Motor cortical excitability in patients with poststroke epilepsy

Area of Science:

• Neuroscience
• Neurology
• Epileptology

Background:

• Poststroke epilepsy (PSE) is a common complication following ischemic or hemorrhagic stroke.
• Understanding the neurophysiological mechanisms of PSE is crucial for developing targeted treatments.
• Cortical excitability changes are implicated in the development of epilepsy after brain injury.

Purpose of the Study:

• To investigate the differences in motor cortical function between chronic stroke patients with and without poststroke epilepsy (PSE).
• To identify potential neurophysiological mechanisms contributing to the development of PSE.

Main Methods:

• Transcranial magnetic stimulation (TMS) was used to assess motor cortical function.
• Measurements included resting motor threshold (RMT), motor evoked potential (MEP) amplitudes, cortical silent period (CSP), intracortical inhibition (ICI), and intracortical facilitation (ICF).
• GABAergic and glutamatergic neurotransmission influences were examined via ICI and ICF, respectively.

Main Results:

• Patients with PSE exhibited larger MEP amplitudes and increased ICF in the affected hemisphere compared to the unaffected hemisphere.
• These findings were not observed in stroke patients without epilepsy.
• Both groups showed higher RMT and longer CSP in the affected hemisphere, with no differences in ICI, H-reflexes, or F-waves.

Conclusions:

• Enhanced cortical excitability in the affected hemisphere, potentially linked to increased glutamatergic activity, may be a key mechanism in the pathogenesis of PSE.
• These findings provide insights into the neurophysiological basis of epilepsy after stroke.