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What do all those squiggly lines mean?

Let's go back to basics to keep your pattern recognition on point! We all know that confidence is key when learning pattern recognition. Remember, we all started at the same place- All the squiggly lines!

When in doubt, go back to the basics. Sometimes we forget that there's no "exact match" for pattern recognition. I like to think of pattern recognition like snowflakes, while it's all made of the same stuff, there're no two patterns that are exactly alike. I wanted to share some helpful hints on going back to the basics to help those just learning or those who are building their confidence.

Remember that EEG can be subjective to who is looking at it and what they see. If you see something that someone else doesn't, go back to the basics and make sure it fits the criteria. Also, this can be used when you can't see what someone else sees. Go back to the basics and work the criteria. It's a helpful learning tool for us all. That's one of the great things about working in Neurodiagnostics, the opportunity to learn is always there for us and it never gets boring!

ACNS Guidelines - Let Them Be Your Guide!

What guidelines to know

Why do we need to know them?

  • While all of the guidelines are important, it's important to know these specific guidelines as you will be tested on them (not just in this academic setting, but also for the boards).

  • Guidelines are your "how to" map when setting up, running and recording an EEG.

  • Guidelines are set to protect the patient, the lab and the technician. While not everyone follows the guidelines, it is up to you to decide what your level of care and EEG practice will be.


  • Knowing your electrode locations is MANDATORY. If you don't know your locations, you won't be able to successfully identify EEG patterns.

  • What is the PDR?

  • What is the patient's level of consciousness?

  • What activity are you seeing and where is it happening?

  • Is this normal or abnormal?

  • How do you verify if you think a pattern is abnormal?

  • What should you expect to see by the patient hx and medication list?

  • Have you followed the ACNS guidelines to verify your findings?


  • Location - Know your electrodes.

  • Location - Know your areas of the brain and what happens in those areas.

  • Location - Is this a normal pattern or waveform in this location (specific to level of consciousness)?


  • Pattern

    • Mu

    • Spindles

    • Hypsarrhythmia

    • Burst suppression

    • K-Complex

    • Wickets

    • 14 & 6

    • 3 Hz Spike and wave

  • Description

    • FIRDA

    • BRD's

    • OIRDA

    • POST

    • These are just a few examples, but let's use the language we have learned. This is how we communicate effectively with our field and our physicians and specialists!


Up is down and down is up except for Tuesdays?????? Just kidding about Tuesdays!

Things to know

Positive is down deflection

Negative is up deflection

END of CHAIN: Positive is upward deflection and negative is downward deflection

Learn to LOVE your polarity square!


If you can fit a plus sign, it is a positive polarity focus.

If you can only fit a minus sign, it is a negative polarity focus.

Use your words: What I mean by that is to use the language you are learning in EEG. Use the vocabulary you are developing and know how to apply it in your recordings.

Know how to apply polarity to your practice for quality recordings: What do I do if I htink I see a focus? Is it positive or negative polarity? How do I verify if this is real? Is there a field?

Use your montages: How do I identify a focus on a referential montage? How do I tell if a focus is real in bipolar montage? Is every phase reversal a focus?

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