The unknown unknown: A framework for assessing environmental DNA assay specificity against unsampled taxa.

Taxon-specific quantitative PCR (qPCR) assays are commonly used for environmental DNA sampling-based inference of animal presence. These assays require thorough validation to ensure that amplification truly indicates detection of the target taxon, but a thorough validation is difficult when there are potentially many non-target taxa, some of which may have incomplete taxonomies. Here, we use a previously published, quantitative model of cross-amplification risk to describe a framework for assessing qPCR assay specificity when there is missing information and it is not possible to assess assay specificity for each individual non-target confamilial. In this framework, we predict assay specificity against unsampled taxa (non-target taxa without sequence data available) using the sequence information that is available for other confamilials. We demonstrate this framework using four case study assays for: (1) An endemic, freshwater arthropod (meltwater stonefly; Lednia tumana), (2) a globally distributed, marine ascidian (Didemnum perlucidum), (3) a continentally distributed freshwater crustacean (virile crayfish; Faxonius virilis, deanae and nais species complex) and (4) a globally distributed freshwater teleost (common carp; Cyprinus carpio and its close relative C. rubrofuscus). We tested the robustness of our approach to missing information by simulating application of our framework for all possible subsamples of 20-all non-target taxa. Our results suggest that the modelling framework results in estimates which are largely concordant with observed levels of cross-amplification risk using all available sequence data, even when there are high levels of data missingness. We explore potential limitations and extensions of this approach for assessing assay specificity and provide users with an R Markdown template for generating reproducible reports to support their own assay validation efforts.

Broad-scale eDNA sampling for describing aquatic species distributions in running waters: Pacific lamprey Entosphenus tridentatus in the upper Snake River, USA.

One of the most fundamental yet challenging tasks for aquatic ecologists is to precisely delineate the range of species, particularly those that are broadly distributed, require specialized sampling methods, and may be simultaneously declining and increasing in different portions of their range. An exemplar is the Pacific lamprey Entosphenus tridentatus, a jawless anadromous fish of conservation concern that is actively managed in many coastal basins in western North America. To efficiently determine its distribution across the accessible 56,168 km of the upper Snake River basin in the north-western United States, we first delimited potential habitat by using predictions from a species distribution model based on conventionally collected historical data and from the distribution of a potential surrogate, Chinook salmon Oncorhynchus tshawytscha, which yielded a potential habitat network of 10,615 km. Within this area, we conducted a two-stage environmental DNA survey involving 394 new samples and 187 archived samples collected by professional biologists and citizen scientists using a single, standardized method from 2015 to 2021. We estimated that Pacific lamprey occupied 1875 km of lotic habitat in this basin, of which 1444 km may have been influenced by recent translocation efforts. Pacific lamprey DNA was consistently present throughout most river main stems, although detections became weaker or less frequent in the largest and warmest downstream channels and near their headwater extent. Pacific lamprey were detected in nearly all stocked tributaries, but there was no evidence of indigenous populations in such habitats. There was evidence of post-stocking movement because detections were 1.8-36.0 km upstream from release sites. By crafting a model-driven spatial sampling template and executing an eDNA-based sampling campaign led by professionals and volunteers, supplemented by previously collected samples, we established a benchmark for understanding the current range of Pacific lamprey across a large portion of its range in the interior Columbia River basin. This approach could be tailored to refine range estimates for other wide-ranging aquatic species of conservation concern.

eDNAssay: A machine learning tool that accurately predicts qPCR cross-amplification.

Environmental DNA (eDNA) sampling is a highly sensitive and cost-effective technique for wildlife monitoring, notably through the use of qPCR assays. However, it can be difficult to ensure assay specificity when many closely related species co-occur. In theory, specificity may be assessed in silico by determining whether assay oligonucleotides have enough base-pair mismatches with nontarget sequences to preclude amplification. However, the mismatch qualities required are poorly understood, making in silico assessments difficult and often necessitating extensive in vitro testing-typically the greatest bottleneck in assay development. Increasing the accuracy of in silico assessments would therefore streamline the assay development process. In this study, we paired 10 qPCR assays with 82 synthetic gene fragments for 530 specificity tests using SYBR Green intercalating dye (n = 262) and TaqMan hydrolysis probes (n = 268). Test results were used to train random forest classifiers to predict amplification. The primer-only model (SYBR Green results) and full-assay model (TaqMan probe-based results) were 99.6% and 100% accurate, respectively, in cross-validation. We further assessed model performance using six independent assays not used in model training. In these tests the primer-only model was 92.4% accurate (n = 119) and the full-assay model was 96.5% accurate (n = 144). The high performance achieved by these models makes it possible for eDNA practitioners to more quickly and confidently develop assays specific to the intended target. Practitioners can access the full-assay model online via eDNAssay (https://NationalGenomicsCenter.shinyapps.io/eDNAssay), a user-friendly tool for predicting qPCR cross-amplification.

