Impact of Clinician Training Background and Stroke Location on Bedside Diagnostic Test Accuracy in the Acute Vestibular Syndrome - A Meta-Analysis

R-cVR, a two-step bedside algorithm for the differential diagnosis of acute dizziness and vertigo

Background

The ability to quickly and accurately differentiate between peripheral and central dizziness or vertigo is vital. We developed the R-cVR algorithm for the early identification of central-type dizziness or vertigo.

Methods

In this single-center, retrospective cohort study, we assessed patients with isolated dizziness or vertigo between December 10, 2023, and February 28, 2024. Classification into central or peripheral types was based on magnetic resonance imaging (MRI)-diffusion-weighted imaging (DWI) results. We reevaluated the diagnostic value of the Romberg test for acute dizziness or vertigo by quantifying the duration of standing and created the R-cVR algorithm. The algorithm's accuracy was subsequently validated against the MRI-DWI results.

Results

After screening, 109 patients were recruited and divided into central (n = 25) and peripheral (n = 84) groups. The central group had a high incidence of cerebral infarction (88.0 %), whereas the peripheral group included patients with vestibular neuronitis, benign paroxysmal positional vertigo, and Meniere's disease (96.4 %). Significant disparities in the incidence of balance disorders were noted between the groups (92.0 % vs. 15.5 %, p < 0.001). Multivariate logistic regression revealed an odds ratio of 61.82 for balance disorders (p < 0.001). The R-cVR algorithm, which integrates the Romberg test and the V-shaped stance with closed-eyes protocol, was tested against MRI-DWI and yielded high diagnostic agreement (kappa = 0.80), with a sensitivity and specificity of 88.0 % and 94.0 %, respectively. There was no significant difference in the diagnostic efficacy of this algorithm for acute dizziness or vertigo with or without nystagmus.

Conclusion

The R-cVR algorithm effectively identifies central-type dizziness or vertigo and is simple for general practitioners to use without specialized equipment, which may be valuable in various clinical settings.

Approach to Acute Dizziness/Vertigo in the Emergency Department: Selected Controversies Regarding Specialty Consultation

Acute dizziness and vertigo are common emergency department presentations (≈4% of annual visits) and sometimes, a life-threatening diagnosis like stroke is missed. Recent literature reviews the challenges in evaluation of these symptoms and offers guidelines for diagnostic approaches. Strong evidence indicates that when well-trained providers perform a high-quality bedside neurovestibular examination, accurate diagnosis of peripheral vestibular disorders and stroke increases. However, it is less clear who can and should be performing these assessments on a routine basis. This article offers a focused debate for and against routine specialty consultation for patients with acute dizziness or vertigo in the emergency department as well as a potential path forward utilizing new portable technologies to quantify eye movements.

Vestibular neurology for the generalist

This review of vestibular neurology for the general neurologist delves into the multifaceted realm of vestibular neurology where we address the diagnostic and therapeutic challenges associated with dizziness, vertigo and balance disorders. We outline the standard vestibular assessments that can be understood and incorporated by the generalist, discussing their use in common vestibular disorders. Key disorders covered include acute and chronic syndromes, benign paroxysmal positional vertigo, Meniere disease, vestibular migraine and persistent postural-perceptual dizziness. We also touch on emerging advances in vestibular genotyping and novel treatment approaches for balance problems.

Bilaterally positive head-impulse tests can differentiate AICA infarction from labyrinthitis

Introduction

Video head-impulse tests (video-HITs) often fail to detect anterior inferior cerebellar artery (AICA) infarction due to peripheral and central vestibular system involvement. Anecdotal studies suggest that video-HITs may reveal bilateral impairment in AICA infarction. However, the diagnostic utility of video-HITs has not been established, particularly when compared to labyrinthitis, which accounts for the majority of acute audiovestibular syndrome (AAVS) cases.

