Rehabilitation for persons with vertigo and balance disorders is becoming commonplace and the literature is expanding rapidly. The present review highlights recent findings of both peripheral and ...central vestibular disorders and provides insight into evidence related to new rehabilitative interventions. Risk factors will be reviewed to create a better understanding of patient and clinical characteristics that may effect recovery among persons with vestibular disorders.
Clinical practice guidelines have recently been developed for peripheral vestibular hypofunction and updated for benign paroxysmal positional vertigo. Diagnoses such as persistent postural-perceptual dizziness (PPPD) and vestibular migraine are now defined, and there is growing literature supporting the effectiveness of vestibular rehabilitation as a treatment option. As technology advances, virtual reality and other technologies are being used more frequently to augment vestibular rehabilitation. Clinicians now have a better understanding of rehabilitation expectations and whom to refer based on evidence in order to improve functional outcomes for persons living with peripheral and central vestibular disorders.
An up-to-date understanding of the evidence related to vestibular rehabilitation can assist the practicing clinician in making better clinical decisions for their patient and hopefully result in optimal functional recovery.
Objective This update of a 2008 guideline from the American Academy of Otolaryngology-Head and Neck Surgery Foundation provides evidence-based recommendations to benign paroxysmal positional vertigo ...(BPPV), defined as a disorder of the inner ear characterized by repeated episodes of positional vertigo. Changes from the prior guideline include a consumer advocate added to the update group; new evidence from 2 clinical practice guidelines, 20 systematic reviews, and 27 randomized controlled trials; enhanced emphasis on patient education and shared decision making; a new algorithm to clarify action statement relationships; and new and expanded recommendations for the diagnosis and management of BPPV. Purpose The primary purposes of this guideline are to improve the quality of care and outcomes for BPPV by improving the accurate and efficient diagnosis of BPPV, reducing the inappropriate use of vestibular suppressant medications, decreasing the inappropriate use of ancillary testing such as radiographic imaging, and increasing the use of appropriate therapeutic repositioning maneuvers. The guideline is intended for all clinicians who are likely to diagnose and manage patients with BPPV, and it applies to any setting in which BPPV would be identified, monitored, or managed. The target patient for the guideline is aged ≥18 years with a suspected or potential diagnosis of BPPV. The primary outcome considered in this guideline is the resolution of the symptoms associated with BPPV. Secondary outcomes considered include an increased rate of accurate diagnoses of BPPV, a more efficient return to regular activities and work, decreased use of inappropriate medications and unnecessary diagnostic tests, reduction in recurrence of BPPV, and reduction in adverse events associated with undiagnosed or untreated BPPV. Other outcomes considered include minimizing costs in the diagnosis and treatment of BPPV, minimizing potentially unnecessary return physician visits, and maximizing the health-related quality of life of individuals afflicted with BPPV. Action Statements The update group made strong recommendations that clinicians should (1) diagnose posterior semicircular canal BPPV when vertigo associated with torsional, upbeating nystagmus is provoked by the Dix-Hallpike maneuver, performed by bringing the patient from an upright to supine position with the head turned 45° to one side and neck extended 20° with the affected ear down, and (2) treat, or refer to a clinician who can treat, patients with posterior canal BPPV with a canalith repositioning procedure. The update group made a strong recommendation against postprocedural postural restrictions after canalith repositioning procedure for posterior canal BPPV. The update group made recommendations that the clinician should (1) perform, or refer to a clinician who can perform, a supine roll test to assess for lateral semicircular canal BPPV if the patient has a history compatible with BPPV and the Dix-Hallpike test exhibits horizontal or no nystagmus; (2) differentiate, or refer to a clinician who can differentiate, BPPV from other causes of imbalance, dizziness, and vertigo; (3) assess patients with BPPV for factors that modify management, including impaired mobility or balance, central nervous system disorders, a lack of home support, and/or increased risk for falling; (4) reassess patients within 1 month after an initial period of observation or treatment to document resolution or persistence of symptoms; (5) evaluate, or refer to a clinician who can evaluate, patients with persistent symptoms for unresolved BPPV and/or underlying peripheral vestibular or central nervous system disorders; and (6) educate patients regarding the impact of BPPV on their safety, the potential for disease recurrence, and the importance of follow-up. The update group made recommendations against (1) radiographic imaging for a patient who meets diagnostic criteria for BPPV in the absence of additional signs and/or symptoms inconsistent with BPPV that warrant imaging, (2) vestibular testing for a patient who meets diagnostic criteria for BPPV in the absence of additional vestibular signs and/or symptoms inconsistent with BPPV that warrant testing, and (3) routinely treating BPPV with vestibular suppressant medications such as antihistamines and/or benzodiazepines. The guideline update group provided the options that clinicians may offer (1) observation with follow-up as initial management for patients with BPPV and (2) vestibular rehabilitation, either self-administered or with a clinician, in the treatment of BPPV.
