Dizziness and the Otolaryngology Point of View

Comparative utility of vestibular function tests in patients with peripheral and central vestibular dysfunction

Background

Bithermal caloric irrigation, video head impulse test (vHIT), and rotational testing are commonly used to assess peripheral vestibular function, but the relative clinical utility of each test in differentiating patients with peripheral vestibulopathy is debated.

Objectives

To determine whether (1) the combination of two or more vestibular tests enhances diagnostic utility over a single test; (2) abnormal test results on vestibular tests correlate with one another.

Methods

Retrospective analysis of data collected from multidisciplinary vestibular clinics at two academic medical centers from 2016 to 2022.

Results

150 patients (54.10 ± 15.09 years, 88 females) were included. No individual test was significantly better at predicting the presence of peripheral vestibular damage (p > 0.05). vHIT test results improved significantly when combined with either the caloric test (p = 0.007) or rotary chair test (p = 0.039). Caloric and rotational testing had high sensitivity (74.65% and 76.06%, respectively) and specificity (83.54% and 78.48%, respectively). vHIT demonstrated excellent specificity (89.87%) but poor sensitivity (47.89%). Caloric, vHIT, and rotary chair tests results did not correlate with one another (p > 0.05).

Conclusions

Vestibular function tests have comparable diagnostic utility, yet each offers unique advantages. Caloric and rotational testing may be best suited for screening peripheral damage and vHIT may function ideally as a confirmatory test.

Delayed Diagnoses in Patients With Dizziness in the US Commonwealth of Virginia and the Tidewater Region

Objective

In a region of approximately 1.7 million people (Tidewater, coastal Virginia), identify secondary diagnoses in persons with dizziness.

Methods

This cross-sectional study utilizing TriNetX included individuals in the region of interest diagnosed with dizziness between 2010 and 2020. Subsequent diagnoses of vestibular disease or medical conditions possibly associated with dizziness in the same subjects were catalogued.

Results

During the study period, 31,670 subjects were identified with diagnoses of dizziness as a symptom; 18,390 subjects were subsequently given a dizziness-related nonvestibular diagnosis, and 930 were given a subsequent vestibular disease diagnosis. The proportion of subjects diagnosed with vestibular disease (3%) after the dizziness diagnosis is far below expected norms (25%-34%) in the general population. There were greater proportions of delayed diagnoses of labyrinth dysfunction (odds ratio [OR], 4.8; P < 0.0001), superior semicircular canal dehiscence (OR, 3.1; P = 0.0023), otolith disease (OR, 3.1; P = 0.0023), among others, and a decreased proportion of delayed diagnosis of benign paroxysmal positional vertigo (OR, 0.56; P < 0.0001).

Conclusions

The discrepancy between expected and observed prevalence in our region indicates that vestibular disease is likely underdiagnosed.

Circ_0000811 acts as a miR-15b sponge and inhibits Prkar2a-mediated JAK2/STAT1 pathway to attenuate cerebral ischemic vertigo

Circular RNAs (circRNAs) have been noted to express in the brain and thus participate in various diseases related to the central nervous system. However, the potential role of circRNAs in cerebral ischemia (CI)-induced vertigo remains unknown. We initially predicted through bioinformatics analysis the poor expression of circ_0000811 related to CI. A mouse model of CI-induced vertigo was then established, which was validated by measurement of escape latency and medial vestibular nucleus (MVN) blood flow, with NeuN/Annexin counterstaining utilized to detect cell apoptosis in the MVN. An oxygen glucose deprivation (OGD)-exposed neuron-like cell model was further established for in vitro gain- and loss- of function assays, with flow cytometry performed to detect cell apoptosis. The poorly expressed circ_0000811, up-regulated miR-15b expression, and down-regulated Prkar2a expression were observed in both mice with CI-induced vertigo and OGD-exposed cells. Our data then demonstrated that circ_0000811 restoration alleviated CI-induced vertigo in mouse models, and that circ_0000811 acted as a miR-15b sponge to inhibit miR-15b expression. Prkar2a was validated as the target gene of miR-15b. Prkar2a restoration was subsequently revealed to repress OGD-induced neuronal apoptosis through JAK2/STAT1 signaling pathway inactivation. Furthermore, inactivation of the JAK2/STAT1 signaling pathway exerted an anti-apoptotic effect in OGD-induced neurons and an alleviatory effect in mice with CI-induced vertigo with Prkar2a overexpression and circ_0000811 overexpression. Taken together, our work suggests that circ_0000811 is involved in neuronal apoptosis of CI-induced vertigo and may be used as a biomarker for ameliorating CI-induced vertigo.