Methods

We reviewed the medical records of consecutive patients presenting with new-onset acute hearing loss and spontaneous vertigo (i.e., AAVS) between March 2018 and July 2023 at a tertiary hospital in South Korea. Video-HIT patterns were categorized as follows: (1) ipsilaterally positive, (2) contralaterally positive, (3) bilaterally normal, and (4) bilaterally positive.

Results

Twenty-eight patients with AICA infarction (mean age ± standard deviation = 67 ± 15 years; 14 men) and 51 with labyrinthitis (63 ± 17 years, 26 men) were included in the analyses. Among the 28 patients with AICA infarction, 15 presented with AAVS in isolation, without other co-morbid neurologic deficits (15/28, 54%). The vestibulo-ocular reflex (VOR) gains of ipsilesional horizontal canals (HCs) ranged from 0.21 to 1.22 (median = 0.81, interquartile range [IQR] = 0.50-0.89). However, those for contralateral HC gain ranged from 0.57 to 1.19 (median = 0.89 [IQR = 0.73-0.97]). Collectively, HITs were bilaterally positive in 13 patients (including 12 patients with bilaterally positive HITs for the horizontal canal), normal in eight, ipsilesionally positive in six, and contralesionally positive in one patient with AICA infarction. The VOR gains were typically decreased ipsilaterally in 28 (28/51, 55%), normal in 17 (17/51, 33%), and decreased bilaterally in six patients with labyrinthitis (6/51, 12%). Logistic regression analysis revealed that bilaterally positive HITs (p = 0.004) and multiple vascular risk factors (p = 0.043) were more frequently associated with AICA infarction than labyrinthitis.

Discussion

Among patients presenting with AAVS, bilaterally positive HITs can be indicative of AICA infarction in patients with multiple vascular risk factors.

Systematic Review and Meta-Analysis of the Diagnostic Accuracy of a Graded Gait and Truncal Instability Rating in Acutely Dizzy and Ataxic Patients

BACKGROUND

In patients presenting with acute prolonged vertigo and/or gait imbalance, the HINTS [Head-Impulse, Nystagmus, Test-of-Skew] are very valuable. However, their application may be limited by lack of training and absence of vertigo/nystagmus. Alternatively, a graded gait/truncal-instability (GTI, grade 0-3) rating may be applied.

METHODS

We performed a systematic search (MEDLINE/Embase) to identify studies reporting on the diagnostic accuracy of bedside examinations in adults with acute vestibular syndrome. Diagnostic test properties were calculated for findings using a random-effects model. Results were stratified by GTI-rating used.

RESULTS

We identified 6515 articles and included 18 studies (n = 1025 patients). Ischemic strokes (n = 665) and acute unilateral vestibulopathy (n = 306) were most frequent. Grade 2/3 GTI had moderate sensitivity (70.8% [95% confidence-interval (CI) = 59.3-82.3%]) and specificity (82.7 [71.6-93.8%]) for predicting a central cause, whereas grade 3 GTI had a lower sensitivity (44.0% [34.3-53.7%] and higher specificity (99.1% [98.0-100.0%]). In comparison, diagnostic accuracy of HINTS (sensitivity = 96.8% [94.8-98.8%]; specificity = 97.6% [95.3-99.9%]) was higher. When combining central nystagmus-patterns and grade 2/3 GTI, sensitivity was increased to 76.4% [71.3-81.6%] and specificity to 90.3% [84.3-96.3%], however, no random effects model could be used. Sensitivity was higher in studies using the GTI rating (grade 2/3) by Lee (2006) compared to the approach by Moon (2009) (73.8% [69.0-78.0%] vs. 57.4% [49.5-64.9%], p = 0.001).

CONCLUSIONS

In comparison to HINTS, the diagnostic accuracy of GTI is inferior. When combined with central nystagmus-patterns, diagnostic accuracy could be improved based on preliminary findings. GTI can be readily applied in the ED-setting and also in patients with acute imbalance syndrome.

