pattern stimuli (PVECP). Despite difficulties, we are able to record PVECPs in 160 subjects, of whom PVECPs were detectable in 140 (87.5%). The amplitudes of PVECPs with spectacles were larger than those without spectacles in 55.2% of the 105 subjects whose PVECPs were examined both with and without spectacles.

Adolescent↗
PubMed1987

Facially distributed pattern-evoked potentials in multiple sclerosis.

Among 56 established cases of multiple sclerosis in our clinic from April 1978 to March 1985, optic neuritis was found in 38; 21 cases were bilateral. We studied pattern-evoked potentials detected with 16 electrodes placed on both the scalp and the facial area. Pattern-evoked potentials (PERGs) were obtainable at the facial area in multiple sclerosis patients with optic neuritis, except in long-standing cases. However, a significant reduction of amplitude was found even in cases without optic neuritis. No correlation was found between visual acuity and amplitude or peak latency of PERGs in MS patients.

Electroretinography↗
PubMed1987

Check size and defocusing effects on equipotential maps of pattern-evoked electroretinograms.

The spatial distribution of the pattern-evoked potentials on the face was studied with a simultaneous 16-channel recording system. The potentials had the first positive component at a peak latency of approximately 55 msec, which was much earlier than the latency of the response picked up from the scalp. The maximal potential value in the maps was found at the region around the stimulated eye. This configuration of the equipotential map was not influenced by defocusing and check size of the pattern, but was altered by changing the contrast. Our results of equipotential maps constructed at around 55 msec after pattern reversal proved that the responses recorded in the facial region originated in the retina and were not a reflection of the scalp potentials.

Electrodes↗
PubMed1987

A case of frosted branch angiitis.

We report a case of frosted branch angiitis in a 16-year-old-girl. She noted a sudden and severe visual disturbance in both eyes, without other systemic symptoms. Diffuse retinal oedema and unusual sheathing of retinal veins were characteristic in both fundi. Fluorescein angiography showed no occlusion of the sheathed retinal veins, but some paravenous extravasation of dye was found in the late phase. With high doses of systemic corticosteroids her fundi and visual acuity improved greatly, though the vessels continued to show severe narrowing. At three months the pattern visually evoked cortical potentials were found to be normal, while flash electroretinograms were absent. No systemic abnormality has been found to explain the aetiology of this condition.

Adolescent↗
PubMed1987

Effects of spatial frequency and orientation on visually evoked cortical potentials.

Visually evoked cortical potentials (VECP) were recorded from an array of 4 electrodes along the midline over the occipital cortex in 10 normal subjects. Grating stimuli of different spatial frequencies were presented on a circular test field and spatial tuning curves and potential distribution evoked by vertical, horizontal and oblique stimuli were compared. The peak latencies were the shortest for the stimuli of 2.3 cycles per degree grating oriented vertically. The peak latencies increased for horizontal and further for oblique gratings. The effects of spatial frequency or orientation on the location of the major positive components of the VECP were not significant when recorded on the midline scalp.

Adult↗
PubMed1985

Pattern electroretinograms recorded with a skin electrode in pigmentary retinal degeneration.

In 24 patients suffering from pigmentary retinal degeneration the electroretinograms to pattern stimulation (PERG) were recorded with a silver-cup electrode placed on the center of the lower eyelid skin referred to an electrode on the earlobe. The results were compared with the responses to flash stimulation (FERG) and pattern visual evoked cortical potentials. None of patients showed normal FERGs. Nineteen of 48 eyes showed subnormal FERGs. The PERG was recorded from those 19 eyes. In the remaining 29 eyes with flat FERG, 8 eyes showed clear PERGs. The peak latency of the first positive component of PERGs was found to be prolonged in these patients. PERGs seemed to be recordable in the patients whose visual acuity and central visual field were relatively well preserved.

Adolescent↗