Case Report: Pendular Nystagmus Presenting in Usher Syndrome Type I.

BACKGROUND: We describe a 42-year-old patient with reported "shaking" vision referred due to concerns of possible vestibular system dysfunction. The patient has known history of Usher syndrome type I, bilateral cochlear implants, and severe vision impairment. PURPOSE: This case describes an unusual nystagmus previously only reported in individuals with central demyelinating disorders, significant light deprivation, or in congenital / early-onset visual pathway impairment. RESEARCH DESIGN: Case study. DATA COLLECTION AND ANALYSIS: Retrospective chart review of vestibular function. RESULTS: Vestibular function was likely absent in this case. There was no evidence of vestibular (jerk) nystagmus for sinusoidal harmonic acceleration stimuli or repeatable responses for cervical vestibular evoked myogenic potentials. Significant pendular low amplitude high frequency oscillations of approximately 6 Hz were present for horizontal and vertical tracings throughout testing. CONCLUSIONS: Nystagmus may not always be associated with vestibular system impairment. In this case, the patient's reported "shaking" vision was attributed to pendular low amplitude high frequency nystagmus and hypothesized to relate to long-standing significant vision impairment. This presentation is unusual in adults and has historically been associated with individuals with significant central pathology or in those with long duration light deprivation.

Clinical Utility of the Standardized Word Recognition Score.

OBJECTIVES: An unexpectedly low word recognition (WR) score may be taken as evidence of increased risk for retrocochlear tumor. We sought to develop evidence for or against using a standardized WR (sWR) score in detecting retrocochlear tumors. The sWR is a z score expressing the difference between an observed WR score and a Speech Intelligibility Index-based predicted WR score. We retrospectively compared the sensitivity and specificity of pure-tone asymmetry-based logistic regression models that incorporated either the sWR or the raw WR scores in detecting tumor cases. Two pure-tone asymmetry calculations were used: the 4-frequency pure-tone asymmetry (AAO) calculation of the American Academy of Otolaryngology-Head and Neck Surgery and a 6-frequency pure-tone asymmetry (6-FPTA) calculation previously optimized to detect retrocochlear tumors. We hypothesized that a regression model incorporating the 6-FPTA calculation and the sWR would more accurately detect retrocochlear tumors. DESIGN: Retrospective data from all patients seen in the audiology clinic at Mayo Clinic in Florida in 2016 were reviewed. Cases with retrocochlear tumors were compared with a reference group with noise- or age-related hearing loss or idiopathic sensorineural hearing loss. Two pure-tone-based logistic regression models were created (6-FPTA and AAO). Into these base models, WR variables (WR, sWR, WR asymmetry [WRΔ], and sWR asymmetry [sWRΔ]) were added. Tumor detection performance for each regression model was compared twice: first, using all qualifying cases (61 tumor cases; 2332 reference group cases), and second, using a data set filtered to exclude hearing asymmetries greater than would be expected from noise-related or age-related hearing loss (25 tumor cases; 2208 reference group cases). The area under the curve and the DeLong test for significant receiver operating curve differences were used as outcome measures. RESULTS: The 6-FPTA model significantly outperformed the AAO model-with or without the addition of WR or WRΔ variables. Including sWR into the AAO base regression model significantly improved disease detection performance. Including sWR into the 6-FPTA model significantly improved disease detection performance when large hearing asymmetries were excluded. In the data set that included large pure-tone asymmetries, area under the curve values for the 6-FPTA + sWR and AAO + sWR models were not significantly better than the base 6-FPTA model. CONCLUSIONS: The results favor the superiority of the sWR computational method in identifying reduced WR scores in retrocochlear cases. The utility would be greatest where undetected tumor cases are embedded in a population heavily representing age- or noise-related hearing loss. The results also demonstrate the superiority of the 6-FPTA model in identifying tumor cases. The 2 computational methods may be combined (ie, the 6-FPTA + sWR model) into an automated tool for detecting retrocochlear disease in audiology and community otolaryngology clinics. The 4-frequency AAO-based regression model was the weakest detection method considered. Including raw WR scores into the model did not improve performance, whereas including sWR into the model did improve tumor detection performance. This further supports the contribution of the sWR computational method for recognizing low WR scores in retrocochlear disease cases.

Static Subjective Visual Vertical (SVV) in Patients with Vestibular Migraine.

