Probabilities of Isolated and Co-Occurring Vestibular Disorder Symptom Clusters Identified Using the Dizziness Symptom Profile.

OBJECTIVES: Dizziness is among the most common reasons people seek medical care. There are data indicating patients with dizziness, unsteadiness, or vertigo may have multiple underlying vestibular disorders simultaneously contributing to the overall symptoms. Greater awareness of the probability that a patient will present with symptoms of co-occurring vestibular disorders has the potential to improve assessment and management, which could reduce healthcare costs and improve patient quality of life. The purpose of the current investigation was to determine the probabilities that a patient presenting to a clinic for vestibular function testing has symptoms of an isolated vestibular disorder or co-occurring vestibular disorders. DESIGN: All patients who are seen for vestibular function testing in our center complete the dizziness symptom profile, a validated self-report measure, before evaluation with the clinician. For this retrospective study, patient scores on the dizziness symptom profile, patient age, and patient gender were extracted from the medical record. The dizziness symptom profile includes symptom clusters specific to six disorders that cause vestibular symptoms, specifically: benign paroxysmal positional vertigo, vestibular migraine, vestibular neuritis, superior canal dehiscence, Meniere disease, and persistent postural perceptual dizziness. For the present study, data were collected from 617 participants (mean age = 56 years, 376 women, and 241 men) presenting with complaints of vertigo, dizziness, or imbalance. Patients were evaluated in a tertiary care dizziness specialty clinic from October 2020 to October 2021. Self-report data were analyzed using a Bayesian framework to determine the probabilities of reporting symptom clusters specific to an isolated disorder and co-occurring vestibular disorders. RESULTS: There was a 42% probability of a participant reporting symptoms that were not consistent with any of the six vestibular disorders represented in the dizziness symptom profile. Participants were nearly as likely to report symptom clusters of co-occurring disorders (28%) as they were to report symptom clusters of an isolated disorder (30%). When in isolation, participants were most likely to report symptom clusters consistent with benign paroxysmal positional vertigo and vestibular migraine, with estimated probabilities of 12% and 10%, respectively. The combination of co-occurring disorders with the highest probability was benign paroxysmal positional vertigo + vestibular migraine (~5%). Probabilities decreased as number of symptom clusters on the dizziness symptom profile increased. The probability of endorsing vestibular migraine increased with the number of symptom clusters reported. CONCLUSIONS: Many patients reported symptoms of more than one vestibular disorder, suggesting their symptoms were not sufficiently captured by the symptom clusters used to summarize any single vestibular disorder covered by the dizziness symptom profile. Our results indicate that probability of symptom clusters indicated by the dizziness symptom profile is comparable to prior published work on the prevalence of vestibular disorders. These findings support use of this tool by clinicians to assist with identification of symptom clusters consistent with isolated and co-occurring vestibular disorders.

The effect of EMG magnitude on the masseter vestibular evoked myogenic potential (mVEMP).

Introduction: The masseter vestibular evoked myogenic potential (mVEMP) is a bilaterally generated, electromyographically (EMG)-mediated response innervated by the trigeminal nerve. The purpose of the present investigation was to 1) determine whether subjects could accurately achieve and maintain a range of EMG target levels, 2) to examine the effects of varied EMG levels on the latencies and amplitudes of the mVEMP, and 3) to investigate the degree of side-to-side asymmetry and any effects of EMG activation. Methods: Subjects were nine neurologically and otologically normal young adults. A high-intensity tone burst was presented monaurally while subjects were seated upright and asked to match a range of EMG target levels by clenching their teeth. Recordings were made from the ipsilateral and contralateral masseter muscles referenced to the ear being monaurally stimulated. Results: We found that the tonic EMG target had no effect on mVEMP latency. Additionally, although mVEMP amplitudes "scaled" to the EMG target, there was a tendency for the subjects' EMG level to "undershoot" the EMG target levels greater than 50 µV. While some individuals did generate differences in EMG activation between sides, there were no significant differences on average EMG activation between sides. Further, while average corrected amplitude asymmetry was similar across EMG targets, some individuals demonstrated large, corrected amplitude asymmetry ratios. Conclusions: The results of this investigation suggest that, as with cVEMP recordings, the underlying EMG activation may vary between subjects and could impact mVEMP amplitudes, yet could be mitigated by amplitude correction techniques. Further it is important to be aware that even young normal subjects have difficulty maintaining large, tonic EMG activity during the mVEMP recording.

