Former neuroscientist and current meditator here (even went to the Mind and Life Summer Research Institute to combine the two once). While it's nice to want objective measures of meditative progress, there are two caveats:
a) Once you start meditating, you will probably notice subjective improvements that will be of more importance than things like vertex electrode amplitude.
b) This is still early days for brain science. Our tools (EEG and fMRI) are way cruder than the populace at large believes, so take their results with a grain of salt.
