Vestibular
dysfunction
Abstract: Chronic fatigue syndrome (CFS) is distinguished by the new onset of debilitating fatigue that lasts at least 6 months, concomitant with other symptoms to be described later. Many CFS patients complain of disequilibrium, yet the exact type of the balance dysfunction and its function and its location (peripheral vs. central) have not been described. Herein we report results of vestibular function testing performed on 11 CFS patients. These results revealed no predominant pattern of abnormalities. Patients typically performed below average in dynamic posturography testing, with a significant number of falls in the tests requiring subjects to depend heavily on the vestibular system. One patient had abnormal caloric testing, while 3 had abnormally low earth vertical axis rotation (EVA) gains at the higher frequencies tested. As a group, the average gain of EVA was significantly lower than normals in the 0.1 - 1.0 Hz range (p < 0.05). In earth horizontal axis rotation, the CFS group had a higher than normal bias value for the optokinetic (OKN) and eyes open in the dark conditions (p < 0.05), but had normal scores during visual vestibular reflex testing. Five of the 11 subjects had an abnormal OKN bias build up over the course of the run, equal to or actually exceeding the 60 degrees/s target velocity by as much as 14 degrees/s. Altogether, these results are more suggestive of central nervous system deficits than of peripheral vestibular disfunction.
Balaban CD. Vestibular nucleus projections to the parabrachial nucleus in rabbits: implications for vestibular influences on the autonomic nervous system. Experimental Brain Research 1996; 108(3): 367-381.
Abstract: Acute vestibular dysfunction and motion sickness are characterized by autonomic effects such as pallor, nausea, and vomiting. Previous anatomic and physiologic studies suggest that one potential mediator of these effects may be light, direct vestibular nuclear projections to the nucleus tractus solitarius and the dorsal motor nucleus of the vagus nerve. This study presents evidence for relatively dense, direct projections from the vestibular nuclei to the parabrachial nucleus. Male albino rabbits received injections of Phaseolus vulgaris leucoagglutinin into the vestibular nuclei. The tracer was visualized immunocytochemically with standard techniques. Anterogradely labeled axons were traced bilaterally from the vestibular nuclei to the parabrachial nuclear complex, where they terminated around somata in the Kolliker-Fuse nucleus, external medial parabrachial nucleus, medial parabrachial nucleus, and lateral parabrachial nucleus. Less dense terminations were observed in the ventrolateral aspect of the medullary reticular formation, the subtrigeminal nucleus, lateral tegmental field, and nucleus ambiguus. These findings have several important implications. First, they suggest that vestibular input converges directly at brain stem levels with visceral sensory input in both nucleus of the solitary tract and the parabrachial complex. Second, they suggest that vestibular input influences brain stem autonomic outflow via two parallel pathways: (1) direct, light projections to the nucleus of the solitary tract, dorsal motor nucleus of the vagus nerve, and ventrolateral medullary reticular formation; and (2) denser projection to regions of the parabrachial nucleus that project to these brain stem regions. Finally, since the parabrachial nucleus regions that receive vestibular input also project to the hypothalamus and the insular and infralimbic prefrontal cortex, the parabrachial nucleus may serve as an important relay and integrative structure for the cognitive impairment and vegetative symptoms associated with motion sickness, vestibular dysfunction, and responses to altered gravitational environments.
Clark MR, Sullivan MD, Katon WJ, Russo JE, Fischl M, Dobie RA, Voorhees R. Psychiatric and medical factors associated with disability in patients with dizziness. Psychosomatics 1995; 34(5): 409-415.
Abstract: Dizziness is a common patient symptom and often remains medically unexplained even after an extensive work-up. The otologic disorders, psychiatric disorders, and functional disability of 75 patients presenting with dizziness to a community otolaryngology practice were assessed in 1991. The patients were classified according to the presence or absence of at least one current DSM-III-R psychiatric disorder and the presence or absence of a peripheral vestibular disorder. Decrements in mental health and role functioning, and increases in bodily pain and hypochondriacal focus were significantly associated with the presence of a psychiatric disorder and whether the etiology of dizziness was due to a peripheral vestibular dysfunction.
Clark MR. Psychiatric and otologic diagnoses in patients complaining of dizziness. Archives of Internal Medicine 1993; 143(12): 1479.
