Developing such a system is challenging because the available datasets are mostly imbalanced; the number of non-seizure EEG signals is larger than the number of EEG seizure signals in the datasets [9]. This imbalanced dataset issue can have a major negative impact on classification performance [10]. Atonic/astatic seizures are characterized by a sudden loss of postural tone, with variable severity from head nods/drops to complete loss of axial posture with falling and injury. Atonic/astatic seizures frequently occur in children with Lennox–Gastaut syndrome or another form of symptomatic generalized epilepsy, but they can have their onset in later life following generalized cerebral hypoxia. Attacks are often refractory to medical therapy, so ambulatory patients may require a prescription for a protective “crash” helmet. EEG shows slow spike-wave or an electrodecremental pattern with generalized fast activity.
If you have to be videotaped, your healthcare provider or technician will give a friend or family member instructions on how to do so. To be set up for an ambulatory EEG, you will go to a provider’s office, clinic, or hospital where a technician will attach electrodes to your scalp as they do for a routine EEG, but with a few differences. Each electrode will be attached using a special paste that, like wax and cream, will wash out of your hair easily when the test is over. Sometimes, a cap with the electrodes already attached to it will be used instead. Some hospitals offer discounts of up to 30% for patients who do not have health insurance or who pay out-of-pocket for an EEG.
Electroencephalography (EEG) is a common diagnostic tool used to detect and monitor seizure activity in the brain. But how far back can an EEG actually detect a seizure? Let’s delve into this question and explore the capabilities of this important medical technology.
TFUS is emerging as a method to improve the relatively low degree of spatial locality offered by TMS and tDCS (127). It is important because a low degree of spatial locality leads to modulating neuronal activity not only in the target but also in surrounding circuits. TFUS can both excite and suppress brain neuronal activity and has millimeter spatial resolutions (177). In 1988, Colemann and Lizzi developed the Sonocare CST-100, which is the first high intensity focused ultrasound and received the FDA pre-market approval10.
These multiple electric fields differ by a frequency within the dynamic range of neural firing. They applied TI-NIBS to a living mouse brain and demonstrated the effects of TI-NIBS by stimulating neurons in subcortical structures (176). While the current experiment has not yet been applied to humans, we believe this is one of the most potential approaches for seizure therapy in the future due to its capability of providing high spatial and temporal resolution. In addition, since the stimulation is only effective at the locations where all the beams are constructive, the beams may not harm the brain cells that are not located in the targeted areas.
Understanding EEG and Seizures
Many related works have used multiclass SVM to classify seizure states (29, 30). SVM is a linear classifier that uses a hyperplane (25) to separate the data space. The mathematical expression of a hyperplane is the general form of a linear equation in multi-dimensional space.
Some anti-seizure medicines can alter the effectiveness of birth control. Ask your health care professional if your medicine may interact with your birth control. The goal of medicine is to find what works best for you and causes the fewest side effects. Sometimes a health care professional might recommend more than one medicine. Treatment of seizures often involves the use of anti-seizure medicines.
In human studies, to the best of our knowledge, there are no existing works to handle the relationship between seizure and tFUS. Legon et al. (40) evaluated if tFUS is capable of modulating brain activity in the human primary somatosensory cortex. From the experiment, tFUS remarkably reduced the amplitude of somatosensory evoked potential. The tFUS induced activation both from the sonicated brain area and from the visual or cognitive network regions. However, tFUS beam might potentially harm brain cells when it passes through them.
An EEG measures electrical activity in the brain by placing electrodes on the scalp. During a seizure, there is abnormal electrical activity that can be detected by the EEG. This helps doctors diagnose seizures, determine the type of seizure, and develop a treatment plan.
Detection Time Frame
The time frame in which an EEG can detect a seizure varies depending on several factors:
- Seizure Type: Some seizures may be easier to detect on an EEG than others. For example, generalized tonic-clonic seizures typically produce more pronounced electrical changes that are easier to identify.
- Duration of Seizure: Longer seizures are more likely to be detected on an EEG compared to shorter seizures.
- Location of Seizure Activity: Seizures originating from certain areas of the brain may be more challenging to detect on an EEG.
FAQs
Q: Can an EEG detect seizures that occurred hours or days ago?
A: While an EEG primarily captures real-time brain activity, it may occasionally pick up residual effects of a recent seizure. However, its ability to detect seizures that occurred hours or days ago is limited.
Q: How soon after a seizure can an EEG detect abnormal brain activity?
A: An EEG can detect abnormal brain activity during or shortly after a seizure. In some cases, the effects of a seizure may still be present on the EEG even after the seizure has ended.
Overall, the time frame in which an EEG can detect a seizure depends on various factors, but it is primarily designed to capture real-time brain activity. It is crucial for healthcare providers to interpret EEG results in conjunction with other diagnostic tools and clinical information to accurately diagnose and treat seizures.