The Role of the Medial Olivocochlear Reflex in Acceptable Noise Level in Adults.

BACKGROUND: The acceptable noise level (ANL) is a measurement used to quantify how much noise a person is willing to accept while listening to speech. ANL has been used to predict success with hearing aid use. However, physiological correlates of the ANL are poorly understood. One potential physiological correlate is the medial olivocochlear reflex (MOCR), which decreases the output of the cochlea and is thereby expected to increase noise tolerance. PURPOSE: This study investigates the relationship between contralateral activation of the MOCR and tolerance of background noise. RESEARCH DESIGN: This study recruited 22 young adult participants with normal hearing. ANL was measured using the Arizona Travelogue recording under headphones presented at the most comfortable level (MCL) with and without multitalker babble noise. The MOCR strength was evaluated in all participants by measuring the cochlear microphonic (CM) with and without 40 dB sound pressure level contralateral broadband noise (CBBN). DATA ANALYSIS: The CM observed in response to a 500-Hz tone was measured with and without CBBN, and changes in response to fast Fourier transform amplitude at 500 Hz were used as an indicator of the MOCR effect. The ANL was calculated by subtracting the maximum acceptable background noise level from the MCL. Participants were divided into two groups based on their ANL: low-ANL (ANL < 7 dB) and moderate-ANL (ANL ≥ 7 dB). An independent samples t-test was used to compare CM enhancement between low-ANL and moderate-ANL groups. Additionally, Pearson's correlation was used to investigate the relationship between the ANL and the MOCR effect on the CM. RESULTS: The results indicated that presentation of CBBN increased the CM amplitude, consistent with eliciting the MOCR. Participants in the low-ANL group had significantly larger CM enhancement than moderate-ANL participants. The results further revealed a significant correlation between the ANL and the MOCR effect on the CM. CONCLUSION: This study suggests that a stronger MOCR, as assessed using CM enhancement, is associated with greater noise tolerance. This research provides a possible objective measure to predict background tolerance in patients and adds to our understanding about the MOCR function in humans.

Strategic considerations for invasive species managers in the utilization of environmental DNA (eDNA): steps for incorporating this powerful surveillance tool.

Invasive species surveillance programs can utilize environmental DNA sampling and analysis to provide information on the presence of invasive species. Wider utilization of eDNA techniques for invasive species surveillance may be warranted. This paper covers topics directed towards invasive species managers and eDNA practitioners working at the intersection of eDNA techniques and invasive species surveillance. It provides background information on the utility of eDNA for invasive species management and points to various examples of its use across federal and international programs. It provides information on 1) why an invasive species manager should consider using eDNA, 2) deciding if eDNA can help with the manager's surveillance needs, 3) important components to operational implementation, and 4) a high-level overview of the technical steps necessary for eDNA analysis. The goal of this paper is to assist invasive species managers in deciding if, when, and how to use eDNA for surveillance. If eDNA use is elected, the paper provides guidance on steps to ensure a clear understanding of the strengths and limitation of the methods and how results can be best utilized in the context of invasive species surveillance.

An improved environmental DNA assay for bull trout (Salvelinus confluentus) based on the ribosomal internal transcribed spacer I.

The majority of environmental DNA (eDNA) assays for vertebrate species are based on commonly analyzed regions of the mitochondrial genome. However, the high degree of mitochondrial similarity between two species of charr (Salvelinus spp.), southern Dolly Varden (S. malma lordii) and bull trout (Salvelinus confluentus), precludes the development of a mitochondrial eDNA assay to distinguish them. Presented here is an eDNA assay to detect bull trout based on the first ribosomal internal transcribed spacer (ITSI), a nuclear marker. This assay successfully detects bull trout and avoids detecting Dolly Varden as well as brook trout (S. fontinalis), Arctic char (S. alpinus), and lake trout (S. namaycush). In addition, this assay was compared with an extensively used mitochondrial bull trout assay and it was found that the ITSI-based assay produced higher detectability. Our results suggest this assay should out-perform the published mtDNA assay across the range of bull trout, while the added specificity allows reliable bull trout detection in areas where bull trout co-occur with other charr such as Dolly Varden. While clearly a superior assay in this instance, basing assays on ITSI is not without problems. For vertebrates, there are fewer ITSI sequences available than commonly sequenced regions of the mitochondrial genome. Thus, the initial in silico screening of candidate assays must be preceded by much more extensive sampling and sequencing of sympatric or closely related taxa. Further, all copies of the internal transcribed spacers within an individual may not be identical, which can lead to complications. Lastly, the copy number for ITSI varies widely across taxa; the greater detectability associated with this assay cannot be assumed for other species.