Distinguishing Peripheral from Central Causes of Dizziness and Vertigo without using HINTS or STANDING

Three validated diagnostic algorithms for diagnosing patients with acute onset dizziness or vertigo (HINTS, HINTS-plus and STANDING) exist. All are extremely accurate in distinguishing peripheral from central causes of dizziness when done by experienced clinicians. However, uptake of these diagnostic tools in routine emergency medicine practice has been sub-optimal, in part, due to clinicians' unease with the head impulse test, the most useful component contained of these algorithms. Use of these validated algorithms is the best way to accurately diagnose patients with acute dizziness. For clinicians who are unfamiliar with or uncomfortable performing or interpreting HINTS and STANDING, this article will suggest alternative approaches to help with accurate diagnosis of patients with acute dizziness or vertigo.

Application of bedside HINTS, ABCD2 score and truncal ataxia to differentiate cerebellar-brainstem stroke from vestibular neuritis in the emergency room

BACKGROUND AND PURPOSE

Acute vestibular syndrome (AVS) typically manifests as isolated dizziness or vertigo with no apparent neurological impairments. However, distinguishing life-threatening stroke from innocuous peripheral vestibular lesions in the emergency room (ER) remains challenging. This study aimed to explore the ability of the head impulse-nystagmus-test of skew (HINTS) combined with truncal ataxia or ABCD2 score to differentiate stroke from peripheral vestibular disease in patients with AVS in the ER.

METHODS

We prospectively recruited 121 patients with AVS from December 2022 to June 2023, 69 of whom presented with vestibular neuritis (VN) and the remaining with posterior circulation stroke (PCS). We analysed the HINTS results, truncal ataxia and ABCD2 score and compared the sensitivity and specificity among HINTS, truncal ataxia, ABCD2 score and their combinations using the McNemar test for paired samples.

RESULTS

HINTS combined with grade 2-3 truncal ataxia achieved significantly higher sensitivity than that of isolated HINTS in differentiating PCS from VN (100% vs 88.5%, p=0.031). The specificity of HINTS plus grade 2-3 truncal ataxia did not significantly differ from that of isolated HINTS (p=0.125); however, the combination of ABCD2 score and HINTS did not improve the diagnostic accuracy. The sensitivity of ABCD2 score ≥4 plus grade 2-3 truncal ataxia was significantly higher than those of isolated ABCD2 score ≥4 or isolated grade 2-3 truncal ataxia (p=0.016 and p<0.001, respectively) and not significantly lower than that of isolated HINTS (p=0.508).

CONCLUSION

Compared with the ABCD2 score, the truncal ataxia is of more valuable assistance to HINTS in differentiating PCS. Although the combination of ABCD2 score and truncal ataxia has a significant implication, it is not a replacement for HINTS.

Assessing clinical reasoning skills following a virtual patient dizziness curriculum

OBJECTIVES

Dizziness is a common medical symptom that is frequently misdiagnosed. While virtual patient (VP) education has been shown to improve diagnostic accuracy for dizziness as assessed by VPs, trainee performance has not been assessed on human subjects. The study aimed to assess whether internal medicine (IM) interns after training on a VP-based dizziness curriculum using a deliberate practice framework would demonstrate improved clinical reasoning when assessed in an objective structured clinical examination (OSCE).

METHODS

All available interns volunteered and were randomized 2:1 to intervention (VP education) vs. control (standard clinical teaching) groups. This quasi-experimental study was conducted at one academic medical center from January to May 2021. Both groups completed pre-posttest VP case assessments (scored as correct diagnosis across six VP cases) and participated in an OSCE done 6 weeks later. The OSCEs were recorded and assessed using a rubric that was systematically developed and validated.

RESULTS

Out of 21 available interns, 20 participated. Between intervention (n=13) and control (n=7), mean pretest VP diagnostic accuracy scores did not differ; the posttest VP scores improved for the intervention group (3.5 [SD 1.3] vs. 1.6 [SD 0.8], p=0.007). On the OSCE, the means scores were higher in the intervention (n=11) compared to control group (n=4) for physical exam (8.4 [SD 4.6] vs. 3.9 [SD 4.0], p=0.003) and total rubric score (43.4 [SD 12.2] vs. 32.6 [SD 11.3], p=0.04).

