Early MRI-negative posterior circulation stroke presenting as acute dizziness

Enhancing Stroke Recognition: A Comparative Analysis of Balance and Eyes-Face, Arms, Speech, Time (BE-FAST) and Face, Arms, Speech, Time (FAST) in Identifying Posterior Circulation Strokes

Background/Objectives: Posterior circulation stroke (PCS) poses a diagnostic challenge due to the diverse and subtle clinical manifestations. While the FAST (Face, Arms, Speech, Time) mnemonic has proven effective in identifying anterior circulation stroke, its sensitivity to posterior events is less clear. Recently, the addition of Balance and Eyes to the mnemonic has been proposed as a more comprehensive tool for stroke recognition. Despite this, evidence directly comparing the effectiveness of BE-FAST and FAST in identifying PCS remains limited. Methods: A retrospective analysis was performed on stroke calls at a comprehensive stroke centre, Sydney, Australia. BE-FAST symptoms first assessed at an emergency department triage were recorded, along with automated acute computerised tomography perfusion (CTP) imaging findings. Haemorrhagic strokes were excluded from analysis. An ischaemic stroke diagnosis was confirmed 48-72 h later with magnetic resonance imaging (MRI) brain. The performance of 1. BE-FAST and FAST and 2. BE-FAST and CTP in the hyperacute detection of posterior circulation ischaemic stroke was compared. Results: Out of 164 identified ischaemic infarcts confirmed on MRIs, 46 were PCS. Of these, 27 were FAST-positive, while 45 were BE-FAST-positive. Overall, BE-FAST demonstrated a higher sensitivity compared to FAST in identifying PCS (97.8 vs. 58.7) but suffered from a lower specificity (10.0 vs. 39.8). Notably, 39.1% (n = 18) of patients with PCS would have been missed if only FAST were used. Furthermore, of the 26 PCS negative on CTP, 25 were BE-FAST-positive, and 14 were FAST-positive. Conclusions: The incorporation of Balance and Eye assessments into the FAST protocol improves PCS detection, although may yield more false positives.

Wake-Up Thrombolysis With Negative Diffusion-Weighted Magnetic Resonance Imaging

This case underscores the importance of treating neurological deficits of an acute stroke presentation despite initial negative diffusion-weighted imaging (DWI), especially in the acute phase when there is high clinical suspicion of stroke. Additionally, it highlights the appropriate use of a WAKE-UP protocol for patients that present with stroke symptoms without a well-defined inception time. A 71-year-old female presented to the emergency department with symptoms of dizziness and double vision upon wake-up. While clinical exam findings revealed left intranuclear ophthalmoplegia (INO) and inability to ambulate due to gait ataxia, magnetic resonance imaging (MRI) was negative for acute stroke. Despite negative DWI MRI, this patient's clinical exam findings of a left INO and gait ataxia were indicative of an ischemic stroke localizing to the medial longitudinal fasciculus (MLF), and the patient received thrombolytics. Repeat MRI about 48 h later revealed an acute infarct in the left midbrain with a DWI lesion in the MLF.

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.

Application of 3D-PCASL combined with t-ASL and MRA in the diagnosis of patients with isolated vertigo induced by posterior circulation ischemia

OBJECTIVES

Isolated vertigo induced by posterior circulation ischemia (PCIV) can further progress into posterior circulation infarction. This study aimed to explore the diagnostic values of three-dimensional pseudo-continuous arterial spin labeling (3D-PCASL) combined with territorial arterial spin labeling (t-ASL) and magnetic resonance angiography (MRA) in visualizing and evaluating PCIV, seeking improved diagnostic tools for clinical guidance.

METHODS

28 PCIVs (11 males, 17 females, aged from 55 to 83 years, mean age: 69.68 ± 9.01 years) and 28 healthy controls (HCs, 12 male, 16 female, aged from 56 to 87 years, mean age: 66.75 ± 9.86 years) underwent conventional magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), MRA, 3D-PCASL, and t-ASL. We compared the incidence of anatomic variants of the posterior circle of Willis in MRA, cerebral blood flow (CBF) and anterior collateral blood flow on postprocessing maps obtained from 3D-PCASL and t-ASL sequence between PCIVs and HCs. Chi-square test and paired t-test were analyzed statistically with SPSS 24.0 software.

