The Tullio phenomenon: a neurologically neglected presentation.
ABSTRACT The Tullio phenomenon refers to sound-induced disequilibrium or oscillopsia. Patients with this condition frequently present to neurologists, many of whom are unfamiliar with the condition and its diagnostic criteria. Indeed, due to the unusual nature of the symptoms patients are often misdiagnosed as having psychiatric disturbances. Tullio patients describe disequilibrium, auditory and visual symptoms, which are recurrent, brief, and often triggered by loud noises or middle ear pressure changes, e.g. the Valsalva manoeuvre. Many cases are associated with superior semicircular canal dehiscence (SCCD). Early work suggested that the presence of sound-induced torsional eye movements and visual field tilts were consequent upon a utricular-mediated ocular tilt reaction. However, more recent evidence from imaging and oculographic research, as well as data from our patient series indicates that these ocular abnormalities are usually the result of superior semicircular canal stimulation. The clinical history and a focussed examination are often sufficient to make the diagnosis, which can be confirmed with high resolution CT imaging of the temporal bones. In some patients, surgical occlusion or resurfacing of the affected canal can ameliorate symptoms and signs. The aim of this paper is two-fold: Firstly, to review the clinical features of the Tullio phenomenon, and secondly, to highlight our own observations in three cases with a new clinical syndrome consisting of Tullio's phenomenon with bilateral vestibular failure, a pure horizontal nystagmus in response to sound, and no evidence of canal dehiscence.