amplitude asymmetry
Unequal voltage measurements between corresponding electrode pairs on opposite sides of the head, potentially indicating underlying pathology.
Full Definition
Amplitude asymmetry describes a significant difference in electrical voltage between homologous brain regions as recorded by EEG electrodes. This asymmetry can manifest in background rhythms, sleep patterns, or specific waveforms. A difference of greater than 50% between corresponding electrode pairs is generally considered significant. Amplitude asymmetry may indicate structural lesions, cortical dysfunction, skull defects, or technical issues such as electrode problems. The pattern and persistence of asymmetry help differentiate pathological findings from benign variants.
Usage
Usage note: Specify the percentage difference and affected regions when describing amplitude asymmetry.
In Context
- "Significant amplitude asymmetry was noted in the alpha rhythm, with reduced voltage over the right posterior regions." — EEG interpretation
- "The amplitude asymmetry persisted across multiple montages, suggesting a structural cause." — Clinical correlation note