How to Identify Change from Initial Values in Time Course Data


I am currently working on my Masters Thesis and am trying to figure out a way to determine when my data is different or not from the initial value during a continuous data series.

Specifically, it is a signal (amplitude and frequency measurements) from the composite of 16 subjects. I initially ran an ANOVA, however, I felt the error was to great to determine when changes from the initial value actually occurred. In addition, it is important to note that the data appears to increase and decrease from the initial value over time.

Any ideas or methods that you may have on analyzing the data would be greatly appreciated.

Thank you all in advance.