High Frequency Oscillations (HFOs) and How They Help Doctors Understand Epilepsy Better

Keisya Talitha

Bandung, Indonesia

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4-5 people of 500

Are likely to have epilepsy

Current situation & problems in diagnosing Epilepsy

Currently, doctors are diagnosing epilepsy through Electroencephalography (EEG) by detecting abnormal electrical waves. It can be challenging because these abnormalities may not be related with epilepsy

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EEG

Neuroimaging (CT scan, MRI, PET, SPECT, etc.)

Blood Tests

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Problems

Current situation

These traditional diagnostic methods might lead to false negative or false positive results

Outline

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What is epilepsy?

What is the relation between epilepsy and HFOs?

What are HFOs?

How can HFOs be used to understand epilepsy better?

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What are neurons?

How neurons communicate?

What are brainwaves?

How can brainwaves be measured?

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Introduction

How HFOs help doctors treat epilepsy better

Conclusion

Neuron-to-neuron Connections

Brainwaves and Electroencephalography (EEG)

Introduction

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• Epilepsy is a condition when the brain is prone to having epileptic seizures.
• Epilepsy affecting around 1% of children in the world.
• Research has shown that HFOs (High frequency oscillations) are seen in patients with epilepsy.
• In contrast with the useful function of HFOs, epileptic HFOs act a sign of the brain when its out of control.
• Research shows that HFOs help doctors treat and understand epilepsy better

Key Terms

Neurons are nerve cells that act as a messenger

Sudden burst of electric activity in the brain that causes loss control of the body

A biological molecule that acts as a sign of normal or abnormal activity

Neurons

Epileptic seizures

Biomarker

An essential tool that studies the brain’s electrical activity

HFOs are fast brain activities observed through EEG

A neurological disorder characterized by recurrent seizures

Electroencephalography (EEG)

High Frequency Oscillations (HFOs)

Epilepsy

Breakthrough in HFOs as biomarker for seizure prediction

A study conducted by Jared M.S., Stephen V.G., Levin. K., & William C. Stacey with a title of “Viability of Preictal High-Frequency Oscillation Rates as a Biomarker for Seizure Prediction” shows a breakthrough discovery.

It shows that HFOs can be functioned as temporal biomarker of seizure. It is also concluded that HFO rates are able to identify the “preictal state” 30 minutes before a seizure.

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Overview of Sub Topics

What are neurons?

How neurons communicate?

What are HFOs?

How can HFOs be used to understand epilepsy better?

What are brainwaves?

How can brainwaves be measured?

Neuron-to-neuron connections

How HFOs help doctors treat epilepsy better

Brain waves and EEG

Neuron-to-neuron connections

• The brains consists of 80 billion neurons and more
• Neurons are brain cells act as messengers send information (electrical signals)
• Neurons help people sense and move body parts
• 3 main parts of neuron: the cell body, an axon, and the dendrites
• Dendrites thought to be like antennae (receive signals)
• Axon carries information in a form of electricity

(send signals)

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Key Terms: Neurons

Neuron-to-neuron connections

• Neurons communicate towards each other
• Neurons communicate by sending electrical impulses (action potential)
• The cell body produce neurotransmitter to communicate
• Neurotransmitter is chemical messenger (carry information)

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Key Points: Neurons

Additional Info

• These connections form like a dense spider web called the nervous system

Neuron-to-neuron connections

• Neurons form connections through conjunct points called “synapses”
• Neurotransmitters used by neurons are placed into these synapses
• Neurotransmitter binds to a specialized receptor (Key fits only particular lock)

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Key Points: Neurons

Brainwaves and Electroencephalography (EEG)

Key Points: Electroencephalography (EEG), high frequency oscillations (HFOs)

• Neurons communicate and produce electrical signals
• These electrical signals are called brain waves
• The faster our brain works, the faster the waves are

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Additional Info

• There are 4 frequency bands as can be seen in the picture

Brainwaves and Electroencephalography (EEG)

Key Points: Electroencephalography (EEG), high frequency oscillations (HFOs)

