ACOUSTIC NEUROMA - CORRELATIONS BETWEEN MORPHOLOGY AND OTONEUROLOGICAL MANIFESTATIONS

Forty-two patients with acoustic neuroma (AN) were studied to determin e whether different types of neuroma could be correlated with specific signs and symptoms of the disease. Based on gadolinium-enhanced T1-we ighted MRI sequences, the 42 Eases of AN could be divided into three g roups, either by size (small: 11.9%, medium: 50%, and large: 38.1%) or by site of origin of the tumour (lateral: 16.7%, intermediate: 69%, a nd medial: 14.3%). Relations were found between the size and the site of origin of the neuromas and certain clinical, audiological and vesti bular findings. The clinical presentation seemed to vary with the site of origin and the size of the tumour: patients with lateral neuromas generally had small rumours, sometimes only located in the internal au ditory canal (IAC)? and presented early subjective hearing loss while patients with medial neuromas had larger rumours which grew without ca using significant audiological symptoms. Normal hearing function was s een only in the patients with medial ANs; however, a significant relat ion between the size or the site of origin of the AN and the average h earing threshold was not demonstrated. The sensitivity of the stapedia l reflex test (SR) was higher for lateral ANs. Anomalies in the brains tem auditory evoked potentials (BAEPs) did not seem to be related to e ither the size or the site of origin of the AN. The vestibular tests d emonstrated a higher frequency of central vestibular involvement in th e large rumours, while normal function was more frequent in the latera l rumours. in the group studied the combination of BAEPs and vestibula r tests allowed us to identify all the ANs with an optimal level of se nsitivity.