The first thing neurodiagnostic techs should know about quantitative electroencephalography (qEEG) is that it is not going to take away their jobs.
That’s according to Dr. Christina Patterson, an epileptologist who spoke at the annual meeting of ASET-The Neurodiagnostic Society in August.
“This kind of [pattern recognition done with qEEG] isn’t a substitute for the qualitative analysis that we all do, but it’s actually a compliment to it,” she said.
Patterson is director of the Epilepsy Monitoring Unit at the University of Pittsburgh School of Medicine. She discussed how she uses qEEG in the Pediatric ICU there.
What is qEEG?
Quantitative EEG is a computer-driven translation of raw EEG signals into numbers (or quantities). Using mathematical and statistical formulas, software analyzes the data and generates patterns and trends that can be hard to see otherwise.
“If you have seven EEGers looking at any EEG, you’re going to get seven different interpretations of it,” said Patterson. “So, there’s poor interrater reliability when humans are interpreting EEG. It’s also a lot of data.
“It’s easy for us to pick up these small bits of data, recognize these discrete patterns, but when given days and days and days of EEG, it is a lot of raw data for us to process. The consequences of this kind of qualitative analysis are that we can sometimes miss subtle features or slow changes. And the overall big picture is harder to see.”
The Added Value of qEEG
The value added by qEEG is especially useful in places like the ICU, where patients can be monitored for days and even months. These cases are complex, and their EEGs will often have multiple abnormalities, says Patterson.
QEEG offers several valuable trends for pediatric patients in the ICU, including:
- Seizure detector
- FTT spectrogram
- Rhythmicity spectrogram
- Asymmetry spectrogram
- Amplitude integrated EEG
- Suppression ratio
The first is the seizure detector.
“Most qEEG software currently on the market is actually really good at seizure detecting in adults — not so great as you get down to the younger ages,” said Patterson. “The rhythmicity spectrogram actually easily shows the seizures even independent of the seizure detector, so this is kind of a cheat.”
Both the rhythmicity and FTT spectrograms “are very useful for seeing long-term changes that we wouldn’t have picked up. The relative asymmetry spectrogram is very useful to see if there’s any unilateral changes occurring over time.”
The suppression ratio “is really your alarm bell and really deserves bedside attention to figure out why it changed or why you’re starting to have an increase in the suppression ratio.”
In the pediatric ICU, Patterson and her team use a split screen, showing both raw EEG data and qEEG trends.
“Once you see something change on the qEEG trend, you always want to go back to the raw EEG, compare it, prove it’s real,” she said. “It’s not a substitute for reading the EEG. It’s never going to replace it, but it can be a very good alarm system in critically ill patients to make sure nothing gets missed.”
An Opportunity for Technologists
In the coming years, quantitative EEG is set to grow in use. Patterson says that many companies are working on improving the functionality of qEEG and neurologists not trained in reading raw EEG love it for the more easilyseen trends it produces.
Neurodiagnostic technologists have thus far not been very involved in the use of qEEG, handling only the raw EEG data typically, but they can be.
Leisha Osburn, a neurodiagnostic tech who also spoke about qEEG at ASET’s annual meeting, told us that it will be covered in ABRET’s forthcoming neuroanalyst credential. Osburn is currently on the ASET committee helping to develop it. She says there is also an independent certification in qEEG available through the International QEEG Certification Board.
Technologists have a real opportunity here. Instead of worrying that qEEG is going to replace them, they should be learning what they can and getting ready to step forward when the jobs become available.