BACKGROUND: Vestibular migraine (VM) is one of the common causes of episodic dizziness, but it is underdiagnosed and poorly understood. Previous research suggests that otolith reflex pathway performance is often impaired in this patient group, leading to altered perception of roll plane stimuli. Clinically, this perception can be measured with subjective visual vertical (SVV) testing. PURPOSE: The aim of this study is to compare static SVV performance (absolute mean SVV tilt, variance) in a cohort of patients diagnosed with VM to results obtained from clinically derived normative data. STUDY DESIGN: Retrospective case review. STUDY SAMPLE: Ninety-four consecutive patients between 18 and 65 years of age diagnosed with VM were included in this comparison to clinically derived normative data. DATA COLLECTION AND ANALYSIS: Retrospective chart review was completed. Demographic data, symptom report, and vestibular laboratory results were documented. SVV performance was documented in terms of absolute mean SVV tilt and response variance. RESULTS: Abnormal mean SVV tilt was described in 54% (n = 51) of patients with VM. Including abnormal response variance increased those identified with abnormal presentation to 67% (n = 63). Laboratory findings were insignificant for semicircular canal function, but of those with abnormal ocular vestibular myogenic potential results (n = 30), 77% (n = 23) demonstrated both abnormal SVV and utriculo-ocular reflex performance. There were no associations noted for SVV performance and demographic or other self-report variables. CONCLUSION: Absolute mean SVV tilt and response variance are often abnormal in patients diagnosed with VM. These findings support theories suggesting atypical intralabyrinthine integration within the vestibular nuclei and cerebellar nodular pathways.

Vestibular-autonomic interactions: beyond orthostatic dizziness.

PURPOSE OF REVIEW: This review aims to summarize the current literature describing vestibular-autonomic interactions and to describe their putative role in various disorders' clinical presentations, including orthostatic dizziness and motion sensitivity. RECENT FINDINGS: The vestibular-autonomic reflexes have long been described as they relate to cardiovascular and respiratory function. Although orthostatic dizziness may be in part related to impaired vestibulo-sympathetic reflex (orthostatic hypotension), there are various conditions that may present similarly. A recent clinical classification aims to improve identification of individuals with hemodynamic orthostatic dizziness so that appropriate recommendations and management can be efficiently addressed. Researchers continue to improve understanding of the underlying vestibular-autonomic reflexes with recent studies noting the insular cortex as a cortical site for vestibular sensation and autonomic integration and modulation. Work has further expanded our understanding of the clinical presentation of abnormal vestibular-autonomic interactions that may occur in various conditions, such as aging, peripheral vestibular hypofunction, traumatic brain injury, and motion sensitivity. SUMMARY: The vestibular-autonomic reflexes affect various sympathetic and parasympathetic functions. Understanding these relationships will provide improved identification of underlying etiology and drive improved patient management.

Discovering Oculometric Patterns to Detect Cognitive Performance Changes in Healthy Youth Football Athletes.

In this paper, we focus on the application of oculometric patterns extracted from raw eye movements during a mental workload task to assess changes in cognitive performance in healthy youth athletes over the course of a typical sport season. Oculometric features pertaining to fixations and saccades were measured on 116 athletes in pre- and post-season testing. Participants were between 7 and 14 years of age at pre-season testing. Due to varied developmental rates, there were large interindividual performance differences during a mental workload task consisting of reading numbers. Based on different reading speeds, we classified three profiles (slow, moderate, and fast) and established their corresponding baselines for oculometric data. Within each profile, we describe changes in oculomotor function based on changes in cognitive performance during the season. To visualize these changes in multidimensional oculometric data, we also present a multidimensional visualization tool named DiViTo (diagnostic visualization tool). These experimental, computational informatics and visualization methodologies may serve to utilize oculometric information to detect changes in cognitive performance due to mild or severe cognitive impairment such as concussion/mild traumatic brain injury, as well as possibly other disorders such as attention deficit hyperactivity disorders, learning/reading disabilities, impairment of alertness, and neurocognitive function.

Clinical Evaluation of the Vestibular Nerve Using Vestibular Evoked Myogenic Potentials.

Vestibular evoked myogenic potentials are currently the most clinically accessible method to evaluate the otolith reflex pathways. These responses provide unique information regarding the status of the utriculo-ocular and sacculo-collic reflex pathways, information that has previously been unavailable. Vestibular evoked myogenic potentials are recorded from tonically contracted target muscles known to be innervated by these respective otolith organs. Diagnosticians can use vestibular evoked myogenic potentials to better evaluate the overall integrity of the inner ear and neural pathways; however, there are specific considerations for each otolith reflex protocol. In addition, specific patient populations may require protocol variations to better evaluate atypical function of the inner ear organs, vestibular nerve transmission, or subsequent reflex pathways. This is a review of the clinical application and interpretation of cervical and ocular vestibular evoked myogenic potentials.