Agreement Between Caloric and Horizontal Video Head Impulse Testing in School-Aged Children Presenting With Dizziness.

OBJECTIVE: The purpose of this investigation was to determine the relationship between the horizontal semicircular canal video head impulse test (hvHIT) and the caloric test in a sample of school-age children evaluated due to complaints of dizziness or imbalance. In adults, these two tests provide different but complementary information regarding vestibular function and/or pathology. However, the most common causes of vestibular loss in children are different than those in adults, and it is not clear how these two tests of horizontal semicircular canal function are related in a pediatric population. METHOD: This is a retrospective study of electronic records of pediatric patients (< 18 years old) who were referred for vestibular function testing and completed both hvHIT and caloric testing. Agreement between both test results was evaluated by examining measures of sensitivity, specificity, and calculating Cohen's kappa. RESULTS: Results from 117 patients (mean age = 13.7 years, age range: 8-17 years, 37 males) were analyzed. Most patients (97/115 [84.3%]) demonstrated both normal hvHIT and caloric test results. Compared to caloric testing, the hvHIT had poor sensitivity (38.9%) and excellent specificity (98.0%). Cohen's kappa analysis revealed moderate agreement between the methods (coefficient = 0.49 [0.24, 0.73]). Where disagreement between the two tests occurred, the final diagnosis was not contingent on either test result. CONCLUSIONS: There is a moderate agreement between the hvHIT and the caloric test in pediatric patients presenting to a tertiary care medical center for a vestibular evaluation. Most patients in this cohort presented with normal findings. The specificity of hvHIT was excellent, although the sensitivity was low. This may be related to the low prevalence of peripheral vestibular system disease in this study cohort, and these results do not generalize to centers that serve populations of children where vestibular disorders are more prevalent (e.g., children with sensorineural hearing loss).

Case Study: Depersonalization and Vestibular Impairment.

BACKGROUND: We describe herein the case of a patient whose primary complaints were episodic vertigo and "depersonalization," a sensation of detachment from his own body. PURPOSE: This case study aims to further clinical knowledge and insight into the clinical evaluation of vertiginous patients with complaints of depersonalization. RESEARCH DESIGN: This is a case study. DATA COLLECTION AND ANALYSIS: A retrospective chart review of vestibular function testing done on a vertiginous patient with complaints of depersonalization was performed. RESULTS: Vestibular function testing revealed absent cervical and ocular vestibular evoked myogenic potentials on the left side with normal vHIT or video Head Impulse Test, videonystagmography, and rotational chair results, suggesting peripheral vestibular impairment isolated to the left saccule and utricle. CONCLUSION: The otolith end organ impairment explains the patient's postural deviation to the left side during attempts to ambulate. We recommend that clinicians should be attentive to patient complaints of depersonalization and perform vestibular evoked myogenic potential testing to determine whether evidence of at least a unilateral peripheral otolith end organ impairment exists.

Test-Retest Reliability of the Dizziness Symptom Profile.

