Julie A. Honaker

Use of the Dynamic Visual Acuity Test as a screener for community-dwelling older adults who fall

Adequate function of the peripheral vestibular system, specifically the vestibulo-ocular reflex (VOR; a network of neural connections between the peripheral vestibular system and the extraocular muscles) is essential for maintaining stable vision during head movements. Decreased visual acuity resulting from an impaired peripheral vestibular system may impede balance and postural control and place an individual at risk of falling. Therefore, sensitive measures of the vestibular system are warranted to screen for the tendency to fall, alerting clinicians to recommend further risk of falling assessment and referral to a falling risk reduction program. Dynamic Visual Acuity (DVA) testing is a computerized VOR assessment method to evaluate the peripheral vestibular system during head movements; reduced visual acuity as documented with DVA testing may be sensitive to screen for falling risk. This study examined the sensitivity and specificity of the computerized DVA test with yaw plane head movements for identifying community-dwelling adults (58-78 years) who are prone to falling. A total of 16 older adults with a history of two or more unexplained falls in the previous twelve months and 16 age and gender matched controls without a history of falls in the previous twelve months participated. Computerized DVA with horizontal head movements at a fixed velocity of 120 deg/sec was measured and compared with the Dynamic Gait Index (DGI) a gold standard gait assessment measurement for identifying falling risk. Receiver operating characteristics (ROC) curve analysis and area under the ROC curve (AUC) were used to assess the sensitivity and specificity of the computerized DVA as a screening measure for falling risk as determined by the DGI. Results suggested a link between computerized DVA and the propensity to fall; DVA in the yaw plane was found to be a sensitive (92%) and accurate screening measure when using a cutoff logMAR value of >0.25.

Age effect on the Gaze Stabilization test

Impairments of the vestibular-ocular reflex (VOR) lead to a decline in visual acuity during head movements. Dynamic visual acuity (DVA) testing is a sensitive assessment tool for detecting VOR impairments. DVA evaluates accuracy of visual acuity during fixed velocity head movements. In contrast, the Gaze Stabilization test (GST) is a new functional evaluation of the VOR that identifies a persons maximum head velocity (in degrees per second) a person can maintain with stable vision of a target (i.e. optotype). The objective of this study was to evaluate the effect of age on the GST in participants without vestibular disease. The study was conducted in a vestibular and balance laboratory at a tertiary medical center. A total of 87 healthy adult volunteers were included in this study. The main outcome measure was the association between age and both GST maximum head velocity in the yaw (right/left) plane and velocity symmetry. A significant negative correlation was found between age and maximum head velocity (r =-0.469, p< 0.001). Our results suggest that age should be considered when interpreting GST results in the yaw plane, however standardization of testing methods should be established as variation in results has been reported in the literature.

Adverse effects of health anxiety on management of a patient with benign paroxysmal positional vertigo, vestibular migraine and chronic subjective dizziness ☆

INTRODUCTION Care of patients with vestibular symptoms focuses primarily on physical otoneurologic disorders; however, psychological factors can sustain symptoms, confound assessment, and adversely affect treatment. Health anxiety is a particularly pernicious process that simultaneously magnifies physical symptoms and inhibits medical care. OBJECTIVE To demonstrate the excess morbidity caused by vestibular health anxiety and its successful management in a patient with otoneurologic disease. METHOD Report of a 41-year-old woman with recurrent benign paroxysmal positional vertigo, vestibular migraine, and chronic subjective dizziness, who expressed grave concerns about her health, repeatedly questioned her otoneurologic diagnoses, and failed physical therapy and medication treatment until her health anxiety and otoneurologic illnesses were addressed simultaneously. CONCLUSION Health anxiety is an empirically validated concept that explains troublesome health-related beliefs and behaviors. It is frustrating for patients and health care teams, but can be treated successfully in otoneurology practice, thereby reducing physical symptoms, emotional distress, functional impairment, and health care overutilization.

Vestibular-evoked myogenic potentials.