CONCLUSIONS

The VP-based dizziness curriculum resulted in improved diagnostic accuracy among IM interns with enhanced physical exam skills retained at 6 weeks post-intervention.

Vascular neuro-otology: vestibular transient ischemic attacks and chronic dizziness in the elderly

PURPOSE OF REVIEW

To explore the differential diagnosis of posterior fossa transient ischemic attacks (TIA) associated with vertigo and/or imbalance.To review the contribution of cerebral small vessel (SVD) disease to balance dysfunction and dizziness in the elderly.

MAIN FINDINGS

TIAs involving vestibular structures that mediate the vestibulo-ocular and vestibulospinal reflexes remain a diagnostic challenge because they overlap with causes of benign episodic vertigo. Here, we summarize the results of multidisciplinary specialty efforts to improve timely recognition and intervention of peripheral and central vestibular ischemia. More papers confirm that SVD is a major cause of gait disability, falls and cognitive disorder in the elderly. Recent work shows that early stages of SVD may also be responsible for dizziness in the elderly. The predominant location of the white matter changes, in the frontal deep white matter and genu of the corpus callosum, explains the association between cognitive and balance dysfunction in SVD related symptoms.

SUMMARY

The evaluation of patients with intermittent vascular vertigo represent a major diagnostic challenge, recent reviews explore the ideal design approach for a multidisciplinary study to increase early recognition and intervention. Hemispheric white matter microvascular ischemia has been the subject of research progress - advanced stages are known to cause gait disorder and dementia but early stages are associated with "idiopathic" dizziness in the elderly.

Quantifying Induced Nystagmus Using a Smartphone Eye Tracking Application (EyePhone)

BACKGROUND

There are ≈5 million annual dizziness visits to US emergency departments, of which vestibular strokes account for over 250 000. The head impulse, nystagmus, and test of skew eye examination can accurately distinguish vestibular strokes from peripheral dizziness. However, the eye-movement signs are subtle, and lack of familiarity and difficulty with recognition of abnormal eye movements are significant barriers to widespread emergency department use. To break this barrier, we sought to assess the accuracy of EyePhone, our smartphone eye-tracking application, for quantifying nystagmus.

METHODS AND RESULTS

We prospectively enrolled healthy volunteers and recorded the velocity of induced nystagmus using a smartphone eye-tracking application (EyePhone) and then compared the results with video oculography (VOG). Following a calibration protocol, the participants viewed optokinetic stimuli with incremental velocities (2-12 degrees/s) in 4 directions. We extracted slow phase velocities from EyePhone data in each direction and compared them with the corresponding slow phase velocities obtained by the VOG. Furthermore, we calculated the area under the receiver operating characteristic curve for nystagmus detection by EyePhone. We enrolled 10 volunteers (90% men) with an average age of 30.2±6 years. EyePhone-recorded slow phase velocities highly correlated with the VOG recordings (r=0.98 for horizontal and r=0.94 for vertical). The calibration significantly increased the slope of linear regression for horizontal and vertical slow phase velocities. Evaluating the EyePhone's performance using VOG data with a 2 degrees/s threshold showed an area under the receiver operating characteristic curve of 0.87 for horizontal and vertical nystagmus detection.

CONCLUSIONS

We demonstrated that EyePhone could accurately detect and quantify optokinetic nystagmus, similar to the VOG goggles.

Competence of Senior Otolaryngology Residents with the Bedside Head Impulse Test-Has There Been Improvement After 5 Years of Competency By Design?

BACKGROUND

The bedside head impulse test (bHIT) is a clinical method of assessing the vestibulo-ocular reflex. It is a critical component of the bedside assessment of dizzy patients and helps differentiate acute stroke from vestibular neuritis. A previous study on senior Otolaryngology residents showed poor competence in performing and interpreting the bHIT and called for specific evaluations in the Competency By Design (CBD) curriculum to remedy this. This study aimed to assess whether those competencies have improved after full implementation of CBD in residency programs.