RESULTS

7 PCIVs (7/28, 25%) and 6 HCs (6/28, 21%) showed fetal posterior cerebral artery (FPCA) on MRA, including 1 HC, and 6 PCIVs with FPCA appeared hypoperfusion. 18 PCIVs (64%) and 2 HCs (7%) showed hypoperfusion in the posterior circulation (PC), including 1 HC and 7 PCIVs displayed anterior circulation collateral flow. Chi-square analyses demonstrated a difference in PC hypoperfusion between PCIVs and HCs, whether in the whole or FPCA-positive group assessment (P < 0.05). Paired t-test showed that the CBF values were significant difference for the bilateral PC asymmetrical perfusion in the PCIVs (P < 0.01). When compared to the bilateral PC symmetrical non-hypoperfusion area in the PCIVs and HCs, the CBF values were not significant (P > 0.05). The CBF values of the PC in PCIVs were lower than in HCs (P < 0.05). The reduction rate in the hypoperfusion side of the bilateral PC asymmetrical perfusion of the PCIVs ranged from 4% to 37%, while the HCs reduction rate was 7.7%. The average PC symmetrical perfusion average reduction rate of the PCIVs was 52.25%, while the HCs reduction rate was 42.75%.

CONCLUSION

3D-PCASL is a non-invasive and susceptible method for detecting hypoperfusion in PC, serving as a potential biomarker of PCIV. The suspected hypoperfusion in PC may be attributed to the emergence of FPCA and the manifestation of anterior collateral flow when combining t-ASL and MRA sequences. These findings demonstrated that 3D-PCASL combined with t-ASL and MRA sequences are the potential method to identify PCIV, leading to early diagnosis of PCIV and reducing the risk of progressing into infarction.

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.

Head impulse, nystagmus, and test of skew examination for diagnosing central causes of acute vestibular syndrome

BACKGROUND

Dizziness is a common reason for people to seek medical care. Acute vestibular syndrome (AVS) is a specific type of dizziness, which can include severe vertigo, nausea and vomiting, nystagmus, or unsteadiness. Acute vestibular syndrome can be due to peripheral or central causes. It is important to determine the cause, as the intervention and outcomes differ if it is from a peripheral or central cause. Clinicians can assess for the cause using risk factors, patient history, examination findings, or advanced imaging, such as a magnetic resonance imaging (MRI). The head impulse, nystagmus, test of skew (HINTS) examination is a three-part examination performed by clinicians to determine if AVS is due to a peripheral or central cause. This includes assessing how the eyes move in response to rapidly turning a person's head (head impulse), assessing the direction of involuntary eye movements (nystagmus), and assessing whether the eyes are aligned or misaligned (test of skew). The HINTS Plus examination includes an additional assessment of auditory function.

OBJECTIVES

To assess the diagnostic accuracy of the HINTS and HINTS Plus examinations, with or without video assistance, for identifying a central etiology for AVS.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Google Scholar, the International HTA database, and two trials registers to September 2022.

SELECTION CRITERIA

We included all retrospective and prospective diagnostic test accuracy studies that evaluated the HINTS or HINTS Plus test used in a primary care clinic, an urgent care clinic, the emergency department, or during inpatient hospitalization against a final diagnosis of a central etiology of AVS, as defined by the reference standard of advanced imaging or final diagnosis by a neurologist.

DATA COLLECTION AND ANALYSIS

Two review authors independently determined eligibility of each study according to eligibility criteria, extracted data, assessed the risk of bias, and determined the certainty of evidence. Disagreements were adjudicated by consensus or a third review author if needed. The primary outcome was the diagnostic accuracy of the HINTS and HINTS Plus examinations for identifying a central etiology for AVS, conducted clinically (clinician visual assessment) or with video assistance (e.g. video recording with goggles); we independently assessed the clinical and video-assisted examinations. Subgroup analyses were performed by provider type (e.g. physicians, non-physicians), time from symptom onset to presentation (e.g. less than 24 hours, longer than 24 hours), reference standard (e.g. advanced imaging, discharge diagnosis), underlying etiology (e.g. ischemic stroke, alternative etiologies [hemorrhagic stroke, intracranial mass]), study setting (e.g. outpatient [outpatient clinic, urgent care clinic, emergency department], inpatient), physician level of training (e.g. resident, fellow/attending), physician specialty (e.g. otolaryngology, emergency medicine, neurology, and neurologic subspecialist [e.g. neuro-ophthalmology, neuro-otology]), and individual diagnostic accuracy of each component of the examination (e.g. head impulse, direction-changing nystagmus, test of skew). We created 2 x 2 tables of the true positives, true negatives, false positives, and false negatives and used these data to calculate the sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio with 95% confidence intervals (95% CI) for each outcome.

