Inter-modality influence on the brainstem using an arithmetic exercise.

This study investigates the inter-modality influence on the brainstem using a mental task (arithmetic exercise). Frequency Following Responses were recorded in quiet and noise, across four stimuli conditions (No Task, Easy, Medium, and Difficult). For the No Task, subjects were instructed to direct their attention to the presented speech vowel while no mental task was performed. For the Easy, Medium, and Difficult conditions, subjects were instructed to direct their attention to the mental task while ignoring simultaneously presented speech vowel /a/. Results from this study suggest that top-down influences such as selective attention and working memory have no significant effects at the level of the brainstem in both listening backgrounds (quiet and noise).