Comparison of two systems for the video head impulse test (vHIT) for the lateral semicircular canal: description of results from normal and pathological subjects

BACKGROUND

The video head impulse test (vHIT) is a recent technique for functional evaluation of semicircular canals (SSCs). The vHIT examines eye movements at high frequencies of stimulation and provides an objective assessment of the functioning of the high-frequency domain of the vestibular system.

OBJECTIVE

To describe the results from vHIT performed using two systems.

METHODS

All subjects were evaluated through an audiological and otoneurological battery of tests and were diagnosed as normal or abnormal by an otorhinolaryngologist. The results from two systems: 1. ICS Impulse (Otometrics/Natus, Denmark) and 2. EyeSeeCam (InterAcoustics, Denmark) were recorded. The same operator delivered every impulse to every subject. The head impulses were performed while the operator was standing behind the subject, using both hands on the top of the subject's head, well away from the goggles strap and forehead skin. Two calibrations were completed in each system, prior to beginning the test.

RESULTS

Test parameters were recorded through both systems for healthy subjects with no history or complaint of any vestibular disorder (N = 12; M/F = 5/7; age 35.1 ± 13.5 y) and for pathological subjects with a diagnosis of unilateral or bilateral vestibular disorder (N = 15; M/F = 7/8; age 53.4 ± 16.7 y).

CONCLUSIONS

The vHIT is an important tool for otoneurological complementary evaluation. Both systems are reliable for vestibular disorders. The EyeSeeCam seems to reject fewer data and provides more information to include in diagnostics. Because of the small sample, there is a need for further in-depth comparison of both systems.

The Efficient Dizziness History and Exam

Dizziness is a common complaint in otolaryngology clinics and can present a diagnostic challenge. A thorough history including onset, duration, and exacerbating and alleviating factors, along with physician persistence, can help differentiate between otologic and nonotologic forms of dizziness. An otologic and neurotologic physical examination, including vestibulo-ocular reflex and cranial nerve function evaluation and postural examination, can shed further light on symptom etiology. Otologic forms of dizziness often result in vertigo and may be associated with unilateral symptoms of hearing loss, aural fullness, or tinnitus. Primary causes of dizziness are more often constant and insidious in onset.

The economic burden of vertigo and dizziness in the United States

BACKGROUND

Vertigo and dizziness are extremely common conditions in the adult population and therefore place a significant social and economic burden on both patients and the healthcare system. However, limited information is available for the economic burden of vertigo and dizziness across various health care settings.

OBJECTIVE

Estimate the economic burden of vertigo and dizziness, controlling for demographic, socioeconomic, and clinical comorbidities.

METHODS

A retrospective analysis of data from the Medical Expenditures Panel Survey (2007-2015) was performed to analyze individuals with vertigo or dizziness from a nationally representative sample of the United States. Participants were included via self-reported data and International Classification of Diseases, 9th Revision Clinical Modification codes. A cross-validated 2-component generalized linear model was utilized to assess vertigo and dizziness expenditures across demographic, socioeconomic and clinical characteristics while controlling for covariates. Costs and utilization across various health care service sectors, including inpatient, outpatient, emergency department, home health, and prescription medications were evaluated.

RESULTS

Of 221,273 patients over 18 years, 5,275 (66% female, 34% male) reported either vertigo or dizziness during 2007-2015. More patients with vertigo or dizziness were female, older, non-Hispanic Caucasian, publicly insured, and had significant clinical comorbidities compared to patients without either condition. Furthermore, each of these demographic, socioeconomic, and clinical characteristics lead to significantly elevated costs due to having these conditions for patients. Significantly higher medical expenditures and utilization across various healthcare sectors were associated with vertigo or dizziness (p < 0.001). The mean incremental annual healthcare expenditure directly associated with vertigo or dizziness was $2,658.73 (95% CI: 1868.79, 3385.66) after controlling for socioeconomic and demographic characteristics. Total annual medical expenditures for patients with dizziness or vertigo was $48.1 billion.