Repurposing environmental DNA samples-detecting the western pearlshell (Margaritifera falcata) as a proof of concept.

Information on the distribution of multiple species in a common landscape is fundamental to effective conservation and management. However, distribution data are expensive to obtain and often limited to high-profile species in a system. A recently developed technique, environmental DNA (eDNA) sampling, has been shown to be more sensitive than traditional detection methods for many aquatic species. A second and perhaps underappreciated benefit of eDNA sampling is that a sample originally collected to determine the presence of one species can be re-analyzed to detect additional taxa without additional field effort. We developed an eDNA assay for the western pearlshell mussel (Margaritifera falcata) and evaluated its effectiveness by analyzing previously collected eDNA samples that were annotated with information including sample location and deposited in a central repository. The eDNA samples were initially collected to determine habitat occupancy by nonbenthic fish species at sites that were in the vicinity of locations recently occupied by western pearlshell. These repurposed eDNA samples produced results congruent with historical western pearlshell surveys and permitted a more precise delineation of the extent of local populations. That a sampling protocol designed to detect fish was also successful for detecting a freshwater mussel suggests that rapidly accumulating collections of eDNA samples can be repurposed to enhance the efficiency and cost-effectiveness of aquatic biodiversity monitoring.

qPCR detection of Sturgeon chub (Macrhybopsis gelida) DNA in environmental samples.

The Sturgeon chub (Macrhybopsis gelida) is a cyprinid fish native to the Missouri and Mississippi River basins of the U.S. Suspected long-term declines in the size of its distribution have prompted a review of its conservation status by the U.S. Fish and Wildlife Service, a process which depends on reliable methods to delineate the distribution and status of extant populations. To facilitate monitoring of Sturgeon chub populations, we developed a quantitative PCR assay to detect Sturgeon chub DNA in environmental samples. The assay consistently detected Sturgeon chub DNA in concentrations as low as 2 copies per reaction, and did not amplify DNA from non-target fish species that are sympatric in the upper Missouri River basin. Field tests of this assay with environmental samples successfully detected Sturgeon chub from sites known to be occupied. This assay offers an extremely sensitive methodology that can be applied to determine the range of Sturgeon chub, regardless of variation in habitat characteristics.

Rationalizing Acid Zeolite Performance on the Nanoscale by Correlative Fluorescence and Electron Microscopy.

The performance of zeolites as solid acid catalysts is strongly influenced by the accessibility of active sites. However, synthetic zeolites typically grow as complex aggregates of small nanocrystallites rather than perfect single crystals. The structural complexity must therefore play a decisive role in zeolite catalyst applicability. Traditional tools for the characterization of heterogeneous catalysts are unable to directly relate nanometer-scale structural properties to the corresponding catalytic performance. In this work, an innovative correlative super-resolution fluorescence and scanning electron microscope is applied, and the appropriate analysis procedures are developed to investigate the effect of small-port H-mordenite (H-MOR) morphology on the catalytic performance, along with the effects of extensive acid leaching. These correlative measurements revealed catalytic activity at the interface between intergrown H-MOR crystallites that was assumed inaccessible, without compromising the shape selective properties. Furthermore, it was found that extensive acid leaching led to an etching of the originally accessible microporous structure, rather than the formation of an extended mesoporous structure. The associated transition of small-port to large-port H-MOR therefore did not render the full catalyst particle functional for catalysis. The applied characterization technique allows a straightforward investigation of the zeolite structure-activity relationship beyond the single-particle level. We conclude that such information will ultimately lead to an accurate understanding of the relationship between the bulk scale catalyst behavior and the nanoscale structural features, enabling a rationalization of catalyst design.

Comparing Loudness Tolerance and Acceptable Noise Level in Listeners With Hearing Loss.

