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Background Identifying dangerous causes of dizziness is a challenging task for neurologists, as it requires interpretation of subtle bedside exam findings, which become even more subtle with time. Nystagmus can be instrumental in differentiating peripheral from central vestibular disorders. Conventional teaching is that peripheral vestibular nystagmus is accentuated by removal of visual fixation. We sought to systematically test the hypothesis that, in some cases, vertical nystagmus due to central vestibular disorders may also be easier to identify when fixation is removed. Methods To identify patients with vertical nystagmus, we retrospectively reviewed clinical, MRI, and VNG data of consecutive patients undergoing VNG in our vestibular clinic over a 9-month period. We analyzed clinical features, bedside neuro-otological examination, MRI results, and VNG findings in fixation as well as those with fixation removed. Results Two hundred and fourteen charts were reviewed. Twenty-six patients had vertical nystagmus with fixation removed on VNG. Only three (11.5%) of these patients had vertical nystagmus apparent with fixation (and only two had nystagmus observed clearly at the bedside with the unaided eye). Thirteen (50%) of the patients had posterior fossa lesions on MRI and eight of the rest (30.8%) were diagnosed with central vestibular disorders. Of the 13 patients with MRI-confirmed lesions, 3 patients (23.1%) had no neurological signs or conventional bedside oculomotor signs; in these cases, vertical nystagmus without fixation was the only sign of a central lesion. Conclusions Our findings go against conventional teaching and show that removing fixation can uncover subtle vertical nystagmus due to central vestibular disease, particularly from focal or chronic lesions.

BackgroundDiagnosis of acute vestibular syndrome (AVS) with hearing loss is challenging because the leading vascular cause—AICA territory stroke—can appear benign on head impulse testing. We evaluated the diagnostic utility of various bedside oculomotor tests to discriminate imaging-positive and imaging-negative cases of AVS plus hearing loss.MethodWe reviewed 13 consecutive inpatients with AVS and acute unilateral hearing loss. We compared neurologic findings, bedside and video head impulse testing (bHIT, vHIT), and other vestibular signs (including nystagmus, skew deviation, and positional testing) between MRI+ and MRI– cases.ResultsFive of thirteen patients had a lateral pontine lesion (i.e., MRI+); eight did not (i.e., MRI–). Horizontal-canal head impulse test showed ipsilateral vestibular loss in all five MRI+ patients but only in three MRI– patients. The ipsilesional VOR gains of horizontal-canal vHIT were significantly lower in the MRI+ than the MRI– group (0.56 ± 0.11 vs. 0.87 ± 0.24, p = 0.03). All 5 MRI+ patients had horizontal spontaneous nystagmus beating away from the lesion (5/5). One patient (1/5) had direction-changing nystagmus with gaze. Two had skew deviation (2/5). Among the 8 MRI– patients, one (1/8) presented as unilateral vestibulopathy, four (4/8) had positional nystagmus and three (3/8) had isolated posterior canal hypofunction.ConclusionThe horizontal-canal head impulse test poorly discriminates central and peripheral lesions when hearing loss accompanies AVS. Paradoxically, a lateral pontine lesion usually mimics unilateral peripheral vestibulopathy. By contrast, patients with peripheral lesions usually present with positional nystagmus or isolated posterior canal impairment, risking misdiagnosis as central vestibulopathy.

ObjectiveTo study the long-term treatment outcome of vestibular paroxysmia (VP).Study designRetrospective study.SettingTertiary referral hospital.MethodsWe analyzed records of 29 consecutive patients who were diagnosed with VP and who were treated with VP-specific anticonvulsants for at least 3 months. Patients were followed for a minimum of 6 months. We recorded and assessed starting and target dosage of medications, time to achieve adequate therapeutic response, adverse effects, and the rates of short-term and long-term remission without medication.ResultsAll 29 patients were started on oxcarbazepine as first-line treatment, and 93.1% and 100% of patients reported good-to-excellent therapeutic response within 2 and 4 weeks, respectively. Three patients switched to other anticonvulsants at 3 months. At long-term follow-up (8–56 months), most (84.6%) oxcarbazepine-treated patients maintained good therapeutic response at doses between 300 and 600 mg/day. Eleven (37.9%) patients experienced complete remission without medication for more than 1 month, of which six (20.7%) had long-term remission off medication for more than 12 months. Nineteen (65.5%) patients had neurovascular compression (NVC) of vestibulocochlear nerve on MRI, but its presence or absence did not predict treatment response or remission.ConclusionLow-dose oxcarbazepine monotherapy for VP is effective over the long term and is generally well-tolerated. About 20% of patients with VP in our study had long-term remission off medication.

