The caloric irrigation test.

The test of caloric thermal irrigations is one of the first tests for sensitivity of the peripheral vestibular systems dating to the late 1800s. This chapter reviews the various protocols that have been developed over the years using thermal irrigations to the external auditory canals. The discussion covers the interpretations of the protocols and makes recommendations for those protocols that have the best performance and at the same time are practical to perform. The primary utility of the caloric test has remained the same since its origination - the comparison of the relative sensitivity of the right versus left peripheral vestibular function. This is now known to be applicable to the horizontal canals without any significant influence of the vertical canals. The hypothesized physiology behind the thermal caloric proposed in the early 1900s has now, with the help of experiments in microgravity, been partially verified. Until recently this was the only test that could investigate one peripheral end organ at a time. It is still the one test that emphasizes the low-frequency function of the horizontal canals individually.

Audiovestibular phenotype associated with a COL11A1 mutation in Marshall syndrome.

BACKGROUND: Marshall syndrome is a dominant disorder characterized by craniofacial and skeletal abnormalities, sensorineural hearing loss, myopia, and cataracts, and is associated with splicing mutations in COL11A1. OBJECTIVE: To determine the auditory and vestibular phenotypes associated with a COL11A1 splicing. DESIGN: Clinical otolaryngologic, audiologic, vestibular, and radiologic evaluations of the auditory and vestibular systems. SUBJECTS: Three affected individuals from a family cosegregating Marshall syndrome and a COL11A1 splice site mutation. RESULTS: The study subjects have progressive sensorineural hearing loss that is predominantly cochlear in origin and asymptomatic dysfunction of the central and peripheral vestibular systems. Computed tomography detected no malformations of temporal bone structures. CONCLUSIONS: The observed auditory and vestibular abnormalities are not caused by defective morphogenesis of the osseous labyrinth, but by more direct effects of the COL11A1 mutation on the membranous labyrinth and the central nervous system. The onset and degree of hearing loss associated with COL11A1 mutations are useful clinical features to differentiate Marshall syndrome from the phenotypically similar Stickler syndrome.

Functional operation of the balance system in daily activities.

This article presents the anatomy and physiology of the balance system focusing on the daily use of the system in normal individuals to accomplish the major goals of the system. These goals include perceptions of movement and orientation, control of eye movements for clear visualization of the world, and control of upright stance during static and dynamic tasks. When discussing various pathologies and the assessment and treatment options available, the information provided sets the foundation on which the remainder of the articles are built.

Balance function testing: a rational approach.

Recent advances in the area of balance function testing have left clinicians with a wide variety of diagnostic tests that provide insights into the function of the balance system. Laboratory tests used to evaluate the balance system include electronystagmography, rotational chair, and dynamic posturography. This article summarizes the currently available balance function testing protocols. A cost-effective and rational protocol for the application of these tests is provided.

The nursing role in radiation oncology.

OBJECTIVES: To reflect on the historical evolution of radiation oncology nursing. DATA SOURCES: Published articles and texts, historical archives of professional organizations, and the authors' experience. CONCLUSIONS: The radiation oncology nursing role is multifaceted. Role components include patient assessment, patient education, support and counseling, physical care, continuity of care, research, and administrative and leadership activities. There is wide variation in staffing patterns and role implementation throughout the world, and in recent years there has been increasing interest in the development of advanced practice nursing roles in this specialized area of oncology. IMPLICATIONS FOR NURSING PRACTICE: Changes in the health care environment make it difficult to predict how the role of the nurse in radiation oncology will evolve in the future. Radiation oncology nurses will need to be proactive in developing the knowledge and skills needed to meet the challenges of the future.

An overview of the clinical use of dynamic posturography in the differential diagnosis of balance disorders.