Safe Use of Acoustic Vestibular-Evoked Myogenic Potential Stimuli: Protocol and Patient-Specific Considerations.

BACKGROUND: Vestibular-evoked myogenic potentials (VEMPs) are commonly used clinical assessments for patients with complaints of dizziness. However, relatively high air-conducted stimuli are required to elicit the VEMP, and ultimately may compromise safe noise exposure limits. Recently, research has reported the potential for noise-induced hearing loss (NIHL) from VEMP stimulus exposure through studies of reduced otoacoustic emission levels after VEMP testing, as well as a recent case study showing permanent sensorineural hearing loss associated with VEMP exposure. PURPOSE: The purpose of this report is to review the potential for hazardous noise exposure from VEMP stimuli and to suggest clinical parameters for safe VEMP testing. RESEARCH DESIGN: Literature review with presentation of clinical guidelines and a clinical tool for estimating noise exposure. RESULTS: The literature surrounding VEMP stimulus-induced hearing loss is reviewed, including several cases of overexposure. The article then presents a clinical calculation tool for the estimation of a patient's safe noise exposure from VEMP stimuli, considering stimulus parameters, and includes a discussion of how varying stimulus parameters affect a patient's noise exposure. Finally, recommendations are provided for recognizing and managing specific patient populations who may be at higher risk for NIHL from VEMP stimulus exposure. A sample protocol is provided that allows for safe noise exposure. CONCLUSIONS: VEMP stimuli have the potential to cause NIHL due to high sound exposure levels. However, with proper safety protocols in place, clinicians may reduce or eliminate this risk to their patients. Use of the tools provided, including the noise exposure calculation tool and sample protocols, may help clinicians to understand and ensure safe use of VEMP stimuli.

The Effect of In-School Saccadic Training on Reading Fluency and Comprehension in First and Second Grade Students.

Efficient eye movements provide a physical foundation for proficient reading skills. We investigated the effect of in-school saccadic training on reading performance. In this cross-over design, study participants (n = 327, 165 males; mean age [SD]: 7 y 6 mo [1y 1 mo]) were randomized into treatment and control groups, who then underwent eighteen 20-minute training sessions over 5 weeks using King-Devick Reading Acceleration Program Software. Pre- and posttreatment reading assessments included fluency, comprehension, and rapid number naming performance. The treatment group had significantly greater improvement than the control group in fluency (6.2% vs 3.6%, P = .0277) and comprehension (7.5% vs 1.5%, P = .0002). The high-needs student group significantly improved in fluency ( P < .001) and comprehension ( P < .001). We hypothesize these improvements to be attributed to the repetitive practice of reading-related eye movements, shifting visuospatial attention, and visual processing. Consideration should be given to teaching the physical act of reading within the early education curriculum.

Postural orthostatic tachycardia syndrome for the otolaryngologist.

OBJECTIVE: To describe the postural orthostatic tachycardia syndrome (POTS), including clinical presentation, pathophysiology, diagnostic methods, and current management models. DATA SOURCES: PubMed, Cochrane Library were searched for articles available prior to October 30, 2015. METHODS: Review of the available English-language literature. RESULTS: Postural orthostatic tachycardia syndrome presentation is discussed, along with underlying associated physiology for POTS and recommended nonpharmacologic and pharmacologic management strategies. CONCLUSION: Postural orthostatic tachycardia syndrome patients commonly present with complaints of postural lightheadedness, or dizziness, which can be associated with various other conditions. Nonpharmacologic and pharmacologic treatment methods are available to improve the underlying pathophysiology of the disorder. Laryngoscope, 127:1195-1198, 2017.

Variability of the modified Balance Error Scoring System at baseline using objective and subjective balance measures.

AIM: To investigate preseason modified Balance Error Scoring System (mBESS) performance in a collegiate football cohort; to compare scores to an objective mobile balance measurement tool. MATERIALS & METHODS: Eighty-two athletes completed simultaneous balance testing using mBESS and the King-Devick Balance Test, an objective balance measurement tool. Errors on mBESS and objective measurements in the double-leg, single-leg (SS) and tandem stances were compared. RESULTS: Mean mBESS error score was 7.23 ± 4.65. The SS accounted for 74% of errors and 21% of athletes demonstrated the maximum error score. There was no significant correlation between mBESS score and objective balance score. CONCLUSION: The high variability and large number of errors in the SS raises concerns over the utility of the SS in identifying suspected concussion.

The Effect of Repetition Rate on Air-Conducted Ocular Vestibular Evoked Myogenic Potentials (oVEMPs).