The present study was a follow-up investigation to a previous study exploring the relationship between listeners' loudness tolerance and listeners' acceptable noise level among normally hearing adults. The present study compared the same two measures, but data were obtained from listeners with hearing loss; 12 adults with sensorineural hearing loss participated in a loudness tolerance measure using a scaling technique initially established for setting hearing aid output limits, in addition to an acceptable noise level measure. The acceptable noise level procedure used in this study quantified the listeners' acceptance of background noise while listening to speech. As with the research involving listeners with normal hearing, the Pearson correlation procedure indicated a lack of any statistically significant correlation between the two measures.

Multimodal psychoanalytic and dialectical behavioral approaches: a case study.

Psychoanalysis and dialectical behavior therapy (DBT) benefit populations that overlap in many ways. Patients who seek both treatments often have significant problems with affect regulation, relationships, and workplace functioning. This article's case report describes a patient receiving both treatments concurrently, and demonstrates that these interventions may be synergistic and can be effective when used together.

The relationship between the acceptance of noise and acoustic environments in young adults with normal hearing: a pilot study.

BACKGROUND: The acceptable noise level (ANL) indicates how much background noise a listener is willing to accept while listening to speech. The clinical impact and application of the ANL measure is as a predictor of hearing-aid use. The ANL may also correlate with the percentage of time spent in different listening environments (i.e., quiet, noisy, noisy with speech present, etc). Information retrieved from data logging could confirm this relationship. Data logging, using sound scene analysis, is a method of monitoring the different characteristics of the listening environments that a hearing-aid user experiences during a period. PURPOSE: The purpose of this study was to determine if the ANL procedure reflects the proportion of time a person spends in different acoustic environments. RESEARCH DESIGN: This was a descriptive quasi-experimental design to collect pilot data in which participants were asked to maintain their regular, daily activities while wearing a data-logging device. STUDY SAMPLE: After completing the ANL measurement, 29 normal-hearing listeners were provided a data-logging device and were instructed on its proper use. DATA COLLECTION/ANALYSIS: ANL measures were obtained along with the percentage of time participants spent in listening environments classified as quiet, speech-in-quiet, speech-in-noise, and noise via a data-logging device. RESULTS: An analysis of variance using a general linear model indicated that listeners with low ANL values spent more time in acoustic environments in which background noise was present than did those with high ANL values; the ANL data did not indicate differences in how much time listeners spent in environments of differing intensities. CONCLUSIONS: To some degree, the ANL is reflective of the acoustic environments and the amount of noise that the listener is willing to accept; data logging illustrates the acoustic environments in which the listener was present. Clinical implications include, but are not limited to, decisions in patient care regarding the need for additional counseling and/or the use of digital noise reduction and directional microphone technology.

Phenylketonuria Scientific Review Conference: state of the science and future research needs.

New developments in the treatment and management of phenylketonuria (PKU) as well as advances in molecular testing have emerged since the National Institutes of Health 2000 PKU Consensus Statement was released. An NIH State-of-the-Science Conference was convened in 2012 to address new findings, particularly the use of the medication sapropterin to treat some individuals with PKU, and to develop a research agenda. Prior to the 2012 conference, five working groups of experts and public members met over a 1-year period. The working groups addressed the following: long-term outcomes and management across the lifespan; PKU and pregnancy; diet control and management; pharmacologic interventions; and molecular testing, new technologies, and epidemiologic considerations. In a parallel and independent activity, an Evidence-based Practice Center supported by the Agency for Healthcare Research and Quality conducted a systematic review of adjuvant treatments for PKU; its conclusions were presented at the conference. The conference included the findings of the working groups, panel discussions from industry and international perspectives, and presentations on topics such as emerging treatments for PKU, transitioning to adult care, and the U.S. Food and Drug Administration regulatory perspective. Over 85 experts participated in the conference through information gathering and/or as presenters during the conference, and they reached several important conclusions. The most serious neurological impairments in PKU are preventable with current dietary treatment approaches. However, a variety of more subtle physical, cognitive, and behavioral consequences of even well-controlled PKU are now recognized. The best outcomes in maternal PKU occur when blood phenylalanine (Phe) concentrations are maintained between 120 and 360 µmol/L before and during pregnancy. The dietary management treatment goal for individuals with PKU is a blood Phe concentration between 120 and 360 µmol/L. The use of genotype information in the newborn period may yield valuable insights about the severity of the condition for infants diagnosed before maximal Phe levels are achieved. While emerging and established genotype-phenotype correlations may transform our understanding of PKU, establishing correlations with intellectual outcomes is more challenging. Regarding the use of sapropterin in PKU, there are significant gaps in predicting response to treatment; at least half of those with PKU will have either minimal or no response. A coordinated approach to PKU treatment improves long-term outcomes for those with PKU and facilitates the conduct of research to improve diagnosis and treatment. New drugs that are safe, efficacious, and impact a larger proportion of individuals with PKU are needed. However, it is imperative that treatment guidelines and the decision processes for determining access to treatments be tied to a solid evidence base with rigorous standards for robust and consistent data collection. The process that preceded the PKU State-of-the-Science Conference, the conference itself, and the identification of a research agenda have facilitated the development of clinical practice guidelines by professional organizations and serve as a model for other inborn errors of metabolism.

