Seizure Risk Is Highest in the Very Young and the Very Old: Why It Peaks at Both Ends of Life

If you look at seizure and epilepsy rates across the lifespan, one pattern shows up again and again: a “U-shaped” (bimodal) curve. In many populations, seizure risk is highest in infancy/early childhood, drops through later childhood and much of adulthood, and then rises again in older age.

This isn’t a mystery of “weak brains.” It’s biology plus circumstance. The very young have rapidly developing brains that are more excitable and more vulnerable to fever, metabolic shifts, and birth-related injury. The very old have brains and bodies that are more likely to accumulate injuries and diseases—especially stroke and dementia—and they also face higher exposure to medications and systemic illnesses that can trigger seizures.

Below is a practical, science-informed tour of why seizure risk peaks at both ends of life, what seizures can look like in each age group, and what to do if you suspect one.

First, a Quick Definition: Seizures vs. Epilepsy

A seizure is a time-limited burst of abnormal electrical activity in the brain that causes symptoms (convulsions, staring spells, confusion, strange sensations, or sudden falls). Epilepsy generally means a tendency to have recurrent unprovoked seizures.

This matters because many seizures in the very young and the very old are “provoked”—triggered by something identifiable and potentially treatable (fever, low sodium, medication toxicity, infection, stroke). Treating the trigger can reduce future risk.

Why Seizure Risk is High in the Very Young (especially under age 1)

1) The developing brain is naturally more “excitable”

Early in life, the brain is wiring itself at high speed. Neurons are forming new connections, and the balance between “go” signals (excitation) and “slow down” signals (inhibition) is still maturing. That developmental state can make it easier for brain networks to synchronize in ways that produce seizures—especially under stress (like fever or illness).

This is one reason incidence is often highest in the first year of life, then declines as the nervous system stabilizes and inhibitory circuits mature.

2) Fever is a major seizure trigger in early childhood

One of the most common seizure events in early childhood is the febrile seizure—a seizure triggered by fever, usually in otherwise healthy kids. Febrile seizures most commonly occur between about 6 months and 5 years, with a peak around the second year of life.

Important nuance: febrile seizures are frightening, but they are often benign and do not automatically mean a child has epilepsy.

3) Newborn and infant seizures can be subtle—and are often linked to a cause

In babies, seizures don’t always look like dramatic shaking. They can appear as:

rhythmic facial twitching or eye deviation
repeated jerking of one limb
stiffening episodes
pauses with unusual breathing or color change (in some cases)

In the very young, seizures are more likely to be associated with underlying issues such as:

birth-related brain injury (hypoxic-ischemic injury)
infections (meningitis/encephalitis)
metabolic disturbances (glucose, calcium, sodium)
genetic epilepsies or structural brain differences

The key point: infant seizures are common enough to drive the early-life peak, and they’re often a “signal” to search for a specific cause.

4) The “provoked seizure” window is wider in childhood

Kids are more likely than healthy adults to experience rapid physiologic swings—high fevers, dehydration from stomach viruses, or quick changes in electrolytes. Those changes can lower the seizure threshold in a developing nervous system.

Why Seizure Risk Rises Again in Older Adults (often after age 60)

Across many high-income settings, new-onset epilepsy and seizures become increasingly common later in life, and older adults are frequently described as having among the highest rates of new epilepsy onset.

1) Stroke is a leading driver of late-life seizures

Stroke—both ischemic and hemorrhagic—can leave scarred or irritated brain tissue that becomes seizure-prone. It’s one of the most important reasons seizure risk climbs in older age. Many sources aimed at clinicians and patients highlight stroke as a major cause of seizures and epilepsy later in life.

2) Dementia and neurodegeneration increase seizure susceptibility

Conditions involving neurodegeneration (including Alzheimer’s disease and other dementias) are linked with higher seizure risk. Large studies in neurology journals note that late-onset epilepsy risk rises after 60 and is especially relevant in people with cognitive decline.

Why? Neurodegeneration alters networks and can create abnormal excitability, while small vessel disease and microscopic injuries add further instability.

3) Brain tumors and head injuries become more relevant

Tumors (primary or metastatic) are more common in older adults than in children. Even benign lesions can irritate cortex and cause seizures. Falls and head injuries also become more common with aging, and traumatic brain injury is a known seizure risk factor.

4) Medications and metabolic problems are frequent “seizure mimics” and triggers

Older adults often take multiple medications and may have kidney or liver changes that alter drug levels. Some medications lower seizure threshold; others can cause confusion or fainting that looks like a seizure. Meanwhile, systemic issues—like low sodium, infection, or low blood sugar—can provoke seizures.

A critical clinical reality: not every “spell” in an older adult is epilepsy, and not every seizure is unprovoked. Sorting this out carefully is essential.

5) Seizures can look different in older adults (and are often missed)

Older adults may have seizures that are not full-body convulsions. They can present as:

sudden confusion or “blanking out”
staring, lip smacking, or repetitive hand movements
brief speech arrest
unexplained falls
post-event sleepiness or “not quite right” behavior for hours

These can be mistaken for dementia progression, transient ischemic attacks, or medication side effects—delaying diagnosis and treatment.

The Shared Theme: Vulnerability + Triggers Differ by Age

So why is seizure risk “highest in the very young and the very old”?

Very young: a rapidly developing, excitable brain + common triggers like fever and metabolic shifts. Febrile seizures cluster tightly in early childhood.
Very old: accumulated brain injury and disease (especially stroke and dementia) + higher exposure to provoking factors (systemic illness, polypharmacy).
Population-level pattern: this produces a recognizable “U-shaped” incidence curve across age groups.

What to do if you Suspect a Seizure (Young or Old)

For anyone: when to seek emergency help

Call emergency services if:

the seizure lasts more than 5 minutes
there are repeated seizures without full recovery
breathing is impaired, serious injury occurs, or it’s the first known seizure
the person is pregnant, has diabetes, or is seriously ill

For first seizures: evaluation matters

In adults, professional guidelines emphasize that a first unprovoked seizure should trigger a structured medical evaluation to estimate recurrence risk and guide treatment decision.

In children, especially infants, evaluation focuses heavily on identifying triggers and underlying causes (fever, infection, metabolic issues, or neurologic conditions).

Bottom Line

The very young and the very old sit at opposite ends of the life course, but they share one thing: their brains are more likely to be pushed into seizures by internal and external stressors—developmental instability early on, and accumulated vulnerability later on. The encouraging news is that in both groups, many seizures are identifiable, treatable, and manageable—especially when recognized early.