Search

Purpose: To investigate whether the multifocal visual evoked potential (mVEP) is dependent on the electrode position, and to confirm the reproducibility of the mVEP. Methods: The mVEPs were recorded using the Veris III system with two different bipolar electrode settings. In Position 1, electrodes were placed at equal distances in vertical alignment 2 cm above and below the inion. In Position 2, the electrodes were placed in horizontal alignment at equal distances 2 cm to the left and right of the inion. Dartboard pattern stimulation was conducted. The mVEPs were repeatedly recorded from 4 volunteers, and mainly the second-order kernel response components were analyzed. Results: Although the reproducibility of mVEP was good in both Position 1 and Position 2, each waveform of the mVEP was drastically different between the two positions. This difference in the waveforms was clearly shown in the center and at the horizontal meridian. We also investigated the first-order kernel response components of the mVEPs. Several traces of the first-order kernel response components did not reveal flat traces. This point is also worthy of consideration. Conclusion: Responses from mVEPs are clearly dependent on the electrode position.

Purpose: It has been reported that the second-order kernel response components of multifocal electroretinograms (mERGs) reflect the electrical activity of the inner retinal layers. In this study, we have investigated whether the amplitudes of the second-order kernel response components correlate with the spatial distribution of human retinal ganglion cells. Methods: Multifocal electroretinograms were recorded using the Veris III™ system from 5 healthy subjects with different stimulus and recording parameters. The mERGs were analyzed using the Veris Science™ software programs. The stimuli consisted of densely arranged arrays of 103, 61, 37 or 19 hexagonal elements. Four minutes were required to record one set of mERG responses using 8 sessions, and 8 minutes using 16 sessions. The second-order kernel response components were extracted and analyzed using the Veris Science™ program. Results: The signal-to-noise ratio of the first-order kernel response components was improved considerably by the summation of the nine reproducible responses from the same subject but the second-order kernel response components were not. The summation of the nine reproducible responses was insufficient to identify an array of the second-order kernel response components. Both the first- and second-order kernel response components were larger when fewer hexagonal elements were used. There was no significant difference in the individual responses between the 4-minute and the 8-minute recordings. A response density analysis revealed a weak correlation between the amplitude distribution of the second-order kernel response components and the spatial distribution of human retinal ganglion cells. Conclusions: The distribution of the amplitudes of the second-order kernel response components of the mERGs elicited from normal subjects did not correlate with the distribution of human ganglion cells. This suggests that the theory that second-order kernel response components arise from the activity of retinal ganglion cells should be reconsidered.

Sight threatening ocular complications are rare in adult patients with dermatomyositis. We encountered a 52-year-old female with dermatomyositis who had severe visual disturbance and rapidly progressive intersitial pneumonia. She was admitted to our hospital because of skin erythema, general fatigue, mild fever, and severe bilateral visual disturbance. Rentinal hemorrhages, cotton wool spots, and macular edema were observed in her fundus at the first ophthalmic examination. A diagnosis of dermatomyositis was made because of the myogenic pattern of her electromyogram, elevation of serum creatine kinase, and skin lesions. Oral prednisolone treatment was started and the retinopathy was improved, but was complicated by acute interstitial pneumonia. The interstitial pneumonia was not respond to steroid pulse therapy with methylprednisolone, and the patient died of respiratory failure on the 47th day after the onset of visual symptoms. In adult dermatomyositis patients, the complication of severe retinopathy should be considered as a risk factor for rapid progress of interstitial pneumonia.