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Focal Seizures (Aware or Unaware)?


In the simplest explanation seizures can usually be classified as transient occurrences that occur because of increased/excessive neuronal activity in all -or- parts of the brain. Neurons, the most basic cells of the nervous system are firing excessively or abnormally -- this is usually best seen with an EEG under the care of a neurologist. Many times (> 50%) of seizures have no clear or definite cause, but they can be classified as either generalized or focal (partial) in nature. It's also important to note that focal seizures, those that are isolated to just one hemisphere of the cerebral cortex can evolve into a generalized event that encompasses both hemispheres.

Focal seizures are unique in that they can be categorized as simple or complex. In a simple focal seizure, the patient never losses their overall ability to be aware of their surroundings. The most widely accepted term for this seizure type today is focal seizure with retained awareness. Keep in mind that the degree of consciousness may, however, be altered. All of this to say that, not all seizures are created equal and not all seizures involve the classic tonic-clonic motor involvement that you may be used to seeing during a 911 call for service.

Focal seizures can further be categorized as one of 4 types depending on where in the brain the abnormal activity is: The seizures can begin because of some old brain scarring from historical trauma, an old stroke, degenerative brain diseases like Alzheimer's or a space occupying lesion, but in some cases, you may never be able to tie it to a singular underlying cause, which can be frustrating for both the patient and the treating clinicians.

Motor: tied to the frontal lobe (think abnormal face and/or hand movements) These are most likely to progress to the traditional grand mal seizure that would require immediate EMS interventions

Sensory: tied to the parietal lobe (think of numbness or tingling) You can also have auditory (tied to temporal lobe) or visual hallucinations (tied to occipital lobe)

Autonomic: tied to your sympathetic (pupil dilation and tachycardia) and parasympathetic nervous systems (GI related complaints, SLUDGE-like components)

Higher level: tied to the pre-frontal cortex (inability to understand language or process information)

The good news is that most anti-seizure medications will work for these focal seizures as well. Sometimes surgery or dietary changes may also provide some long-term benefits.

While in an emergent setting focal seizures may get pushed aside and not get the same attention as grand mal seizures or status epilepticus. Focal seizures can evolve into major events that spread to the entire brain and cause tonic-clonic seizures. These seizures are important to treat and prevent since they can cause respiratory problems and secondary traumatic injuries. As a 911 provider and patient advocate, you should always encourage transportation to the hospital or at minimum have them follow-up with primary care or a specialty physician.

Feel free to visit the epilepsy foundation at if this particular topic is of interest to you and you'd like to find out more information outside of this blog post.

April 22, 2024

Author: Joshua Ishmael, MBA, MLS(ASCP)CM, NRP

Pass with PASS, LLC.

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