Seizures in Adults: What Causes Them Later in Life?

“A lot of older adults might present with funny spells,” says Dr. Alice Lam, associate professor of neurology at Harvard Medical School and Massachusetts General Hospital. “Some patients notice that every now and then they get a weird, flushed sensation in their face, or a really funny feeling in the pit of their stomach, or a quick ‘brain blip’ where their thinking just feels a little off,” she adds. That makes the experience easy to miss or ignore.

One tipoff that Sirven says helps him diagnose seizures is their short duration. “They average from 45 to 50 seconds,” he says. If someone is having vague symptoms that are less than a minute long and then go away, and then come back, it’s time to see a doctor, he says.

One more clue for people who suspect epilepsy is that it’s not a one-time event. “If you’re having these kinds of spells in a cookie-cutter fashion. if it’s always that same feeling over and over, bring it to your doctor’s attention,” Lam says. 

Another important hint that raises her suspicion: “People often feel really tired afterward. They feel wiped out and may just want to take a nap.” Older people take significantly longer to recover after a seizure than younger people, from less than one hour in younger adults to two hours or more in older people. 

Diagnosing seizures

To evaluate someone who may be having seizures, “we perform an EEG, a brainwave test,” Lam says. It’s noninvasive. Wires are attached to a person’s head to measure their brain’s electrical activity over time. Routine EEGs last 20 to 40 minutes while the person is awake. A doctor may order a 24-hour ambulatory EEG for extended monitoring at home to capture abnormalities during sleep.

AARP Brain Health Resource Center

Find in-depth journalism and explainers on diseases of the brain — dementia, stroke, Parkinson’s disease, mental-health topics. Learn about healthy habits that support memory and mental skills.

Learn, take action, build healthy habits

“Capturing sleep is really critical if your initial EEG is negative,” Punia says. “If the 24-hour EEG is not possible, at least a 60-minute or longer EEG, which can be done in any office,” will improve the likelihood of capturing seizure activity among the brain waves. 

What causes seizures in adults?

To help learn why the seizures are happening, Lam advises that you keep a log of the circumstances of your episodes. For example, have there been any recent changes to your medications? Are the spells triggered during meals or exercise?  “That can be really helpful, just in terms of trying to tease things apart,” she says. 

Getting the family involved helps. “People who are having seizures often experience them very differently from what those around them actually see,” she says. Because the seizures may affect awareness, it can be helpful to have an eyewitness join you for your doctor visit to provide more details about the event.  

People suspected of having late-onset epilepsy typically undergo an MRI of the brain to look for possible causes of their seizures, such as stroke, brain tumor, traumatic brain injury or neurodegenerative disease. However, in one-third of the cases, no cause can be found; this condition is called late-onset unexplained epilepsy.  

Sirven says that as MRIs get stronger and more sensitive, they are picking up more tiny strokes that were not visible before.   

Epilepsy increases dementia risk

Studies have shown that 10 to 25 percent of older adults with an unknown cause of epilepsy develop dementia within three to four years following their first seizure.  Lam is leading a long-term study of 600 people age 55 or older with late-onset unexplained epilepsy to learn the risk factors associated with dementia and cognitive decline. 

“We are searching for new biomarkers that can help us better understand what processes lead to epilepsy in these older adults, and also why some people might go on to develop dementia in a few years, while others stay healthy,” she says. She hopes to learn if the seizures have a direct impact or if the epilepsy and dementia share similar neurologic causes. 

How is late-onset epilepsy treated?

“The good news is that we are able to control the seizures of late-onset epilepsy with one or two medications,” Punia says. About 90 percent of people will stop having seizures on one medication; a few require a second drug. 

The goal is to find an effective drug and dosage without side effects, although people 50 and older are more prone to side effects, include drowsiness, dizziness, lack of balance and cognitive impairment. “It’s better to start anti-seizure drugs at low doses and slowly, slowly go up,” Punia says.

Handelman experienced a side effect on the first anti-seizure medication he tried, as well as an unusual drug interaction when a water pill was later added for blood pressure control. After the latter was discontinued five months ago, he’s remained seizure-free since May 2025.