bluuebunny/crossref_metadata_2025 huggingface dataset:
Historiography and the politics of land, identity, and belonging in the twentieth-century North Caucasus
Authors: Lanzillotti Ian T.
Published: June 2016

Intercommunal, socio-economic, and political relations in the North Caucasus have historically revolved around access to this mountain region's prized pasturage and scarce farmland. Given the centrality of the land question in the North Caucasus, it is unsurprising that historiography on land relations in the region has been highly politicized. This article examines how indigenous writing on the history of land relations in the central Caucasus – a region inhabited by today's Kabardians, Balkars, Ossetians, Ingushes, and Karachais, and dominated by the princely confederation of Kabarda before the tsarist conquest – has been subject to wide revision in response to changes in local and national political dynamics and the emergence of ethnicized identity politics. In the late-imperial and early Soviet periods, Karachai, Balkar, and Ossetian elites-cum-historians, writing for an audience of imperial policy-makers, crafted histories to influence state policies toward land reform. By the 1930s, historians from the region tailored their histories of land relations to the prerogatives of Soviet nationality policies. The ideas contained in these histories impacted the construction of national identities in the Soviet period. Post-Soviet Karachai and Balkar intellectuals, seeking to establish new post-colonial national histories for their peoples, have reinterpreted the history of land relations in order to depict their ancestors as independent of Kabarda's land-based dominance. This revisionism is part of the struggle of the Karachais and Balkars against their historiographical erasure, which was a product of the exclusion of the Karachais and Balkars from the family of Soviet nations during their deportation and exile to Central Asia from 1944 to 1957 and their subsequent political and cultural marginalization.
Effects of various concentrations of carbohydrate mouth rinse on cycling performance in a fed state
Authors: Devenney Simon , Collins Kieran , Shortall Marcus
Published: June 2016

The objective of this study was to identify the effects of mouth rinsing with a 6% and 16% carbohydrate solution (CHO) on time trial performance when compared to a 0% control (PLA) when in a fed state. Twelve recreationally active males underwent three trials by which they had to complete a set workload (600 ± 65 W) in a fed state. Throughout each trial, participants rinsed their mouths with a 25 ml bolus of a 0% PLA, 6% or 16% CHO (maltodextrin) for every 12.5% of work completed. Rating of perceived exertion (RPE) and heart rate were recorded every 12.5% of total work. Performance times and power output improved significantly when using the 6% and 16% CHO versus the PLA trial (6% versus PLA, p = .002 and 16% versus PLA, p = .001). When comparing the performance times of the 6% to 16% CHO, no significance was observed (p = .244). There was no significant difference between heart rate levels or RPE values across the three trials. In conclusion, mouth rinsing with a 6% or 16% CHO solution has a positive effect on a cycling time trial performance undertaken in a fed state.
Biogeography and evolutionary diversification in one of the most widely distributed and species rich genera of the Pacific
Authors: Cantley Jason T. , Markey Adrienne S. , Swenson Nathan G. , Keeley Sterling C.
Published: June 2016

The historical biogeography of many lineages—of both terrestrial and marine ocean habitats—remains poorly investigated even though remote ocean habitat covers approximately 66% of the Earth’s surface. One such lineage with poorly understood biogeographic affinities across vast ocean habitat is the genus Coprosma (Rubiaceae) with numerous species, and a widespread and disjunct distribution among the far-flung insular localities of multiple Pacific Islands. Here, the first taxonomically robust phylogeny for Coprosma s.s. was dated using molecular clock techniques and indicated Coprosma s.s. diverged from its sister genus Nertera likely during or shortly after the Oligocene Marine Transgression of New Zealand. Diversification of the five major clades identified occurred in New Zealand during the Miocene, which was then followed by multiple independent dispersals from New Zealand to various localities in many directions. The pattern of Coprosma ’s distribution in the Pacific appears stochastic both temporally and spatially, but evolution of an orange to red fruit colour prior to nearly all inferred dispersals hints at endozoochory by birds. The number of inferred long-distance dispersals of Coprosma s.s. (>30), and number of repeated dispersals to the same insular locality from unrelated Coprosma s.s. sublineages (>8) is perhaps the most currently known for a remote Pacific-centred genus investigated to date. A New Zealand origin for a Pacific-wide dispersal of taxa is not novel, but the manner in which the temporal and spatial distribution for Coprosma s.s. was achieved contributes to a novel understanding of the historical biogeography of widespread Pacific genera that have origins in the Southern Hemisphere.
Influence of management regime and harvest date on the forage quality of rangelands plants: the importance of dry matter content
Authors: Bumb Iris , Garnier Eric , Bastianelli Denis , Richarte Jean , Bonnal Laurent , Kazakou Elena
Published: June 2016

