Which of the following would not be considered a normal EEG pattern for a full-term infant?

Persistent focal alpha frequency activity is not considered a normal EEG pattern for a full-term infant. In infants, particularly in the first year of life, alpha activity is typically not prominent, as alpha rhythms generally emerge later during development, around the ages of 2 to 5 years. When alpha frequencies do appear, they are usually symmetrical and diffuse rather than focal, indicating that the brain is maturing correctly. Therefore, the presence of persistent focal alpha activity may signify an underlying abnormality or atypical brain maturation, which is why this pattern would be viewed as abnormal in a full-term infant's EEG.

The other mentioned patterns are well-documented as normal EEG features in full-term infants. For example, trace alternant is a common pattern seen in infants, characterized by alternating low-voltage mixed-frequency activity. Isolated frontal sharp waves can also be considered a benign finding in this age group, often seen in healthy infants. Beta-delta complexes can occur during quiet sleep and are generally regarded as a normal variant. Collectively, these patterns align with the expected developmental EEG characteristics of infants, making them normal variants.