When is a spike a spike?

Criteria for these have existed for many years, but there have been recent attempts to refine and standardise them, using an evidence-based approach.

Here are some recent attempts:

Criteria for defining interictal epileptiform discharges in EEG: A clinical validation study - PubMed

The criteria used in this study will result in a 5% false positive rate; in other words, one in 20 spikes will be interpreted as representing an inter-ictal epileptiform discharge when this is not the case. This begs the question about the gold standard, which is a discussion for another day.