MAIN RESULTS

We included 16 studies with a total of 2024 participants (981 women and 1043 men) with a mean age of 60 years. Twelve studies assessed the HINTS examination; five assessed the HINTS Plus examination. Thirteen studies were performed in the emergency department; half were performed by neurologists. The clinical HINTS examination (12 studies, 1890 participants) was 94.0% (95% confidence interval [CI] 82.0% to 98.2%) sensitive, and 86.9% (95% CI 75.3% to 93.6%) specific (low-certainty evidence). The video-assisted HINTS examination (3 studies, 199 participants) was 85.0% to 100% sensitive (low-certainty evidence), and 38.9% to 100% specific (very low-certainty evidence). The clinical HINTS Plus examination (5 studies, 451 participants) was 95.3% (95% CI 78.4% to 99.1%) sensitive, and 72.9% (95% CI 44.4% to 90.1%) specific (low-certainty evidence). The video-assisted HINTS Plus examination (2 studies, 163 participants) was 85.0% to 93.8% sensitive, and 28.6% to 38.9% specific (moderate-certainty evidence). Subgroup analyses were limited, as most studies were conducted in the emergency department, by physicians, and with MRI as a reference standard. Time from symptom onset to presentation varied across studies. Three studies were at high risk of bias and three studies were at unclear risk of bias for participant selection. Three studies were at unclear risk of bias for the index test. Four studies were at unclear risk of bias for the reference standard. Two studies were at unclear risk of bias for flow and timing. One study had unclear applicability concerns for participant selection. Two studies had high applicability concerns for the index test and two studies had unclear applicability concerns for the index test. No studies had applicability concerns for the reference standard.

AUTHORS' CONCLUSIONS

The HINTS and HINTS Plus examinations had good sensitivity and reasonable specificity for diagnosing a central cause for AVS in the emergency department when performed by trained clinicians. Overall, the evidence was of low certainty. There were limited data for the role of video-assistance or specific subgroups. Future research should include more high-quality studies of the HINTS and HINTS Plus examination; assessment of inter-rater reliability across users; accuracy across different providers, specialties, and experience; and direct comparison with no HINTS or MRI to assess the effect on clinical care.

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.

Visual symptoms in acute stroke - A systematic review of observational studies

OBJECTIVE

Atypical symptoms of stroke, such as non-specific visual symptoms, are a challenging aspect of acute stroke diagnostics. Among patients evaluated for stroke in the Emergency Department, 2-28% present with stroke chameleons, and 30-43% with stroke mimics. We aimed to identify the type of visual symptoms present in typical strokes, stroke mimics, and stroke chameleons.

PATIENTS AND METHODS

By use of Preferred Reporting Items for Systematic Reviews and Meta-Analysis we searched PubMed and Embase for studies with reports of acute visual symptoms in typical strokes vs mimics or chameleons (PROSPERO protocol, ID CRD42022364749). Risk of bias was assessed by The Critical Appraisal Skills Program.

RESULTS

Thirteen papers were included, comprising data from 9248 patients evaluated for stroke. Compared to mimics, visual symptoms in stroke presented more frequently as hemianopia (28.2% vs 4.8%, 7,4% vs 2.3%, 22% vs 0%), visual loss (11.6% vs 1.8%), visual field defect (11.6% vs 4%, 24% vs 2%, 19% vs 1.7%), eye movement disorder (19.4% vs 6.4%), eye deviation (9.6% vs 0.9%), gaze palsy (32.1% vs 8.6%), oculomotor disturbance (37% vs 0%), and visual inattention (17.5% vs 4%). Compared to strokes, mimics more often presented "non-systematized visual trouble" (10% vs 3%) and blurred vision (22% vs 5%), whereas "visual disturbance" was reported more often in stroke chameleons than in typical strokes (10% vs 3%).

CONCLUSION

Detailed reports of visual symptoms were lacking in most studies, however blurred vision and "non-systematized visual trouble" were more frequent in mimics, "visual disturbance" in stroke chameleons, and negative visual symptoms such as visual field defects in typical strokes. A more systematic and detailed approach to visual symptoms may facilitate acute stroke recognition in patients with visual symptoms.

