Which of the following is NOT a CORE type of disfluency?

Disfluencies in speech are categorized into two main types: core behaviors and secondary behaviors. Core types of disfluency include blocks, prolongations, and repetitions, which are fundamental features observed in stuttering. Blocks involve a complete halt in the flow of speech, prolongations refer to extending sounds in words, and repetitions involve repeating parts of words, whole words, or phrases.

Eye-blinking, however, is not considered a core type of disfluency. It is classified as a secondary behavior, which can occur as individuals who stutter develop physical responses to manage their stuttering, such as eye-blinking, head movements or other adaptations in an attempt to cope with the moment of disfluency. Secondary behaviors are often learned responses that accompany the primary disfluencies as a way to ease the pressure and anxiety associated with stuttering.

Thus, the identification of eye-blinking as the correct answer stems from its classification outside the core disfluency types that define the speech fluency challenge itself.