.... Straight-line graphs look neater than noisy ones, esp when you're looking for That Simple Answer to complex questions*. But with cognitive decline, where should one draw the line? to show changes over time in the minima, the maxima, or the average? if so, which average? or instead show the variation between worst and best? place your bets, mesdames et messieurs: I remember seeing a paper where the writer carefully excluded all sub-par events from his data, and ended up with a signal which he admitted was all but indistinguishable from pure noise.

* As famously satirised by Douglas Adams.