Optimal CT perfusion thresholds for core and penumbra in acute posterior circulation infarction

Background

At least 20% of strokes involve the posterior circulation (PC). Compared to the anterior circulation, posterior circulation infarction (POCI) are frequently misdiagnosed. CT perfusion (CTP) has advanced stroke care by improving diagnostic accuracy and expanding eligibility for acute therapies. Clinical decisions are predicated upon precise estimates of the ischaemic penumbra and infarct core. Current thresholds for defining core and penumbra are based upon studies of anterior circulation stroke. We aimed to define the optimal CTP thresholds for core and penumbra in POCI.

Methods

Data were analyzed from 331-patients diagnosed with acute POCI enrolled in the International-stroke-perfusion-registry (INSPIRE). Thirty-nine patients with baseline multimodal-CT with occlusion of a large PC-artery and follow up diffusion weighted MRI at 24-48 h were included. Patients were divided into two-groups based on artery-recanalization on follow-up imaging. Patients with no or complete recanalisation were used for penumbral and infarct-core analysis, respectively. A Receiver operating curve (ROC) analysis was used for voxel-based analysis. Optimality was defined as the CTP parameter and threshold which maximized the area-under-the-curve. Linear regression was used for volume based analysis determining the CTP threshold which resulted in the smallest mean volume difference between the acute perfusion lesion and follow up MRI. Subanalysis of PC-regions was performed.

Results

Mean transit time (MTT) and delay time (DT) were the best CTP parameters to characterize ischaemic penumbra (AUC = 0.73). Optimal thresholds for penumbra were a DT >1 s and MTT>145%. Delay time (DT) best estimated the infarct core (AUC = 0.74). The optimal core threshold was a DT >1.5 s. The voxel-based analyses indicated CTP was most accurate in the calcarine (Penumbra-AUC = 0.75, Core-AUC = 0.79) and cerebellar regions (Penumbra-AUC = 0.65, Core-AUC = 0.79). For the volume-based analyses, MTT >160% demonstrated best correlation and smallest mean-volume difference between the penumbral estimate and follow-up MRI (R ² = 0.71). MTT >170% resulted in the smallest mean-volume difference between the core estimate and follow-up MRI, but with poor correlation (R ² = 0.11).

Conclusion

CTP has promising diagnostic utility in POCI. Accuracy of CTP varies by brain region. Optimal thresholds to define penumbra were DT >1 s and MTT >145%. The optimal threshold for core was a DT >1.5 s. However, CTP core volume estimates should be interpreted with caution.

Risk of Future Stroke in Patients with a Diagnosis of Peripheral Vertigo in the Emergency Department

BACKGROUND

We evaluated the temporal characteristics of stroke risks in the emergency department patients who had a diagnosis of peripheral vertigo. We also attempted to reveal the stroke risk factor among those with peripheral vertigo.

METHODS

This is a parallel group cohort study in a tertiary referral hospital. After assigning each of matched 4367 patients to the comparative set of peripheral vertigo and appendicitis-ureterolithiasis groups and each of matched 4911 to the comparative set of peripheral vertigo and ischemic stroke groups, we evaluated the relative stroke risk. In addition, to predict the individual stroke risk in patients with peripheral vertigo, any association between the demographic factors and stroke events was evaluated in the peripheral vertigo group.

RESULTS

The peripheral vertigo group had a higher stroke risk than the appendicitis-ureterolithiasis group (HR=1.73, 95% CI=1.18-2.55) but a lower risk than the ischemic stroke group (HR=0.30, 95% CI=0.24-0.37). The stroke risk of the peripheral vertigo group was just below that of small vessel stroke. The stroke risk of the peripheral vertigo group differed markedly by time: higher within seven days, moderate between seven days and one year, and diminished thereafter. Old age (>65), male gender, and diabetes mellitus were the risk factors for stroke in the peripheral vertigo group.

CONCLUSION

Patients with a diagnosis of peripheral vertigo in the ED showed a moderate future stroke risk so that requires a stroke preventive strategy tailored to the timing of symptom onset and individual risk.

The Outpatient Approach to Dizziness

The evaluation of the dizzy patient is complicated by many common pitfalls. The patient's description of symptoms and the standard neurologic examination are often nonspecific or unrevealing, and neuroimaging is most often normal. Over the past several years, research has demonstrated that a refocusing of history taking results in more reliable and diagnostically helpful information. This can guide a targeted expansion of the exam, often with an emphasis on eye movements.

