Which area of the brain increases the risk of seizures?

Brain Areas That Increase Risk of Seizures

The temporal lobe, particularly the mesial temporal structures, is the most common brain area associated with increased risk of seizures. 1

Key Epileptogenic Brain Regions

Temporal Lobe

• Mesial temporal structures (including hippocampus) are highly epileptogenic and commonly associated with:

  • Temporal lobe epilepsy (TLE) - one of the most common forms of epilepsy
  • Complex partial seizures that are often drug-resistant 2
  • Mesial temporal sclerosis, which shows a specific pattern of neuronal loss and axonal reorganization 2

• Temporal lobe seizures are characterized by:

  • Stereotypic semiology (consistent pattern of symptoms)
  • Autonomic manifestations including increased heart rate 3
  • Potential triggers such as musical stimuli in musicogenic epilepsy 4

Other Epileptogenic Regions

• Frontal lobe: Superior frontal regions show higher seizure risk in patients with glioblastoma 1
• Occipital lobe: Inferior occipital regions also demonstrate increased seizure susceptibility 1
• Limbic system: Abnormalities in the dentate gyrus (part of hippocampus) are found in 41% of sudden unexpected infant deaths, suggesting a link between limbic system dysfunction and seizure-related mortality 1

Neurobiological Mechanisms of Seizure Generation

Neurotransmitter Abnormalities

• Glutamate dysregulation: Increased glutamate transport and binding of NMDA receptors are found in focal epilepsy 1
• Serotonin system: Abnormalities in brainstem serotonin (5-HT) neurons and receptors are associated with seizure risk 1
• Dopamine alterations: Changes in dopamine neurotransmission are observed in various types of drug-resistant epilepsy 1

Structural and Functional Factors

• Cortical dysplasia: Often associated with epileptogenic foci 1
• Neuroinflammation: Increased translocator protein (TSPO) signal in epileptic lesions, associated with reduced glucose metabolism 1
• Synaptic reorganization: Contributes to the pathophysiology of mesial temporal sclerosis and recurrent seizures 2

Risk Factors and Clinical Implications

Factors That Increase Seizure Risk

• History of status epilepticus: Can initiate an epileptogenic process leading to persistent, possibly drug-refractory epilepsy 5
• History of tonic-clonic seizures: Patients with tonic-clonic seizures in the year preceding surgery are more likely to experience seizure recurrence after temporal lobe surgery 6
• Tumor location: Tumors in superior frontal, inferior occipital, and inferior-posterior temporal regions are associated with higher seizure risk 1

Clinical Management Considerations

• Levetiracetam is recommended over older antiepileptic drugs for patients with brain tumors to reduce side effects 1
• Prophylactic anticonvulsant use is not warranted in brain tumor patients who have never had a seizure 1
• Surgical resection or laser ablation of well-defined epileptogenic foci can provide seizure freedom in many patients with drug-resistant temporal lobe epilepsy 2, 4

Diagnostic Approach

• Imaging should focus on identifying structural lesions in the suspected focal area 7
• Electroencephalography (EEG) is essential to identify epileptiform activity and localize seizure onset 1
• Careful differentiation between epileptic seizures and non-epileptic events is critical, with attention to specific clinical features such as eye movements, duration of unconsciousness, and movement patterns 1

Understanding the specific brain regions most associated with seizure risk allows for targeted diagnostic evaluation and more effective treatment approaches, ultimately improving morbidity, mortality, and quality of life outcomes for patients with epilepsy.