Cortical excitability changes correlate with fluctuations in glucose levels in patients with epilepsy

- Cortical excitability varies with fluctuations in blood glucose levels.
- This variation is more prominent in patients with epilepsy.
- Decreased glucose levels may be an important physiological seizure trigger.

ObjectiveWe used transcranial magnetic stimulation (TMS) to investigate motor cortical excitability changes in relation to blood glucose levels.MethodsTwenty-two drug-naïve patients with epilepsy [11 generalized and 11 focal] and 10 controls were studied twice on the same day; first after 12 h of fasting and then 2 h postprandial. Motor threshold and paired-pulse TMS at a number of short and long interstimulus intervals were measured. Serum glucose levels were measured each time.ResultsDecreased long intracortical inhibition was seen in patients and controls during fasting compared to postprandial studies. This effect was much more prominent in patients with generalized epilepsy (with effect sizes of up to 0.8) in whom there was also evidence of increased intracortical facilitation (effect size: 0.3).ConclusionCortical excitability varies with fluctuations in blood glucose levels. This variation is more prominent in patients with epilepsy. Decreased glucose levels may be an important physiological seizure trigger.