Central nystagmus plus ABCD2 identifying stroke in acute dizziness presentations

OBJECTIVE

The objective was to explore the ability of head impulse-nystagmus-test of skew (HINTS) combined with ABCD²  score to identify cerebrovascular causes of dizziness.

MATERIALS AND METHODS

We prospectively recruited 85 patients with acute onset of dizziness from September 2016 to December 2018 and analyzed their clinical characteristics, ABCD²  scores, HINTS, and neuroimages data.

RESULTS

Acute stroke was identified by MRI in 21 of 85 patients. The mean ± SD ABCD²  scores were significantly higher among patients with acute stroke than those without acute stroke (4.0 ± 0.8 h vs. 2.5 ± 0.7 h, p < 0.01). The majority (71.4%) of patients with cerebrovascular causes had central pattern of nystagmus at the initial 48 h from symptoms onset. The sensitivity and specificity of HINTS were 100% and 87% for the presence of stroke in patients with nystagmus. When combined central pattern of nystagmus and ABCD²  ≥ 4, the sensitivity increased to 100% for identifying cerebrovascular causes. Nystagmus were absence at time of examination in 16.5% of our patients, and ABCD²  scores in patients who had cerebrovascular diagnoses were all ≥ 4.

CONCLUSION

HINTS examinations could efficiently differentiate stroke from nonstroke under the condition that patients remaining symptomatic, including spontaneous or gaze-evoked nystagmus. It is more practical to apply the combination of central pattern of nystagmus and ABCD²  ≥ 4 in ED setting. If patients were absence of central nystagmus at admission, cerebrovascular event should be a priority diagnosis when their ABCD²  ≥ 4.

Patterns of ischemic posterior circulation strokes: A clinical, anatomical, and radiological review

Background

Posterior circulation and anterior circulation strokes share many clinical, pathogenetic and radiological features, although some clinical signs are highly specific to posterior circulation strokes. Arterial stenosis and occlusions occur in significant numbers in both acute posterior circulation and anterior circulation strokes, making them good candidates for endovascular treatment. Among posterior circulation strokes, basilar artery occlusions stand out because of the diagnostic and acute treatment challenges.

Methods

We reviewed the literature on clinical stroke syndromes and neuroimaging findings and systematically describe for each anatomical site of stroke the detailed clinical and radiological information (anatomical representation, diffusion weighted imaging and angiographic sequences). The principles of neuroimaging of posterior circulation strokes and the prognosis for each stroke localization are also discussed.

Review summary

Stroke syndromes in the territories of the vertebral, basilar, cerebellar, and posterior cerebral arteries are presented. Features typical of posterior circulation strokes are highlighted, including patterns of basilar artery occlusions. Clinical severity and prognosis of posterior circulation strokes are highly variable, and given that they are more difficult to detect on CT-based neuroimaging, magnetic resonance imaging is the technique of choice in suspected posterior circulation strokes. Rapid identification of arterial occlusion patterns may provide prognostic information and support acute revascularization decisions.

Conclusions

Posterior circulation stroke syndromes tightly reflect lesion localization and arterial occlusion patterns. Although many clinical and pathogenetic features are similar to anterior circulation strokes, notable differences exist in terms of clinical presentation, stroke mechanism, prognosis, and response to acute recanalization.

The spectrum of acute vestibular neuropathy through modern vestibular testing: A descriptive analysis

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Video head impulse testing and vestibular evoked myogenic potentials show that acute vestibular neuropathy is heterogeneous.

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Peripheral vestibular pathway vulnerability is approximately inversely correlated with its proportion of afferent fibers.

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Caloric testing, while useful, should no longer be considered the gold standard for diagnosing acute vestibular neuropathy.

Objective

Acute vestibular neuropathy (AVN), often referred to as vestibular neuritis, is a cranial neuropathy responsible for a significant proportion of cases of acute vertigo. This study describes the spectrum of lesion patterns in AVN as identified by video head impulse testing (vHIT) which assesses the high frequency vestibulo-ocular reflex function of the semicircular canals, and cervical and ocular vestibular evoked myogenic potentials (VEMPs) which assess otolith function.

