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BackgroundWeak nystagmus with fixation removed can be seen both in normal individuals and in recovery from a unilateral vestibular insult, thus its clinical significance is unclear in patients with dizziness. We thus sought to compare features of nystagmus at various stages following unilateral vestibular loss (UVL).MethodsWe enrolled thirty consecutive patients after acute UVL with impaired vestibulo-ocular reflex (VOR) gain. The patients were allocated into three groups according to time from onset of symptoms: acute (1–7 days), subacute (8–30 days), and chronic (>30 days). Patients underwent video-oculography (with and without fixation) and video head impulse testing (vHIT) to determine VOR gain. We examined the relationships amongst SPV, VOR gain, and time from symptom onset across groups.ResultsThere were 11, 10, and 9 patients in the acute, subacute, and chronic stages of UVL, respectively. With visual fixation, only 8 patients (26.7%) demonstrated nystagmus, all from the acute group. With fixation removed, 26 patients (86.7%) exhibited spontaneous nystagmus, including 90.9%, 90%, and 77.8% of the patients from the acute, subacute, and chronic groups, respectively. Horizontal nystagmus was paralytic (i.e., fast phase contralesional) in 25 (96.7%) cases. Horizontal SPV was negatively correlated with logarithm of time from onset to examination (r = −0.48, p = 0.007) and weakly negatively correlated with ipsilesional VOR gain (r = −0.325, p = 0.08).ConclusionIn the subacute or chronic stages of UVL, paralytic nystagmus with fixation removed persisted at a low intensity. Therefore, weak nystagmus in the dark may have diagnostic value in chronic dizziness.

Summary: Does the circadian clock keep running under such hypothermic states as daily torpor and hibernation? This fundamental question has been a research subject for decades but has remained unsettled. We addressed this subject by monitoring the circadian rhythm of clock gene transcription and intracellular Ca2+ in the neurons of the suprachiasmatic nucleus (SCN), master circadian clock, in vitro under a cold environment. We discovered that the transcriptional and Ca2+ rhythms are maintained at 22°C–28°C, but suspended at 15°C, accompanied by a large Ca2+ increase. Rewarming instantly resets the Ca2+ rhythms, while transcriptional rhythms reach a stable phase after the transient state and recover their phase relationship with the Ca2+ rhythm. We conclude that SCN neurons remain functional under moderate hypothermia but stop ticking in deep hypothermia and that the rhythms reset after rewarming. These data also indicate that stable Ca2+ oscillation precedes clock gene transcriptional rhythms in SCN neurons.

Abstract Biological tissues and their networks frequently change dynamically across large volumes. Understanding network operations requires monitoring their activities in three dimensions (3D) with single-cell resolution. Several researchers have proposed various volumetric imaging technologies. However, most technologies require large-scale and complicated optical setups, as well as deep expertise for microscopic technologies, resulting in a high threshold for biologists. In this study, we propose an easy-to-use light-needle creating device for conventional two-photon microscopy systems. By only installing the device in one position for a filter cube that conventional fluorescent microscopes have, single scanning of the excitation laser light beam excited fluorophores throughout over 200 μm thickness specimens simultaneously. Furthermore, the developed microscopy system successfully demonstrated single-scan visualization of the 3D structure of transparent YFP-expressing brain slices. Finally, in acute mouse cortical slices with a thickness of approximately 250 μm, we detected calcium activities with 7.5 Hz temporal resolution in the neuronal population.

Abstract Sophora davidii is an important plant resource in the karst region of Southwest China, but S. davidii plant-height mutants are rarely reported. Therefore, we performed phenotypic, anatomic structural, transcriptomic and metabolomic analyses to study the mechanisms responsible for S. davidii plant-height mutants. Phenotypic and anatomical observations showed that compared to the wild type, the dwarf mutant displayed a significant decrease in plant height, while the tall mutant displayed a significant increase in plant height. The dwarf mutant cells were smaller and more densely arranged, while those of the wild type and the tall mutant were larger and loosely arranged. Transcriptomic analysis revealed that differentially expressed genes (DEGs) involved in cell wall biosynthesis, expansion, phytohormone biosynthesis, signal transduction pathways, flavonoid biosynthesis and phenylpropanoid biosynthesis were significantly enriched in the S. davidii plant-height mutants. Metabolomic analysis revealed 57 significantly differential metabolites screened from both the dwarf and tall mutants. A total of 8 significantly different flavonoid compounds were annotated to LIPID MAPS, and three metabolites (chlorogenic acid, kaempferol and scopoletin) were involved in phenylpropanoid biosynthesis and flavonoid biosynthesis. These results shed light on the molecular mechanisms of plant height in S. davidii mutants and provide insight for further molecular breeding programs.

