03/25/2026
⚙️ When Asymmetry Speaks Volumes
Subtle amplitude asymmetry can reveal early hemispheric dysfunction – even before rhythmic or periodic activity appears.
🧠 Why it matters: Persistent voltage asymmetry, even without clear slowing, can indicate evolving structural or vascular pathology (e.g., acute ischemia, subdural hematoma, or focal edema). When amplitude reduction localizes consistently across montage types, it’s rarely benign.
💡 When evaluating asymmetry:
✔️ Confirm across multiple montages to rule out technical artifact.
✔️ Note whether asymmetry is persistent vs. state-dependent (e.g., appearing only during sleep or stimulation).
✔️ Document relative amplitude ratio (e.g., “right hemisphere voltage 40% lower than left”).
✔️ Correlate with reactivity – loss of reactivity on one side strengthens concern for focal dysfunction.
Even before periodic discharges appear, a consistent amplitude asymmetry trend may be the first sign that neuroimaging or clinical correlation is warranted.