Rotational Chair Testing Research Articles

Sensitivity and Specificity of the Head-Shaking Test for Detecting Vestibular System Abnormalities

The head-shaking nystagmus (HSN) test has been reported to be a sensitive screening test for the presence of peripheral and central vestibular system disease. Previous investigations have utilized few subjects who were drawn from well-defined patient populations. The purpose of the present investigation was twofold: first, to determine the prevalence of HSN in a large unselected population of dizzy patients seen in an otology and neurotology practice, and second, to determine the sensitivity and specificity of this evaluation in the detection of vestibular system abnormalities as reflected by results of electronystagmography and rotary chair testing. The results of the investigation have suggested that the HSN test has a 27% sensitivity and an 85% specificity. The HSN test yields an acceptable number of false positives (15%) and an unacceptably large number of false negatives (73%).

Vestibular Effects of Chronic Perilymph Fistula in the Cat

Chronic, unilateral perilymph fistulae were created in cats by removal of the round window membrane and placement of a tympanostomy tube into the round window. Rotary chair, fistula, caloric, and vestibulospinal tests were performed before and after fistulization, and periodically for 2 weeks. At 2 weeks, patency of the fistula was documented by fluorescein injection into the spinal fluid and visualization of leakage into the middle ear bulla via the fistula. All the cats had a patent fistula at 2 weeks, but one of the three cats had a greater perilymph leak than the others. The cat with the more active leak had a spontaneous nystagmus toward the side of the fistula on the first postoperative day; this changed to nystagmus toward the opposite side by the third postoperative day. The other cats had a spontaneous nystagmus toward the opposite side from the first postoperative day. Most abnormal test results returned to normal in the first week after fistulization. Histologic study of the temporal bones revealed that the cat with the greater leak had a wider cochlear aqueduct than the other cats.

The Sinusoidal Harmonic Acceleration Rotary Chair Test: Theoretical and Clinical Basis

Sinusoidal harmonic acceleration has become a common method used in diagnostic vestibular testing. When properly used, it can produce normal and abnormal patterns that can be interpreted in the context of the nature of the stimulus and the physiologic processes that describe the responses to it. Thus, the aim of this review is to present specific information regarding the sinusoidal harmonic acceleration stimulus and vestibular physiology in a way that will hopefully aid in test interpretation.

Automatic Electronystagmus Analysis and Documentation: Recent Advances in the Study of Vestibular, Optokinetic and Pursuit Tracking Function (With 3 color plates)

A normal or pathologically altered peripheral vestibular system and associated brainstem structures can be diagnosed from the pattern of eye movement responses elicited by appropriate stimuli. Recent advances in two stages crucial to an accurate assessment of pathological or normal responses are described in this article. The first stage involves the automatic analysis of electronystagmus signals to yield the main parameters of clinical and scientific interest, slow phase eye velocity and fast phase frequency. Since four algorithms based on the first derivative of eye position perform this task remarkably well on-line, it is not necessary to employ features of the stimulus to separate the slow and fast phases of nystagmus. Examples are used liberally to illustrate the accuracy, advantages and limitations of the algorithms. The second stage involves a numerical and graphical comparison of measurements from a patient's analyzed responses with normal responses. This documentation phase permits immediate recognition of normal, borderline, or pathological optokinetic, eye tracking, caloric and rotating chair test results. Selected examples of pathological responses illustrate the documentation technique.

General autonomic components of motion sickness.

ABSTRACTThis report refers to a body of investigations directed toward the examination of autonomic nervous system responses to motion sickness. Heart rate, respiration rate, finger pulse volume, and basal skin resistance were measured on 127 men and women before, during, and after exposure to a nauseogenic rotating chair test. Significant changes in all autonomic responses were observed across the tests (p<.05). Significant differences in autonomic responses among groups divided according to motion sickness susceptibility were also observed (p<.05). Results suggest that the examination of autonomic responses as an objective indicator of motion sickness malaise is warranted and may contribute to the overall understanding of the syndrome.

Endolymphatic shunt: an evaluation by test results.

Failure in the endolymphatic shunt operation for Meniere's disease is reportedly 30% or more. The fact that many patients have relief from their symptoms following this surgery offers validity to the procedure. Pure tone audiograms and sinusoidal harmonic acceleration (rotary chair or rotary test, RT) were used concurrently to evaluate end-results of this operation in 31 patients with Meniere's disease. RT shows parameters of phase and labyrinthine preponderance (LP) calculated by a computer. LP was determined by separately integrating the total slow-phase output of the vestibulo-ocular reflex (VOR) to the left and right and converting the differences to percentages. Irritative and destructive lesions in Meniere's disease may be accurately resolved using this technique. It was not possible to predict with any accuracy the irritative-destructive parameter using pure tone audiometry. Patients who had irritative lesions fared better with the shunt operation. An analysis of these patients is made with RT.