In longitudinal event data, a crude rate is a simple quantification of the event rate, defined as the number of events during an evaluation window, divided by the at-risk population size at the beginning or mid-time point of that window. The crude rate recently received revitalizing interest from medical researchers who aimed to improve measurement of misdiagnosis-related harms using administrative or billing data by tracking unexpected adverse events following a "benign" diagnosis. The simplicity of these measures makes them attractive for implementation and routine operational monitoring at hospital or health system level. However, relevant statistical inference procedures have not been systematically summarized. Moreover, it is unclear to what extent the temporal changes of the at-risk population size would bias analyses and affect important conclusions concerning misdiagnosis-related harms. In this article, we present statistical inference tools for using crude-rate based harm measures, as well as formulas and simulation results that quantify the deviation of such measures from those based on the more sophisticated Nelson-Aalen estimator. Moreover, we present results for a generalized multibin version of the crude rate, for which the usual crude rate is a single-bin special case. The generalized multibin crude rate is more straightforward to compute than the Nelson-Aalen estimator and can reduce potential biases of the single-bin crude rate. For studies that seek to use multibin measures, we provide simulations to guide the choice regarding number of bins. We further bolster these results using a worked example of stroke after "benign" dizziness from a large data set.

PurposeThis research examines how macroeconomic variables can precisely predict bull/bear stock markets in China and Taiwan.Design/methodology/approachThis paper adopts a two-state Markov switching model to characterize the bull and bear markets spanning from 1994 to 2019 and then conduct a bear stock market predictability test by running regressions between the filtered probabilities of bear markets and a series of macroeconomic variables in turn at different horizons of 1, 3, 6, 12 and 24 months.FindingsThis paper shows that inflation rates, changes in real exchange rates, and foreign currency reserve growth are key predictors of bear markets in China, while term spreads, unemployment rates and foreign reserve growth are major factors that can predict bear markets in Taiwan. Remarkably, industrial production growth does not have predictive power for bear markets, which may suggest emerging markets are driven by fund flows rather than real economic activities. Besides, the impact directions of foreign currency reserve growth are opposite, which may be due to different proportions of the financial accounts in their balance of payments.Practical implicationsIn practical respect, this paper provides market participants the usefulness, impact direction and implications of bear market predictors when building their market-timing strategies in China and Taiwan stock markets. The government institutions may also thereby make appropriate policies to prevent huge stock market downturns and serious drawbacks.Originality/valueIt highlights the “fund-driven market hypothesis” and “foreign currency reserve effects” that commonly dominate Taiwan and China stock markets since both are highly affected by international funds.

To verify the accuracy of automated nystagmus detection algorithms.Video-oculography (VOG) plots were analyzed from consecutive patients with dizziness presenting to a neurology clinic. Data were recorded for 30 s in upright position with fixation block. For automated nystagmus detection, slow-phase algorithm parameters included mean and median slow-phase velocity (SPV), and slow-phase duration ratio. Quick-phase algorithm parameters included saccadic difference and saccadic ratio. For verification, two independent blinded assessors reviewed VOG traces and videos and coded presence or absence of nystagmus. Assessor consensus was used as reference standard. Accuracy of slow-phase and quick-phase algorithm parameters were compared, and ROC analysis was performed.Among 524 analyzed VOG traces, 99 were verified as nystagmus present and 425 were verified as nystagmus absent. Prevalence of nystagmus in the sample population was 18.9%. In ROC analysis, areas under the curve of individual algorithm parameters were 0.791-0.896. With optimal thresholds for determining presence or absence of nystagmus, algorithm sensitivity (70.7-87.9%), specificity (71.8-84.0%), and negative predictive value (91.7-96.4%) were ideal, but positive predictive value (38.8-53.4%) was not ideal. Combining algorithm parameters using logistic regression models mildly improved detection accuracy.Both slow-phase and fast-phase algorithms were accurate for detecting nystagmus. Due to low positive predictive value, the utility of independent automated nystagmus detection systems is limited in clinical settings with low prevalence of nystagmus. Combining parameters using logistic regression models appears to improve detection accuracy, indicating that machine learning may potentially optimize the accuracy of future automated nystagmus detection systems.

Background and purpose Convergence of the eyes during head rotation increases the gain (eye velocity/head velocity) of the vestibulo-ocular reflex (VOR). We sought to know whether convergence would increase the VOR gain (mean + SD) in unilateral vestibular hypofunction (UVH). Methods Vestibulo-ocular reflex gain during ipsi- and contralesional horizontal head rotation at near (15 cm) and far (150 cm) targets was measured in 22 subjects with UVH and 12 healthy controls. Retinal slip was estimated (retinal slip index [RSI]) as the difference between ideal VOR gain (no retinal slip) and the actual VOR gain. Results Convergence did not significantly enhance VOR gain for ipsilesional rotation (mean difference, 0.04; 95% confidence interval [CI], -0.01 to 0.09), near viewing (0.77 ± 0.34) versus far viewing (0.72 ± 0.29), yet the VOR gain during contralesional rotation was greater for near viewing (1.20 ± 0.23) than for far viewing (0.97 ± 0.21; mean difference, 0.23; 95% CI, 0.13-0.32). In the 36% of subjects with recovery of their ipsilesional VOR gain, the vergence effect trended to recover (far VOR gain: 1.06 ± 0.17 vs near VOR gain 1.16 ± 0.21; mean difference, 0.10; 95% CI, -0.02 to 0.22). Ipsilesional head rotation induced greater retinal slip for near (RSI = 0.90 ± 0.34) targets than for far targets (RSI = 0.35 ± 0.29; mean difference, 0.56; 95% CI, 0.51-0.61). Discussion and conclusions The convergence-mediated VOR gain enhancement is preserved during contralesional but impaired during ipsilesional head rotation. Recovery of ipsilesional passive VOR gain does not equate to restored convergence enhancement, although it did increase ∼10%. These data suggest head motion viewing near targets will increase retinal slip, which warrants consideration as a gaze stability exercise for subjects with UVH.Video Abstract available for more insights from the authors (see Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A325).

