The assessment of depression in people with multiple sclerosis : a systematic review of psychometric validation studies

Background: The prevalence of depression in people with multiple sclerosis (PwMS) is high; however, symptoms common to both conditions makes measurement difficult. There is no high quality overview of validation studies to guide the choice of depression inventory for this population. Methods: A systematic review of studies validating the use of generic depression inventories in people with MS was conducted using MEDLINE and PsycINFO. Studies validating the use of depression inventories in PwMS and published in English were included; validation studies of tests for cognitive function and general mental health were excluded. Eligible studies were then quality assessed using the COSMIN checklist and findings synthesised narratively by instrument and validity domain. Results: Twenty-one studies (N=5,991 PwMS) evaluating 12 instruments were included in the review. Risk of bias varied greatly between instrument and validity domain. Conclusions: The review of validation studies was constrained by poor quality reporting and outcome reporting bias. Well-conducted evaluations of some instruments are unavailable for some validity domains. This systematic review provides an evidence base for trade-offs in the selection of an instrument for assessing self-reported symptoms of depression in research or clinical practice involving people with MS. We make detailed and specific recommendations for where further research is needed. Registration: PROSPERO CRD42014010597 Keywords Depression; Multiple Sclerosis; Reproducibility of Results; Psychometrics; Chronic Diseas

Examining techniques for measuring the effects of nutrients on mental performance and mood state

Purpose: Intake of specific nutrients has been linked to mental states and various indices of cognitive performance although the effects are often subtle and difficult to interpret. Measurement of so-called objective variables (e.g. reaction times) is often considered to be the gold standard for assessing outcomes in this field of research. It can, however, be argued that data on subjective experience (e.g. mood) are also important and may enrich existing objective data. The aim of this review is to evaluate methods for measuring mental performance and mood, considering the definition of subjective mood and the validity of measures of subjective experience. Methods: A multi-stakeholder expert group was invited by ILSI Europe to come to a consensus around the utility of objective and subjective measurement in this field, which forms the basis of the paper. Therefore, the present review reflects a succinct overview of the science but is not intended to be a systematic review. Results: The proposed approach extends the traditional methodology using standard ‘objective’ measurements to also include the consumers’ subjective experiences in relation to food. Specific recommendations include 1) using contemporary methods to capture transient mood states; 2) using sufficiently sensitive measures to capture effects of nutritional intervention; 3) considering the possibility that subjective and objective responses will occur over different time frames; and 4) recognition of the importance of expectancy and placebo effects for subjective measures. Conclusions: The consensus reached was that the most informative approach should involve collection and consideration of both objective and subjective data

International Consensus Statement on Rhinology and Allergy: Rhinosinusitis

Background: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR‐RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR‐RS‐2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence‐based findings of the document. Methods: ICAR‐RS presents over 180 topics in the forms of evidence‐based reviews with recommendations (EBRRs), evidence‐based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. Results: ICAR‐RS‐2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence‐based management algorithm is provided. Conclusion: This ICAR‐RS‐2021 executive summary provides a compilation of the evidence‐based recommendations for medical and surgical treatment of the most common forms of RS

Calculation of MRI-Induced Heating of an Implanted Medical Lead Wire with an Electric Field Transfer Function

Purpose: To develop and demonstrate a method to calculate the temperature rise that is induced by the radio frequency (RF) field in MRI at the electrode of an implanted medical lead. Materials and Methods: The electric field near the electrode is calculated by integrating the product of the tangential electric field and a transfer function along the length of the lead. The transfer function is numerically calculated with the method of moments. Transfer functions were calculated at 64 MHz for different lengths of model implants in the form of bare wires and insulated wires with 1 cm of wire exposed at one or both ends. Results: Heating at the electrode depends on the magnitude and the phase distribution of the transfer function and the incident electric field along the length of the lead. For a uniform electric field, the electrode heating is maximized for a lead length of approximately one-half a wavelength when the lead is terminated open. The heating can be greater for a worst-case phase distribution of the incident field. Conclusion: The transfer function is proposed as an efficient method to calculate MRI-induced heating at an electrode of a medical lead. Measured temperature rises of a model implant in a phantom were in good agreement with the rises predicted by the transfer function. The transfer function could be numerically or experimentally determined.116962sciescopu

MRI Safety: RF-Induced Heating near Straight Wires

One of the most crucial magnetic resonance (MR) safety concerns is related to excessive heating of metallic implants by the radio frequency (RF) magnetic field. In this study, heating by the MR imaging (MRI) RF magnetic field of bare and insulated wires was evaluated to model the heating of medical lead wires. Currents induced in the wire were calculated using the method of moments. The electric field in the tissue surrounding the wire was calculated to determine the power deposition. From the power, the temperature rise was calculated using the bioheat equation. For bare wires, the calculated and maximal temperature rise, which is about 28 degrees C, occurred for a length of 20 cm. For lengths exceeding 20 cm, temperature rises for the insulated wires were greater, and the resonance length exceeded 40 cm.114139sciescopu

Implantable microstimulator: magnetic resonance safety at 1.5 Tesla.

