Oscillucusis and sudden deafness in a migraine patient Oscilucusia e perda auditiva em um paciente com migranea

Migraine is a complex disease that includes neurologic, gastrointestinal and autonomic symptoms, although headache is most common feature. In a portion of cases headache is preceded by focal neurologic symptoms termed auras. Auditory symptoms only rarely occur as part of an aura. We describe a patient whose 13-year migraine history that included the abnormal perception an oscillation of the intensity of ambient sounds (oscillucusis). During a migraine attack immediately after oscillucusis, the patient developed acute and permanent sudden deafness. Clinical and neurologic examinations revealed only profound hearing loss in her left ear. Audiometric testing confirmed the sensorineural nature of the hearing loss. The clinical aspects and physiopathology of auditory symptoms in this case and in patients with migraine is reviewed.<br>Migrânea é desordem complexa que inclui sintomas neurológicos, gastrointestinais e autonômicos, na qual a cefaléia é o achado predominante. Em uma parcela de pacientes o quadro álgico pode ser antecipado por sinais neurológicos focais conhecidos como aura. Descrevemos um paciente que iniciou sua historia de migrânea acompanhada por sensações de flutuações nos sons ambientes (oscillucusis) por treze anos. Durante uma crise de cefaléia imediatamente após a oscillucusia o paciente desenvolveu um quadro agudo e permanente de perda auditiva. Exames clínicos e neurológicos revelaram somente uma perda profunda da audição em ouvido esquerdo, cuja natureza sensorioneural foi confirmada por uma avaliação audiométrica. Os aspectos clinicos e fisiopatológicos dos sintomas auditivos encontrados neste caso e em pacientes com migrânea com aura são revisados e comentados

Asymmetric short-term adaptation of the vertical vestibulo-ocular reflex in humans

Anatomical and electrophysiological studies have demonstrated up-down asymmetries in vertical ocular motor pathways. We investigated whether these asymmetries extend to the capacity for short-term adaptation of the vertical vestibulo-ocular reflex (VVOR) in humans. Specifically, we asked whether smooth pursuit signals are sufficient to asymmetrically adapt the VVOR. Healthy human subjects (N=8), positioned 90° left-ear-down and fixating with their eyes upon a small laser dot (diameter: 0.1°) projected on a sphere (distance: 1.4m) were trained toward low VVOR gain for 30min with symmetric and asymmetric visual VVOR cancellation paradigms, while being oscillated (0.2Hz, ±20°) on a motorized turntable about the interaural earth-vertical axis. During asymmetric VVOR cancellation, the target was head-fixed in either the pitch-up or pitch-down half-cycles of oscillation (=trained direction) and space-fixed during the other half-cycles (=untrained direction). During symmetric VVOR cancellation, the target was head-fixed throughout the oscillations. Before and after adaptation, the pitch-up and pitch-down VOR gains were assessed during turntable oscillation in complete darkness. Before adaptation, average gains of pitch-up (0.75±0.15 SD) and pitch-down (0.79±0.19 SD) VOR were not significantly different (paired t test: P>0.05). On an average, relative gain reductions induced by selective pitch-up (pitch-up VOR: 32%; pitch-down VOR: 21%) and pitch-down (pitch-up VOR: 18%; pitch-down VOR: 30%) VOR cancellation were significantly (P<0.05) larger in the trained than in the untrained direction. Symmetric visual VVOR cancellation led to a significantly (P<0.01) larger relative gain reduction of the pitch-down (41%) than the pitch-up (33%) VOR. None of the paradigms led to significant changes of phase or offset. We conclude that, in human subjects, the smooth pursuit system is capable to asymmetrically decrease the gain of the VVOR equally well in both the upward and downward direction. The unexpected asymmetric decrease of the VVOR gain after symmetric visual cancellation may be related to the directional preferences of vertical gaze-velocity sensitive Purkinje cells in the flocculus for the downward directio