Most prior studies of the subjective visual vertical (SVV) focus on inaccuracy of subjects' SVV responses with the head in an upright position. Here we investigated SVV imprecision during lateral head tilt in patients with chronic dizziness compared to healthy controls. Forty-five dizzy patients and 45 healthy controls underwent SVV testing wearing virtual reality (VR) goggles, sitting upright (0°) and during head tilt in the roll plane (± 30°). Ten trials were completed in each of three static head positions. The SVV inaccuracy and SVV imprecision were analyzed and compared between groups, along with systematic errors during head tilt, i.e., A-effect and E-effect (E-effect is a typical SVV response during head tilts of ± 30°). The SVV imprecision was found to be affected by head position (upright/right head tilt/left head tilt, p 0.001) and underlying dizziness (dizzy patients/healthy controls, p = 0.005). The SVV imprecision during left head tilt was greater in dizzy patients compared to healthy controls (p = 0.04). With right head tilt, there was a trend towards greater SVV imprecision in dizzy patients (p = 0.08). Dizzy patients were more likely to have bilateral (6.7%) or unilateral (22.2%) A-effect during lateral head tilt than healthy controls (bilateral (0%) or unilateral (6.7%) A-effect, p 0.01). Greater SVV imprecision in chronically dizzy patients during head tilts may be attributable to increased noise of vestibular sensory afferents or disturbances of multisensory integration. Our findings suggest that SVV imprecision may be a useful clinical parameter of underlying dizziness measurable with bedside SVV testing in VR.

This paper uses the ratio of 52‐week high to low prices to construct a self‐financing portfolio strategy, which buys stocks with a low range ratio and sells stocks with a high range ratio according to the behavioral perspective. The results indicate that the profits from this range strategy are substantial and outperform those of 52‐week high and conventional momentum strategies. Moreover, the incremental effect of the range strategy on 52‐week high momentum is significantly positive, while the 52‐week high strategy diminishes this strategy's profitability. Overall, the range measure is better than conventional measures at predicting future returns.

Identifying dangerous causes of dizziness is a challenging task for neurologists, as it requires interpretation of subtle bedside exam findings, which become even more subtle with time. Nystagmus can be instrumental in differentiating peripheral from central vestibular disorders. Conventional teaching is that peripheral vestibular nystagmus is accentuated by removal of visual fixation. We sought to systematically test the hypothesis that, in some cases, vertical nystagmus due to central vestibular disorders may also be easier to identify when fixation is removed.To identify patients with vertical nystagmus, we retrospectively reviewed clinical, MRI, and VNG data of consecutive patients undergoing VNG in our vestibular clinic over a 9-month period. We analyzed clinical features, bedside neuro-otological examination, MRI results, and VNG findings in fixation as well as those with fixation removed.Two hundred and fourteen charts were reviewed. Twenty-six patients had vertical nystagmus with fixation removed on VNG. Only three (11.5%) of these patients had vertical nystagmus apparent with fixation (and only two had nystagmus observed clearly at the bedside with the unaided eye). Thirteen (50%) of the patients had posterior fossa lesions on MRI and eight of the rest (30.8%) were diagnosed with central vestibular disorders. Of the 13 patients with MRI-confirmed lesions, 3 patients (23.1%) had no neurological signs or conventional bedside oculomotor signs; in these cases, vertical nystagmus without fixation was the only sign of a central lesion.Our findings go against conventional teaching and show that removing fixation can uncover subtle vertical nystagmus due to central vestibular disease, particularly from focal or chronic lesions.

Objectives Isolated dizziness is a challenging stroke presentation in the emergency department, but little is known about this problem in other clinical settings. We sought to compare stroke hospitalizations after treat-and-release clinic visits for purportedly “benign dizziness” between general and specialty care settings. Methods This was a population-based retrospective cohort study from a national database. We included clinic patients with a first incident treat-and-release visit diagnosis of non-specific dizziness/vertigo or a peripheral vestibular disorder (ICD-9-CM 780.4 or 386.x [not 386.2]). We compared general care (internal medicine, family medicine) vs. specialty care (neurology, otolaryngology) providers. We used propensity scores to control for baseline stroke risk differences unrelated to dizziness diagnosis. We measured excess (observed>expected) stroke hospitalizations in the first 30 d (i.e., missed strokes associated with an adverse event). Results We analyzed 144,355 patients discharged with “benign dizziness” (n=117,117 diagnosed in general care; n=27,238 in specialty care). After propensity score matching, patients in both groups were at higher risk of stroke in the first 30 d (rate difference per 10,000 treat-and-release visits for “benign dizziness” 24.9 [95% CI 18.6–31.2] in general care and 10.6 [95% CI 6.3–14.9] in specialty care). Short-term stroke risk was higher in general care than specialty care (relative risk, RR 2.2, 95% CI 1.5–3.2) while the long-term risk was not significantly different (RR 1.3, 95% CI 0.9–1.9), indicating higher misdiagnosis-related harms among dizzy patients who initially presented to generalists after adequate propensity matching. Conclusions Missed stroke-related harms in general care were roughly twice that in specialty care. Solutions are needed to address this care gap.