Abstract: BACKGROUND: Dizziness is a common and disabling symptom in primary care practice, especially among the elderly. Though there are many organic causes of dizziness, the results of medical workups are negative in the majority of patients. METHODS: A total of 75 patients with dizziness who were referred to a community otolaryngology practice received a structured psychiatric diagnostic interview (National Institute of Mental Health Diagnostic Interview Schedule) and questionnaires that assessed psychological distress as well as a complete otologic evaluation, including electronystagmogram. Patients with evidence of a peripheral vestibular disorder were compared with those without such evidence. RESULTS: While psychiatric diagnoses were present in both those with and without evidence of a peripheral vestibular disorder, those without such evidence had a greater mean number of lifetime psychiatric diagnoses as defined by the Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition, and specifically, a greater lifetime prevalence of major depression and panic disorder. This group also more frequently met criteria for somatization disorder, had more current and lifetime unexplained medical symptoms, and had more severe current depressive, anxiety, and somatic symptoms. CONCLUSIONS: Psychiatric diagnoses are common among patients with dizziness referred for otologic evaluation who do not show evidence of a peripheral vestibular disorder. Specific psychiatric disorders should be part of the differential diagnosis of patients who present with dizziness.
Clark MR. Psychiatric and medical factors associated with disability in patients with dizziness. Psychosomatics 1993; 34(5): 409.
Abstract: Dizziness is a common patient symptom and often remains medically unexplained even after an extensive work-up. The otologic disorders, psychiatric disorders, and functional disability of 75 patients presenting with dizziness to a community otolaryngology practice were assessed in 1991. The patients were classified according to the presence or absence of at least one current DSM-III-R psychiatric disorder and the presence or absence of a peripheral vestibular disorder. Decrements in mental health and role functioning, and increases in bodily pain and hypochondriacal focus were significantly associated with the presence of a psychiatric disorder and whether the etiology of dizziness was due to a peripheral vestibular dysfunction.
Fagioli LR. Vestibular function test anomalies in patients with chronic fatigue syndrome. Acta Oto-Laryngologica 1995; 115(1): 9.
Furman JMR. Testing of vestibular function: an adjunct in the assessment of chronic fatigue syndrome. Reviews of Infectious Diseases 1991; 13(Suppl 1): S109-11.
Abstract: Patients with chronic fatigue syndrome (CFS) often complain of dysequilibrium that is nonspecific. The basis of this complaint is unknown but may be related to vestibular system abnormalities, in that an association between inner-ear deficits and infectious mononucleosis has been established in the medical literature. An overview of quantitative vestibular function testing is given, including vestibulo-ocular and vestibulospinal tests. The basic principles of caloric and rotational testing are provided, including the interaction between vision and the vestibular system. Moving-platform posturography is described. Preliminary results from quantitative vestibular function testing of a small group of individuals with CFS are provided.
Harris JP, Ryan AF. Fundamental immune mechanisms of the brain and inner ear. Otolaryngology and Head and Neck Surgery 1995; 112(6): 639-53.
Abstract: Because of the blood-brain and blood-labyrinthine barriers, the brain and inner ear were once thought to be immunoprivileged sites. Although these barriers provide protection from inflammatory damage to the delicate structures of the organs, both sites have since been shown to be capable of active immune responses when appropriately stimulated. In the inner ear, perisacular tissue around the endolymphatic sac hosts resident lymphocytes and serves as a site of immunosurveillance. Lymphocytes also enter the inner ear from the circulation, and in the cochlea this occurs via the spiral modiolar vein. Immune responses can protect the labyrinth from infection, but they can also cause bystander injury. Moreover, the cochlea can itself become the target of immune responses that damage hearing. Such autoimmune sensorineural hearing loss can be site specific, with the primary manifestation of the disorder being hearing loss and dysequilibrium. Some of these cases can be diagnosed by antibody or lymphocyte responses to inner ear antigens. Alternately, systemic autoimmune disorders can result in inner ear dysfunction as part of a broader spectrum of disease. Both forms of immune-mediated inner ear dysfunction may respond to immunosuppressive therapies, including steroids, cytotoxic agents, and plasmapheresis.
Jacob RG, Furman JM, Durrant JD, Turner SM. Surface dependence: a balance control strategy in panic disorder with agoraphobia. Psychosomatic Medicine 1997; 59(3): 323-330.