A combination of statistical studies and 18 case studies have been used to investigate the structure of the induced Martian magnetosphere. The different plasma and magnetic pressure forces on the ...dayside of the induced magnetosphere of Mars have been studied using 3.5 years of Mars Atmosphere and Volatile Evolution (MAVEN) and Mars Express (MEX) observations. We present estimates of typical values for the dominant pressure terms, that is, the thermal pressures of the ionosphere and the magnetosheath, the magnetic pressure of the magnetic pile‐up region, and the solar wind dynamic pressure. For 18 typical orbits the altitudes and relative distances of the pressure balance boundaries, the photoelectron boundary, the ion composition boundary, and the induced magnetosphere boundary are estimated. The magnetic pile‐up boundary is discussed but not further studied since earlier characterizations of the magnetic pile‐up boundary do not agree with our results. This study focuses on the transition region between the ionosphere and the magnetosheath on the dayside of Mars. We show that earlier definitions of the photoelectron boundary, ion composition boundary, and induced magnetosphere boundary do not characterize the transition region well, mainly because each boundary is based on measurements from only one or two instruments. In order to characterize the transition region correctly, changes in magnetic field strength and fluctuations, dominant ion species, electron and ion densities and energy distributions need to be considered. This article confirms a complex interaction between Mars and the solar wind and can explain why previous studies have had difficulties to describe the force balance.
Key Points
This article presents an overview of the Martian dayside magnetospheric structure based on the dominant pressure terms
Typical altitudes of the pressure balance boundaries, the PEB, ICB, and IMB are provided
We show that earlier defined boundaries are not a sufficient characterization of the ionosphere/magnetosheath transition region
Spacecraft charging is a well‐known effect that occurs when a spacecraft is located in a charged environment such as plasma. In this process, the surface of the spacecraft acquires an electrostatic ...potential through the accumulation and emission of positive and negative charges. In addition to causing severe electrostatic discharges, it also significantly affects low‐energy particle measurements performed by instruments onboard the spacecraft as it causes a change in energy and a distortion of the Field Of View (FOV) of the instrument by modifying the trajectory of measured particles. Spacecraft charging is therefore an important aspect to consider for Jovian plasma Dynamics and Composition analyzer (JDC), an instrument which aims to perform cold plasma measurements around the Galilean moons onboard JUpiter ICy moons Explorer (JUICE). In this study we use SPIS to perform simulations to study the FOV distortion of JDC for positive ions caused by spacecraft charging in two environments of the JUICE mission: the ionosphere of Ganymede and the Jovian magnetosphere. We show that the resulting distortion of the instrument FOV is highly space dependent and varies in shape and intensity from a pixel to another. However, we show that in both environments the complexity of the interactions between measured positive ions and the spacecraft can be decomposed and described as a superposition of a finite number of elementary interactions (i.e., modes). We show that each mode is caused by a specific element of the spacecraft and leads to a characteristic distortion of the instrument FOV. This study constitutes a first step toward necessary spacecraft potential corrections of the measurements performed by JDC.
Key Points
The spacecraft potential affects charged particle measurements by distorting the instrument field of view
Interactions between JUpiter ICy moons Explorer spacecraft and Jovian plasma Dynamics and Composition analyzer positive ion measurements are simulated
The spacecraft potential causes complex and highly geometry dependent distortions, especially for particles with low energy
In Huybrighs et al. (2020, https://doi.org/10.1029/2020gl087806) we investigated energetic proton depletions along Galileo's Europa flyby E26. Based on a particle tracing analysis, we proposed that ...depletions are caused by perturbed electromagnetic fields combined with atmospheric charge exchange and possible plumes. One depletion feature identified as a plume signature was shown to be an artifact (Jia et al., 2021, https://doi.org/10.1029/2020gl091550). Despite that, here we emphasize that Huybrighs et al. (2020, https://doi.org/10.1029/2020gl087806) demonstrates that plumes can cause proton depletions and that these features should be sought after. Furthermore, the conclusions on the importance of perturbed electromagnetic fields and atmospheric charge exchange on the depletions are unaffected. We suggest that the artifact's cause is a mistagging of protons as heavier ions by EPD. The artifact prevents us from confirming or excluding that there is a plume‐associated depletion. We also address comments on the MHD simulations and demonstrate that 540–1,040 keV losses are not necessarily inconsistent with 115–244 keV losses by plume‐associated charge exchange.