This study aims to examine how the social networks of top management affect the recovery of their companies when facing a financial crisis. We mainly use the logit and Cox regression models to investigate whether social networks help overcome the financial distress and shorten the crisis duration. The empirical findings suggest that companies with characteristics of low degree centrality of the chairman’s bank networks and high closeness centrality of the general manager’s general networks and bank networks are more likely to overcome financial distress and get back to normal status. Furthermore, for companies with characteristics of low degree centrality of the chairman’s personal general networks, low closeness centrality of the financial executive’s personal general networks, and high degree centrality of the financial executive’s personal bank networks, it was easier to shorten the crisis duration. The practical implication is that companies need to prioritize quality over quantity in order to survive or shorten the crisis. All company top managers should not look only at the size of the company but consider how the social network is configured.

A 65-year-old woman with right-sided Meniere disease experienced one of her usual and frequent acute vertigo attacks during eye movement recording (video 1). The attacks were associated with right-sided tinnitus, hearing loss, and vomiting. She initially demonstrated right-beating nystagmus, but after 2 minutes, the nystagmus gradually reversed and became left-beating (video 1). During the reversal, downbeat nystagmus was present temporarily. The left-beating nystagmus then persisted for 2 hours.

The pathophysiology of acute, vertical spontaneous eye movements following pontine hemorrhage is not well understood. Here, we present and discuss the video-oculography findings of a patient with acute pontine hemorrhage who developed vertical pendular oscillation and ocular bobbing while comatose. The amplitudes, peak velocities, frequency distribution, and phase planes (velocity versus position) of the eye movements were analyzed. The vertical pendular oscillation was rhythmic with a peak frequency of 1.7 Hz, but amplitudes (mean 1.9°, range 0.2-8.2°) and peak velocities (mean 20.6°/s; range 5.9-60.6°/sec) fluctuated. Overall, their peak velocities were asymmetric, faster with downward than upward. Higher peak velocities were seen with larger amplitudes (downward phase r = 0.95, p < 0.001; upward phase r = 0.91, p < 0.001) and with movements beginning at eye positions lower in the orbit (downward phase r = - 0.64, p < 0.001; upward phase r = - 0.86, p < 0.001). Interspersed were typical ocular bobbing waveforms with a fast (peak velocity 128.8°/s), large-amplitude (17.5°) downward movement, sometimes followed by a flat interphase interval (0.5 s) when the eye was nearly stationary, and then a slow return to mid-position with a decaying velocity waveform. To account for the presence and co-existence of pendular oscillations and bobbing, we present and discuss three hypothetical models, not necessarily mutually exclusive: (1) oscillations originating in the inferior olives due to disruption of the central tegmental tract(s); (2) unstable neural integrator function due to pontine cell group damage involving neurons involved in gaze-holding; (3) low-frequency saccadic intrusions following omnipause neuron damage.

Background Amongst the most challenging diagnostic dilemmas managing patients with vestibular symptoms (i.e. vertigo, nausea, imbalance) is differentiating dangerous central vestibular disorders from benign causes. Migraine has long been recognized as one of the most common causes of vestibular symptoms, but the clinical hallmarks of vestibular migraine are notoriously inconsistent and thus the diagnosis is difficult to confirm. Here we conducted a prospective study investigating the sensitivity and specificity of combining standard vestibular and neurological examinations to determine how well central vestibular disorders (CVD) were distinguishable from vestibular migraine (VM). Method Twenty-seven symptomatic patients diagnosed with CVD and 36 symptomatic patients with VM underwent brain imaging and clinical assessments including; 1) SVV bucket test, 2) ABCD2, 3) headache/vertigo history, 4) presence of focal neurological signs, 5) nystagmus, and 6) clinical head impulse testing. Results Mean absolute SVV deviations measured by bucket testing in CVD and VM were 4.8 ± 4.1° and 0.7 ± 1.0°, respectively. The abnormal rate of SVV deviations (> 2.3°) in CVD was significantly higher than VM (p

