Investigation of the Effect of Cognitive Additional Tasks on Functional Head Impulse Test in Healthy Individuals.

Introduction: Performing two tasks simultaneously may present various challenges for the human cognitive system. This study investigates how concurrent cognitive tasks impact the performance of the functional head impulse test (fHIT) in healthy adults. It was hypothesized that adding a cognitive load during fHIT would reduce the test's scores due to shared attentional resources.

Method: Twenty-seven participants completed the functional head impulse test (fHIT) and verbal fluency tests simultaneously. The study was designed in three stages: (1) recording fHIT results without any cognitive task, (2) completing the categorical fluency test and fHIT concurrently, and (3) administering the phonemic fluency test and fHIT simultaneously, with results recorded.

Results: Significant differences were observed in fHIT performance with and without additional cognitive tasks. Categorical tasks (e.g., animal and furniture categories) and phonemic tasks (e.g., words starting with "K," "A," or "S") impacted fHIT results, with notable performance reductions.

Conclusion: This study demonstrates that dual-task scenarios involving cognitive and vestibular demands adversely affect fHIT performance. The findings underscore the importance of attentional capacity in tasks requiring simultaneous cognitive and visual-oculomotor processing. These insights could guide future clinical applications in assessing and rehabilitating vestibular and cognitive deficits.