1. (C): During PSVEP, the patient is seated at a distance of 1 m from the monitor. Greater distance can affect the visual acuity and delay in P100 latency. The eyes are always tested one at a time and the opposite eye is covered with a patch. (Chiappa 1997, p. 45)

2. (C): Pattern luminance is very important in PSVEP testing and changes in it have marked effect on P100 latency. For this particular reason, normal values obtained and used for clinical interpretation in one laboratory cannot be used in another laboratory. Changes in luminance have a marked effect on P100 latency. Increased papillary diameter will illuminate more of retina resulting in false decrease in P100 latency, while decreasing the luminance will delay P100 latency. (Chiappa 1997, p. 52)

3. (D): Signal-to-noise ratio for PSVEP is very low. The PSVEP signal has to be amplified to make it prominent compared to the electroencephalographic (EEG) signal. Averaging increases the signal-to-noise ratio and improves signal quality. At least, amplification of 20,000 is needed to make the signal more prominent than the EEG signal. (Chiappa 1997, p. 13)

4. (A): In healthy subject, the P100 amplitude is highest at inion. In abnormal cases, P100 may be displaced and appear higher in amplitude at Pz. (Chiappa 1997, p. 48)

5. (A): P100, sometimes presents as two peaks separated by 10 to 50 ms. Bifid P100 is very rarely seen in healthy individuals. It may be produced with upper visual field contributing inverted-polarity activity to the inion resulting in bifid waveform, or because of visual field defects the inverted-polarity activity may be recorded over the contralateral scalp. This results in two peaks. Using only the lower field stimulation may correct the waveform in the first scenario or recording from laterally placed electrodes will show the true P100. (Chiappa 1997, p. 102)

6. (A): Smaller checks produce larger amplitude P100. However, if the checks size is too small such that the visual acuity is affected then this relationship does not hold true and P100 amplitudemay decrease. This is why it is important to use check size that is not smaller than the visual acuity for the eye. (Chiappa 1997, p. 62)