Converting apogeotropic into geotropic lateral canalolithiasis by head-pitching manoeuvre in the sitting position.

Liberatory treatment of lateral canalolithiasis is more effective for the geotropic, than for the apogeotropic forms and, therefore, it is worthwhile attempting to convert the apogeotropic forms into the geotropic forms. In 36 cases of apogeotropic lateral canalolithiasis, one to five Head-Pitch Manoeuvres were performed in the sitting position (Head-Pitch Test) in the attempt to transform apogeotropic into geotropic lateral canalolithiasis. The Head Pitch Test was performed by a quick 60 degrees forward-flexion and a slow maximal backward-extension of the head. The Head-Pitch Test was effective in 36.1% of cases, less than the repeated Head-Rolling in the supine position, but it was always well tolerated by patients. The quick 60 degrees forward-flexion of the head can evoke a horizontal nystagmus beating towards the healthy side in apogeotropic lateral canalolithiasis and towards the affected side in geotropic lateral canalolithiasis (Bow Nystagmus). Slow backward-extension of the head can evoke a horizontal nystagmus beating towards the affected side in apogeotropic lateral canalolithiasis and toward the healthy side in geotropic lateral canalolithiasis (Lean Nystagmus). Conversion from apogeotropic to geotropic lateral canalolithiasis by the Head-Pitch Test was effective when Bow and Lean Nystagmus changed directions or when the Head-Pitch Test evoked Bow Nystagmus toward the affected side and Lean Nystagmus toward the healthy side. Conversion occurred in 10 patients during the 60 degrees forward-flexion of the head. In contrast, in 3 patients, it occurred during extension of the head, when a "Lean Nystagmus" toward the healthy side appeared. In addition, Pseudospontaneous Nystagmus and Positioning Nystagmus that arose when the patient moved from the sitting to the supine position changed direction or were evoked ex-novo, both directed toward the healthy side. In all cases, Pagnini-McClure diagnostic manoeuvre confirmed the transformation with a Positional Paroxysmal Horizontal Geotropic Nystagmus, which was more intense when the affected ear was brought down. The Head-Pitch Test can be used as the method of choice to transform apogeotropic into geotropic lateral canalolithiasis. However, anterior flexion of the head in the geotropic forms must be avoided since involuntary and harmful transformations from the geotropic into the apogeotropic form can occur, moving otoliths towards the anterior arm and cupula.