This is known as the Blood-Oxygenation Level Dependent response (otherwise known as BOLD). A certain part of my brain will increase its activity to send the message to complete this action, and that area of the brain will receive ever-so-slightly more oxygen-rich blood. MRI is a complex imaging methodology, but we’ll try to give you an overview here. The cost of an EEG test varies depending on the facility performing the test. More advanced EEG tests such as ambulatory EEG monitoring may cost several thousand dollars.
When it comes to understanding brain activity and function, two common imaging techniques used are EEG (electroencephalogram) and MRI (magnetic resonance imaging). While both tests provide valuable information about the brain, they have distinct differences in terms of what they can show. One common question that arises is: What can an EEG show that an MRI cannot?
The EEG technician will measure the person’s head, and they might use a wax crayon to mark where the electrodes should go. They will rub a paste called conductive gel between the electrodes and the scalp to make sure that the electrodes receive a strong signal from the brain. During an EEG test, a skilled EEG technician will place an electrode cap on the person’s head.
Occipital meningiomas, mainly of the tentorium, can cause more focal EEG changes. Since EEG reflects activity of cortical neurons, hemispheric tumors affect EEG most consistently and prominently. Slowing is Location is an important determinant of the likelihood and nature of EEG abnormalities.
EEG vs. MRI: A Comparison
With the technical challenges under control, researchers have begun to utilise this trimodal approach to investigate aspects of brain function. Golkowski et al. [164] used EEG-fMRI-PET to investigate brain activity in patients with disorders of consciousness. The trimodal approach will also be valuable for investigating the fundamentals of brain function, for example, resting state networks that underpin many processes can be altered in disease states. Recent work [165] has shown that event related potential components that are affected by disease states and disorders can also be useful in this trimodal approach. An EEG (electroencephalogram) test is a non-invasive diagnostic procedure that measures electrical activity in the brain. The test records the electrical signals that neurons (nerve cells) in the brain produce by tracking these signals across the scalp.
Electroencephalogram (EEG)
The EEG may also be used to monitor blood flow in the brain during surgical procedures. The symmetrical approaches can be model driven or data driven, both of which have their advantages and disadvantages. The asymmetrical approaches have been used more frequently in the literature and will be described in more detail below. For quicker, affordable, and accessible insights about brain function, with a tight temporal resolution, EEG is the method of choice. Following resection, dramatic changes may occur in the EEG; these usually stabilize over periods of weeks to months.
- Measures electrical activity in the brain
- Provides real-time information on brain function
- Useful for diagnosing epilepsy, sleep disorders, and brain injuries
- Can detect abnormal brain patterns
The role of EEG in detecting focal cerebral disturbances has undergone a significant change since the development of CT scan and MRI. They will tell the provider who ordered your EEG what the test showed. You’ll probably want to wash your hair to get rid of any remaining glue. You may find that your scalp is red and irritated in the spots where the electrodes were placed, but it shouldn’t last long.
For a review and guidance on whether simultaneous EEG-fMRI is an appropriate method for a study see Scrivener (2020) [9]. Understanding the structure and function of the human brain is one of the most fascinating, yet challenging, of scientific endeavours. The brain is the centre for coordinating the senses, regulating emotions, processing our thoughts, and initiating actions. Understanding its function in both healthy and diseased states can provide a valuable insight into human behaviour. As such, the brain has been the focus of scientific interest for many years leading to remarkable developments in technology that enable the measurement of different aspects of brain structure and function. As new technologies develop into routine techniques, a natural progression is to begin to combine the different technologies to further our understanding beyond what we can learn from a single modality alone.
Magnetic Resonance Imaging (MRI)
- Uses magnetic fields and radio waves to create detailed images of the brain
- Shows structural abnormalities such as tumors, lesions, and bleeding
- Helps in identifying physical damage or abnormalities in the brain
- Does not provide real-time information on brain function
What Can an EEG Show that an MRI Cannot?
An EEG is particularly useful for detecting changes in brain activity that may not be visible on an MRI scan. Some specific advantages of an EEG over an MRI include:
- Detecting abnormal brainwaves in conditions like epilepsy
- Monitoring brain activity during sleep studies
- Identifying seizure activity that may not be visible on an MRI
- Evaluating brain function in real-time
Overall, while an MRI provides detailed structural information about the brain, an EEG can offer valuable insights into brain function and activity that may not be apparent on imaging studies. Both tests play important roles in diagnosing and monitoring various neurological conditions, and a healthcare provider may recommend one or both based on the specific needs of the patient.
