Optimising the steady-state multifocal visual evoked potential.

      Аннотация: The multifocal Visual Evoked Potential (mfVEP) is used in clinical diagnosis and basic research. Employing steady-state stimuli rather than the usual m-sequence stimuli may simplify statistical evaluation and reduce examination durations. In one aspect, this study attempted to optimize the ssmfVEP by comparing different pattern densities to check if the response was increased for smaller regions. The ssmfVEPs results showed that the larger regions gave larger responses and spatially sparse stimulation did not improve the response when coupled with continuous stimuli. Additionally, this study optimized the testing viewing distance in the sense that it showed for annular stimuli that a comfortable viewing distance was as good as any other. Alternatively the study showed that different viewing distances could be used to detect central and peripheral visual defects without a change in SNR. Lastly, strong long-range interactions as expressed by second order interactions, do not seem to inhibit the ssmfVEP response.

Ключевые слова: Visual Field, multifocal Visual Evoked Potential (mfVEP), steady-state, M-sequence, signal noise ratio (SNR), sinusoidal luminance gratings, Spatial summation, norm channels, stimulus regions, viewing distances