IntroductionA lack of soil phosphorus (P) is a principal factor restricting the normal growth of Lotus corniculatus in the karst area of Guizhou Province, China, but the response mechanism of L. corniculatus under low-phosphorus stress remains unclear.MethodsTherefore, we treated two selected L. corniculatus lines (low-P-intolerant line 08518 and low-P-tolerant line 01549) from 13 L. corniculatus lines with normal phosphorus (0.5 mmol/L KH2PO4, NP) and low phosphorus (0.005 mmol/L KH2PO4, LP) concentrations to study changes in morphological, physiological and transcriptome data under low-phosphorus stress.ResultsThe low-P-tolerant line 01549 exhibited better performance under low-phosphorus stress. Compared with the NP treatment, all root morphological indicators of the low-P-tolerant line 01549 increased, and those of the low-P-intolerant line 08518 decreased under low-P stress. Compared with the NP treatment, acid phosphatase (ACP), catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) activities, and the malondialdehyde (MDA), soluble sugar (SS), soluble protein (SP) and proline (Pro) contents of the two L. corniculatus lines increased under low-P stress. A transcriptome analysis of L. corniculatus showed that a total of 656 and 2243 differentially expressed genes (DEGs) were identified in line 01549 and line 08518, respectively. Meanwhile, the main pathways, such as carbohydrate metabolism, acid phosphatases, phosphate transporters and biosynthesis of secondary metabolites, as well as related genes were also screened by performing a KEGG enrichment analysis.DiscussionThe findings provide an essential point of reference for studying the physiological and molecular mechanism of the response to low-P stress in L. corniculatus.

Super-resolution in two-photon excitation (2PE) microscopy offers new approaches for visualizing the deep inside the brain functions at the nanoscale. In this study, we developed a novel 2PE stimulated-emission-depletion (STED) microscope with all-synchronized picosecond pulse light sources and time-gated fluorescence detection, namely, all-pulsed 2PE-gSTED microscopy. The implementation of time-gating is critical to excluding undesirable signals derived from brain tissues. Even in a case using subnanosecond pulses for STED, the impact of time-gating was not negligible; the spatial resolution in the image of the brain tissue was improved by approximately 1.4 times compared with non time-gated image. This finding demonstrates that time-gating is more useful than previously thought for improving spatial resolution in brain tissue imaging. This microscopy will facilitate deeper super-resolution observation of the fine structure of neuronal dendritic spines and the intracellular dynamics in brain tissue.

Super-resolution in two-photon excitation (2PE) microscopy offers new approaches for visualizing the deep inside the brain functions at the nanoscale. In this study, we developed a novel 2PE stimulated-emission-depletion (STED) microscope with all-synchronized picosecond pulse light sources and time-gated fluorescence detection, namely, all-pulsed 2PE-gSTED microscopy. The implementation of time-gating is critical to excluding undesirable signals derived from brain tissues. Even in a case using subnanosecond pulses for STED, the impact of time-gating was not negligible; the spatial resolution in the image of the brain tissue was improved by approximately 1.4 times compared with non time-gated image. This finding demonstrates that time-gating is more useful than previously thought for improving spatial resolution in brain tissue imaging. This microscopy will facilitate deeper super-resolution observation of the fine structure of neuronal dendritic spines and the intracellular dynamics in brain tissue.

This research examines whether Google search volume index (GSVI), a proxy of investor attention, can predict the excess returns and abnormal trading volumes of TPEx 50 index constituents. It also explores the motive underlying GSVI based on positive or negative shocks to stock prices. The empirical data include 48 companies from TPEx 50 index constituents and cover a period from 1 September 2016 to 31 August 2019. The empirical results present that (1) lagged GSVI negatively affects current excess returns, perhaps due to the characteristics of TPEx, in which there are a higher proportion of retail investors, smaller listed companies, and a higher information asymmetry problem. (2) Lagged GSVI can positively affect abnormal current trading volumes. (3) If GSVI is driven by positive shocks, then it can predict excess returns and abnormal trading volumes positively.

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.