• Brain waves can be measured through electroencephalography (EEG)
• Tiny sensors “electrodes” placed on the person’s head
• Speed of waves called frequency and unit measurement called Hertz (Hz)

Additional Info

• The electrical signals can only be measured when several neurons generate similar electrical signals at the same time

How HFOs help doctors treat epilepsy better

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Key Points: high frequency oscillations (HFOs), epileptic seizure, epilepsy

• In some cases, neurons can communicate too fast or less coordinated
• Mostly happens in adults and kids >> epilepsy
• Epilepsy >> sudden lost control of body because not receiving information properly
• That events called epileptic seizures
• During seizures >> body starts moving uncontrollably

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How HFOs help doctors treat epilepsy better

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Key Points: high frequency oscillations (HFOs), epileptic seizure, epilepsy

• HFOs are faster than usual brain waves (80-150 Hz)
• HFOs are seen when a person is engaged in a high-focused activity >> require many parts or brain work together
• Examples: computer games (fighting games) >> to plan movements
• HFOs help transport memories >> remember even weeks later

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How HFOs help doctors treat epilepsy better

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Key Points: high frequency oscillations (HFOs), epileptic seizure, epilepsy

• HFOs can be seen through EEG in epilepsy patient.
• In contrast with previous HFOs, epileptic HFOs are a sign when the brain is out of control
• This finding >> helps understand patient’s epilepsy better
• HFOs help doctors predict which patients might have epilepsy or one seizure
• HFOs help doctors determine medication for epilepsy
• HFOs help doctors learn deeper on which particular parts of the brain that cause epileptic seizures >> especially for surgery
• HFOs act as biomarkers for epilepsy >> help doctors measuring how active the disease is and how to treat it

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Additional Info

• Surgery helps remove the seizure-causing brain region

Implications of HFOs in understanding epilepsy better

Despite being useful for high-focused activities (playing computer games that require many movements such as fighting), HFOs that are find in patient’s epilepsy (epileptic HFOs) can be a sign that the brain is out of control. However, doctors can take advantage to learn about epilepsy in patient better

HFOs help doctors learn deeper particular parts of the brain that cause epileptic seizures >> especially for surgery

High Frequency Oscillations (HFOs)

Implication 1

Implication 2

HFOs act as biomarkers for epilepsy >> help doctors measuring how active the disease is and how to treat it

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Conclusion

Neurons communicate between each other and produce electrical signals that carry information

There are several types of waves, the fastest one is called HFOs. HFOs happen in a high-focused activity such as fighting computer games

These electrical signals form a wave called brain waves that can be measured through EEG and

HFOs are seen in patient’s epilepsy (epileptic HFOs). They act as a sign when the brain is out of control. HFOs help doctor study and treat epilepsy better.

Neurons communication

High Frequency Oscillations (HFOs)

Brain waves and EEG

HFOs and epilepsy

References

1. Blanchette, S.J., Brault, F.LM., Allaire-Duquette, G., Masson, S. (2020). Understanding Your Brain to Help You Learn Better. Front. Young Minds. 8:54. DOI: 10.3389/frym.2020.00054
2. Chase, J.P., Seung, B.H. (2019). High Frequency Oscillations in Epilepsy: Detection Methods and Considerations in Clinical Application. J Epilepsy Res. 9(1): 1–13. DOI: 10.14581/jer.19001
3. Ludwig, M. (2017). How Your Brain Cells Talk to Each Other–Whispered Secrets and Public Announcements. Front. Young Minds. 5:39. DOI: 10.3389/frym.2017.00039
4. Matselva, M., Klotz, K.S., Jacobs. (2024). What Can Happen When Brain Cells Communicate Improperly?. Front. Young Minds. 12:1274957. DOI: 10.3389/frym.2024.1274957
5. Rayi, A., Murr, NI. (2022). Electroencephalogram. Treasure Islam (FL): StatPearls Publishing. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK563295/
6. Scott, J.M., Gliske, S.V., Kuhlmann, L., Stacey, W.C. (2021). Viability of Preictal High-Frequency Oscillation Rates as a Biomarker for Seizure Prediction. Front, Hum. Neurosci. 14:612899. DOI: 10.3389/fnhum.2020.612899

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