CONCLUSION

Vertigo and dizziness lead to substantial expenses for patients across various healthcare settings. Determining how to limit costs and improve the delivery of care for these patients is of the utmost importance given the severe morbidity, disruption to daily living, and major socioeconomic burden associated with these conditions.

Clinical Balance Testing to Screen for Patients With Vestibular Disorders: A Retrospective Case-control Study

OBJECTIVE

Identify clinical screening tests to proficiently screen for patients with vestibular disorders.

STUDY DESIGN

Retrospective case-control study.

SETTING

Tertiary referral center.

PATIENTS

318 healthy individuals and 331 subjects with vestibular disorders.

INTERVENTIONS

All subjects performed Romberg and Jendrassic maneuver with eyes closed (ROMJec), standing on foam with eyes open (SOFeo) and eyes closed (SOFec), Tandem Romberg with eyes open (TReo) and eyes closed (TRec), single leg stance with eyes open (SLSeo) and eyes closed (SLSec), Tandem gait (TG) and Timed Up and Go (TUG).

MAIN OUTCOME MEASURES

Significant differences in performance on the balance tests.

RESULTS

For the age-group <40 years, TUG >6 seconds (OR 102.4; p <0.0001) and SLSec <30 seconds (OR 48.0; p <0.0001) proved to be the most predictive combination of testing (AUC 0.9; LR+ 15.8; LR- 0.2), with a positive predictive value (PPV) of 88.4%. For the age-group 40-60, TUG >7 seconds (OR 4.0; p = 0.0107) and TRec <30 seconds (OR 63.1; p < 0.0001) was the most predictive combination of tests (AUC 0.9 LR+ 6.0; LR- 0.1), with a PPV of 93.8%. For the age-group >60 the combination of TUG >8 seconds (OR 17.4; p < 0.0001) and SOFec <30 seconds (OR 10.4; p < 0.0001) was the most predictive (AUC 0.9 LR+ 6.3; LR- 0.2), with a PPV of 84.8%.

CONCLUSIONS

Combinations of clinical tests are proposed to promptly screen for vestibular disorders in specific age groups. To interpret the results for the individual patient, the physician must take the history and the general examination into consideration.

Vestibular Schwannoma Tumor Size Is Associated With Acute Vestibular Symptoms After Gamma Knife Therapy

OBJECTIVE

To assess how pretreatment vestibular schwannoma (VS) tumor characteristics are associated with vestibular symptoms after gamma knife (GK) surgery.

STUDY DESIGN

Retrospective chart review of patients undergoing GK treatment for VS at our institution from 2005 to 2018.

SETTING

Academic tertiary referral center.

PATIENTS

Patients receiving primary GK surgery for vestibular schwannomas with at least 6 months of follow up. Patients with neurofibromatosis 2 or previous surgery were excluded.

MAIN OUTCOME MEASURES

The presence of posttreatment vestibular symptoms within 6 months after GK. Clinical records were assessed for pretreatment tumor, patient, and treatment characteristics that impacted posttreatment symptoms.

RESULTS

All patients received radiation doses between 12 and 13 Gy. Of 115 patients, the average age was 60. Thirty-seven (32%) patients developed vestibular symptoms within 6 months post-GK, and 18 patients were referred for vestibular rehabilitation. Ten of 13 patients undergoing vestibular rehabilitation reported improvement. Overall, 112 patients had tumor measurements. Pretreatment tumors were significantly smaller for patients with acute vestibular symptoms (mean 1.43 cm versus 1.71 cm, p = 0.007). On multivariate analysis, smaller tumor size (p = 0.009, odds ratio [OR] = 0.29, 95% confidence interval [CI] [0.12-0.73]) was significantly associated with vestibular symptoms within 6 months of GK. Patients with tumors less than 1.6 cm were more likely to receive referrals for vestibular rehabilitation within 6 months posttreatment (25% versus 9.4%, p = 0.026, OR = 3.22, 95% CI [1.00, 11.32]).

CONCLUSIONS

Smaller vestibular schwannomas were significantly associated with higher rates of post-GK vestibular symptoms. Pretreatment tumor size may be used to counsel patients on the likelihood of post-GK vestibular symptoms and vestibular rehabilitation.