Harmonic acceleration as a measure of vestibular compensation

The results of conventional electronystagmography (ENG) sometimes are confusing. The Hallpike alternate binaural bithermal (ABB) caloric test is helpful diagnostically except for the group of "sick patients that have a normal test". Conventional ENG tests also fall short in the area of objective confirmation of patient progress. What does each test tell us regarding site of lesion? Alternate binaural bithermal stimulation gives us information about the semicircular canals--particularly the horizontal semicircular canal--pickup head. Simultaneous binaural bithermal stimulation gives information about brain stem connections--switching and relay. Rotation testing gives information about the processing by the brain--central control.