Abstract: OBJECTIVE: Previous studies have reported vestibular dysfunction and impaired balance in patients with agoraphobia. Vestibular dysfunction may lead to an information processing strategy focusing on spatial stimuli from two nonvestibular sensory channels, vision and proprioception. This nonvestibular balance control strategy may in turn lead to discomfort in situations involving inadequate visual or proprioceptive spatial cues (space and motion discomfort). The objective of this study was to examine sensory integration of spatial information in agoraphobia. Because of previous findings that space and motion discomfort and vestibular dysfunction are common in agoraphobia, we hypothesized that agoraphobics would use a nonvestibular balance control strategy. METHOD: Using computerized dynamic posturography, we examined balance performance in patients with panic disorder with agoraphobia, uncomplicated panic disorder, nonpanic anxiety disorders, and depression without anxiety, as well as healthy subjects for comparison. The posturography procedure included six sensory conditions in which visual and proprioceptive balance information was manipulated experimentally by permutations of sway-referencing the support surface or the visual surround or by having patients close their eyes. RESULTS: The agoraphobics had impaired balance when proprioceptive balance information was minimized by sway-referencing the support surface (p < 0.02). This pattern, called surface dependence, tended to be more pronounced in agoraphobics who reported space and motion discomfort, including fear of heights or boats. CONCLUSION: Agoraphobics rely on proprioceptive cues for maintenance of upright balance. This strategy may lead to intolerance of situations characterized by unstable support.
Jacob RG. Panic, agoraphobia, and vestibular dysfunction. American Journal of Psychiatry 1996; 153(4): 503.
Abstract: OBJECTIVE: Otoneurological abnormalities have been reported in panic disorder. The purpose of this investigation was to determine the prevalence of such findings in panic disorder with and without agoraphobia and to discern whether vestibular dysfunction was associated with specific symptoms. METHOD: Clinical audiological and vestibular tests were administered to 30 patients with uncomplicated panic disorder (without agoraphobia or with only mild agoraphobia), 29 patients with panic disorder with moderate to severe agoraphobia, 27 patients with anxiety but no history of panic attacks, 13 patients with depressive disorders but no history of anxiety or panic attacks, and 45 normal comparison subjects. Evaluators were blind to subjects' diagnostic group. Quantitative measures of subjects' discomfort with space and motion and of the frequency of certain symptoms between and during panic attacks were obtained. Anxiety state levels were measured during the vestibular tests. RESULTS: Vestibular abnormalities were common in all the groups but most prevalent in the patients with panic disorder with moderate to severe agoraphobia. Vestibular dysfunction was associated with space and motion discomfort and with frequency of vestibular symptoms between, but not during, panic attacks. There were no major differences between the two panic groups in anxiety levels during vestibular testing. There were no significant differences between groups on the audiological component of the test battery. Exploratory data analysis indicated that the constellation of vestibular tests most specific for agoraphobia was one indicating compensated peripheral vestibular dysfunction. CONCLUSIONS: Subclinical vestibular dysfunction, as identified by clinical tests, may contribute to the phenomenology of panic disorder, particularly to the development of agoraphobia in panic disorder patients.
Jacob RG. Balance complaints and panic disorder: A clinical study of panic symptoms in members of self-help group for balance disorders. Journal of Anxiety Disorders 1996; 6: 47.
Kroenke K, Lucas CA, Rosenberg ML, Scherokman B, Herbers JE Jr, Wehrle PA, Boggi JO. Causes of persistent dizziness. A prospective study of 100 patients in ambulatory care. Annals of Internal Medicine 1992; 117(11): 898-904.
Abstract: OBJECTIVE: To determine the causes of persistent dizziness in outpatients. DESIGN: Consecutive adult outpatients presenting with a chief complaint of dizziness. SETTING: Four clinics (internal medicine, walk-in, emergency room, and neurology) in a teaching hospital. PATIENTS: Of 185 patients presenting during the 10-month study period, 51 (28%) had minimal or no dizziness at 2-week follow-up. Of the remaining 134 patients, 100 completed the study protocol (mean age, 62 years; range, 20 to 85 years). MEASUREMENTS: Evaluation included a detailed study questionnaire, standardized physical examination, vestibular testing by a neuro-ophthalmologist, laboratory tests, audiometry, and a structured psychiatric interview. Data were abstracted onto a standard form and reviewed by three raters. Raters independently assigned diagnoses using explicit criteria, with the final cause determined by consensus. RESULTS: Primary causes of dizziness included vestibular disorders (54 patients), psychiatric disorders (16 patients), presyncope (6 patients), dysequilibrium (2 patients), and hyperventilation (1 patient); dizziness was multicausal in 13 patients and of unknown cause in 8 patients. Many of those with a single primary cause, however, had at least one other condition contributing to their dizziness; only 52% of patients had a single "pure" cause. Thirty patients had a potentially treatable primary cause, the most common being benign positional vertigo (BPV) (16%) and psychiatric disorders (6%). Central vestibulopathies detected in 10 patients were presumably vascular or idiopathic in origin. No brain tumors or cardiac arrhythmias were found. CONCLUSIONS: Vestibular disease and psychiatric disorders are the most common causes of persistent dizziness in outpatients. In about 50% of patients with dizziness, more than one factor causes or aggravates symptoms. Life-threatening causes were rare, even in our elderly population.
