Development and validation of the trauma-specific emotional counting Stroop paradigm for fMRI study

The emotional-counting Stroop (ecStroop) is a cognitive task to evaluate emotional information processing. This study aimed to develop a trauma-specific ecStroop protocol for firefighters and assess its validity as a functional magnetic resonance imaging (fMRI) activation paradigm.

To develop the ecStroop protocol, trauma-related words for firefighters were selected from previous studies, and general negative and neutral words were matched corresponding to the number of letters and syllables, parts of speech, and frequency in the Korean language. The negative emotional valence of whole words was investigated in 520 healthy participants. To compare brain activation between three categories, 25 healthy individuals underwent fMRI during the ecStroop task.

Eight trauma-related words, eight general negative words, and sixteen neutral words were selected by emotional valence scores. The general negative words were related to increased activation in the right inferior and middle temporal gyrus, right medial frontal gyrus, and left superior frontal gyrus compared to the neutral words. When exposed to the trauma-related words, participants' brain activation was increased in the right inferior temporal gyrus, right medial frontal gyrus, left superior temporal gyrus, and left inferior frontal gyrus as compared to when exposed to the neutral words.

The fact that all participants in the phase 2 fMRI study were male could limit generalization to all genders.

These findings suggest that the ecStroop paradigm successfully activated the brain regions for emotional processing. This paradigm could be valuable in assessing the trauma-specific neural changes in firefighters.