Methods

We used vHIT and VEMPs to assess 35 patients with vestibular neuropathy in the acute stage.

Results

Unilateral superior division vestibular nerve involvement was the most common variant (57.1%), followed by unilateral superior and inferior division (28.5%), bilateral superior division (8.5%) and unilateral inferior division (5.7%). We observed a partial inverse correlation between the proportion of afferent fibers from an organelle, and the likelihood that the test of that organelle’s function will be abnormal.

Conclusion

vHIT and VEMPs provide more detailed characterization of lesion pattern in AVN than caloric testing.

Significance

Comparison of lesion patterns from neuro-physiological testing with what is known about the proportional distribution of afferent fibers from the vestibular end-organelles suggests a new, neuro-anatomically based insight regarding susceptibility of these pathways to AVN.

Vertigo and dizziness in the emergency room

PURPOSE OF REVIEW

To provide an update on diagnostic algorithms for differential diagnosis of acute vertigo and dizziness and swift identification of potentially harmful causes.

RECENT FINDINGS

About 25% of patients with acute vertigo and dizziness have a potentially life-threatening diagnosis, including stroke in 4-15%. Diagnostic work-up relies on the combination of symptom features (triggers, duration, history of vertigo/dizziness, accompanying symptoms) and a comprehensive vestibular, ocular motor, and balance exam. The latter includes head impulse, head-shaking nystagmus, positional nystagmus, gaze-holding, smooth pursuit, skew deviation, and Romberg's test. Recent standardized diagnostic algorithms (e.g., HINTS, TriAGe+) suggest the combination of several elements to achieve a good diagnostic accuracy in differentiation of central and peripheral vestibular causes. Neuroimaging with MRI must be applied and interpreted with caution, as small strokes are frequently overlooked, especially in the acute setting (false-negative rate of up to 50%).

SUMMARY

Diagnostic differentiation of acute vertigo and dizziness remains a complex task, which can be tackled by a structured clinical assessment focusing on symptom characteristics and constellations of ocular motor and vestibular findings. Specific challenges arise in cases of transient or atypical vestibular syndromes.

Nystagmus characteristics of healthy controls

BACKGROUND:

Healthy controls exhibit spontaneous and positional nystagmus which needs to be distinguished from pathological nystagmus.

OBJECTIVE:

Define nystagmus characteristics of healthy controls using portable video-oculography.

METHODS:

One-hundred and one asymptomatic community-dwelling adults were prospectively recruited. Participants answered questions regarding their audio-vestibular and headache history and were sub-categorized into migraine/non-migraine groups. Portable video-oculography was conducted in the upright, supine, left- and right-lateral positions, using miniature take-home video glasses.

RESULTS:

Upright position spontaneous nystagmus was found in 30.7% of subjects (slow-phase velocity (SPV)), mean 1.1±2.2 degrees per second (°/s) (range 0.0 – 9.3). Upright position spontaneous nystagmus was horizontal, up-beating or down-beating in 16.7, 7.9 and 5.9% of subjects. Nystagmus in at least one lying position was found in 70.3% of subjects with 56.4% showing nystagmus while supine, and 63.4% in at least one lateral position. While supine, 20.8% of subjects showed up-beating nystagmus, 8.9% showed down-beating, and 26.7% had horizontal nystagmus. In the lateral positions combined, 37.1% displayed horizontal nystagmus on at least one side, while 6.4% showed up-beating, 6.4% showed down-beating. Mean nystagmus SPVs in the supine, right and left lateral positions were 2.2±2.8, 2.7±3.4, and 2.1±3.2°/s. No significant difference was found between migraine and non-migraine groups for nystagmus SPVs, prevalence, vertical vs horizontal fast-phase, or low- vs high-velocity nystagmus (<5 vs > 5°/s).

CONCLUSIONS:

Healthy controls without a history of spontaneous vertigo show low velocity spontaneous and positional nystagmus, highlighting the importance of interictal nystagmus measures when assessing the acutely symptomatic patient.

Modern machine-learning can support diagnostic differentiation of central and peripheral acute vestibular disorders

BACKGROUND

Diagnostic classification of central vs. peripheral etiologies in acute vestibular disorders remains a challenge in the emergency setting. Novel machine-learning methods may help to support diagnostic decisions. In the current study, we tested the performance of standard and machine-learning approaches in the classification of consecutive patients with acute central or peripheral vestibular disorders.

