What does my EEG (Electroencephalogram) report indicate?

Understanding EEG Reports and Their Clinical Significance

Without having your specific EEG report to interpret, I cannot provide personalized analysis of your results, but I can explain what EEG reports typically contain and how they are used in clinical decision-making.

EEG (electroencephalogram) is a critical neurophysiological test that records electrical activity of the brain and serves as the best study for evaluating brain electrophysiologic function 1. The interpretation of an EEG report requires specialized expertise and should be performed by a neurologist or clinical neurophysiologist.

Key Components of an EEG Report

Technical Parameters

• Electrode Placement: Typically follows the standardized 10-20 International System with 19 electrodes for diagnostic purposes 2
• Recording Duration: Usually 20-30 minutes to capture variations in vigilance levels, though shorter 5-10 minute recordings may be sufficient in some cases 2
• Recording Conditions: Eyes closed and eyes open states are typically recorded when possible 2

Normal EEG Findings

• Background Activity: Dominant posterior rhythm (alpha) at 8-12 Hz in adults
• Normal Variants: Certain patterns that may appear unusual but are considered normal variants
• Age-Appropriate Patterns: Different normal patterns based on age

Abnormal EEG Findings

• Slowing: Focal or generalized slowing of background activity
• Epileptiform Discharges: Spikes, sharp waves, or spike-and-wave complexes
• Specific Patterns: Such as triphasic waves (seen in metabolic encephalopathy) or extreme delta brush (occasionally seen in NMDAR-antibody encephalitis) 3

Clinical Applications of EEG

Seizure Disorders

• EEG is essential for diagnosing epilepsy, classifying seizure types, and guiding management 1
• Interictal epileptiform discharges support a clinical diagnosis of seizures, but only when an electrographic seizure is recorded is the diagnosis confirmed 1
• Early EEG has a high diagnostic yield in patients with suspected new-onset seizures 4

Encephalopathy Assessment

• EEG can provide evidence of focal or multifocal brain abnormality when MRI is negative, supporting encephalitis over metabolic encephalopathy 3
• EEG can help differentiate autoimmune encephalitis from other conditions, with findings such as focal slowing/seizures or lateralized periodic discharges 3

Critical Care Applications

• Recommended for all patients with acute brain injury and unexplained altered consciousness 2
• Essential for detecting nonconvulsive seizures in approximately half of cases that would be missed by routine "spot" EEG 2
• Valuable for post-cardiac arrest prognostication and assessment of disorders of consciousness 2

Hepatic Encephalopathy

• EEG provides information on the severity of hepatic encephalopathy (minimal to severe), independent of patient cooperation 3
• Can detect patterns highly suggestive of hepatic encephalopathy in confused/stuporous patients (triphasic waves) 3

Limitations of EEG

• EEG is influenced by drugs, electric noise, and when suppressed in severe coma, cannot reliably provide information on residual cortical or subcortical activity 3
• A normal EEG does not exclude certain conditions like autoimmune encephalitis 3
• Interpretation requires expertise to distinguish normal variants from pathological patterns 2

Next Steps After Receiving an EEG Report

1. Discuss with your neurologist: Your doctor should explain the findings and their clinical significance
2. Consider additional testing: Depending on the findings, additional tests like MRI might be recommended
3. Follow treatment recommendations: If abnormalities are found, your doctor will recommend appropriate treatment

Remember that EEG is just one tool in neurological assessment, and its findings should be interpreted in the context of your clinical presentation and other diagnostic tests.