Objective: The objective is to investigate the test-retest reliability of subjective visual vertical (SVV) in the upright position and with lateral head tilts through a computerized SVV measuring system using virtual reality (VR) goggles. Materials and Methods: Thirty healthy controls underwent SVV test in upright position, with the head tilted to the right 30°, and with the head tilted to the left 30°. Subjects wore SVV VR goggles, which contained a gyroscope for monitoring the angle of head tilt. Each subject completed 10 adjustments in each head position. The mean value of SVV deviations and SVV imprecision (the intra-individual variability of SVV deviations from the 10 adjustments) were recorded and compared across different head positions. The participants then repeated the same SVV protocol at least 1 week later. The test-retest reliability of SVV deviation and SVV imprecision were analyzed. Results: The SVV deviation (mean ± standard deviation) was 0.22° ± 1.56° in upright position, −9.64° ± 5.91° in right head tilt, and 7.20° ± 6.36° in left head tilt. The test-retest reliability of SVV deviation was excellent in upright position (intra-class correlation coefficient [ICC] = 0.77, P < 0.001), right head tilt (ICC = 0.83, P < 0.001) and left head tilt (ICC = 0.84, P < 0.001). The SVV values from the 10 adjustments made during right and left head tilts were less precise than when measured at upright (P < 0.001). The test-retest reliability of SVV imprecision was poor at upright (ICC = 0.21, P = 0.26) but fair-to-good in right head tilt (ICC = 0.72, P < 0.001) and left head tilt (ICC = 0.44, P = 0.04). Conclusion: The test-retest reliability of SVV deviation during lateral head tilts via VR goggles is excellent, which supports further research into the diagnostic value of head-tilt SVV in various vestibular disorders. In addition, the degree of SVV imprecision during head tilt has fair-to-good test-retest reliability, which suggests SVV imprecision may have clinical applicability.

When evaluating patients with dizziness, knowledge of basic vestibular physiology and bedside examination techniques is critical to reach the correct diagnosis. During the vestibular examination, the clinician should look for signs of static and dynamic vestibular imbalance in the semicircular canal and otolith function. Here we outline the key components of the clinical vestibular examination considering recent technical advances in video-oculography and mobile devices such as tablet computers. Using these portable technologies, the vestibular examination can be quantified at the bedside to improve diagnostic accuracy and clinical management. In this process, a careful and thorough clinical evaluation of all subtypes of eye movements, stance, and gait is critical because of the close anatomic and physiologic connections among vestibular, postural, and ocular motor functions.

Table S1. Diagnostic criteria of vestibular migraine [7]. (DOCX 13 kb)

Figure S1. Bucket test for examining subjective visual vertical [27]. (DOCX 969 kb)

Table S2. ABCD2 scoring system [28]. (DOCX 13 kb)

Table S3. Clinical features of the patients with VM. (DOCX 24 kb)

Patients with vestibular migraine (VM) often report dizziness with changes in the head or body position. Such symptoms raise the possibility of dysfunction in neural mechanisms underlying spatial orientation in these patients. Here we addressed this issue by investigating the effect of static head tilts on errors of upright perception in a group of 27 VM patients in comparison with a group of 27 healthy controls. Perception of upright was measured in a dark room using a subjective visual vertical (SVV) paradigm at three head tilt positions (upright, ±20°). VM patients were also surveyed about the quality of their dizziness and spatial symptoms during daily activities. In the upright head position, SVV errors were within the normal range for VM patients and healthy controls (within 2° from true vertical). During the static head tilts of 20° to the right, VM patients showed larger SVV errors consistent with overestimation of the tilt magnitude (i.e., as if they felt further tilted toward the right side) (VM: −3.21° ± 0.93 vs. Control: 0.52° ± 0.70; p = 0.002). During the head tilt to the left, SVV errors in VM patients did not differ significantly from controls (VM: 0.77° ± 1.05 vs. Control: −0.04° ± 0.68; p = 0.52). There was no significant difference in SVV precision between the VM patients and healthy controls at any head tilt position. Consistent with the direction of the SVV errors in VM patients, they largely reported spatial symptoms toward the right side. These findings suggest an abnormal sensory integration for spatial orientation in vestibular migraine, related to daily dizziness in these patients.

A nationwide, population-based, retrospective cohort study.To investigate whether benign paroxysmal positional vertigo (BPPV) is associated with an increased risk of fracture.Benign paroxysmal positional vertigo is a brief rotational vertigo induced by head position change that may increase the risk of falls and, therefore, fracture.Data from the Taiwan National Health Insurance Research Database were used for this study. We selected a case cohort comprising 3796 patients aged over 20 years who were newly diagnosed with BPPV between 2000 and 2006. In addition, we randomly selected a control cohort of 15 184 individuals without BPPV. Patients with BPPV were matched to individuals in the control group according to sex, age, and index year. A Cox proportional hazard regression was performed to compute the hazard ratio of fracture, after adjusting for demographic characteristics and comorbidities.The prevalence of comorbidities was higher among patients with BPPV. After adjusting for age, sex, and comorbidities, patients with BPPV exhibited a 1.14-fold (95% confidence interval [CI]: 1.04, 1.25; P.01) higher risk of fracture than those without BPPV. Trunk fracture (vertebra, rib, and pelvis) was the fracture type with the highest adjusted hazard ratio (1.24; 95% CI: 1.06, 1.45; P.01) in patients with BPPV relative to those without BPPV. An analysis stratified according to demographic factors revealed that men with BPPV exhibited a 1.43-fold (95% CI: 1.22, 1.66; P.001) higher risk of fracture. Patients with BPPV aged over 65 years exhibited a significantly higher risk of fracture (adjusted hazard ratio = 1.17; 95% CI: 1.03, 1.33; P.05) than did those without BPPV.Patients with BPPV exhibited a higher risk of fracture than did those without BPPV.Prognosis, level 2b.