Parker W. Migraine and the vestibular system in adults. American Journal of Otolaryngology 1991; 12(1): 25-34.
Abstract: The purpose of this paper is to explore the relationships between migraine and the vestibular system in adults. A review of the literature on migraine reveals that paroxysmal vertigo is not uncommonly associated with migraine in various temporal relationships with headache and/or other neurologic symptoms. Vertigo (or nonvertiginous dizziness) may be the chief presenting complaint sometimes masking less dramatic symptoms causing patients to be directed to an otolaryngologist. Meticulous family, past personal, and present history are necessary to produce the information leading to suspicion of the association of paroxysmal vertigo with the migraine diathesis. A careful prospective study of a large neurotologic population seems indicated to further define this relationship leading to diagnostic and therapeutic benefits. Sixteen cases are presented, six of them in detail.
Rosenberg M L. Vestibular diseases and psychiatric disorders are the most common causes of persistent dizziness. Annals of Internal Medicine 1992; 117(11): 898.
Yates BJ, Miller AD. Properties of sympathetic reflexes elicited by natural vestibular stimulation: implications for cardiovascular control. Journal of Neurophysiology 1994; 71(6): 2087-2092.
Abstract: 1. To study the properties of vestibulosympathetic reflexes we recorded outflow from the splanchnic nerve during natural vestibular stimulation in multiple vertical planes in decerebrate cats. Most of the animals were cerebellectomized, although some responses were recorded in cerebellum-intact preparations. Vestibular stimulation was produced by rotating the head in animals whose upper cervical dorsal roots were transected to remove inputs from neck receptors; a baroreceptor denervation and vagotomy were also performed to remove visceral inputs. 2. The plane of head rotation that produced maximal modulation of splanchnic nerve activity (response vector orientation) was measured at 0.2-0.5 Hz. The dynamics of the response were then studied with sinusoidal (0.05- to 1-Hz) stimuli aligned with this orientation. 3. Typically, maximal modulation of splanchnic nerve outflow was elicited by head rotations in a plane near pitch; nose-up rotations produced increased outflow and nose-down rotations reduced nerve discharges. The gains of the responses remained relatively constant across stimulus frequencies and the phases were consistently near stimulus position, like regularly firing otolith afferents. Similar response dynamics were recorded in cerebellectomized and cerebellum-intact animals. 4. The splanchnic nerve responses to head rotation could be abolished by microinjections of the excitotoxin kainic acid into the medial and inferior vestibular nuclei, which is concordant with the responses resulting from activation of vestibular receptors. 5. The properties fo vestibulosympathetic reflexes recorded from the splanchnic nerve support the hypothesis that the vestibular system participates in compensating for posturally related changes in blood pressure.
Yates BJ. Vestibular influences on the autonomic nervous system. Annals of the New York Academy of Science 1996; 781: 458-73.
Abstract: Considerable evidence exists to suggest that both sympathetic and respiratory outflow from the central nervous system are influenced by the vestibular system. Otolith organs that respond to pitch rotations seem to play a predominant role in producing vestibulo-sympathetic and vestibulo-respiratory responses in cats. Because postural changes involving nose-up pitch challenge the maintenance of stable blood pressure and blood oxygenation in this species, vestibular effects on the sympathetic and respiratory systems are appropriate to participate in maintaining homeostasis during movement. Vestibular influences on respiration and circulation are mediated by a relatively small portion of the vestibular nuclear complex comprising regions in the medial and inferior vestibular nuclei just caudal to Deiters' nucleus. Vestibular signals are transmitted to sympathetic preganglionic neurons in the spinal cord through pathways that typically regulate the cardiovascular system. In contrast, vestibular effects on respiratory motoneurons are mediated in part by neural circuits that are not typically involved in the generation of breathing.
Yates BJ. Vestibular influence on the sympathetic nervous system. Brain Research 1992; 17(1): 51.
Abstract: Studies using both electrical and natural stimulation have established that the vestibular system has prominent effects on sympathetic outflow and blood pressure. Preliminary evidence suggests that receptors in both otolith organs and semicircular canals are involved in producing these effects. Furthermore, vestibulosympathetic reflexes appear to be mediated by the medial vestibular nucleus and slowly conducting projections from the rostral ventrolateral medulla and caudal medullary raphe nuclei to preganglionic neurons in the thoracic spinal cord. However, many details are missing from our knowledge and understanding of the functional significance and neural substrate of vestibular influences on the sympathetic nervous system.
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