METHODS

Thirty post-graduate year 4 Otolaryngology residents in Canada were evaluated on the use of the bHIT using a written multiple-choice question (MCQ) examination, interpretation of bHIT videos, and performance of a bHIT. Ratings of bHIT performance were completed by 2 expert examiners (DT, DL) using the Ottawa Clinic Assessment Tool.

RESULTS

Only 6.7% (rater DT) and 20% (rater DL) of residents were found able to perform the bHIT independently. Inter-rater reliability was moderate (0.55, intraclass correlation). Mean scores were 70% (13.4% standard deviation) for video interpretation and 59% (20.6% standard deviation) for multiple-choice questions. Video interpretation scores did not correlate with bHIT ratings (Pearson r = 0.11), but MCQs and bHIT ratings did correlate moderately (Pearson r = 0.52).Comparing to the prior study, residents performed worse on the bHIT (3.14 average score vs 3.64, P < .01) and fewer residents performed the bHIT independently (6.7% vs 22%-rater DT, 20% vs 39%-rater DL). Residents also performed worse on MCQs (58.7% vs 70.9%, P = 0.038), though similarly on video interpretation (70% vs 65%, P = .198).

CONCLUSION

Fourth year OTL-HNS residents in Canada are not competent in performing the bHIT. These findings have implications for refining competency-based curricula in the evaluation of critical physical exam skills.

What is the current status of primary care in the diagnosis and treatment of patients with vertigo and dizziness in Switzerland? A national survey

Background

Vertigo and dizziness are among the most frequent presenting symptoms in the primary care physicians' (PCPs) office. With patients facing difficulties in describing their complaints and clinical findings often being subtle and transient, the diagnostic workup of the dizzy patient remains challenging. We aimed to gain more insights into the current state of practice in order to identify the limitations and needs of the PCPs and define strategies to continuously improve their knowledge in the care of the dizzy patient.

Materials and methods

Board-certified PCPs working in Switzerland were invited to participate in an online survey. A descriptive statistical analysis was performed, and prospectively defined hypotheses were assessed using regression analyses.

Results

A vast majority of participating PCPs (n = 152) were familiar with the key questions when taking the dizzy patient's history and with performing provocation/repositioning maneuvers when posterior-canal benign paroxysmal positional vertigo (BPPV) was suspected (91%). In contrast, strong agreement that performing the alternating cover test (21%), looking for a spontaneous nystagmus with fixation removed (42%), and performing the head-impulse test (47%) were important was considerably lower, and only 19% of PCPs were familiar with lateral-canal BPPV treatment. No specific diagnosis could be reached in substantial fractions of patients with acute (35% [25; 50%], median [inter-quartile range]) and episodic/chronic (50% [40; 65.8%]) dizziness/vertigo. Referral to specialists was higher in patients with episodic/chronic dizziness than in acutely dizzy patients (50% [20.3; 75] vs. 30% [20; 50]), with younger PCPs (aged 30-40 years) demonstrating significantly increased odds of referral to specialists (odds ratio = 2.20 [1.01-4.81], p = 0.048).

Conclusion

The assessment of dizzy patients takes longer than that of average patients in most primary care practices. Many dizzy patients remain undiagnosed even after a thorough examination, highlighting the challenges faced by PCPs and potentially leading to frequent referrals to specialists. To address this, it is crucial to promote state-of-the-art neuro-otological examination and treatment techniques that are currently neglected by most PCPs, such as "HINTS" and lateral-canal BPPV treatment. This can help reduce referral rates allowing more targeted treatment and referrals.