This research introduces the context-dependent total-factor energy efficiency (CD-TFEE) and applies it to find the frontier levels of China’s regions in 2014. In this empirical example, CD-TFEE generates different results from the context-dependent data envelopment analysis (CD-DEA) proposed by Seiford and Zhu (Omega, 31(5):397–408, 2003). China’s regions in 2014 can be categorized into five levels of TFEE frontiers, and almost two-thirds of Chinese regions can target the domestic benchmarks to improve their energy efficiency.

This paper investigates the non-monotonic and non-linear effect of diversification on mutual fund performance. We apply a frontier-based efficiency measure, the stochastic frontier approach, to estimate fund efficiency and the benefit of diversification. The empirical results indicate that concentration strategy may not be appropriate for fund managers, and the benefit of diversification disappears or negatively affects performance when a fund holds too large a number of different stocks. Moreover, this paper examines whether market conditions moderate the relation between diversification and fund performance. The result shows that the benefit of diversification increases within low market return, high market volatility, and financial crisis, implying that the number of stocks needed to achieve a well-diversified portfolio increases under such market conditions.

This study examines the Granger causality between Taiwan's aggregate and disaggregate energy consumption and trade variables, including total imports (IM), total exports (EX), total energy consumption (ENERGY), oil and petroleum products consumption (OIL), coal and coal products consumption (COAL), natural gas consumption (GAS), export value of the industrial sector (EX_I), export value of heavy-chemical industrial products (EX_HI), and export value of non-heavy-chemical industrial products (EX_NHI) with monthly data during 1998–2009. Via applying Hsiao's version of the Granger causality method, the results find causality running from ENERGY to IM, EX, EX_I, and EX_HI. The impulse-response simulations show that the above relations have positive responses at the initial period. OIL Granger causes all trade variables. The impulse directions to IM and EX_NHI are negative, whereas others are positive. On the other hand, COAL responds to impulses in all trade variables. The impulse-response simulations show that these relations have positive responses at the initial period except for causality running from EX_HI and EX_NHI to COAL. GAS positively responds to impulses in EX, EX_I, and EX_HI at the initial period. The bidirectional Granger causality between pairs of variables (such as GAS and EX_NHI as well as GAS and EX_HI) is found.

This study investigates the sources of bank productivity growth in China over the period 2002–2009. In order to perform this research, we propose an advanced index – input slack-based productivity index (ISP) – a model that disaggregates total factor productivity growth into each input productivity change. Funds, capital, and employees are chosen as the inputs, whereas loans and other earning assets are outputs in this study. Our results show that technological gains transcend the efficiency regressions and result in total factor productivity growth. More specifically, technical progress in capital productivity reveals the dominant force behind the total factor technical change and productivity improvement. In addition, this paper uses these disaggregation terms to find out the competitive advantages and disadvantages of input usages for each Chinese bank. These findings indicate that the ISP index provides more insights than traditional total factor productivity indices.

This study investigates the role of risk in determining the cost efficiency of international banks in eight emerging Asian countries. Researchers of this paper consider three distinct risk aspects under a total of eight risk measures: credit risk, operational risk, and market risk. We apply a heteroscedastic stochastic frontier model to estimate bank cost efficiency in our analysis. Additionally, this study analyzes the marginal effects of all risk measures on the inefficiency effect in order to explore a more detailed relationship between risks and efficiency. The empirical results indicate that the risk measures represent significant effects on both the level and variability of bank efficiency. We also find that these effects vary across countries and over time.

This article introduces total-factor energy productivity change index (TFEPI) based on the concept of total-factor energy efficiency and the Luenberger productivity index to evaluate the energy productivity change of regions in China with a total-factor framework. Moreover, the TFEPI can be decomposed into change in energy efficiency and shift in the energy use technology. According to the computation results, China’s energy productivity was decreasing by 1.4% per year during 2000–2004. The average total-factor energy efficiency improves about 0.6% per year, while total-factor energy technical change declines progressively 2% annually. The factors affecting TFEPI are also examined: (1) The east area has a higher TFEPI than the central and west area; (2) increasing the development status and electricity share of energy consumption will improve the region’s TFEPI performance, while increasing the proportion of GDP generated by the secondary industry deteriorates TFEPI of a region.