Dynamic posturography comprises a series of balance control tests which help physicians overcome numerous diagnostic and treatment challenges arising when examining patients complaining of a debilitating balance disorder. These challenges include the specific differential diagnosis, documentation of symptoms and assessment of functional disability. It must be determined whether the cause of the disability is an organic sensory, deficit, a central nervous system (CNS) lesion or a non-organic (that is, possibly psychogenic or just overtly simulated) disorder. This review is targeted towards providing the reader (a) an overview of the effects sensorimotor deficits have on balance control, specifically vestibulospinal and proprioceptive reflex deficits; and, (b) how these effects may be assessed objectively in a clinical setting to differentiate between various organic and non-organic balance-disorders. The techniques used to study these effects are based on the analysis of both rapid balance-correcting and slow balance-stabilizing responses to fast and slow movements in the pitch plane of the support surface on which the test subject stands.

EquiTest modification with shank and hip angle measurements: differences with age among normal subjects.

The Sensory Organization Test protocol of the EquiTest system (NeuroCom International, Clackamas Oregon) tests utilization of visual, vestibular, and proprioceptive sensors by manipulating the accuracy of visual and/or somatosensory inputs during quiet stance. In the standard Sensory Organization Test, both manipulation of sensory input (sway-referencing) and assessment of postural sway are based on ground reaction forces measured from a forceplate. The purpose of our investigation was to examine the use of kinematic measurements to provide a more direct feedback signal for sway-referencing and for assessment of sway. We compared three methods of sway-referencing: the standard EquiTest method based on ground reaction torque, kinematic feedback based on servo-controlling to shank motion, and a more complex kinematic feedback based on servo-controlling to follow position of the center of mass (COM) as calculated from a two-link biomechanical model. Fifty-one normal subjects (ages 20-79) performed the randomized protocol. When using either shank or COM angle for sway-referencing feedback as compared to the standard EquiTest protocol, the Equilibrium Quotient and Strategy Score assessments were decreased for all age groups in the platform sway-referenced conditions (SOT 4, 5, 6). For all groups of subjects, there were significant differences in one or more of the kinematic sway measures of shank, hip, or COM angle when using either of the alternative sway-referencing parameters as compared to the standard EquiTest protocol. The increased sensitivities arising from use of kinematics had the effect of amplifying differences with age. For sway-referencing, the direct kinematic feedback may enhance ability to reduce proprioceptive information by servo-controlling more closely to actual ankle motion. For assessment, kinematics measurements can potentially increase sensitivity for detection of balance disorders, because it may be possible to discriminate between body sway and acceleration and to determine the phase relationship between ankle and hip motion.

Evaluation of clinical measures of equilibrium.

OBJECTIVE: Evaluate the clinical utility of several simple measures of static and dynamic equilibrium in human subjects. In particular, one proposed clinical measure, the Clinical Test of Sensory Integration and Balance (CTSIB) was compared with dynamic posturography for the measurement of postural control capabilities. STUDY DESIGN: Cross-sectional study of normal subjects and prospective observational study of the same performance measures in vestibular disorder patients. SETTING: Academic tertiary care referral center. PARTICIPANTS: Data were collected for all test measures from a group of normal subjects (ages, 20 to 79 years), as well as for a group of patients undergoing treatment for vestibular dysfunction. RESULTS: Data suggest that several semiquantitative clinical tests of static and dynamic equilibrium can be helpful in evaluating and monitoring patients with chronic vestibular dysfunction. The CTSIB results seem to correlate well with dynamic posturography, suggesting that this measure may be useful in identifying patients with abnormal postural control. Formal dynamic posturography testing appears to be more sensitive in detecting abnormal postural control and more exact in defining the specific pattern of dysfunction. CONCLUSION: Simple clinical measures of static and dynamic equilibrium can reliably distinguish vestibular disorder patients from normal subjects. Dynamic posturography continues to play an important role in the functional evaluation and management of vestibular disorder patients.

Disability from vestibular symptoms after acoustic neuroma resection.

