Unusual Visual Evoked Potentials in Patients with Age-Related Macular Degeneration

Abstract

Among a series of patients with age-related macular degeneration (ARMD), a few individuals could be identified showing larger amplitudes of pattern reversal visual evoked potentials (prVEP) after stimulation of a central 3° field compared to stimulation of a 13° field although in the majority of ARMD patients and in normals, VEP amplitudes increased with increasing field size. An analysis of prVEPs recorded after stimulation of different macular zones showed that the 3° central area and the perifoveal zone contributed differently to the 13° response or macular response. Perifoveal activity in this subgroup of ARMD patients seemed to mask the foveal contribution to the macular prVEP. The cortical magnification factor in ARMD may be higher than in normal controls. Small-field stimulation techniques are therefore also recommended in patients with central retinal pathology.

Dichoptic multifocal visual evoked potentials identify local retinal dysfunction in age-related macular degeneration

“…The purpose of this study was to examine responses and diagnosticity in early and late stages of AMD using dichoptic stimulation of 84 regions using a sparse pattern pulse mfVEP. While conventional VEPs measure amplitude attenuation and delayed latencies in AMD [12,15,28,29], it is not a distinguishing attribute because it is also found in eyes with other macular diseases [12,15] and in optic neuropathy [11][12][13][14]. The use of higher-resolution mfVEP techniques may define local effects with Summary of two linear models quantifying effects on peak gfRMS amplitude and delay (rightmost three columns).…”

Pattern-reversal visual-evoked potential in patients with occult macular dystrophy

“…Thus for delayed N2 latencies, the differential diagnosis is between optic nerve disease and macular disease. There are a number of studies that have examined how macular diseases affect the pVEPs 6–17. However, the results are not all in agreement.…”

“…However, the results are not all in agreement. In general, the pVEPs are attenuated and the latencies are delayed in several macular diseases such as age-related macular degeneration,6,10,14,16,17 macular hole,6,12,13 central serous chorioretinopathy,6,10,11,15,18 branch retinal vein occlusions,10 and macular dystrophies 6,8,19…”

Neural signal processing of mfVEP responses from AMD patients

“…Stimuli presented in eccentricities 6 and 7 were thus outside the anatomically defined macula. Since small stimulation technique like this study is recommended in patients with retinal pathology [15]; therefore one might expect the focal retinal abnormalities in AMD to affect the mfVEP responses from the central retina more than the responses from the peripheral retina as the reductions in the response density and amplitude considered being indicative of photoreceptors or outer retinal changes in AMD and ARM patients. The mean responses of the normal control subjects exhibits waveforms that at all eccentricities (Fig.…”