The Study Of Clinical Application Of Video-electronystagmography In The Patients Of Acoustic Neuroma

Objective:Analyse the factors affecting the results of Video-Electronystagmography in the patients with the unilateral acoustic neuroma, and thus provide the meaningful clinical clues by the video-Electronystagmography for early discovery,early diagnosis, early treatment of the acoustic neuroma,reducing the risks of surgery and improving the quality of the life for the patients.Materials and methods:36cases of unilateral acoustic neuroma who were confirmed by operation and pathology in the neurosurgeons of xiangya hospital of central south university were collected.All patients were checked by Video-Electronystagmography which concludes saccade test,gaze test,smooth tracking test,optokinetic test,spontaneous nystagmus test(SN),positional nystagmus test,caloric test.Factors that were assumed to affect the results of the Video-Electronystagmography,such as gender,age,tumor size.the nature of the tumor,preoperative vestibular manifestations,preoperative hearing were analyzed with all pramaters of the Video-Electronystagmography. Results:The Pathological manifestation of the saccade test is mainly the extend of the latency and the rate is46.67%.Compared with the normal group,the average age is younger、the tumor size is larger and the average course is shorter in the group of the unilateral extended latency,the difference is statistically significant(P<0.05);2、The patients who have spontaneous nystagmus(SNO are six and The fast phase is to the contralateral.Compared with the patients who don’t have SN,the patients who have SN have larger tumor size、shorter course、and are prone to have longer vestibular symptoms postoperationly, the difference is statistically significant.3The patients who have positional nystagmus are six and whose tumor grade are T4b,accompanied by spontaneous nystagmus or gaze nystagmus.The fast phase of the positional nystagmus is to the contralateral.4The patients who have gaze nystgmus are six.Five patients have horizontal gaze nystagmus and one patients have vertical gaze nystagmus.The fast phase of the gaze nystagmus is to the contralateral in two cases who have horizontal gaze nystagmus.One cases who have horizontal gaze nystagmus have bilateral gaze nystagmus and the same amplitude and two cases have bilateral horizontal nystagmus and different amplitude(Brun’s nystagmus).Compared to the cases who have not gaze nystagmus,the tumor size is larger and the duration of the vestibular symptoms preoperationaly is longer in the cases who have gaze nystagmus,the differences is statistically significant(P<0.05).5The type II is23and the type III is13in the smooth-puisuit test.The difference of the tumor size between type II and Type III is not statistically significant;10cases have the abnormality of the Optokinetic(OPK) test which present reduced eye movement speed.The average tumor size is larger in the patients who have the abnormal OPK test compared with the cases who have normal OPKtest and the difference is statically significant.6There are two cases who have normal caloric reaction and34cases who have weakened caloric reaction.Four cases have bilateral weakened caloric response and thirty cases have ipsilateral weakened caloric reaction.Seven cases have directional preponderance to the contralateral.7Compared with the the patients who don’t have caloric response,the patients whose caloric responses are retained are more likely to longer vestibular symptoms postoperatively.8The results of remaining statistical analysis are not significant.Conclusions:(1) The patients whose tumor had larger size and involved central vestibular system are easy to have extended latency in saccades tes、Spontaneous nystagmus、gaze nystagmus、abnormal OPK test、Positional nystagmus.Otherwise;the present of positional nystagmus often indicate that the tumor has invovled Fourth ventricle.(2) The patients whose vestibular symptoms last longer preoperatively are prone to have gaze nstagmus. The present of Brun’s nystagmus indicated that the tumor has involved brainstem and cerebellum.It is special manifestation of the tumor in cerebellopontine angle.(3) The rate of ipsilateral weakend caloric response is higher in the Video-Electronystagmography. The origin of the tumor of those patients who have normal caloric responses can be indicated by combining clinical symptoms and related inspection.(4) The emerge of saccade test、 Spontaneous nystagmus and gaze nystagmus can indicate the fast grow rate of the tumor.(5) The patients that the function of the lateral semicircular canal are retained and are companied with SN are are more likely to have longer vestibular symptoms postoperatively.