In spite of their recognized ecological value, relatively little is known about the nutritional value of species-rich rangelands for herbivores. We investigated the sources of variation in dry matter digestibility (DMD), neutral detergent fibre content (NDF) and nitrogen concentration (NC) in plants from species-rich Mediterranean rangelands in southern France, and tested whether the dry matter content (DMC) was a good predictor of the forage quality of different plant parts. Sixteen plant species with contrasting growth forms (rosette, tussock, extensive and stemmed-herb) were studied, representative of two management regimes imposed in these rangelands: (i) fertilization and intensive grazing and (ii) non-fertilization and moderate grazing. Among the 16 plant species, four species were found in both treatments, allowing us to assess the intraspecific variability in forage quality and DMC across the treatments. The components of nutritional value (DMD, NDF and NC) as well as the DMC of leaves, stems and reproductive plant parts, were assessed at the beginning of the growing season and at peak standing biomass. All components of nutritional value and DMC were affected by species growth form: rosettes had higher DMD and NC than tussocks; the reverse being found for NDF and DMC. As the season progressed, DMD and NC of the different plant parts decreased while NDF and DMC increased for all species. DMC was negatively related to DMD and NC and positively to NDF, regardless of the source of variation (species, harvest date, management regime or plant part). Path analysis indicated that NDF was the main determinant of DMD. Better assessment of forage quality in species-rich systems requires consideration of their growth form composition. DMC of all plant parts, which is closely related to NDF, emerged as a good predictor and easily measured trait to estimate DMD in these species-rich systems.
SERAPHIM: studying environmental rasters and phylogenetically informed movements
Authors: Dellicour Simon , Rose Rebecca , Faria Nuno R. , Lemey Philippe , Pybus Oliver G.
Published: June 2016

Summary: SERAPHIM (“Studying Environmental Rasters and PHylogenetically Informed Movements”) is a suite of computational methods developed to study phylogenetic reconstructions of spatial movement in an environmental context. SERAPHIM extracts the spatio-temporal information contained in estimated phylogenetic trees and uses this information to calculate summary statistics of spatial spread and to visualize dispersal history. Most importantly, SERAPHIM enables users to study the impact of customized environmental variables on the spread of the study organism. Specifically, given an environmental raster, SERAPHIM computes environmental “weights” for each phylogeny branch, which represent the degree to which the environmental variable impedes (or facilitates) lineage movement. Correlations between movement duration and these environmental weights are then assessed, and the statistical significances of these correlations are evaluated using null distributions generated by a randomization procedure. SERAPHIM can be applied to any phylogeny whose nodes are annotated with spatial and temporal information. At present, such phylogenies are most often found in the field of emerging infectious diseases, but will become increasingly common in other biological disciplines as population genomic data grows.

Availability and Implementation: SERAPHIM 1.0 is freely available from http://evolve.zoo.ox.ac.uk/. R package, source code, example files, tutorials and a manual are also available from this website.

