A comprehensive review of the raw EEG may be performed, either as part of a full QEEG analysis or as a separate service unto itself. The purpose of this analysis is to detect seizure or spike and wave events. This can be extremely helpful to understand EEG dynamics and underlying brain functioning. While this analysis can be performed as described below and these events detailed, only a Neurologist or Epileptologist can diagnose true seizures and epilepsy.
Specialized software, outside the realm of QEEG databases, is utilized for this purpose. This is done using the Persyst Seizure and Spike Detection Software, with an algorithm that is rated as 98% accurate in detecting such events. This is also an excellent program/tool for viewing EEG of multiple formats and in various montages. Both frank seizures, spike and wave, and even simple spike events can be automatically detected and displayed. This program also has the ability to apply artifacting filters that can display the difference between traditional artifact and seizure like events. Seizure events are highlighted “live” as the EEG is scrolled across the screen. In fact, this software is often used to monitor seizure patients in ICU’s. Spike events are also listed with their location, duration and exact time in the record when they occurred.
Individual spikes can then be displayed, sensitivity adjusted, and all spike events reviewed. These are categorized by their location of greatest focus and can then be selected or discarded based on their appearances (artifact vs. spike and wave patterns). All events can then be displayed, viewing their location, amount and duration.
One can even alter montages and display these events in different views. When using laplacian or similar montages, voltage plots can be utilized to image high and low values and their spatial distributions. This enables an understanding of distributions of activities and neuronal systems that may be involved in such events. Coherence metrics can be used to clarify or confirm such patterns that can then be treated with neurofeedback approaches.