OBJECTIVES: This investigation was conducted to measure the test-retest reliability of the Dizziness Symptom Profile (DSP). The DSP was developed to assist primary care providers, general otolaryngologists, and other health care providers in the development of a differential diagnosis for patients who present with dizziness, vertigo, or unsteadiness. The DSP yields a score ranging from 0 to 100% for each of 7 subscales. Each subscale represents a different diagnosis including benign paroxysmal positional vertigo, Ménière's disease, persistent postural-perceptual dizziness (PPPD), superior semi-circular canal dehiscence, vestibular migraine, vestibular neuritis, and general unsteadiness. DESIGN: Subjects were 150 adult patients (mean age 56.79 years, SD 15.69 years) referred to the Balance Disorders Clinic at Vanderbilt University Medical Center. Subjects completed two administrations of the DSP. The mean interval between test administrations was 1.58 days (SD 1.78 days). The response modes for the DSP were both a 0 to 100 mm visual analog scale (scored 0 mm = "strongly disagree" to 100 mm = "strongly agree") and, by extrapolation, the original 5-point Likert scale where the anchors were "strongly disagree" (scored 0 points) and "strongly agree" (scored 4 points). RESULTS: Pearson correlation coefficients were calculated to assess test-retest reliability for individual DSP items, and ranged from r = 0.67 to 0.91 (mean 0.80; p < 0.001). Cronbach's α coefficients were calculated to assess internal consistency reliability of items comprising the seven subscales. Each subscale had an acceptable level of internal consistency (Cronbach's α coefficients > 0.7) with the exception of PPPD which approached 0.7. Intraclass correlation coefficient estimates and their 95% confidence intervals were also calculated to assess the relative reliability of the subscales. All 7 subscales showed moderate to strong test-retest reliability, with intraclass correlation coefficients ranging from 0.85 to 0.94. Minimal detectable change (MDC) scores were calculated to assess absolute variability/measurement error for the seven subscale scores (which range from 0 to 100%). MDC values ranged from 16% (PPPD) to 25% (unsteadiness). CONCLUSIONS: (1) The test-retest reliability of the DSP is moderate to strong. (2) MDC values for each subscale were determined. (3) The DSP coupled with the Dizziness Handicap Inventory enables the clinician to evaluate the constructs of dizziness impairment, and disability/handicap. (4) The DSP may help provide a window to the natural history of dizziness disease(s). (5) The DSP provides a less biased assessment of the symptoms reported by the patient.

Multiple Co-Occurring Vestibular Disorders Identified Using the Dizziness Symptom Profile.

Purpose The purpose of the current investigation was to determine the interrelations among vestibular disorders from a data set generated from the patient perspective as compared to previous data generated from the physician's perspective. Method The data for the current investigation originated from a previously published study describing the development of the Dizziness Symptom Profile (DSP; Jacobson et al., 2019). The DSP is a 31-item patient self-report tool designed to help primary care physicians in the development of a differential diagnosis using the patient's level of agreement with each dizziness and symptom-related statement. Responses to these items converge on common vestibular diagnoses and were previously found to agree with ear specialist differential diagnoses 70.3% of the time. Data were collected for 131 subjects (M age = 56.7 years, 72 women) seen for evaluation in a tertiary dizziness specialty clinic. For this study, the data were analyzed using descriptive statistics to determine the frequency of single diagnoses, multiple diagnoses, co-occurring diagnoses, and patterns of co-occurrence. Results Results indicated that 52.7% of patients endorsed a single vestibular diagnosis and 47.3% endorsed two or more vestibular diagnoses. Benign paroxysmal positional vertigo (BPPV) and vestibular migraine were the most common single diagnoses and also the most common co-occurring diagnoses. As the number of diagnoses endorsed on the DSP increased, so did the percentage of time that BPPV and vestibular migraine would occur. Conclusions Results support and extend the work of others but using data generated from the perspective of the patient. A slight majority of patients endorsed a single disorder, but almost as many patients endorsed more than one vestibular diagnosis. BPPV and vestibular migraine were the most common single vestibular diagnoses and also the most common co-occurring vestibular diagnoses; vestibular migraine was more common when multiple diagnoses were endorsed. Results suggest it is common for patients to volunteer symptoms that cannot be explained by a single vestibular diagnosis. This finding is in agreement with physician-generated diagnosis data. Clinicians should consider the possibility of co-occurring diagnoses in complicated patients or in patients who are not responding optimally to management of a single vestibular disorder. The DSP is a tool that encourages clinicians to consider multiple co-occurring vestibular disorders as the source of patient complaints.