OBJECTIVE: This study aimed to evaluate the recovery of balance function after acoustic neuroma resection. STUDY DESIGN: This study was a retrospective case review with patient survey. SETTING: The surgery was conducted at a tertiary referral center. PATIENTS: Patients who underwent surgical resection of acoustic neuroma and had preoperative vestibular function testing were eligible for entering the study. INTERVENTIONS: All patients received surgical resection of acoustic neuroma. Patients treated since 1990 received postoperative vestibular habituation exercises. MAIN OUTCOME MEASURES: These included postoperative symptom and disability scores, dizziness handicap inventory (DHI) total and subset scores, time after surgery at which patients were able to walk independently, whether patients returned to their usual professional responsibility, and time to return to full activities at work. RESULTS: Significant correlation was found between several preoperative symptoms and vestibular testing results and the resulting postoperative disability from dizziness. CONCLUSIONS: This information may be helpful in counseling patients before surgery with respect to the degree of postoperative dysequilibrium and may suggest that the clinician should initiate more aggressive vestibular rehabilitation exercises in patients who may be at greater risk of having persistent dysequilibrium develop after surgery.

Computerized dynamic platform posturography.

Computerized dynamic platform posturography is defined in this technology assessment. The review discusses what computerized dynamic platform posturography measures, what the reliability and validity of the information are, and the uniqueness of the information provided. The clinical contribution and indications for testing are discussed. There are comments on future directions for research on computerized dynamic platform posturography and a summary and conclusion.

Two types of oscillopsia in a patient with idiopathic vestibulopathy.

A patient with an idiopathic bilateral vestibulopathy described two types of oscillopsia, one induced by head movement, the other induced by changing pressure in the right external auditory canal. This is the first report of both types of oscillopsia occurring in the same individual and illustrates their different mechanisms and symptomatology.

Characterization of human type II procollagen and collagen-specific antibodies and their application to the study of human type II collagen processing and ultrastructure.

Type II collagen is the most abundant collagen in articular cartilage and, together with other tissue-specific collagens and proteoglycans, provides the tissue with its shock-absorbing properties and its resiliency to stress. Specific antibodies which recognize various collagen types have been very useful in the study of collagen biosynthesis, structure and metabolism in normal and pathological conditions. Antibodies which recognize epitopes of type II collagen have been described previously; however, many of these antibodies display cross-reactivity with other collagens or with type II collagen from other species, reflecting the high degree of homology of the helical domains of fibrillar collagens. In this study, we prepared antibodies to sequential determinants of human type II procollagen employing synthetic peptides with sequences deduced from the nucleotide sequence of the human alpha 1 (II) procollagen cDNA. The antibodies were highly specific for epitopes in either the C-terminal propeptide or the telopeptide of the human type II collagen and did not cross-react with other human interstitial collagens or with murine type II collagen. These antibodies were used in conjunction with biosynthetic labeling to study the secretion and processing of human type II procollagen and collagen in human chondrocytes in vitro. The results indicated that a lag period of about 90 min was required for the secretion of newly synthesized type II procollagen. Conversion of the secreted procollagen into fully processed alpha-chains and their deposition in the cell layer were first apparent 240 min following the initiation of biosynthetic labeling. The antibodies were also used to examine, by immunoelectron microscopy, the structure of the extracellular matrix produced by human chondrocytes maintained in long-term cultures under conditions which permit the preservation of the cartilage-specific phenotype. These highly specific antibodies provide valuable tools to study the metabolism and structure of human type II procollagen and collagen in normal and pathologic conditions.

Familial large vestibular aqueduct syndrome.

The large vestibular aqueduct syndrome (LVAS) is a distinct clinical entity characterized by stepwise progressive sensorineural hearing loss associated with isolated enlargement of the vestibular aqueduct. A correlative clinical, audiologic, vestibular, cytogenetic, and radiographic analysis of a family with inherited LVAS was performed. The male proband and his affected brother are offspring of unaffected parents, and have no other abnormalities. Pedigree analysis suggests autosomal recessive or X-linked inheritance with variable expressivity of LVAS in this family. This study is the first description of familial inheritance of LVAS. LVAS may account for a significant number of patients with nonsyndromal, genetic sensorineural hearing loss. Future molecular analyses of this study family may identify the causative gene(s) in LVAS.

Update on vestibular rehabilitation therapy.

