A seizure is a sudden, uncontrolled electrical disturbance in the brain. This temporary disruption affects how a person acts or feels for a brief period.
The Brain’s Electrical Activity During a Seizure
Brain cells, known as neurons, normally communicate through organized electrical impulses. During a seizure, this orderly communication breaks down as neurons fire signals excessively and in a synchronized manner. This abnormal, rapid firing is like an electrical storm, overloading specific brain areas and disrupting their normal function.
This process involves neurons experiencing sustained electrical excitation and rapid, repetitive firing. Normally, inhibitory mechanisms in the brain work to contain such activity, but during a seizure, these controls can fail, allowing the abnormal electrical signals to spread. The location and extent of this uncontrolled electrical activity determine the specific manifestations observed during the seizure.
Bodily Responses During a Seizure
During a seizure, the body undergoes various physical changes depending on the brain regions involved. Involuntary muscle contractions are common, appearing as stiffening (tonic), rhythmic jerking (clonic), or a combination (tonic-clonic). Other seizures may cause sudden, brief muscle twitches (myoclonic jerks), or a sudden loss of muscle tone leading to collapse (atonic seizures).
Loss of consciousness is common, especially in generalized seizures affecting both sides of the brain. Breathing patterns can change, from gasping to a temporary cessation, potentially causing the face to appear dusky or bluish. Eye movements might include rolling, deviation, or a blank stare. Increased salivation or frothing at the mouth can also occur.
Loss of bladder or bowel control is frequent, especially during tonic-clonic seizures, due to muscle contractions and relaxation. Internally, the body’s systems react to the intense electrical activity. The temporary disruption of oxygen supply to the brain and muscles is a common internal change.
The Post-Seizure State
Immediately following a seizure, an individual enters the post-ictal phase, a recovery period as the brain returns to its normal state. This phase involves a range of symptoms like confusion and disorientation. Individuals often experience fatigue and drowsiness, needing rest.
Headaches are common, sometimes presenting as migraines. Temporary memory loss, particularly amnesia regarding the seizure, is also frequently reported. The post-ictal state can vary in duration, lasting from minutes to several hours, or even days, depending on the seizure’s severity and type. Other symptoms include muscle soreness, difficulty speaking, thirst, nausea, and emotional changes like fear or embarrassment.
Variations in Seizure Manifestations
Seizures vary considerably in their bodily expressions. This diversity stems from where abnormal electrical activity originates in the brain and how widely it spreads. Some seizures, termed focal seizures, begin in a limited area of one side of the brain. These might result in localized bodily responses, such as a twitching limb, tingling sensations, or changes in how things look, smell, or sound.
Consciousness might be preserved during certain focal seizures, meaning the person remains aware of their surroundings. Other focal seizures can impair awareness, causing a person to stare blankly, perform repetitive movements like lip-smacking or hand rubbing, and not remember the event. In contrast, generalized seizures involve electrical activity affecting both sides of the brain, leading to widespread effects and often complete loss of consciousness.