Which kind of montage would better isolate right hemisphere abnormalities?

The choice of using a montage that includes the right mastoid to the contralateral mastoid is advantageous for isolating right hemisphere abnormalities because it allows for a comparison of electrical activity between the right side of the brain and the left side, specifically by focusing on the mastoid regions which are close to the respective hemispheres. This configuration enhances the detection of localized abnormalities that may be present in the right hemisphere, as the signals recorded can be more effectively contrasted against the background activity from the left hemisphere.

In contrast, some other montages may not provide the same level of lateralization. For instance, a bipolar montage from the right ear to the left ear primarily captures activity from the temporal regions without isolating specific hemispheric information. Frontal to occipital montages span a broader area, which can dilute any specific abnormalities that might be occurring in the right hemisphere, as they may be averaged out or masked by activity from the left. Semi-circumferential montages, while useful for some assessments, may not specifically hone in on differences between the two hemispheres in the same effective manner as the mastoid setup does. Thus, the right mastoid to contralateral mastoid montage is particularly well-suited for this purpose.