The damped pendular rotation test in central vestibular disorders

Abstract

Nystagmic rhythm in the damped pendular rotation test (DPRT) was analysed electronystagmographically both in healthy subjects (control) and patients with peripheral and central vestibular lesions. The patients were tested in a semi-dark room with eyes open and, in addition, a serial subtraction task was performed to maintain the state of alertness throughout the rotation. In the controls 49 years of age and under dysrhythmia was found in 11%, while in persons 50 years of age and over the abnormal rate was 29%. In patients with acoustic tumors, who had undergone surgery in which the translabyrinthine and middle fossa approach had been utilized, dysrhthmia was present post-operatively in only a few cases. In patients 49 years of age and under, operated on through the suboccipital approach, dysrhythmia was found post-operatively, or was at least more remarkable than pre-operatively in most cases. Nystagmic rhythm was, on the other hand, regular with cerebellar degenerative process or atrophy. Pre-operative dysrhythmia in patients with cerebellar and cerebral tumors was in some cases post-operatively converted to regular rhythmic nystagmus in pendular stimulations. Therefore, in cerebellar and cerebral tumors, dysrhythmia was thought to be due to secondary effects in brainstem, as these tumors can cause intracranial hypertension and circulatory disturbances in surrounding brain tissues. In Menière's disease and sudden deafness, dysrhythmia and salvos in DPRT were found in the age groups, 49 years of age and under and 50 years and over, as frequently as in the healthy and control group. In one case with Menière's disease which showed dysrhythmia, labyrinthectomy was done. This surgical manipulation of the labyrinth did not eliminate dysrhythmia, though a temporary improvement was obtained. This result indicates that the dysrhythmia may be of central origin. These findings also suggest that nystagmic rhythm in DPRT with mental arithmetic is significant in assessing brainstem dysfunctions, when the age and state of alertness of the patient are taken into consideration, or when comparing the pre- and post-operative findings in intracranial lesions.

Differential Diagnosis of Central Vestibular Disorders by Combined Tests with Perrotatory Ocular Fixation and Auditory Brain Stem Response

“…The 74 cases of central vestibular disorders used in this study are as follows: The DPRT used in this study was the same as that of Greiner and co-workers [6]. Our previous report [8] described the procedure of DPRT as well as OFT.…”

“…We have made several previous reports on the findings of the damped pendular rotation test (DPRT) given in the dark and also on an ocular fixation test (OFT) given during DPRT in some central vestibular disorders [6,8], Furthermore, the clinical value of auditory brain stem response (ABR) in the diagnosis of cerebellopontine angle lesions, including acoustic neuromas and lower brain stem lesions, is generally accepted [9]. Accordingly, in this report, we investigated the diagnostic value of DPRT in the dark, OFT during DPRT, and ABR as a battery of tests for the differ ential diagnoses of CP angle lesions, brain stem lesions, and cerebellar lesions.…”

Results of Surgery by the Modified Extended Middle Cranial Fossa Approach in 100 Patients with Acoustic Neuroma

“…It was also known through postoperative neurotological examinations (damped pen dular rotation test, optokinetic nystagmus test, and eye tracking test) that the TL ap proach produces little effect on the brain stem or the cerebellum [4], Around that time, the extended middle cranial fossa (EMCF) approach was reported by Bochenek and Kukwa [1], and the translabyrinthine-transtentorial approach was pro posed by Morrison and King [9]. Based on these reports, we developed a modified EMCF approach, in which labyrinthectomy is performed by the MCF approach rather than by the transmastoid approach, so that neuro surgeons and otologists working as a team can have the same operative field [5].…”