Nitrogen is an important nutrient for plant growth and development. Soil microorganisms have been used to curb the imbalance between the limited content of natural environmental nitrogen and the pollution caused by increasing nitrogen fertilizer use in ecologically fragile areas. Bacillus amyloliquefaciens GB03 has been shown to confer growth promotion and abiotic stress tolerance in Arabidopsis thaliana. This study provided a new insight into the role of the plant growth-promoting rhizobacterium B. amyloliquefaciens GB03 as an initiator of defense against nitrogen deficiency in non-leguminous grass tall fescue (Festuca arundinacea). Two-week-old seedlings of tall fescue were grown with or without GB03 for 4 weeks under total nitrogen (3.75 mM NO3-) or low nitrogen (0.25 mM NO3-) treatment. Growth parameters, chlorophyll content, endogenous total nitrogen, total phosphorus content, and phytohormone content, including those of auxin indole-3-acetic acid, cytokinin, gibberellic acid, and abscisic acid, were determined at the time of harvest. Tall fescue grown in GB03-inoculated soil was more robust than the non-inoculated controls with respect to plant height, root length, plant biomass, chlorophyll concentration, and nutrient (total nitrogen and total phosphorus) contents under total nitrogen treatment. GB03 increased indole acetic acid content by 24.7%, whereas decreased cytokinin and abscisic acid contents by 28.4% and 26.9%, respectively, under a total nitrogen level. Remarkably, GB03 increased indole acetic acid content by more than 80% and inhibited abscisic acid production by nearly 70% under a low nitrogen level. These results showed, for the first time, that GB03 played a crucial role in mediating NO3–dependent regulation of tall fescue growth and development, especially revealing the mechanism of soil bacteria improve resistance to nitrogen deficiency stress in non-nitrogen-fixing species.

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.

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.

Global warming has far-reaching effects on plant growth and development. As a warm-season forage grass, Paspalum wettsteinii is highly adaptable to high temperatures. However, the response mechanism of P. wettsteinii under high-temperature stress is still unclear. Therefore, we investigated the physiological indicators, transcriptome and metabolome of P. wettsteinii under different heat stress treatments. Plant height, the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), and the contents of soluble sugar, proline, chlorophyll a, and chlorophyll b increased and then decreased, while the malondialdehyde (MDA) content decreased and then increased with increasing heat stress. Transcriptomic analysis revealed that genes related to energy and carbohydrate metabolism, heat shock proteins (HSPs), and transcription factors (TFs), secondary metabolite biosynthesis and the antioxidant system significantly changed to varying degrees. Metabolomic analysis showed that only free fatty acids were downregulated, while amino acids and their derivatives, organic acids, flavonoids, and sugars were both up- and downregulated under heat stress. These combined analyses revealed that growth was promoted at 25–40°C, while at 45°C, excess reactive oxygen species (ROS) damage reduced antioxidant and osmoregulatory effects and inactivated genes associated with the light and electron transport chains (ETCs), as well as damaged the PS II system and inhibited photosynthesis. A small number of genes and metabolites were upregulated to maintain the basic growth of P. wettsteinii. The physiological and biochemical changes in response to high-temperature stress were revealed, and the important metabolites and key genes involved in the response to high temperature were identified, providing an important reference for the physiological and molecular regulation of high-temperature stress in plants.

Soil aridification and desertification are particularly prominent in China’s karst areas, severely limiting crop yields and vegetation restoration. Therefore, it is very important to identify naturally drought-tolerant plant species. Sophora davidii (Franch.) Skeels is resistant to drought and soil infertility, is deeply rooted and is an excellent plant material for soil and water conservation. We studied the transcriptomic and metabolomic changes in S. davidii in response to drought stress (CK, control; LD, mild drought stress; MD, moderate drought stress; and SD, severe drought stress). Sophora davidii grew normally under LD and MD stress but was inhibited under SD stress; the malondialdehyde (MDA), hydrogen peroxide (H2O2), soluble sugar, proline, chlorophyll a, chlorophyll b and carotenoid contents and ascorbate peroxidase (APX) activity significantly increased, while the superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities and soluble protein content significantly decreased. In the LD/CK, MD/CK and SD/CK comparison groups, there were 318, 734 and 1779 DEGs, respectively, and 100, 168 and 281 differentially accumulated metabolites, respectively. Combined analysis of the transcriptomic and metabolomic data revealed the metabolic regulation of S. davidii in response to drought stress. First, key candidate genes such as PRR7, PRR5, GI, ELF3, PsbQ, PsaK, INV, AMY, E2.4.1.13, E3.2.1.2, NCED, PP2C, PYL, ABF, WRKY33, P5CS, PRODH, AOC3, HPD, GPX, GST, CAT and SOD1 may govern the drought resistance of S. davidii. Second, three metabolites (oxidised glutathione, abscisic acid and phenylalanine) were found to be related to drought tolerance. Third, several key candidate genes and metabolites involved in 10 metabolic pathways were identified, indicating that these metabolic pathways play an important role in the response to drought in S. davidii and possibly other plant species.