Plain Language Summary
In Huybrighs et al. (2020, https://doi.org/10.1029/2020gl087806) we identified why fast protons were disappearing during Europa flyby E26 by Galileo. Beyond impacting on the surface, we identified several contributing factors: First, perturbed electromagnetic fields resulting from the interaction of Europa's atmosphere with the magnetospheric plasma, which deflect the protons. Second, atmospheric charge exchange. We also showed that a water plume eruption could cause a region in which disappearances occur due to a combination of charge exchange and magnetic deflections. We identified a 20s decrease of protons as evidence of such a plume. However, an artifact in the data reported by Jia et al. (2021, https://doi.org/10.1029/2020gl091550) coincides with this 20s moment and prevents us from reaching a conclusion on the occurrence of a plume‐associated depletion. We emphasize that our conclusions on the importance of perturbed fields and charge exchange are unaffected, as the artifact only affects a short segment of the data we analyzed. Furthermore, our results demonstrate that plumes can cause proton depletions and that these features should be sought after in the data.
Key Points
EPD artifact does not affect the conclusion that perturbed fields and atmospheric charge exchange drive energetic proton losses at Europa
Energetic proton measurements could be used to infer the presence of plumes with density profiles consistent with the literature
The artifact reported by Jia et al. (2021) prevents a definite conclusion on the presence of a plume during E26 from EPD data
Strong depletions of energetic protons (115–244 keV) were observed during Galileo flyby E26 of Europa. We simulate the flux of energetic protons using a Monte Carlo particle backtracing code and show ...that energetic proton depletions during E26 are reproduced by taking into account the perturbations of the electromagnetic fields calculated by magnetohydrodynamic (MHD) simulations and charge exchange with a global atmosphere and plume. A depletion feature occurring shortly after closest approach is driven by plume associated charge exchange, or a combination with plume associated field perturbations. We therefore conclude, with a new method and independent data set, that Galileo could have encountered a plume during E26.
Plain Language Summary
We investigate why (normally abundant) fast protons were disappearing during Europa flyby E26 by Galileo. We do this by simulating the proton motion. In some cases we detect few protons because Europa is blocking the field of view. What is new here is that part of the decrease can be explained by charge exchange, a process whereby the protons are removed after they lose their electrical charge in Europa's thin atmosphere. Furthermore, we see that there is a special decrease, which can be explained by an erupting plume of water vapor, thereby providing additional evidence for an active plume during Galileo flyby E26.
Key Points
Energetic proton flux depletions during Galileo flyby E26 are driven by inhomogeneous fields, atmospheric charge exchange, and a plume
Plumes can deplete protons through charge exchange and field perturbations
Plumes are a source of energetic neutral atoms
Carboxylesterase 1 (CES1) hydrolyzes the prodrug clopidogrel to an inactive carboxylic acid metabolite. We studied the pharmacokinetics and pharmacodynamics of 600 mg oral clopidogrel in healthy ...white volunteers, including 10 carriers and 12 noncarriers of CES1 c.428G>A (p.Gly143Glu, rs71647871) single nucleotide variation (SNV). Clopidogrel carboxylic acid to clopidogrel area under the plasma concentration‐time curve from 0 hours to infinity (AUC0–∞) ratio was 53% less in CES1 c.428G>A carriers than in noncarriers (P = 0.009), indicating impaired hydrolysis of clopidogrel. Consequently, the AUC0–∞ of clopidogrel and its active metabolite were 123% (P = 0.004) and 67% (P = 0.009) larger in the c.428G>A carriers than in noncarriers. Consistent with these findings, the average inhibition of P2Y12‐mediated platelet aggregation 0–12 hours after clopidogrel intake was 19 percentage points higher in the c.428G>A carriers than in noncarriers (P = 0.036). In conclusion, the CES1 c.428G>A SNV increases clopidogrel active metabolite concentrations and antiplatelet effects by reducing clopidogrel hydrolysis to inactive metabolites.
We have used Spacecraft Plasma Interaction Software (SPIS) simulations to study the characteristics (i.e., dimensions, ion depletion, and evolution with the changing spacecraft attitude) of the ...Cassini ion wake. We focus on two regions, the plasma disk at 4.5–4.7 RS, where the most prominent wake structure will be formed, and at 7.6 RS, close to the maximum distance at which a wake structure can be detected in the Cassini Langmuir probe (LP) data. This study also reveals how the ion wake and the spacecraft plasma interaction have impacted the Cassini LP measurements in the studied environments, for example, with a strong decrease in the measured ion density but with minor interference from the photoelectrons and secondary electrons originating from the spacecraft. The simulated ion densities and spacecraft potentials are in very good agreement with the LP measurements. This shows that SPIS is an excellent tool to use for analyses of LP data, when spacecraft material properties and environmental parameters are known and used correctly. The simulation results are also used to put constraints on the ion temperature estimates in the inner magnetosphere of Saturn. The best agreement between the simulated and measured ion density is obtained using an ion temperature of 8 eV at ∼4.6 RS. This study also shows that SPIS simulations can be used in order to better constrain plasma parameters in regions where accurate measurements are not available.