Although the concept of using exercises as part of the treatment for patients with persistent vertigo was introduced several decades ago, organized vestibular rehabilitation therapy programs have only recently been introduced. These programs typically involve a three-pronged approach, customized to the needs of the individual patient: (1) habituation exercises designed to facilitate central nervous system compensation by extinguishing pathologic responses to head motion, (2) postural control exercises, and (3) general conditioning activities. This article provides an update regarding the status of vestibular rehabilitation, reviewing the concept of vestibular compensation and patient selection criteria for current rehabilitative techniques.

Postural control in young and elderly adults when stance is perturbed: dynamics.

Responses in maintaining or restoring standing balance were measured in 24 healthy young and 15 healthy elderly adults (mean ages 26 and 72) under four task conditions: two involving self-generated motions and two involving imposed disturbances. The two primary objectives of the study were to quantify the whole-body dynamics of these responses and to identify any age related differences in those dynamics. Response dynamics were analyzed using a seven-link biomechanical model. In terms of approximate population-mean values, maximum whole-body center of mass (CM) excursions ranged to 3 cm, maximum center of support-surface reaction (CR) excursions ranged to 8 cm, vertical reaction force changes ranged to 50 N, anteroposterior support surface reactions ranged to 30 N, maximum joint torques used per side ranged to 20 Nm and peak angular momenta about a transverse axis through the ankles ranged to 6 kg m2 s-1. The elderly adults, compared to the young tended to exhibit higher-frequency oscillations in excursions and larger horizontal excursions of their CM and CR, tended to develop larger support surface reactions and use larger response joint torques, and tended to arrest less of their angular momentum in their first cycle of response during the two imposed-disturbance tasks. Only some of these tendencies proved statistically significant. The results suggest that healthy elderly subjects with no apparent musculoskeletal or neurological impairments differ from healthy young adult subjects in their responses to modest perturbations of upright stance. However, the differences are generally not large and their magnitudes are perturbation-specific.

Clinical utility of lateral head tilt posturography.

The Sensory Organization Test (SOT) of dynamic posturography, a functional test of balance, has a low sensitivity for compensated unilateral peripheral vestibular lesions. Tilting the head 45 degrees laterally during SOT [i.e. lateral heat tilt (LHT) SOT] may better detect such lesions. Normal subjects and vestibular clinic patients were studied using SOT and LHT SOT. Caloric, rotational chair, and oculomotor testing were also performed for patients, in either a double-blind or non-double-blind manner. The results for both patient groups were similar and thus were collapsed. Normative LHT SOT performance ranges were established to be slightly lower than corresponding SOT scores, for subjects aged 20-59 years. Subjects in older age groups performed with similar equilibrium scores in both SOT and LHT SOT. Normal subjects aged 20-59 and 60-69 years performed similarly, whereas those aged 70-79 performed significantly worse. Sensitivity of LHT SOT to unilateral peripheral vestibular lesions was poor (24%). Specificity of LHT SOT from patients having balance-system weakness was 90%. The results of this study indicate that LHT posturography does not facilitate significant discrimination of patients with compensated unilateral peripheral weakness from those without such lesions.

The septoclast, a cathepsin B-rich cell involved in the resorption of growth plate cartilage.

At the transition between growth plate cartilage and the endochondral bone region, transverse septa are being eroded to allow the advance of invasive capillaries. To find out whether resorption is due to proteinase activity, tissue sections prepared from the growth plate/metaphyseal interface of young rats were immunostained with antibodies to the cysteine proteinase cathepsin B. Intense staining was found in a cell that is associated with the growing portion of the invasive capillaries and extends between them and the transverse septum. This cell has a single nucleus, actively synthesizes protein, and shows two other characteristic features: the cytoplasm is packed with multivesicular and dense bodies rich in cathepsin B, and the cell apex ends in a ruffled border extending into the transverse septum and signs of dissociated extracellular matrix. Even though the ruffled border resembles that of the osteoclast, the cell was not immunostained by a monoclonal antibody that recognizes a 97 KD protein known as ED1 which characterizes rat osteoclasts, monocytes, and macrophages. Therefore, this distinctive cell produces the proteinase cathepsin B and appears to be involved in the resorption of the transverse septum. The cell has been named the "septoclast."