METHODS

40 Patients with vestibular stroke (19 with and 21 without acute vestibular syndrome (AVS), defined by the presence of spontaneous nystagmus) and 68 patients with peripheral AVS due to vestibular neuritis were recruited in the emergency department, in the context of the prospective EMVERT trial (EMergency VERTigo). All patients received a standardized neuro-otological examination including videooculography and posturography in the acute symptomatic stage and an MRI within 7 days after symptom onset. Diagnostic performance of state-of-the-art scores, such as HINTS (Head Impulse, gaze-evoked Nystagmus, Test of Skew) and ABCD2 (Age, Blood, Clinical features, Duration, Diabetes), for the differentiation of vestibular stroke vs. peripheral AVS was compared to various machine-learning approaches: (i) linear logistic regression (LR), (ii) non-linear random forest (RF), (iii) artificial neural network, and (iv) geometric deep learning (Single/MultiGMC). A prospective classification was simulated by ten-fold cross-validation. We analyzed whether machine-estimated feature importances correlate with clinical experience.

RESULTS

Machine-learning methods (e.g., MultiGMC) outperform univariate scores, such as HINTS or ABCD2, for differentiation of all vestibular strokes vs. peripheral AVS (MultiGMC area-under-the-curve (AUC): 0.96 vs. HINTS/ABCD2 AUC: 0.71/0.58). HINTS performed similarly to MultiGMC for vestibular stroke with AVS (AUC: 0.86), but more poorly for vestibular stroke without AVS (AUC: 0.54). Machine-learning models learn to put different weights on particular features, each of which is relevant from a clinical viewpoint. Established non-linear machine-learning methods like RF and linear methods like LR are less powerful classification models (AUC: 0.89 vs. 0.62).

CONCLUSIONS

Established clinical scores (such as HINTS) provide a valuable baseline assessment for stroke detection in acute vestibular syndromes. In addition, machine-learning methods may have the potential to increase sensitivity and selectivity in the establishment of a correct diagnosis.

Acute binocular diplopia: peripheral or central?

Objectives

Acute diplopia is a diagnostic challenge for clinicians, in particular in the emergency department. The most common cause of acute diplopia are ocular motor nerve palsies (OMP). In this prospective study, we focused on identifying the most crucial signs and symptoms for differentiating between peripheral and central OMP.

Methods

We prospectively evaluated 56 non-consecutive patients who presented at our emergency department with acute binocular diplopia (≤ 10 days). The patient history was taken using a standardized questionnaire and patients underwent a neurological, neuro-ophthalmological and neuro-otological examination, including measurement of the subjective visual vertical (SVV), Harms tangent screen test, and cranial MRI.

Results

Forty-six out of 56 patients were diagnosed with an ocular motor cranial nerve palsy (OMP), 21 of peripheral and 23 of central origin; in two patients, the etiology remained unknown. The following features were different in peripheral and central OMP: (1) the presence of vertigo/dizziness was more frequent in central (43.5%) than in peripheral (9.5%) OMP. (2) Central ocular motor signs, such as saccadic smooth pursuit, additional internuclear ophthalmoplegia, skew deviation, and saccade palsies, were also found more frequently in the central than in the peripheral group (86.7% vs. 33.3%). (3) Further, a pathological SVV deviation by monocular testing of the non-affected eye was also more common in central (77.3%) than in peripheral OMP (38.9%). The presence of all three factors has a positive predictive value of 100% (CI 50–100%) for the presence of a central lesion.

Conclusions

In acute diplopia due to central OMP, the most important accompanying symptom is vertigo/dizziness, and the most important clinical signs are central ocular motor disorders (which require examination of the non-paretic eye) and an SVV deviation in the non-paretic eye.

What guides decision-making on intravenous thrombolysis in acute vestibular syndrome and suspected ischemic stroke in the posterior circulation?

