Investigation of Variations in Brain Activity Associated with Dizziness and Head Position Alterations During Gait

Background/Objectives: Dizziness is a common clinical symptom that can develop from various diseases and affect activities of daily living. This study investigated and compared brain activation in people with and without dizziness during different head position gait sessions using functional near-infrared spectroscopy (fNIRS). Methods: We included eight adults with symptoms of dizziness as the dizziness group and eight control participants without dizziness. Dizziness symptoms were evaluated using the Dizziness Handicap Inventory (DHI) and Vertigo Symptom Scale-short form (VSS-sf). Results: Compared with the control group, we found the activation of the bilateral middle temporal gyrus (MTG) when looking forward, the activation of the left superior parietal lobule (SPL) and right angular gyrus (AG) when looking upward, the activation of the left AG and the deactivation of the right MTG when looking rightward, the activation of the right SPL when looking leftward, and the activation of the left MTG and the deactivation of the right MTG when looking downward in the dizziness group at an exploratory, uncorrected threshold (p < 0.05). Notably, while all identified regions exhibited large effect sizes (Cohen's d > 0.8), only the activation in the left SPL (channel 11) remained statistically significant after false discovery rate (FDR) correction when looking upward compared with the control group (corrected p < 0.05). Conclusions: These exploratory and hypothesis-generating findings suggest that altered cortical activation associated with multisensory integration may reflect changes in sensory reweighting during gait in individuals with dizziness under different head position conditions.