Palinopsia Following Acute Unilateral Partial Vestibular Deafferentation: A Case Report.

Palinopsia is defined as the persistence or reappearance of images after cessation of the visual stimulus. One patient presented episodes of palinopsia after the functional loss of the 3 semicircular canals of the right ear while the otolithic function was preserved. None of classical causes was identified in this patient, intoxications, brain tumors, migraines, psychiatric disorders, etc. For a movement to be perceived as a single event, central processes of temporal integration are necessary to correct the shift between the rapid vestibular information, and the slow visual information. However, it has been shown on animal models that vestibular inputs are slower than normal in case of peripheral deafferentation limited to the canalar function with preservation of the otolithic function, which is the case in this patient. Therefore, we hypothesize that episodes of palinopsia he presents result from the fact that temporal integration processes do not take into account the slower than normal vestibular information due to the peripheral disorder and continue to slow it down. Thus, the patient keeps the visual image in memory until the late arrival of the vestibular information.

[A crazy patient or an additional weird experience vestibular in origin ?] / Une histoire de fou ou encore un trouble bizarre d'origine vestibulaire ?

We present a patient suffering from persistence of images after cessation of the visual stimulus, a phenomenon called palinopsia. As none of classical causes existed in this patient, we hypothethized that the phenomenon is related to the particular dysfunction of his right inner ear associating a canalar deficit with a preserved otolithic function. In such a situation, the vestibular inputs are slower than normal. Therefore, palinopsia could result from an abnormal temporal integration of visual and vestibular informations.

Nous présentons un patient souffrant de la persistance des images après la cessation du stimulus visuel, un phénomène appelé « palinopsie ¼. Comme aucune des causes classiques n'existait chez ce patient, nous avons émis l'hypothèse que le phénomène soit lié au dysfonctionnement particulier de son oreille interne droite associant un déficit canalaire à une fonction otolithique préservée. Dans une telle situation, les entrées vestibulaires sont plus lentes que la normale. Par conséquent, les épisodes de palinopsie pourraient résulter d'une intégration temporelle anormale des informations visuelles et vestibulaires.