Intravenous thrombolysis (IVT) is rarely performed in dizzy patients with acute vestibular syndrome (AVS) or acute imbalance (AIS) even if posterior circulation stroke (PCS) is suspected. Decision-making may be affected by uncertainties in discriminating central from peripheral vestibulopathy or concerns of IVT-related harm, particularly intracerebral hemorrhage (ICH), but related studies are missing. Using an in-house register of dizzy patients coming to the emergency room, we identified 29 AVS/AIS patients who presented within 4.5 h after onset, revealed clinical signs indicative of PCS (central oculomotor signs, mild focal abnormalities), and had non-contrast computed tomography (NCCT). Patients treated with IVT (n = 15) were compared to NoIVT patients (n = 14) with regard to clinical and imaging (including perfusion computed tomography, CTP) parameters, occurrence of ICH and short-term clinical outcome (NIHSS improvement; ability to walk independently). IVT and NoIVT patients did not differ in baseline characteristics, central oculomotor signs, or clinical outcome. IVT patients more often exhibited disabling vestibular symptoms (severe dizziness/vertigo, inability to stand unsupported) and focal abnormalities than NoIVT patients. There was no ICH in either group. CTP was performed in 0% of NoIVT versus 80% of IVT patients, seven of twelve revealing posterior circulation hypoperfusion. Comparison of initial hypoperfusion (CTP) and final stroke (NCCT) revealed IVT-related benefit (smaller lesion) in three of seven IVT patients. In AVS/AIS patients with suspected PCS, disabling vestibular symptoms, focal neurological deficits, and hypoperfusion on CTP seem to direct decision-making pro IVT. In our small cohort, there were no significant IVT-related clinical benefits, no IVT-related ICHs, and salvage of brain tissue in some patients.

Differential diagnosis of acute vascular vertigo

PURPOSE OF REVIEW

The current review covers recent advances in vascular vertigo in terms of diagnostic strategies, clinical/laboratory features, pathophysiology, and differential diagnosis.

RECENT FINDINGS

Acute strokes presenting with isolated dizziness/vertigo without other obvious symptoms or signs of central nervous system involvements may be easily mistaken as peripheral vestibulopathy. For correct diagnosis of vascular vertigo, the importance of clinical history (timing and triggers) and targeted bedside examination cannot be overemphasized. In addition to Head Impulse-Nystagmus-Test of Skew, several differential strategies have been advanced by adopting a combination of clinical history, bedside or laboratory examination, and imaging for diagnosis of vascular vertigo. Circumscribed cerebellar and brainstem lesions may cause isolated central vestibular syndromes with characteristic vestibular and ocular motor manifestations. Recognition of these findings would aid in localizing the lesions and understanding the function of each central vestibular structure. Central positional nystagmus (CPN) may mimic benign paroxysmal positional vertigo (BPPV), but additional oculomotor or neurological findings mostly permit differentiation of CPN from BPPV.

SUMMARY

In acute vestibular syndrome, discriminating vascular causes is still challenging especially when other central symptoms and signs are not evident. An integrated approach based on understanding of clinical features, laboratory findings, speculated mechanisms, and limitations of current diagnostic tests will lead to better clinical practice.

High-sensitivity C-reactive protein as an indicator of ischemic stroke in patients with isolated acute vestibular syndrome: Retrospective observational study

Ischemic strokes presenting with isolated acute vestibular syndrome (AVS) are not rare and still are challenging for diagnosis. In this retrospective study, we aimed to investigate the association of high-sensitivity C-reactive protein (hs-CRP) with stroke in patients with isolated AVS. A total of 217 patients with isolated AVS within 3 days of symptom onset were included. Serum hs-CRP levels were assessed within 24 hours of admission. The relationship between hs-CRP levels and stroke in patients with AVS were analyzed using univariate and multivariate models. The results showed that hs-CRP levels were significantly higher in infarction patients than that in noninfarction group. The stroke occurrence was increased with increasing quartile levels of hs-CRP. The highest quartile level of hs-CRP was associated with a higher occurrence of stroke compared with the lowest quartile group (adjusted odds ratio [OR], 4.099; 95% confidence interval [CI], 1.272-13.216; P = .018). We also found that male gender (adjusted OR, 5.635; 95% CI, 2.212-14.352; P < .001) and increased low-density lipoprotein cholesterol (LDL-C) (adjusted OR, 2.543; 95% CI, 1.175-5.505; P = .018) were independently associated with stroke in patients with AVS. In addition, using the receiver operating characteristic curve analysis, our study yielded a threshold value of hs-CRP at 1.82 mg/L, and demonstrated that combining hs-CRP with LDL-C improved the discriminatory ability to identify stroke patients with AVS (area under the curve of the combined model: 0.753; 95% CI = 0.684-0.821; P < .001). Hs-CRP may be a useful indicator of stroke in patients with AVS. More attention should be paid to the patients with elevated hs-CRP level.