The deformation mechanism of a medium-Mn advanced high strength steel (AHSS) over a temperature range from 25 °C to 400 °C has been studied. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the microstructures of specimens after the tensile test at different temperatures. Four deformation mechanisms were found, namely deformation-induced martensitic (DIM) transformation, deformation-induced bainitic (DIB) transformation, deformation twinning and dislocation glide. Among these deformation mechanisms, DIM and DIB were very effective mechanisms to contribute work hardening. The product of ultimate tensile strength (UTS) and total elongation (TEL) of the AHSS reached a value higher than 65 GPa%, when these two mechanisms occurred. The highest UTS × TEL value of 84 GPa% was obtained at 150 °C. From the results of the present research, it is suggested that warm working is a good processing route for obtaining a combination of high strength and high ductility in medium-Mn AHSS.

Abstract 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

Abstract The paleoclimatic sensitivity to atmospheric greenhouse gases (GHGs) has recently been suggested to be nonlinear, however a GHG threshold value associated with deglaciation remains uncertain. Here, we combine a new sea surface temperature record spanning the last 360,000 years from the southern Western Pacific Warm Pool with records from five previous studies in the equatorial Pacific to document the nonlinear relationship between climatic sensitivity and GHG levels over the past four glacial/interglacial cycles. The sensitivity of the responses to GHG concentrations rises dramatically by a factor of 2–4 at atmospheric CO2 levels of >220 ppm. Our results suggest that the equatorial Pacific acts as a nonlinear amplifier that allows global climate to transition from deglacial to full interglacial conditions once atmospheric CO2 levels reach threshold levels.

This paper applies the context-dependent total-factor energy efficiency (CD-TFEE) to determine the multi-layer disaggregate energy efficiency frontiers of twenty administrative regions in Taiwan for the year of 2016. The CD-TFEE overcomes the shortcoming of conventional TFEE index that TFEE is not able to find the “closest target” for each inefficient region in the short run. Furthermore, the CD-TFEE scores here deal with four types of energy inputs (electricity for production, electricity for household and non-household lighting, diesel sales, and gasoline sales), illustrating that multi-layer TFEE frontiers for each energy input in the case of Taiwan can be computed. Empirical results indicate that there are three levels of TFEE frontiers for electricity for production and four levels for other types of energy inputs. In addition, New Taipei City, Taipei City, Keelung City, and Penghu County are at the top level of TFEE frontier for all four energy inputs. This paper also demonstrates that the CD-TFEE procedure generates results different from the CD-DEA introduced by Seiford and Zhu (2003).

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.

Benign paroxysmal positional vertigo (BPPV), the most common type of vertigo in the general population, is thought to be caused by dislodgement of otoliths from otolithic organs into the semicircular canals. In most cases, however, the cause behind the otolith dislodgement is unknown. Dental procedures, one of the most common medical treatments, are considered to be a possible cause of BPPV, although this has yet to be proven. This study is the first nationwide population-based case-control study conducted to investigate the correlation between BPPV and dental manipulation.Patients diagnosed with BPPV between January 1, 2007 and December 31, 2012 were recruited from the National Health Insurance Research Database in Taiwan. We further identified those who had undergone dental procedures within 1 month and within 3 months before the first diagnosis date of BPPV. We also identified the comorbidities of the patients with BPPV, including head trauma, osteoporosis, migraine, hypertension, diabetes, hyperlipidemia and stroke. These variables were then compared to those in age- and gender-matched controls.In total, 768 patients with BPPV and 1536 age- and gender-matched controls were recruited. In the BPPV group, 9.2% of the patients had undergone dental procedures within 1 month before the diagnosis of BPPV. In contrast, only 5.5% of the controls had undergone dental treatment within 1 month before the date at which they were identified (P = 0.001). After adjustments for demographic factors and comorbidities, recent exposure to dental procedures was positively associated with BPPV (adjusted odds ratio 1.77; 95% confidence interval 1.27-2.47). This association was still significant if we expanded the time period from 1 month to 3 months (adjusted odds ratio 1.77; 95% confidence interval 1.39-2.26).Our results demonstrated a correlation between dental procedures and BPPV. The specialists who treat patients with BPPV should consider dental procedures to be a risk factor, and dentists should recognize BPPV as a possible complication of dental treatment.