Contact:  simon.dellicour@kuleuven.be or oliver.pybus@zoo.ox.ac.uk

Supplementary information: Supplementary data are available at Bioinformatics online.
Population structure, gene flow, and historical demography of a small coastal shark (Carcharhinus isodon) in US waters of the Western Atlantic Ocean
Authors: Portnoy David S. , Hollenbeck Christopher M. , Bethea Dana M. , Frazier Bryan S. , Gelsleichter Jim , Gold John R.
Published: June 2016

Patterns of population structure, genetic demographics, and gene flow in the small coastal shark Carcharhinus isodon (finetooth shark) sampled from two discrete nurseries along the southeastern US coast (Atlantic) and three nurseries in the northern Gulf of Mexico (Gulf), were assessed using 16 nuclear-encoded microsatellites and 1077 base pairs of the mitochondrial DNA (mtDNA) control region. Significant heterogeneity in microsatellite allele distributions was detected among all localities except between the two in the Atlantic. Significant heterogeneity in mtDNA haplotypes was not detected, a result likely due to extremely low mtDNA diversity. The genetic discontinuities combined with seasonal movement patterns, a patchy distribution of appropriate nursery habitat, the apparent absence of sex-biased gene flow, and the occurrence of mating in the vicinity of nursery areas, suggest that both male and female finetooth sharks display regional philopatry to discrete nursery areas. Global and local tests of neutrality, using mtDNA haplotypes, and demographic model testing, using Approximate Bayesian Computation of microsatellite alleles, supported a range-wide expansion of finetooth sharks into US waters occurring less than ∼9000 years ago. These findings add to the growing number of studies in a variety of coastally distributed marine fishes documenting significant barriers to gene flow around peninsular Florida and in the eastern Gulf. The findings also provide further evidence that the traditional model of behavioural ecology, based on large coastal sharks, may not be appropriate for understanding and conserving small coastal sharks.
A review of methods used to analyse albatross diets—assessing priorities across their range
Authors: McInnes Julie C. , Raymond Ben , Phillips Richard A. , Jarman Simon N. , Lea Mary-Anne , Alderman Rachael
Published: June 2016

Many seabird populations are threatened by interactions with commercial fisheries, and climate change. Understanding their prey requirements and dietary flexibility in this context is important for effective conservation and management. However, changes in the methods used to assess diet, as well as the spatial and temporal coverage of monitoring schemes, may reduce our ability to detect and monitor these marine threats. To help assess conservation priorities linked to diet, we performed a systematic review of 109 albatross diet papers published between 1950 and 2016, which corresponded to 296 studies when stratified by sampling year, breeding site, and breeding species. We assessed the methods used, changes over time, and spatial and temporal sampling coverage by species and island group. Most albatross studies have focused on chick-rearing, and diet during other breeding phases is comparatively poorly known. Furthermore, chicks are more commonly sampled than adults and very rarely immature birds, all of which may differ in diet composition. There was a pronounced shift over time in the preferred method of characterising diet, from the morphological examination of prey remains to stable isotope analysis of tissue. This shift has reduced the volume of detailed taxonomic information available from morphological studies. This difference in resolution hinders the ability to detect changes in prey species, with implications for management of threatened albatrosses and for monitoring broader changes in marine ecosystems. In a knowledge gap analysis for important breeding colonies (with >5% of global population), we identified key sites where existing monitoring has provided a foundation for robust longitudinal diet studies. Maintaining and augmenting these long-term research programmes will enable analyses of the impacts of changing climate and fishing practices on seabird populations and facilitate the timely identification and implementation of management options.
Basics of Neurophysiology
Authors: Stead Squire M. , Daube Jasper R.
Published: June 2016

The transmission of information in the nervous system depends on the generation of a resting potential that acts as a reserve of energy poised for release when the valve is turned on. Ionic channels act as the valve, controlling the energy in the ionic concentration gradient. The release of energy is seen either as local graded potentials or as propagated action potentials that arise when local potentials reach threshold. Information is moved from one area to another as action potentials conducted by single cells. The information is integrated in neurons by the interaction of local potentials generated in response to the neurotransmitters released from depolarized nerve terminals., The combined activity of large numbers of cells and axons determines the behavior of the organism. Each type of alteration in neuronal or muscle cell physiology can produce symptoms of short-duration, transient disorders.
Electrophysiological Generators in Clinical Neurophysiology
Authors: Lagerlund Terrence D.
Published: June 2016

