Heat-Epilepsy Link: How High Temperatures Affect Brain Activity

Understanding the impact of extreme weather on neurological conditions is becoming increasingly crucial as climate change intensifies. The study, published in Brain Communications, investigates the effects of heatwaves on individuals with medication-resistant epilepsy. Using intracranial electroencephalography (icEEG), researchers monitored the brain activity of nine patients undergoing evaluation for surgical treatment of epilepsy at the National Hospital for Neurology and Neurosurgery.

Their brain activity was monitored using intracranial electroencephalography (icEEG) tests, which measure electrical impulses by inserting tiny electrodes into the brain's substance.

Heatwave and Epilepsy Association

No participant had a known genetic epilepsy, which is already linked to seizures being worse during heatwaves, based on genomic testing.

In London, they define a heatwave as three or more days with daily maximum temperatures exceeding 28 degrees Celsius.

The nine individuals in the study happened to have icEEG recordings obtained during spontaneous heatwaves in London, allowing the researchers to directly observe their brain activity amid exceptionally hot conditions.

Once all other parameters, aside from temperature, were held constant, the researchers compared this data to icEEG recordings made from the patients during non-heatwave periods.

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During four 10-minute intervals, both inside and outside of heatwaves, the researchers recorded any unusual electrical activity for every subject and monitored every seizure session.

Do Heatwaves Cause More Seizure Episodes?

They discovered that, on average, more seizures were detected by the icEEG during heatwaves than during the non-heatwave time. In addition to convulsions during heatwaves, three patients also exhibited other unusual electrical brain activity.

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Senior author, Professor Sanjay Sisodiya (UCL Queen Square Institute of Neurology), said: “Our research shows that for some people with epilepsy – in particular those with the most severe epilepsies – higher ambient temperatures increase the likelihood of having seizures.

“This is an important finding, providing some of the first evidence that for some people who already have epilepsy, higher temperatures seen during heatwaves can make their condition worse."

“Such information is important for the care of individual people with epilepsy, and also for broader efforts to ensure people with epilepsy can be kept safe as the climate changes.”

The current study sample size is relatively small as icEEG is not commonly undertaken and a heatwave had to have happened, by chance, during the recording.

However, the team now hope to have a bigger prospective study, and data are currently being collected.

Professor Sisodiya said: “Despite the study’s limited sample size, our findings remain valuable in the context of climate change. As global temperatures rise and extreme weather events become more frequent, understanding the effects of heatwaves on brain activity is crucial.”

Professor Sisodiya recently led a review of 332 papers published across the world, that explored the scale of potential effects of climate change on neurological diseases.

The researchers found that the effect of climate change on weather patterns and adverse weather events is likely to negatively affect the health of people with brain conditions, including stroke, migraine, Alzheimer’s, meningitis, epilepsy and multiple sclerosis. The new research adds to this analysis.

Reference:

1. The influence of temperature and genomic variation on intracranial EEG measures in people with epilepsy - (https:academic.oup.com/braincomms/article/6/5/fcae269/7748968)

Source-Eurekalert