The triad of Lennox-Gastaut syndrome (LGS) consists of multiple seizure types, characteristic electroencephalogram (EEG) findings, and intellectual impairment.
Lennox-Gastaut syndrome is a severe epileptic encephalopathy that typically begins in childhood. This means it is a condition where frequent seizures and abnormal brain activity contribute to developmental delays and cognitive difficulties. The triad represents the core features used to diagnose the condition.
Here's a breakdown of each component:
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Multiple Seizure Types: Individuals with LGS experience a variety of seizure types, including:
- Tonic seizures: Sudden stiffening of the body, often occurring during sleep.
- Atonic seizures: Sudden loss of muscle tone, leading to falls (also known as "drop attacks").
- Absence seizures: Brief periods of unresponsiveness or staring.
- Myoclonic seizures: Brief, shock-like muscle jerks.
- Atypical absence seizures: Absence seizures with more gradual onset and offset, often accompanied by other motor symptoms.
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Characteristic EEG Findings: The EEG (electroencephalogram) is a test that measures brain activity. In LGS, the EEG typically shows:
- Slow spike-and-wave complexes: These are specific patterns of abnormal electrical activity that occur at a slow rate (usually 1-2.5 Hz).
- Other abnormalities: The EEG may also show other abnormalities, such as multifocal spikes or bursts of slow activity.
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Intellectual Impairment: Cognitive and developmental delays are common in LGS. The degree of impairment can vary from mild to severe. These cognitive difficulties may be due to the underlying brain abnormality causing the seizures, or they may result from frequent seizures and their impact on brain development.
The presence of all three components of the triad – multiple seizure types, characteristic EEG findings, and intellectual impairment – is crucial for a diagnosis of Lennox-Gastaut syndrome.