The variety of clinical neurophysiological studies corresponds to a variety of structural generators in the body, including muscles, sweat glands, peripheral nerves, and various components of the central nervous system. Each structural generator may have associated with it several different types of physiological potential. This chapter reviews the generators of electrophysiological potentials in terms of basic cellular electrophysiology and the anatomical structures that generate electrophysiological potentials of clinical interest. Knowledge of the generators of the potentials recorded in clinical neurophysiological studies is helpful in understanding the characteristics and distribution of the recorded potentials and is the first step in correlating the alterations seen in disease states with the pathological changes demonstrated in the underlying generators.
Waveforms and Artifacts
Authors: Rubin Devon I. , Daube Jasper R.
Published: June 2016

Spontaneously generated or stimulus-induced electrical signals from neural tissue in the central, peripheral, and autonomic systems are recorded and displayed as waveforms through digital equipment in neurophysiological testing. The waveforms recorded in clinical neurophysiology are divided into continuous waveforms and intermittent, discrete waveforms or events. Continuous waveforms are described by their frequency components, amplitudes, and distributions. Discrete waveforms are described by their individual amplitudes, durations, and configurations as well as by their patterns of occurrence and distribution. Changes in each of these waveform parameters may occur in diseases, and discrete waveforms themselves may be abnormal. Artifacts can alter all of the variables used to describe the continuous and discrete waveforms recorded in clinical neurophysiology. This chapter reviews concepts related to the various waveforms recorded in clinical neurophysiology.
Adult Electroencephalography
Authors: Britton Jeffrey W.
Published: June 2016

EEG is an important tool used to assess patients with central nervous system symptoms. Recognition of normal EEG patterns and normal variants is necessary to appropriately interpret the study. This chapter reviews the features of the normal awake and asleep EEG and discusses important variants of normal, called “benign variants.” It is critical that any person interpreting EEGs be knowledgeable regarding the range of findings seen in the normal EEG, and become familiar with benign variants that can be mistaken for pathological abnormalities, leading to misdiagnosis and inappropriate treatment. Multiple illustrative figures are provided to aid the reader in recognizing these key features.
Adult EEG
Authors: Britton Jeffrey W.
Published: June 2016

Artifacts are ubiquitous in EEG, and can significantly affect EEG interpretation. Artifacts may mimic pathological abnormalities, and may obscure the underlying EEG; thereby contributing to errors of omission. Artifacts may result from physiological phenomena (such as electrical cardiac signal, eye movement, etc.) or due to external, non-physiological electrical sources. Recognition of common artifacts is essential in order to avoid erroneous EEG interpretation. Identification of the source of EEG artifact is also essential in order to rectify them early during EEG acquisition. This chapter discusses numerous artifact types caused by physiological phenomena, equipment issues, and environmental factors. Multiple figures are provided to aid the reader in recognizing these key features of the EEG.
Adult EEG
Authors: Noe Katherine H. , Drazkowski Joseph F.
Published: June 2016

Epileptiform discharges present on routine EEG recordings highly correlate with a tendency for clinical seizures. When present, they can help confirm a diagnosis of epilepsy and classify epilepsy type, localization, and syndrome. EEG’s sensitivity for detecting epileptiform activity depends on many factors, including the site of seizure origin and seizure frequency. Even in persons with known epilepsy, a routine EEG can often be normal; thus a normal interictal EEG should not be used to exclude an epilepsy diagnosis. Misinterpretation or “over-reading” of artifacts and normal background activity on the EEG as epileptiform is common by inexperienced readers. Unfortunately, this can lead to misdiagnosis and inappropriate treatment. The EEG reader should be familiar with the commonly encountered epileptiform patterns of generalized spike and wave, generalized slow spike and wave, generalized paroxysmal fast activity, focal spike and sharp waves, and temporal intermittent rhythmic delta activity.
Pediatric EEG
Authors: Wong-Kisiel Lily C. , Wirrell Elaine C.
Published: June 2016