Purpose of reviewThis article reviews the literature on vestibular-evoked myogenic potential testing, a short latency electromyogram evoked by high acoustic stimuli and recorded via surface electrodes over the sternocleidomastoid muscle. Applications and refinements of this technique are described for different pathologies and in adults and children. Recent findingsVarious techniques for electrode placement have been described to elicit a vestibular-evoked myogenic potential response, which has been clinically investigated in normal individuals, under pathological conditions, and in adult and pediatric patients. As vestibular-evoked myogenic potential amplitude is linearly related to the level of background activity of the sternocleidomstoid muscle, maintaining steady contraction of the muscle can be challenging in some patients. SummaryVestibular-evoked myogenic potential testing may provide additional information about the vestibular system and allow site of lesion testing (e.g. saccule and inferior vestibular nerve) in patients of all ages. Its role has yet to be defined in the diagnosis and treatment of common vestibular disorders, including Menieres disease, vestibular neuronitis, labyrinthitis, and other diseases. Further research is needed to support its clinical usefulness in patients with balance disorders, to optimize patient selection, and to establish its cost effectiveness.

Performance of Fukuda Stepping Test as a Function of the Severity of Caloric Weakness in Chronic Dizzy Patients

BACKGROUND The purpose of the Fukuda Stepping Test (FST) is to measure asymmetrical vestibulospinal reflex tone resulting from labyrinthine dysfunction. The FST is a low cost evaluation for dizzy patients; however, when compared with gold standard caloric irrigation unilateral weakness (UW) value ≥25%, the FST has not been shown to be a sensitive tool for identifying unilateral vestibular hypofunction. PURPOSE The purpose of this technical report is to further evaluate the clinical utility of FST with and without headshake as a function of increased caloric asymmetry for individuals with unilateral peripheral vestibular pathology. RESEARCH DESIGN Retrospective review of FST results with and without head shaking component as compared to gold standard, caloric irrigation UW outcome values at four severity levels: 0-24% UW (normal caloric value); 25-50% UW (mild caloric UW); 51-75% UW (moderate caloric UW); 76-100% UW (severe caloric UW). STUDY SAMPLE 736 chronic (≥8 wk symptom complaints) dizzy patients. RESULTS Standard FST and FST following a head shake task are insensitive to detecting mild to moderate peripheral vestibular paresis. Increased test performance was observed for patients with severe canal paresis (>76% UW); however, continued inconsistencies were found in turn direction toward the severe unilateral vestibular dysfunction. CONCLUSIONS Overall, the FST provides little benefit to clinicians when used in the vestibular bedside examination.

Clinical use of the gaze stabilization test for screening falling risk in community-dwelling older adults.

Objective This study examined the clinical use of the computerized gaze stabilization test (GST) as a screener for falls. Design Cross-sectional, descriptive. Setting Tertiary medical center. Subjects Fifteen older community-dwelling adults with a history of falls and 15 controls without a history of falls were recruited for participation in the study. Main Outcome Measures Participants performed GST with yaw plane head movements. The GST velocity was measured and compared with the dynamic gait index (DGI). Receiver operating characteristic (ROC) curves and area under the ROC curve (AUC) identified GST velocity cut points for identification of fallers based on history of falls and as compared with DGI score. Results Our results suggested that GST can discriminate between individuals at risk for falls versus those not at risk. ROC analysis identified an AUC of 0.92 (⩽100.5 degrees per second criterion value) for GST based on history of falls and an AUC of 0.85 (⩽100.5 degrees per second criterion value) based on DGI for classifying falling risk. When GST and DGI scores were combined, the protocol identified an AUC of 1.0 (100% sensitivity, 100% specificity) for identifying falling risk. Conclusion There were significant head movement velocity differences from participants classified by history of falls and the DGI. Therefore, GST may serve as a potential falling risk assessment measure for older individuals with a history of falls. It is recommended that GST be used in a combined protocol with DGI to accurately identify individuals with falling risk rather than used in isolation.

Migraine-associated vestibulopathy

Purpose of reviewIn the past few years, otologists have been seeing an increasing number of patients with vestibular disorders due to migraine-associated vestibulopathy. This article reviews some of the latest developments in the understanding of this disease process, specifically its incidence, symptoms, diagnosis, and treatment. Recent findingsMigraine-associated vestibular symptoms may include episodic true vertigo, movement-provoked dysequilibrium, imbalance/unsteadiness, and complaints of lightheadedness. The pathophysiology of migraine-associated vestibulopathy is not completely understood; however, both peripheral and central deficits have been observed. Although the International Headache Society classification does not include migraine-associated vestibulopathy as a subclassification of migraine, there is emerging evidence to support this development, which should then lead toward improved diagnosis and treatment. Currently, migraine-associated vestibulopathy is still considered a diagnosis of exclusion. SummaryTreatment of migraine-associated vestibulopathy is effective and includes lifestyle changes, such as reducing triggers that increase susceptibility to migraines (e.g. stress, poor diet, nicotine, or irregular sleep patterns), prophylactic and abortive medications, vestibular therapy, or a combination of these. Further research is needed to better understand migraine-associated vestibulopathy and improve treatment.

