Supplementary motor cortex involvement in reading epilepsy revealed by magnetic source imaging

Area of Science:

• Neuroscience
• Epileptology
• Medical Imaging

Background:

• Reading epilepsy (RE) is a rare reflex epilepsy syndrome.
• It is characterized by perioral myoclonic jerks (PMJs) during reading.
• Associated with left-dominant frontotemporal spike-wave discharges (SWDs).

Observation:

• A 45-year-old patient with RE was studied using magnetic source imaging (MSI).
• Two whole-head magnetoencephalography (MEG) recordings were performed while the patient read aloud.
• Forty-two SWDs linked to PMJs were recorded and analyzed.

Findings:

• MSI identified two primary brain sources: the left supplementary motor cortex (SMC) and the left primary sensorimotor face area (PSMFA).
• Analysis revealed a spatiotemporal cross-talk between these regions, originating in the left SMC.
• This suggests a sequence of hyperexcitable neuronal activation and secondary propagation.

Implications:

• The findings suggest RE-PMJs originate from reading-induced activation of hyperexcitable neurons in the left SMC.
• Secondary propagation to the left PSMFA leads to the characteristic myoclonus.
• This study enhances understanding of RE pathophysiology using advanced neuroimaging techniques.