Ionoluminescence in the helium ion microscope.

Ionoluminescence (IL) is the emission of light from a material due to excitation by an ion beam. In this work, a helium ion microscope (HIM) has been used in conjunction with a luminescence detection system to characterize IL from materials in an analogous way to how cathodoluminescence (CL) is characterized in a scanning electron microscope (SEM). A survey of the helium ion beam induced IL characteristics, including images and spectra, of a variety of materials known to exhibit CL in an SEM is presented. Direct band-gap semiconductors that luminesce strongly in the SEM are found not do so in the HIM, possibly due to defect-related nonradiative pathways created by the ion beam. Other materials do, however, exhibit IL, including a cerium-doped garnet sample, quantum dots, and rare-earth doped LaPO4 nanocrystals. These emissions are a result of transitions between f electron states or transitions across size dependent band gaps. In all these samples, IL is found to decay with exposure to the beam, fitting well to double exponential functions. In an exploration of the potential of this technique for biological tagging applications, imaging with the IL emitted by rare-earth doped LaPO4 nanocrystals, simultaneously with secondary electron imaging, is demonstrated at a range of magnifications.

Relationship between loudness tolerance and the acceptance of background noise for young adults with normal hearing.

This study investigated the relationship between listener loudness tolerance and listener acceptable noise level (ANL). Twenty-five normal hearing adults completed loudness tolerance and acceptable noise level measures. Loudness tolerance was measured using a scaling technique. The acceptable noise levels were calculated from a procedure designed to quantify a listener's willingness to accept background noise while listening to speech. Pearson correlation confirmed that loudness tolerance and acceptable noise levels are not related.

Comparing pure-, pulsed, and warbled tone thresholds in adults at 3000 and 6000 Hz.

PURPOSE: Pulsed and warbled tones are suitable substitutions for pure tones in hearing threshold measurement according to the 2005 American Speech-Language-Hearing Association guidelines. These guidelines also recommend measuring thresholds at 3000 and 6000 Hz. To date, there is no research directly supporting substitution of pulsed or warbled tones for pure tones at 3000 and 6000 Hz for listeners with normal hearing or with hearing loss. This study compared pure-, pulsed, and warbled tone thresholds at 3000 and 6000 Hz. METHOD: Forty-seven adults with normal hearing and 16 adults with sensorineural hearing loss participated in this study. Air-conduction thresholds were elicited with pure tones at octave intervals from 250 to 8000 Hz and with pure-, pulsed, and warbled tone stimuli at 3000 and 6000 Hz. RESULTS: Small mean differences in thresholds were obtained using each of the 3 stimulus types for both listeners with normal hearing and hearing loss. Some of the mean differences tested were found to be statistically significant. The differences were nevertheless small and in all cases within the clinically accepted 5-dB step size. CONCLUSION: Although substitutions did not violate the 5-dB step size, the slope of a listener's hearing loss may be a factor in the inaccuracy of measurement during the substitution of warbled tones for pure tones.

Does minor trauma cause serious low back illness?

