Challenging frontal lobe capacity using lateralized vestibular stress: A functional cerebral systems approach to a clinical risk for falls
A conceptual model was originally proposed that linked the vestibular modality with executive domains by means of a functional cerebral systems framework. The claim was that frontal regions exert regulatory control over posterior systems for sensation and autonomic functions in a dense, interconnected network with right hemisphere specialization. As a preponderance of evidence demonstrates that a design fluency task is often associated with right frontal functioning, it was hypothesized that proficiency on a design fluency task would yield differences in QEEG and skin conductance after vestibular activation. Fifty-eight total (29 high- and 29 low-fluent performers on the Ruff Figural Fluency Test were subjected to 20 whole-body passive rotations about the neuroaxis at a constant rate of approximately 120 degrees per second. EEG and skin conductance levels were recorded prior to and post-rotation. Analyses were conducted on delta (1-4 Hz.) and beta (13-21 Hz.) frequencies. Overall, delta activity increased from baseline to post-rotation with higher levels at frontal sites, however no group differences were found across conditions. Regarding beta activation, high design fluency was associated with increased beta activation at the right temporal site (T6). In contrast to expectations, beta activity diminished from baseline to post-stress over both groups. Skin conductance levels increased from baseline to post-stress. Methodological considerations are discussed regarding gender issues and procedures of the experiment. The results indicate that vestibular disorientation yields systematic delta changes in the frontal regions, but that future refinements to the vestibular stressor may elicit QEEG and skin conductance differences in fluency groups.