The cerebral projection of vestibular signaling was studied by using PET with a special differential experimental protocol. Caloric vestibular stimulation (CVS)-induced regional cerebral blood flow (rCBF) changes were investigated in two populations. Butanol perfusion scans were carried out on six healthy volunteers and on six patients following the removal of tumors from the right cerebello pontine angle. The complete loss of the vestibular function postoperatively allowed a comparison of the rCBF changes in the populations with or without this input and offered a promising functional approach whereby to delineate the cortical region most responsive to pure vestibular input. The activations by left-sided and right-sided CVS were determined for both the healthy volunteers and the patient population. Statistical analysis of the data obtained following left-sided CVS did not reveal any cerebral region for which there was a significant difference in CVS-induced response by these two populations. In the case of right-sided CVS, however, the statistical comparison of the CVS-related responses demonstrated a single contralateral area characterized by a significantly different degree of response. This cortical area corresponds to part of the cortical region described recently which can be activated by both CVS and neck vibration. It appears to be anatomically identical to the aggregate of the somatosensory area SII and the retroinsular cortex described in primates, a region identified by other investigators as an analog of the parietoinsular vestibular cortex.

We are the first to point out the functional connection between the hippocampus and the vestibular system in this report.

There are a number of well-known stimulation methods for the investigation of the central projection of the vestibular system. In addition to optokinetic, galvanic and neck vibration tests, the most widespread method is caloric stimulation. These listed methods cause not only vestibular, but also other effects on the central nervous system (CNS) (acoustic, tactile and nociceptive). In this paper, positron emission tomography (PET) was used to investigate whether caloric stimulation contains a non-vestibular (extravestibular) component, which would cause a distortion in the cortical activity and therefore in the vestibular effect on the CNS. Caloric stimulation was carried out in six patients who had been operated on due to cerebello-pontine angle tumour. These patients suffered post-operatively from a complete lesion of the vestibular system and anacusis on the operated side. Ipsilaterally activated areas were the inferior pole of the post-central gyrus and temporoparietal junction, caudal part of the post-central gyrus (SI, SII), inferior parietal lobule and medial frontal gyrus. Contralaterally activated areas were the anterior cingulate gyrus, medial frontal gyrus, posterior part of the insula, post-central gyrus and temporoparietal junction (SII). Ipsilaterally deactivated areas were the caudal and cranial part of the medial occipital gyrus (V2, V3, V4, V5). Contralaterally deactivated areas were the lingual gyrus, inferior occipital gyrus (V2, V3) and fusiform gyrus. On the basis of these data, it was postulated that, during caloric stimulation, extravestibular reaction also occurs, which corresponds to the subjective feeling of heat and pain. The deactivation of the occipital cortex due to an extravestibular effect was demonstrated. This is the first observation to suggest the possibility of nociceptivevisual interaction.

Aim: To report a child with an extensive tumor invading multiple anatomical structures within the left side of her neck. Material and methods:Presentation of a case including patient's history, physical exam, molecular data, MRI imaging, histopathology and molecular genetics. Results:The life-threatening compression as well as the dislocation of the trachea required meticulous surgical removal of the tumor. Histology revealed a plexiform neurofibroma related to a frame shift mutation in the NF1 gene. Conclusion:Surgical removal of this extensive tumor saved the patient's life. The long term success of management will be related to the effectiveness of the maintenance therapy that currently includes interferon-α2a. This report highlights unique aspects of a rare but life threatening condition in a young girl.

Die Verfasser berichten Über die Ergebnisse der prospektiven Untersuchungen von 40 Kranken mit Neuronitis vestibularis. Auf Grund des SchwindelgefÜhls, des Spontannystagmus und der kalorischen Reaktion stellen sie fest, dass der Heilungsprozess, d.h. die Kompensation, verhÄltnismÄssig lange dauerte und fiuktuierend war. Sie empfehlen solche Rechenverfahren, die bei der Computerbearbeitung der otoneurologischen Befunde behilflich sind.

The parameters for vestibular dysfunction were modified after our own studies. This index includes the degree of vertigo present, spontaneous nystagmus, dysfunction of the vestibulospinal reflexes and caloric and postrotatory side differences. The index is applicable for defining the extent of a lesion, follow-up, defining its stage and the results of therapy. Introduction of the modified vestibular index is proposed for use in clinical diagnosis. Classification of vestibular neuronitis into groups A, B and C is suggested on the basis of the reversibility of spontaneous nystagmus after caloric stimulation.