The markers at the top of the amplitude/Hz trace indicate 1 minute intervals. The time markers during the EP write out are at 50MS intervals.
Analysed EEG and evoked potential (EP). This was recorded from a subject found to have an EEG asymmetry in the parietal occipital region, but who was otherwise neurologically clinically normal. At the start of the example the CFAM1 was automatically alternating between channels A (left) and B (right) to give sequential comparisons. During B a visual evoked potential computation was initiated by remote computer control. The period for which stimuli were given is marked by the thicker line in the time marker trace.
The upper EP is from the left (A) and the lower from the right (B). The difference between left and right is not initially great: in the first 250MS there are possibly larger amplitude faster waves in channel B, but in the second 250MS the near to 10Hz waves in B are of the order of twice the size of those in A, reflecting the asymmetry of the earlier amplitude distribution plot. The trend of the impedance trace in channel B shows that the electrode jelly is drying out.
Reproduced with permission from "The cerebral function analysing monitor: initial clinical experience, application and further development", D E Maynard and J L Jenkinson, Anaesthesia, 1984, Volume 39, pages 678-690.Published by Blackwell Science. http://www.blackwell-science.com/ana