Falls in the audiology clinic: a pilot study.

BACKGROUND Falls are a common and often preventable cause of injury and death among older adults. Hearing loss, vestibular disorders, dizziness, and imbalance are common risk factors for falls; however, the rate of falls among older audiology patients has never been assessed. PURPOSE To examine the fall history and risk factors of older adults seen in a university audiology clinic. RESEARCH DESIGN A descriptive and correlational retrospective chart review of fall history and characteristics of patients seen in a university audiology clinic. STUDY SAMPLE 88 (51 women, 37 men) patients aged 60 yr and older seen in a university audiology clinic. DATA COLLECTION AND ANALYSIS At the time of hearing evaluation, clinic patients filled out the Activities-Specific Balance Confidence (ABC) Scale, as well as a history form containing fall-related questions. These measures, as well as demographic information (gender and age) were retrieved during a retrospective chart review. Data were analyzed with independent-samples t-tests, Pearson correlations, and descriptive statistics. RESULTS Fifty percent of the study sample reported falling within the preceding 12 mo, while 70% reported having fallen at some point in the past. ABC Scale score was negatively correlated with age and number of recent falls. CONCLUSIONS There appears to be a higher prevalence of falls within a university audiology clinic relative to previously published fall rates in the general population.

Effects of Hand Placement Technique on the Video Head Impulse Test (vHIT) in Younger and Older Adults

Objective To investigate the effects of hand placement techniques on the video head impulse test (vHIT) responses (i.e., gain, velocity) in older and younger adults and to determine intra-rater and inter-rater reliability of the horizontal vHIT. Design Descriptive, reliability study. Setting University research laboratory. Subjects Forty healthy adults grouped by age with negative history of current or previous vestibular diseases between the ages of 20 and 88 years (mean = 46.60, standard deviation 23.20). Main Outcome Measures Three examiners each used two hand placement techniques (chin and head) to elicit the horizontal vHIT responses. Both the examiner and hand placement orders were counterbalanced to account for order and fatigue effects. The outcome measures of interest were vHIT gain and velocity. Results A two-way between-subject factorial analysis of variance revealed a significant main effect for hand placement technique and gain response. Mean values for vHIT gain were higher for head technique. Significant main effects were observed for the velocity response for hand placement technique and age group. Mean velocity values were higher for chin technique and lower velocities were observed in the older age group. Intra- and inter-rater reliability scores were consistent for gain values; however, poor to fair inter-rater reliability scores were observed for velocity values. Conclusion It is suggested that clinical sites select one hand placement technique for the measure to provide consistency of protocol. Establishing clinical norms using the one selected method to verify reliability within and across clinicians is suggested before examination with a disordered population.

Examining postconcussion symptoms of dizziness and imbalance on neurocognitive performance in collegiate football players

Objective This study examined the effects of symptom reports of dizziness and imbalance on cognitive function in concussed collegiate football players. Design Retrospective, descriptive. Setting University athletic medicine facility. Subjects Twenty-seven collegiate football players were included in the final analysis: 16 with symptoms of dizziness/imbalance resulting from concussion and 11 without dizziness/imbalance resulting from concussion. Main Outcome Measures Participants completed the Immediate Postconcussion Assessment and Cognitive Testing (ImPACT) at baseline, at 1 to 2 days postconcussion and 5 to 7 days postconcussion. The ImPACT neurocognitive assessment consists of 6 modules, yielding 4 composite scores: verbal memory, visual memory, visual-motor processing speed, and reaction time. In addition, it includes a postconcussion symptom scale total score. Results Results revealed that participants with reports of dizziness and imbalance had significantly lower scores on the ImPACT composite scores; however, these individuals also had an overall higher symptom inventory. When accounting for the additional postconcussion symptoms, time was the only significant effect. Conclusion Dizziness and imbalance are common symptoms postconcussion; however, these symptoms did not predict performance on acute ImPACT scores. Further research is needed to understand the mechanisms causing postconcussion symptoms, including symptoms of dizziness and imbalance, and influence on outcomes postconcussion.