Electroencephalography (EEG) is an important part of the evaluation of many disorders in infants and children, including seizures and spells. This chapter identifies abnormal epileptiform patterns seen in infants and children and correlates these patterns to specific seizure types and electroclinical syndromes. Generalized discharge (associated with genetic generalized epilepsies as well as epileptic encephalopathies), focal discharge (associated with benign focal epilepsies as well as lesional epilepsies), and hypsarrhythmia are discussed. Additionally, abnormal, but non-epileptiform patterns—including periodic patterns, triphasic waves, intermittent rhythmic delta activity, suppression, asymmetry, and slowing—are reviewed. Specific etiologies associated with various abnormalities on pediatric EEG are identified.
Computer-Assisted Ambulatory Electroencephalography
Authors: Shih Jerry J. , Tatum William O.
Published: June 2016

Computer-assisted ambulatory electroencephalography (CAAEEG) is a useful tool when a diagnosis of paroxysmal events cannot be made on the basis of the clinical history, neurological examination, and routine outpatient awake and asleep EEG studies. CAEEG is uniquely able to monitor EEG and electrocardiography (ECG) in an outpatient environment over one to three days. Its most common use is to support a clinical diagnosis of epileptic seizures by identifying interictal epileptiform discharges. Studies indicate ambulatory EEG provides useful clinical information for patient management in over 70% of recordings. CAAEEG may be particularly useful in the pediatric age group, as well as in diagnosing psychogenic events. CAAEEG can assist in the quantification of seizures or determining seizure frequency. A few centers have used CAAEEG to assist in the presurgical evaluation of epilepsy patients. Its niche involves lower cost and less resource utilization compared with in-patient video-EEG monitoring and is more sensitive than routine outpatient EEG in detecting interictal epileptiform discharges.
EEG Trend Analysis in the ICU
Authors: Crepeau Amy Z.
Published: June 2016

Continuous EEG monitoring can increase the detection of subclinical seizures, and is important in managing nonconvulsive status epilepticus. In the ICU it presents challenges not routinely encountered in the outpatient EEG laboratory or the epilepsy monitoring unit: multiple sources of artifact, and the need for imaging-compatible electrodes and a robust IT support system. Rhythmic and periodic patterns of indeterminate significance are encountered. There is much debate as to the true significance of these patterns, and clinical correlation is always required. Special techniques can be employed in the application and analysis of ICU EEG monitoring. EEG has been useful in monitoring for ischemia, prognosis, and depth of medication-induced suppression. Quantitative EEG can also be utilized to assist in rapid seizure detection, and to monitor for subtle gradual changes in cerebral function and seizure detection. The special environment, however, requires close attention to technical considerations, and thoughtful interpretations of indeterminate patterns.
Clinical Applications
Authors: So Elson L.
Published: June 2016

Many electrophysiological assessment and techniques of clinical neurophysiology can be used in the assessment of patients with suspected disease of the central nervous system. Each of the techniques is applied either to assist clinicians in assessing disease of the central nervous system or, less commonly, to monitor changes in neural function. These techniques can be used to monitor neural function in observing progression of disease, such as the frequency of seizures, or improvement in a patient’s condition with specific treatment. They are also used in the intensive care unit and operating room to identify progressive neural damage. The clinical neurophysiological testing technique that is most appropriate for a patient depends on the clinical problem, and, often, some combination of techniques best provides the necessary data. This chapter focuses on the application of clinical neurophysiological techniques in assessing patients with suspected central nervous system disorders.
Late Responses
Authors: Laughlin Ruple S.
Published: June 2016

Late responses are a group of responses occurring after the compound muscle action potential (M-wave) in motor nerve conduction studies and include F-waves, H-reflexes, and axon reflexes. These responses can indirectly measure aspects of proximal conduction that are not obtained with routine motor nerve conduction studies and may be useful in assessing diseases that affect proximal nerves, such as polyradiculopathies. A thorough understanding of the physiological basis, sources of error, and clinical applications and limitations enhances the usefulness of F-waves and H-reflexes as one means to evaluate proximal functioning of the motor and sensory nerves. This chapter will discuss the study methods and applications of F-waves and H-reflexes.
Quantitative Motor Unit Number Estimates
Authors: Sorenson Eric J. , Daube Jasper R.
Published: June 2016