Rationale and Objective: Ex vivo testing is necessary to characterize implants to determine if it is safe for the patient to undergo a magnetic resonance imaging (MRI) examination. Therefore, the objective of this study was to evaluate MR safety for an implantable microstimulator in association with a 1.5 Tesla MR system. Methods: A microstimulator (RF BION, Alfred E. Mann Foundation for Scientific Research, Valencia, CA) was evaluated for magnetic field interactions and MRI-related heating. The functional aspects of this implant were assessed immediately before and after exposure to MRI (15 different pulse sequences). Artifacts were also characterized. Results: Magnetic field interactions exhibited by the microstimulator will not pose a hazard after a suitable postimplantation period has elapsed. Temperature changes will not pose a risk. The function of the microstimulator was unaffected by MRI. Artifacts will only create a problem if the area of interest is in proximity to this implant (largest artifact area: T1-weighted spin echo, 2291 mm(2); gradient echo, 3310 mm(2)). Conclusion: The overall findings indicated that it is safe for a patient with the microstimulator to undergo MRI at 1.5 Tesla by following specific safety guidelines described herein.112527sciescopu

Power Deposition inside a Phantom for Testing of MRI Heating

A patient in MRI is exposed to the time varying gradient and radio-frequency (RF) fields. Measurements of RF-induced temperature rise in implant in phantoms are used to predict the in-vivo temperature rise. This paper focuses on the numerical computation of power deposition inside such a phantom. The finite-difference time domain (FDTD) was used for the calculations. The phantom was placed inside a whole body bird cage coil. For landmarks in the torso of the phantom, the power deposition is concentrated near the edges. The whole phantom average specific absoprtion rate (SAR) for a mean square field intensity of 1(mu T)(2) ranged from 0.032 W/kg for the eyes landmark to 0.151 W/kg for the waist landmark. The SAR increased with increasing conductivity in the range 0.2 to 0.8 S/m. The distribution of the measured temperature rise versus lateral position at the landmark was consistent with the calculation. The electric field is tangential to the phantom edges but has significant elliptical polarization near the corners.113028sciescopu

MRI and Implanted Medical Devices: Basic Interactions with an Emphasis on Heating

There are three principal magnetic fields in magnetic resonance imaging (MRI) that may interact with medical implants. The static field will induce force and torque on ferromagnetic objects. The pulsed gradients are of audio frequency and the implant may concentrate the induced currents, with a potential for nerve stimulation or electrical inference. The currents induced in the body by the radio frequency (RF) field may also be concentrated by an implant, resulting in potentially dangerous heating of surrounding tissues. This paper presents basic information about MRI interactions with implants with an emphasis on RF-induced heating of leads used for deep brain stimulation (DBS). The temperature rise at the electrodes was measured in vitro as a function of the overall length of a DBS lead at an RF frequency of 64 MHz. The maximal temperature rise occurred for an overall length of 41 cm. The method of moments was used to calculate the current induced in the lead. From the induced currents, the RF power deposition near the electrodes was calculated and the heat equation was used to model the temperature rise. The calculated temperature rises as a function of lead length were in good agreement with the measured values.1177sciescopu

Gelled versus nongelled phantom material for measurement of MRI-induced temperature increases with bioimplants

Measurements in phantoms are used to predict temperature changes that would occur in vivo for medical implants due to the radio frequency (RF) field in magnetic resonance imaging (MRI). In this study, the impact of concentration of the gelling agent in a saline-based phantom on the RF-induced temperature rise was measured using an apparatus that accurately reproduces the RF environment present in a 1.5-T whole-body MR system. The temperature was measured using fluoroptic thermometry at the electrode and other sites foe a deep brain neurostimulation system. The average power deposition in the 30-kg phantom was about 1.5 W/kg. Four phantom formulations were evaluated, using different concentrations of polyacrylic acid -(PAA) added to saline solution, with NaCl concentration adjusted to maintain an electrical conductivity near 0.24 S/m. The greatest temperature rises occurred at the electrode, ranging from 16.2degreesC for greatest concentration of PAA to 2.9degreesC for only saline solution. The temperature rise attained the maximal value for sufficient concentration of PAA. Similar behavior was observed in the temperature versus time relationship near a current-carrying resistor, immersed in gel and saline, which was used to model a localized heat source. The temperature rise for insufficient PAA concentration is reduced due to convection of phantom material. In conclusion, an appropriate gelling agent is required to accurately simulate the thermal properties of body tissues for measurements of RF-induced heating with medical implants.115451sciescopu