Bedside Testing in Acute Vestibular Syndrome-Evaluating HINTS Plus and Beyond-A Critical Review

Acute vertigo and dizziness are frequent presenting symptoms in patients in the emergency department. These symptoms, which can be subtle and transient, present diagnostic challenges because they can be caused by a broad range of conditions that cut across many specialties and organ systems. Previous work has emphasized the value of combining structured history taking and a targeted examination focusing on subtle oculomotor signs. In this review, we discuss various diagnostic bedside algorithms proposed for the acutely dizzy patient. We analyzed these different approaches by calculating their area-under-the-curve (ROC) characteristics and sensitivity/specificity. We found that the algorithms that incorporated structured history taking and the use of subtle oculomotor signs had the highest diagnostic accuracy. In fact, both the HINTS+ bedside exam and the STANDING algorithm can more accurately diagnose acute strokes than early (<24 to 48 h after symptom onset) MRI with diffusion-weighted imaging (DWI). An important caveat is that HINTS and STANDING require moderate training to achieve this accuracy. Therefore, for physicians who have not undergone adequate training, other approaches are needed. These other approaches (e.g., ABCD2 score, PCI score, and TriAGe+ score) rely on vascular risk factors, clinical symptoms, and focal neurologic findings. While these other scores are easier for frontline providers to use, their diagnostic accuracy is far lower than HINTS+ or STANDING. Therefore, a focus on providing dedicated training in HINTS+ or STANDING techniques to frontline clinicians will be key to improving diagnostic accuracy and avoiding unnecessary brain imaging.

Systematic review and meta-analysis of the diagnostic accuracy of spontaneous nystagmus patterns in acute vestibular syndrome

Objectives

For the assessment of patients presenting with acute prolonged vertigo meeting diagnostic criteria for acute vestibular syndrome (AVS), bedside oculomotor examinations are essential to distinguish peripheral from central causes. Here we assessed patterns of spontaneous nystagmus (SN) observed in AVS and its diagnostic accuracy at the bedside.

Methods

MEDLINE and Embase were searched for studies (1980-2022) reporting on the bedside diagnostic accuracy of SN-patterns in AVS patients. Two independent reviewers determined inclusion. We identified 4,186 unique citations, examined 219 full manuscripts, and analyzed 39 studies. Studies were rated on risk of bias (QUADAS-2). Diagnostic data were extracted and SN beating-direction patterns were correlated with lesion locations and lateralization.

Results

Included studies reported on 1,599 patients, with ischemic strokes (n = 747) and acute unilateral vestibulopathy (n = 743) being most frequent. While a horizontal or horizontal-torsional SN was significantly more often found in peripheral AVS (pAVS) than in central AVS (cAVS) patients (672/709 [94.8%] vs. 294/677 [43.4%], p < 0.001), torsional and/or vertical SN-patterns were more prevalent in cAVS than in pAVS (15.1 vs. 2.6%, p < 0.001). For an (isolated) vertical/vertical-torsional SN or an isolated torsional SN specificity (97.7% [95% CI = 95.1-100.0%]) for a central origin etiology was high, whereas sensitivity (19.1% [10.5-27.7%]) was low. Absence of any horizontal SN was more frequently observed in cAVS than in pAVS (55.2 vs. 7.0%, p < 0.001). Ipsilesional and contralesional beating directions of horizontal SN in cAVS were found at similar frequency (28.0 vs. 21.7%, p = 0.052), whereas for pAVS a contralesional SN was significantly more frequent (95.2 vs. 2.5%, p < 0.001). For PICA strokes presenting with horizontal SN, beating direction was ipsilesional more often than contralesional (23.9 vs. 6.4%, p = 0.006), while the opposite was observed for AICA strokes (2.2 vs. 63.0%, p < 0.001).

Conclusions

(Isolated) vertical and/or torsional SN is found in a minority (15.1%) of cAVS patients only. When present, it is highly predictive for a central cause. A combined torsional-downbeating SN-pattern may be observed in pAVS also in cases with isolated lesions of the inferior branch of the vestibular nerve. Furthermore, in cAVS patients the SN beating direction itself does not allow a prediction on the lesion side.