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S Tobimatsu

Publications and source records attributed to S Tobimatsu.

93 records · Page 6Linked to original sources
PubMedDate not supplied

Age-related changes in pattern visual evoked potentials: differential effects of luminance, contrast and check size.

We recorded visual evoked potentials (VEPs) to checkerboard pattern-reversal stimulation in 109 normal subjects (51 males and 59 females; aged 19-84 years) in order to study the aging effect on the multiple channels of the visual system in humans. Transient VEPs to 3 check sizes (15', 30' and 50') were obtained by monocular stimulation. Two test conditions were employed: (1) a high luminance (180 cd/m2) and a low luminance (11 cd/m2) both with a fixed contrast (90%), and (2) a high contrast (85%) and a low contrast (10%) both at a fixed luminance (57 cd/m2). The major features of our results included: (1) the presence of a curvilinear relationship between P100 latency and age for all conditions, while the P100 amplitude did not show any such aging effect, (2) the age-latency function was similar between the two luminance conditions, while it was different between the two contrast conditions, and (3) the differential age effect on the P100 latency caused by changes in contrast depended on the check size. These results suggest that age-related changes in the human visual system are not uniform, but rather are different in the specific functional subdivisions. It is thus hypothesized that aging may differentially influence the separate channels of the human visual system.

Adult↗
PubMedDate not supplied

[A variant form of septo-optic-pituitary dysplasia (SOPD) complicated with acute optic neuritis].

We herein report a case of a variant form of septo-optic-pituitary dysplasia (SOPD). A 40-year-old man was admitted due to sudden occurrence of left blurred vision and lasting polyuria. He showed short statue of height of 144 cm and the neurological examination revealed hypesthesia of the left trigeminal nerve and temporal pallor in the left fundus oculi. Brain MR imaging demonstrated agenesis of the septum pellucidum and hypoplasia of the corpus callosum with subcortical spotty lesions, but optic nerve hypoplasia was not detected. The left eye showed a prolonged P100 latency of pattern reversal VEPs. He was diagnosed as having hypopituitarism since growth hormone-releasing factor did not stimulate growth hormone secretion and restriction of water-intake did not induce secretion of antidiuretic hormone. Thus we regarded this case as a variant form of SOPD. The mutation of HESX 1 gene, however, was not detected in the case. P100 of the left eye showed a reduction in latency four months after discharge. This case was considered to be a variant form of SOPD complicated by acute optic neuritis.

Acute Disease↗