Key Points
The Cassini ion wake is characterized and it is demonstrated that the ion wake can have a substantial impact on the Cassini LP measurements
Our study indicates that earlier estimates of the ion temperature in the inner magnetosphere of Saturn are overestimated
The software SPIS provides accurate simulation results for typical magnetospheric conditions
We present statistical results from the Cassini Radio and Plasma Wave Science (RPWS) Langmuir probe measurements recorded during the time interval from orbit 3 (1 February 2005) to 237 (29 June ...2016). A new and improved data analysis method to obtain ion density from the Cassini LP measurements is used to study the asymmetries and modulations found in the inner plasma disk of Saturn, between 2.5 and 12 Saturn radii (1 RS=60,268 km). The structure of Saturn's plasma disk is mapped, and the plasma density peak, nmax, is shown to be located at ∼4.6 RS and not at the main neutral source region at 3.95 RS. The shift in the location of nmax is due to that the hot electron impact ionization rate peaks at ∼4.6 RS. Cassini RPWS plasma disk measurements show a solar cycle modulation. However, estimates of the change in ion density due to varying EUV flux is not large enough to describe the detected dependency, which implies that an additional mechanism, still unknown, is also affecting the plasma density in the studied region. We also present a dayside/nightside ion density asymmetry, with nightside densities up to a factor of 2 larger than on the dayside. The largest density difference is found in the radial region 4 to 5 RS. The dynamic variation in ion density increases toward Saturn, indicating an internal origin of the large density variability in the plasma disk rather than being caused by an external source origin in the outer magnetosphere.
Key Points
The plasma density of the inner plasma disk of Saturn shows a solar EUV flux dependency
The ion density measured between 4 and 5 RS shows a clear dayside/nightside asymmetry
The plasma disk peak density is shifted ∼0.6 RS out from the main source, due to hot electron impact ionization
We investigate the causes of energetic proton (80–540 keV) depletions measured during the two most distant flybys of Europa by Galileo, E17 and E25A, which encountered the Alfvén wings. First, by ...simulating the proton flux with a Monte Carlo particle tracing code we investigate the effect of: electromagnetic field perturbations, the induced dipole, atmospheric charge exchange and plumes. Inhomogeneous fields associated with the Alfvén wings and the ionosphere strongly affect the depletions. For homogeneous fields the depletion along the trajectory is focused on a narrow pitch angle range and has no structure, whereas the depletion for perturbed (inhomogeneous) fields represents a wider and complex structure. Furthermore, also the induced dipole alters the depletion structure. The effect of plumes (density 2.5 × 1015 m−3) and charge exchange on the proton depletion is minor. Second, we compare the simulations to the proton measurements. The simulations with inhomogeneous fields describe the data qualitatively better than the homogeneous case, suggesting that indeed field perturbations are responsible for the measured losses. We attribute discrepancies between the simulations and the proton measurements to discrepancies between the simulated and real fields. We argue that simulating the fields along the trajectory is a good first step, but that ideally the energetic ion flux is reconstructed well to gain confidence in the interpretation of the simulated magnetic field. In conclusion, energetic ion observations along distant flybys through the Alfvén wings are suitable for isolating the characteristics of the global configuration of the magnetospheric interaction region of Europa (or other moons).
Plain Language Summary
Europa is a moon of Jupiter with a potentially habitable subsurface ocean. Located in Jupiter's giant magnetic field, it is exposed to extremely fast protons. Galileo measured the disappearance of normally abundant protons when it encountered Europa's Alfvén wings, during its two furthest flybys. The Alfvén wings are cylindrical regions of disturbed magnetic field, extending north and south of Europa. Using simulations of the protons' motion we show that disturbances of the magnetic field associated with the Alfvén wings and Europa's ionosphere can deflect fast protons and cause their local disappearance. Europa's ocean, which causes an induced magnetic field of its own, will also modify the proton losses. Europa's ocean thus influences the motion of protons at distances of several 1,000 km. This effect could be used by future missions to find evidence of oceans on other moons, such as Triton. Lastly, the simulations with disturbed magnetic fields have a better qualitative agreement with the measurement, as opposed to those without. This implies that the field perturbations are indeed affecting the proton disappearances. We argue that to gain confidence in our understanding of the magnetic field, both the magnetic field measurements and the energetic ion measurements should be reproduced well.
Key Points
Field perturbations (Alfvén wings, ionosphere, induced dipole) create complex proton (80–540 keV) losses during distant Alfvén wing flybys
Energetic proton depletions measured by Galileo are consistent with dropouts caused by the perturbed fields
Energetic proton measurements can be used to probe Europa's magnetospheric interaction during distant flybys
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