PURPOSE: Ocular vestibular evoked myogenic potentials (oVEMPs) are used to describe utricular/superior vestibular nerve function; however, optimal recording parameters have not been fully established. This study investigated the effect of repetition rate on air-conducted oVEMPs. METHOD: Ten healthy adults were evaluated using 500-Hz tone bursts (4-ms duration, Blackman gating, 122 dB pSPL). Four repetition rates were used (1.6, 4.8, 8.3, and 26.6 Hz) and resulting oVEMP response presence, amplitude, amplitude asymmetry, and n1/p1 latency were assessed. RESULTS: Response presence was significantly reduced for 26.6 Hz using monaural stimulation and for 8.3 Hz and 26.6 Hz for binaural stimulation. For monaural stimulation using 1.6, 4.8, and 8.3 Hz, no significant differences were noted for amplitude or latency. Responses obtained using binaural stimulation demonstrated a significant effect of rate on amplitude, with 8.3 Hz producing significantly reduced amplitude. Binaural amplitudes were significantly larger than monaural contralateral responses but with reduced response presence. No significant differences were noted for latency or amplitude asymmetry. CONCLUSION: Using repetition rates of approximately 5 Hz or less may produce more consistent oVEMP response presence with minimal effects on amplitude for monaural or binaural recordings.

Labyrinthine concussion following gunshot injury: A case report.

OBJECTIVE: Labyrinthine concussion due to a postauricular gunshot wound has not been well reported. DESIGN: Retrospective chart review. STUDY SAMPLE: We describe an otherwise healthy 22-year-old male who received a gunshot wound to the left mastoid and subsequently reported hearing loss and rotational vertigo. RESULTS: Audiometric testing demonstrated significant inverted scoop shaped sensorineural hearing loss. Vestibular diagnostic testing indicated a significant uncompensated left peripheral vestibulopathy. Imaging demonstrated no structural changes to the middle ear or labyrinth, suggesting that the auditory and vestibular losses noted on diagnostic examination were likely due to labyrinthine concussion. CONCLUSIONS: Labyrinthine concussion may lead to reduced vestibular reflex pathway following gunshot wounds to the temporal bone. Clinical presentation is likely to vary significantly among cases.

The effect of muscle contraction level on the cervical vestibular evoked myogenic potential (cVEMP): usefulness of amplitude normalization.

BACKGROUND: The cervical vestibular evoked myogenic potential (cVEMP) is a reflexive change in sternocleidomastoid (SCM) muscle contraction activity thought to be mediated by a saccular vestibulo-collic reflex. CVEMP amplitude varies with the state of the afferent (vestibular) limb of the vestibulo-collic reflex pathway, as well as with the level of SCM muscle contraction. It follows that in order for cVEMP amplitude to reflect the status of the afferent portion of the reflex pathway, muscle contraction level must be controlled. Historically, this has been accomplished by volitionally controlling muscle contraction level either with the aid of a biofeedback method, or by an a posteriori method that normalizes cVEMP amplitude by the level of muscle contraction. A posteriori normalization methods make the implicit assumption that mathematical normalization precisely removes the influence of the efferent limb of the vestibulo-collic pathway. With the cVEMP, however, we are violating basic assumptions of signal averaging: specifically, the background noise and the response are not independent. The influence of this signal-averaging violation on our ability to normalize cVEMP amplitude using a posteriori methods is not well understood. PURPOSE: The aims of this investigation were to describe the effect of muscle contraction, as measured by a prestimulus electromyogenic estimate, on cVEMP amplitude and interaural amplitude asymmetry ratio, and to evaluate the benefit of using a commonly advocated a posteriori normalization method on cVEMP amplitude and asymmetry ratio variability. RESEARCH DESIGN: Prospective, repeated-measures design using a convenience sample. STUDY SAMPLE: Ten healthy adult participants between 25 and 61 yr of age. INTERVENTION: cVEMP responses to 500 Hz tone bursts (120 dB pSPL) for three conditions describing maximum, moderate, and minimal muscle contraction. DATA COLLECTION AND ANALYSIS: Mean (standard deviation) cVEMP amplitude and asymmetry ratios were calculated for each muscle-contraction condition. Repeated measures analysis of variance and t-tests compared the variability in cVEMP amplitude between sides and conditions. Linear regression analyses compared asymmetry ratios. Polynomial regression analyses described the corrected and uncorrected cVEMP amplitude growth functions. RESULTS: While cVEMP amplitude increased with increased muscle contraction, the relationship was not linear or even proportionate. In the majority of cases, once muscle contraction reached a certain "threshold" level, cVEMP amplitude increased rapidly and then saturated. Normalizing cVEMP amplitudes did not remove the relationship between cVEMP amplitude and muscle contraction level. As muscle contraction increased, the normalized amplitude increased, and then decreased, corresponding with the observed amplitude saturation. Abnormal asymmetry ratios (based on values reported in the literature) were noted for four instances of uncorrected amplitude asymmetry at less than maximum muscle contraction levels. Amplitude normalization did not substantially change the number of observed asymmetry ratios. CONCLUSIONS: Because cVEMP amplitude did not typically grow proportionally with muscle contraction level, amplitude normalization did not lead to stable cVEMP amplitudes or asymmetry ratios across varying muscle contraction levels. Until we better understand the relationships between muscle contraction level, surface electromyography (EMG) estimates of muscle contraction level, and cVEMP amplitude, the application of normalization methods to correct cVEMP amplitude appears unjustified.

