What is the expected dominant background rhythm in an EEG by one year of age?

By one year of age, the expected dominant background rhythm in an EEG is typically around 5 to 6 Hz. This age marks a significant phase in the development of brain activity patterns, where the slower rhythms that were predominant in infancy adapt and begin to increase in frequency.

During this period, brain maturation is occurring, leading to the establishment of more organized and consistent EEG patterns. As infants grow, they shift from irregular brain wave patterns to more rhythmic and defined waves, moving toward the characteristic alpha rhythms that appear in later childhood. The 5 to 6 Hz frequency aligns with the transition towards more complex and synchronized brain activity, which is indicative of cognitive and neurological development.

Understanding this background rhythm is crucial for interpreting EEG results in young children and identifying normal versus abnormal brain activity.