Importance It is important to know whether recovery of the vestibuloocular reflex (VOR) as measured by the video head impulse test (vHIT) is associated with the recovery of dynamic balance. It is also critical to know how much change in VOR gain is clinically relevant for establishing the recovery of dynamic balance. Objectives To investigate the association between improved VOR gain as measured by the vHIT and improved dynamic balance (reduced fall risk) as measured by the dynamic gait index (DGI) and to calculate the minimal clinically important difference of VOR gain. Design, Setting, and Participants This retrospective case series study was performed at a tertiary referral center at the Johns Hopkins University School of Medicine. Thirty-eight consecutive patients with subacute or chronic dizziness from January 1, 2014, through May 31, 2017, who visited the vestibular physical therapy clinic were included in the study. Interventions Each patient was evaluated with room light and video-infrared oculomotor examination, vHIT, and balance testing before and after vestibular physical therapy. Main Outcomes and Measures Gain of the lesioned VOR and score on the DGI. Results Among the 38 patients (25 women [66%]; mean [SD] age, 65 [14] years), the mean (SD) initial lesioned VOR gain was 0.66 (0.23) and initial DGI score was 16 (3). No correlation was found between initial VOR gain and initial DGI score (r = −0.04; 95% CI, −0.35 to 0.28). At follow-up, 15 patients (39%) had an improved VOR gain and 30 (79%) had an improved DGI score, which was correlated (r = 0.49; 95% CI, 0.20-0.69). In those 15 patients with improved VOR gain, 14 (93%) had improvement of DGI score. In the 23 patients without improvement of VOR gain, 16 (70%) still showed improvement in their DGI score. When using VOR gain to estimate improvement of DGI, the minimal clinically important difference of VOR gain was −0.06. Conclusions and Relevance The change of VOR gain in the vHIT was moderately associated with the change of DGI score. Improved VOR gain was associated with a high probability of improved dynamic balance. However, in most of the patients whose VOR gains did not improve, balance improvement occurred putatively through sensory reweighting strategies.

This article examines the profitability of trading rules based on the smoothed probability of Markov-switching models and executes two models in Taiwan's case. The results present that both proposed models can earn excess returns over the buy-and-hold strategy and support that both can be used to trade. However, the univariate Markov-switching model, which only uses daily returns series does not successfully capture the trend in the stock market, especially during a bull market. This implies that high-frequency returns series contain lots of noises. In order to overcome this problem, the Markov-switching vector autoregression model that combines a leading indicator and returns is performed in this study. The results indicate a better trading pattern. We conclude that the leading indicator chosen from open interest in the future market increases useful information and reduces noises to improve model estimation, which can well identify the position of bull and bear markets.

This article follows a three-stage data envelopment analysis (DEA) approach proposed by Fried et al. (2002) to decompose mutual fund underperformance, in order to obtain pure managerial performance. In the first stage, DEA is used to compute each fund's performance. In the second stage, a stochastic frontier regression decomposes fund underperformance into characteristics (including fund and management attributes), managerial inefficiency, and statistical noise. In the third stage, DEA with slack-adjusted data is used to find out the pure performance. It is found that a fund's performance significantly increases with its size, previous performance, manager's tenure and education, while it decreases with the age of the fund and number of managed funds.

Along with rapid economic growth over the past decades, China is now facing a dual challenge of improving both energy and emission efficiencies. To trace the trends of energy and pollution efficiencies, this chapter proposes two indices: ecological total-factor energy efficiency (ETFEE), and ecological total-factor pollution efficiency (ETFPE) based on the Russell-based directional distance function. Using regional data from 2001 to 2011, the result shows that the ETFPE is always lower than the ETFEE for any area in China in the same year, indicating that the country is facing a more serious situation with respect to pollution control compared to energy saving.

This chapter demonstrates how to use different types of DEA models to compute the total-factor energy efficiency (TFEE) scores, including CCR, Russell, QFI, SBM, DF, and DDF models. The TFEE is a disaggregate input efficiency index. Moreover, the TFEE framework which uses cross-section data can be extended to the total-factor energy productivity (TFEP) growth index by following Malmquist, Leunberger, and Malmquist-Leunberger models which use panel data. Finally, the regional data of Chinese regions during 2010–2011 with inputs and desirable as well as undesirable outputs are used for illustrating the computation of TFEE and TFEP scores.

The reported prevalence of cavum septum pellucidum (CSP) and cavum Vergae (CV) in brain computed tomography (CT) is 5.5% in Great Britain and 1.24% in China but unknown in Taiwan. Moreover, CSP and/or CV has generally been thought to decrease as age progresses, but the evidence of actual prevalence at different age levels is still limited in the literature.A total of 19,031 patients with brain CT at a regional hospital in northern Taiwan from July 2008 to August 2010 were included in this study. Their radiological official reports were retrospectively reviewed to check for CSP and/or CV. An X2 test was used for statistical analysis (α = .05).The prevalence of CSP and/or CV in all brain CT was 0.93% (n = 177), which was lower. than that in the Chinese and British studies. Among them, 2.8% (n = 5) had only CSP, 1.7% (n = 3) had only CV, and 95.5% (n = 169) had coexistent CSP and CV. There is a significant difference in prevalence between the age groups (p = .009), and the prevalence is the highest in the group aged 20-29 years (1.56%) and lowest in the group aged above 80. After age 20-29, the prevalence tends to decrease with increasing age.This is not only the first study of CSP and CV in the Taiwanese population but the study population is also larger than those in the literature. The prevalence was found to approximately decrease as age progresses, but would reach the peak in the young adult group rather than the children or adolescent group.