Dizziness handicap after cartilage cap occlusion for superior semicircular canal dehiscence.

OBJECTIVE: To evaluate the change in self-reported dizziness handicap after surgical repair using the cartilage cap occlusion technique in cases of superior canal dehiscence (SCD). STUDY DESIGN: Repeated measures, retrospective chart review. SETTING: Tertiary referral center. PATIENTS: Twenty patients over a 2-year period who underwent surgical repair of SCD using the cartilage cap occlusion technique. INTERVENTION: Therapeutic. MAIN OUTCOME MEASURE: Preoperative and postoperative Dizziness Handicap Inventory (DHI) questionnaires were completed (median, interquartile range). RESULTS: Preoperative (48, 28-56) and postoperative (33, 19-50) total scores were not significantly different. Scores for patients with moderate/severe preoperative DHI scores (DHI, >30; n = 14) demonstrated significant change (p = 0.001, Wilcoxon paired sample test), whereas those with mild scores did not (DHI, ≤ 30; n = 6; p = 0.67). CONCLUSION: Change in DHI score is variable. As described by DHI score, patients with higher preoperative handicap may demonstrate significant improvement after surgery, whereas those with mild handicap may not. These results are similar to previous reports and indicate that the cartilage cap occlusion technique may provide an alternative to middle fossa craniotomy approach for surgical management of symptomatic SCD.

Pure-tone hearing asymmetry: a logistic approach modeling age, sex, and noise exposure history.

BACKGROUND: Asymmetric hearing loss (AHL) can be an early sign of vestibular schwannoma (VS). However, recognizing VS-induced AHL is challenging. There is no universally accepted definition of a "medically significant pure-tone hearing asymmetry," in part because AHL is a common feature of medically benign forms of hearing loss (e.g., age- or firearm-related hearing loss). In most cases, the determination that an observed AHL does not come from a benign cause involves subjective clinical judgment. PURPOSE: Our purpose was threefold: (1) to quantify hearing asymmetry distributions in a large group of patients with medically benign forms of hearing loss, stratifying for age, sex, and noise exposure history; (2) to assess how previously proposed hearing asymmetry calculations segregate tumor from nontumor cases; and (3) to present the results of a logistic regression method for defining hearing asymmetry that incorporates age, sex, and noise information. RESEARCH DESIGN: Retrospective chart review. STUDY SAMPLE: Five thousand six hundred and sixty-one patients with idiopathic, age- or noise exposure-related hearing loss and 85 untreated VS patients. DATA COLLECTION AND ANALYSIS: Audiometric, patient history, and clinical impression data were collected from 22,785 consecutive patient visits to the audiology section at Mayo Clinic in Florida from 2006 to 2009 to screen for eligibility. Those eligible were then stratified by VS presence, age, sex, and self-reported noise exposure history. Pure-tone asymmetry distributions were analyzed. Audiometric data from VS diagnoses were used to create four additional audiograms per patient to model the hypothetical development of AHL prior to the actual hearing test. The ability of 11 previously defined hearing asymmetry calculations to distinguish between VS and non-VS cases was described. A logistic regression model was developed that integrated age, sex, and noise exposure history with pure-tone asymmetry data. Regression model performance was then compared to existing asymmetry calculation methods. RESULTS: The 11 existing pure-tone asymmetry calculations varied in tumor detection performance. Age, sex, and noise exposure history helped to predict benign forms of hearing asymmetry. The logistic regression model outperformed existing asymmetry calculations and better accounted for normal age-, sex-, and noise exposure-related asymmetry variability. CONCLUSIONS: Our logistic regression asymmetry method improves the clinician's ability to estimate risk of VS, in part by integrating categorical patient history and numeric test data. This form of modeling can enhance clinical decision making in audiology and otology.