A factor analytic assessment of the English translation of the neuropsychological vertigo inventory (NVI).

PURPOSE: Vestibular impairments have been associated with a variety of cognitive deficits, most notably deficits in visuo-spatial memory. The Neuropsychological Vertigo Inventory (NVI) was developed to measure self-reported cognitive deficits in patients with dizziness and/or vertigo. The original French language version of the NVI includes 28 items and 7 subscales. The purpose of the present investigation was to determine whether the statistical assessment of an English language version supported the presence of the same cognitive constructs as the French version of the NVI. METHOD: The English language adaptation of the NVI (referred to here as the NVIe) was administered to an unselected sample of 280 patients that were being evaluated for dizziness and/or vertigo in a tertiary care dizziness clinic. The individual item scores from the NVIe were subjected to an exploratory factor analysis (EFA). RESULTS: The results of the data analysis supported a 22-item NVIe consisting of 4 constructs: affective state, temporal memory, spatial memory, visual spatial cognition. CONCLUSIONS: The NVIe is a new tool for screening cognitive constructs that may be affected by vestibular impairments. Prior to clinical implementation of the NVIe, additional studies of reliability and convergent validity are needed.

The Clinical Significance of the Failure to Perceive Vertigo in the Postcaloric Period Despite a Robust Caloric Response.

Purpose The purpose of this project was to explore the association between the perception of motion during caloric testing and two tasks associated with central vestibular processing: postural stability and visuospatial memory. Method This was a prospective study of 25 patients who were found to have nonvestibular etiologies of their symptoms and normal vestibular function test results and who underwent caloric testing with a mean maximum slow phase eye velocity for each irrigation of 15° or greater. Following each caloric irrigation, patients were asked whether they had any sensation of movement. Patients were grouped based on the presence or absence of motion during the caloric exam (motion perception vs. absent perception). Postural stability was assessed using computerized dynamic posturography, and visuospatial memory was assessed using a memory match card game application. Results There were no significant differences between groups on any measures of peripheral vestibular function. However, the Absent Perception Group showed greater postural instability during Condition 5 of posturography and performed significantly worse on a task of visuospatial working memory. Both age and absence of motion perception predicted abnormal performance on measures of postural stability and visuospatial working memory. Conclusions There appears to be clinical implications to a lack of motion perception during the caloric exam in patients with an otherwise normal peripheral vestibular system. Based on the current findings, we are unable to determine whether differences in postural stability and visuospatial memory were due to age or a central vestibular processing deficit.

Short Communication: The Belly-Tendon Derivation Yields Superior Ocular Vestibular Evoked Myogenic Potential Amplitudes in a Normal Pediatric Sample.

Purpose The purpose of the investigation was to determine whether the "belly-tendon" electrode derivation produced ocular vestibular evoked myogenic potentials (oVEMPs) in children that were superior to those recorded with the infraorbital-chin electrode derivation. Method This was a prospective observational study using a sample of convenience at a tertiary care medical center. Subjects were 13 children between the ages of 5 and 12 years. We compared the latency of the N1 wave and the N1-P1 peak-to-peak amplitude for the belly-tendon electrode derivation to the infraorbital-chin electrode derivation. Results The belly-tendon electrode derivation was associated with superior N1-P1 amplitudes compared to the infraorbital-chin electrode derivation. However, the large amplitude was also associated with greater variability compared to the infraorbital-chin derivation. There were no significant electrode derivation-based differences in N1 latency. Additionally, there was no predictable relationship between age and oVEMP amplitude. Conclusion As shown previously in adults, the belly-tendon electrode derivation produces significantly larger oVEMP amplitudes compared to the infraorbital-chin electrode derivation.