To investigate whether patients with vestibular migraine (VM) are more susceptible to carsickness than patients with non-vestibular migraine (NVM) or Meniere's disease (MD).Consecutive patients with a diagnosis of definite VM, probable VM, NVM, or MD at our Headache and Dizziness clinics were interviewed using the same three questions to investigate the history of carsickness. The patients who had experienced carsickness in their lifetime and those who had still experienced carsickness in the past ten years were identified. The rates of carsickness were compared between groups.78.4% of the VM patients had experienced carsickness in their lifetime, which was significantly higher than the patients with NVM (43.6%) and MD (18.2%). Both the lifetime rate of carsickness and the rate in the past ten years were highest in the patients with definite VM, followed by probable VM, NVM, and MD (p less than 0.05, chi-square test). The odds ratio of lifetime carsickness for VM versus MD was high (8.7).Both patients with definite VM and probable VM were more susceptible to carsickness than the patients with NVM or MD. This reinforces the theory of vestibular hypersensitivity in VM. We suggest that a past history of carsickness may help in the diagnosis of VM, and especially in distinguishing VM from MD.

Vestibular paroxysmia is defined as paroxysmal, brief, and carbamazepine-responsive vertigo. Although neurovascular cross-compression (NVCC) of the vestibulocochlear nerve is believed to be the cause of vestibular paroxysmia, the mechanism remains controversial. Herein, we describe the case of a man with NVCC who presented with paroxysmal vertigo associated with paroxysmal pulsatile tinnitus.A 68-year-old man presented with paroxysmal vertigo for one month. Paroxysmal pulsatile tinnitus in the right ear occurred simultaneously with the vertigo. Magnetic resonance imaging demonstrated that the right anterior inferior cerebellar artery was compressing the right vestibulocochlear nerve. The vertigo and tinnitus completely disappeared within one week after treatment with carbamazepine.The pulsatile nature of the patient's tinnitus implied that the auditory nerve was being compressed by a pulsating artery and was found to consolidate the causal relationship between NVCC and vestibular paroxysmia.

A 68-year-old man developed vertigo with a lateral medullary syndrome (figure). Right-beating nystagmus, seen under Frenzel lenses, reversed when a vibrator (60 Hz) was applied on either sternocleidomastoid muscle or either mastoid. When the vibrator was turned off, the nystagmus returned to right-beating (video on the Neurology ® Web site at [www.neurology.org][1]). The authors thank Prof. David Zee for critically reviewing the manuscript. [1]: http://www.neurology.org

A 60-yr-old man presented with chronic vestibulopathy induced by Ramsay Hunt syndrome for 1 yr. Prolonged dizziness and postural imbalance affected his quality-of-life. He was treated using a 2-mo protocol of customized vestibular rehabilitation therapy consisting of 16 treatment sessions in a rehabilitation clinic and daily home exercises. Significant improvements in the subjective perception of dizziness and objective balance function were found. The results suggest that vestibular rehabilitation therapy may be an effective therapeutic method for chronic vestibulopathy of Ramsay Hunt syndrome.

We report a case of a tiny infarct on the left dorsolateral pons in a 50-year-old man who presented with prolonged and isolated vertigo. The clinical features mimic vestibular neuritis and can easily lead to misdiagnosis. Selective involvement of the left superior vestibular nucleus might explain the resemblance to acute peripheral vestibulopathy.

Since the outbreak of novel influenza A (H1N1) in 2009, various neurological complications have been cited. We described a male patient with H1N1-associated encephalopathy/encephalitis presenting with severe neurological symptoms and signs. Residual neurological sequelae were dominant. This is the first report of extensive cortical-subcortical necroses over the bilateral frontal-parietal areas based on an MRI study.

We describe a patient who presented with unilateral paresthesia after acute isolated infarct of the splenium.A 74-year-old woman presented with acute onset of right sided numbness and tingling. MR imaging of the brain showed hypointensity on T1-weighted images and on apparent diffusion coefficient maps, and hyperintensity on T2-weighted and on diffusion-weighted images in the splenium, suggestive of acute infarction. MR angiography showed narrowing of left posterior cerebral artery with decreased branches. On detailed high cortical function assessment, she did not have frontal lobe dysfunction, alien hand syndrome, apraxia, optic ataxia, cortical sensation dysfunction, alexia, agraphia, visual field defect, nor color agnosia.Infarcts of the splenium are not common. Splenial lesion may be associated with altered mental status, ataxia, recent seizure, hemispheric disconnection, and dysarthria. The presentation of isolated unilateral paresthesia makes the patient different from those previously described. The paresthesia could be caused by selective lacunar infarcts in the diencephalic and mesencephalic regions or could be caused by the diaschisis in the parietal cortex. Single photon emission CT may be indicated to provide further information of central nervous system dysfunction in splenial lesion.