amplitude
Pronunciation: AM-pli-tood
The magnitude or strength of electrical activity measured in neurophysiological recordings.
Full Definition
Amplitude in neurophysiology refers to the vertical measurement of electrical signal strength, typically expressed in microvolts (μV) for EEG recordings or millivolts (mV) for EMG and nerve conduction studies. Amplitude measurements provide important diagnostic information about the integrity and function of neural tissue, with abnormally high or low amplitudes indicating various pathological conditions. In EEG, amplitude changes may reflect cortical dysfunction, while in nerve conduction studies, reduced amplitude may indicate axonal damage or muscle weakness. Amplitude analysis must consider technical factors such as electrode impedance, amplifier settings, and measurement standardization. Comparison of amplitudes between corresponding regions or time periods helps identify asymmetries and abnormal patterns.
Usage
Usage note: Always specify units (microvolts for EEG, millivolts for EMG/NCS) when reporting amplitude measurements.
In Context
- "The EEG showed reduced amplitude in the right hemisphere compared to the left." — Neurophysiology diagnostic report
- "Motor nerve conduction studies revealed significantly decreased amplitude suggesting axonal neuropathy." — Nerve conduction study report