Each study subject/patient will have a total of two (2) EGGs with Water load tests performed for this study. Each EGG exam will be performed approximately one (1) week of each other, but no more than 4 weeks apart, and will be read in a blinded fashion by three (3) separate independent readers, in order to see if the readings are consistent with the previous readings that were obtained, as well as, by the readers themselves (Inter-reader rater reliability). Each reader will be blinded to the subject status (normal/healthy or patient) and also to the specific test they are reading (initial exam [Visit 1], or follow-up exam 1 week after Visit 1 [Visit 2]). All EGG exam results will be coded in order to keep them blind.