STUDY DESIGN: Prospective, 5-year, cohort study of working subjects. OBJECTIVES: To assess whether the occurrence of common minor trauma events affects the risk of developing serious low back pain (LBP) and LBP disability in subjects with and without degenerative changes to the lumbar spine. SUMMARY OF BACKGROUND DATA: Although some theories suggest that minor traumatic events in combination with preexisting degenerative changes commonly cause significant structural injury to spinal segments and serious LBP illness, no prospective data exist on the relationship of minor trauma, detailed structural changes, and outcome measures of serious LBP episodes and occupational disability. METHODS: Two hundred subjects without clinical LBP problems were recruited, and underwent baseline clinical and imaging studies. Every 6 months, subjects completed a scripted, algorithm-based interview assessing interval back pain episodes, severity, medical treatment, occupational disability, and the subject's perceived relation of this LBP episode to any preceding event. If a serious LBP episode clinically required a new magnetic resonance examination, the follow-up imaging was obtained and compared to baseline for interval changes. RESULTS: There was no association of minor trauma to adverse LBP events. For each 6-month study interval, the risk of developing a serious LBP episode was 2.1% unassociated with minor trauma and 2.4% following minor trauma (P = 0.59). Neither the frequency of minor trauma events nor the reported severity of the event correlated with adverse outcomes. Subjects with advanced structural findings were not more likely to become symptomatic with minor trauma events than with spontaneously evolving LBP episodes. Follow-up magnetic resonance imaging evaluating new serious LBP illness rarely revealed new clinically significant findings. Age and sex-adjusted prediction models, including abnormal psychometric testing, smoking, and compensation issues, accurately identified 80% of serious LBP events and 93% of LBP disability events. CONCLUSIONS: In this study cohort, minor trauma does not appear to increase the risk of serious LBP episodes or disability. The vast majority of incident-adverse LBP events may be predicted not by structural findings or minor trauma but by a small set of demographic and behavioral variables.

Are first-time episodes of serious LBP associated with new MRI findings?

BACKGROUND: Magnetic resonance (MR) imaging is frequently used to evaluate first-time episodes of serious low back pain (LBP). Common degenerative findings are often interpreted as recent developments and the probable anatomic cause of the new symptoms. To date no prospective study has established a baseline MR status of the lumbar spine in subjects without significant LBP problems and prospectively surveyed these subjects for acute changes shortly after new and serious LBP episodes. This method can identify new versus old MR findings possibly associated with the acute symptomatic episode. PURPOSE: To determine if new and serious episodes of LBP are associated with new and relevant findings on MRI. STUDY DESIGN: Prospective observational study with baseline and post-LBP MRI monitoring of 200 subjects over 5 years. OUTCOME MEASURES: Clinical outcomes: LBP intensity (visual analogue scale), Oswestry Disability Index, and work loss. MRI outcomes: disc degeneration, herniation, annular fissures, end plate changes, facet arthrosis, canal stenosis, spondylolisthesis, and root impingement. METHODS: 200 subjects with a lifetime history of no significant LBP problems, and a high risk for new LBP episodes were studied at baseline with physical examination, plain radiographs, and MR imaging. Subjects were followed every 6 months for 5 years with a detailed telephone interview. Subjects with a new severe LBP episode (LBP>or=6/10,>1 week) were assessed for new diagnostic tests. New MR imaging, taken within 6 to 12 weeks of the start of a new LBP episode, was compared with baseline (asymptomatic) images. Two independent and blinded readers evaluated each baseline and follow-up study. RESULTS: During the 5-year observation period of 200 subjects, 51 (25%) subjects were evaluated with a lumbar MRI for clinically serious LBP episodes, and 3/51 (6%) had a primary radicular complaint. These 51 subjects had 67 MR scans. Of 51 subjects, 43 (84%) had either unchanged MR or showed regression of baseline changes. The most common progressive findings were disc signal loss (10%), progressive facet arthrosis (10%), or increased end plate changes (4%). Only two subjects, both with primary radicular complaints, had new findings of probable clinical significance (4%). Subjects having another MR were more likely to have had chronic pain at baseline (odds ratio [OR]=3.19; 95% confidence interval [CI] 1.61-6.32), to smoke (OR=5.81; 95% CI 1.99-16.45), have baseline psychological distress (OR 2.27; 95% CI 1.15-4.49), and have previous disputed compensation claims (OR=2.35; 95% CI 0.97-5.69). Subjects involved in current compensation claims were also more likely to have an MR scan to evaluate the LBP episode (risk ratio=4.75, p<.001), but were unlikely to have significant new findings. New findings were not more frequent in subjects with LBP episodes developing after minor trauma than when LBP developed spontaneously. CONCLUSION: Findings on MR imaging within 12 weeks of serious LBP inception are highly unlikely to represent any new structural change. Most new changes (loss of disc signal, facet arthrosis, and end plate signal changes) represent progressive age changes not associated with acute events. Primary radicular syndromes may have new root compression findings associated with root irritation.

Qualitative research: implications for description and assessment.

As clinical speech-language pathologists seeking different ways to understand the complexity of communication within naturalistic and social contexts, we are progressively adapting the qualitative research methods of the social sciences for our assessment purposes. This article discusses some basic principles and practices discussed previously in this forum on qualitative research and demonstrates how they can be employed to provide effective and sufficient clinical communicative assessment.