A downward deflection occurs in EEG readings if?

A downward deflection occurs in EEG readings if?

• A. Input 1 is equal to input 2
• B. Input 1 is more negative than input 2
• C. Input 2 is more positive than input 1
• D. Input 1 is more positive than input 2

Answer: (D)

In electroencephalography (EEG), the direction of deflection in the waveforms displayed on the EEG can be understood in terms of the electrical potential differences between two electrode inputs. A downward deflection occurs when the potential of the input used as a reference (in this case, input 2) is more positive than the potential of the active input (input 1). This phenomenon is based on the principle that when the active electrode detects a lower voltage compared to the reference, the recorded trace moves downward. When input 1 is more positive than input 2, that means input 2 is relatively less positive (or more negative) compared to input 1. This difference causes the neurophysiological signal from input 1 to be represented as a downward deflection on the EEG. Understanding this principle is crucial for interpreting EEG data, as it influences how brain waves are read and understood clinically. A correct grasp of the concepts of positivity and negativity in relation to electrode inputs is fundamental for anyone working in the field of electroencephalography.

In electroencephalography (EEG), the direction of deflection in the waveforms displayed on the EEG can be understood in terms of the electrical potential differences between two electrode inputs. A downward deflection occurs when the potential of the input used as a reference (in this case, input 2) is more positive than the potential of the active input (input 1). This phenomenon is based on the principle that when the active electrode detects a lower voltage compared to the reference, the recorded trace moves downward.

When input 1 is more positive than input 2, that means input 2 is relatively less positive (or more negative) compared to input 1. This difference causes the neurophysiological signal from input 1 to be represented as a downward deflection on the EEG.

Understanding this principle is crucial for interpreting EEG data, as it influences how brain waves are read and understood clinically. A correct grasp of the concepts of positivity and negativity in relation to electrode inputs is fundamental for anyone working in the field of electroencephalography.