Visual cortex hyperexcitability in idiopathic generalized epilepsies with photosensitivity: a TMS pilot study

Area of Science:

• Neuroscience
• Epileptology
• Visual Cortex Research

Background:

• Understanding photosensitivity mechanisms in epilepsy remains limited.
• Current research suggests visual cortex hyperexcitability as a key factor.

Purpose of the Study:

• To investigate visual cortex excitability in patients with idiopathic generalized epilepsy (IGE).
• To determine if the phosphene threshold (PT) can serve as a biomarker for photosensitive IGE.

Main Methods:

• Transcranial magnetic stimulation (TMS) was used to measure resting motor threshold (rMT) and phosphene threshold (PT).
• 33 patients with IGE (8 with photosensitivity) and 12 healthy controls participated.

Main Results:

• Phosphenes were reported less frequently in IGE patients (46%) compared to controls (92%).
• Patients with photosensitive IGE reported phosphenes more frequently than non-photosensitive IGE patients.
• Photosensitive IGE patients exhibited a decreased PT and higher phosphene prevalence, suggesting visual cortex hyperexcitability.

Conclusions:

• A decreased PT and high phosphene prevalence in photosensitive IGE indicate primary visual cortex hyperexcitability.
• The PT shows potential as a biomarker for assessing excitability in IGE patients with photosensitivity.