Quantitative motor unit number estimates (MUNE) quantify the number of viable motor axons that innervate a muscle or muscle group. Various techniques have been developed to accomplish this, but no single technique has demonstrated superiority. The MUNE is calculated from the supramaximal compound muscle action potential (CMAP) by dividing the CMAP by the mean size of the motor unit potentials. The resulting unit-less number represents the number of motor units within a muscle or muscle group. MUNE has been applied most widely to disorders of the motor neuron such as ALS, spinal muscular atrophy, and polio, and it has been used in animal and human studies, and as an outcome measure in clinical trials for ALS and spinal muscular atrophy. Because of the limitations of MUNE (including patient discomfort, prolonged time to perform, and technical expertise for reliable results), it has not entered into routine clinical practice at this time.
Quantitative Electromyography
Authors: Smith Benn E.
Published: June 2016

Semi-quantitative EMG methods are in common use in clinical electromyography laboratories but have a number of drawbacks and limitations, including examiner bias in MUP analysis and challenges distinguishing between MUP categories of normal and neurogenic and normal and myopathic waveforms. An array of formal MUP quantitation methods has been developed in recent decades, which seek to address many of the shortcomings of semiquantitative EMG. The advantages of quantitative EMG (QEMG) include: (1) making measurements of MUP recordings consisting of numerical values derived from precise measurements, (2) generating normative data and allowing comparisons with data from patients with suspected neuromuscular diseases, (3) allowing for reproducible results that can be compared at different times by different examiners and in different labs, and (4) allowing accurate assessment of improvement or deterioration in disease severity over time.
Neuromuscular Ultrasound in the EMG Lab
Authors: Boon Andrea J.
Published: June 2016

Neuromuscular ultrasound is a portable, relatively inexpensive, widely available imaging modality that can be used to enhance the electrodiagnostic evaluation by improving its safety and accuracy, particularly in high-risk settings such as obesity, altered anatomy, anticoagulation, or other technically challenging situations. Furthermore, the emerging field of neuromuscular ultrasound has the potential to significantly increase diagnostic yield in patients presenting for electrodiagnostic testing. Focal lesions affecting nerve or muscle as well as more generalized polyneuropathy and myopathy can be diagnosed and characterized with ultrasound, including certain cases in which electrodiagnostic testing is inconclusive or negative. This chapter will review the rationale for combining electrodiagnosis with sonography in the clinical setting, including use of ultrasound to enhance safety and diagnostic yield when evaluating for neuromuscular respiratory failure.
Pitfalls and Potential Complications of Needle EMG
Authors: Rubin Devon I.
Published: June 2016

Needle EMG is an important component of a neuromuscular electrodiagnostic evaluation, and is performed by inserting a small needle electrode into a muscle, moving the electrode through multiple different sites within the muscle, and recording the electrical signals generated from the muscle fibers at rest and during voluntary activation at each of these sites. Technical problems may be encountered during the insertion and movement of the needle electrode into a muscle and during the recording of the electrical signals. These can interfere with accurate collection and interpretation of the data. Also, since the technique involves inserting a needle percutaneously into muscle tissue and moving the needle through the muscle, there are potential risks in certain situations. This chapter reviews technical problems and the risks that may be encountered during needle EMG.
Application of Clinical Neurophysiology
Authors: Rubin Devon I. , Daube Jasper R.
Published: June 2016

Clinical neurophysiology testing primarily assesses and characterizes neurological disease. Selection of appropriate studies for the problem of an individual patient requires a careful clinical evaluation to determine possible causes of the patient’s symptoms. The approach to testing can be assisted by deciding which structures are likely to be involved. For example, motor and sensory symptoms are best assessed using the different methods of motor and sensory NCS. Deciding which neurophysiological measures to apply in peripheral disorders is sometimes assisted by applying guideline protocols based on the patient’s clinical findings and what is found during testing. Although a clinical neurophysiological assessment rarely provides evidence for a specific diagnosis, it can provide valuable information about the severity, progression, and prognosis of the disease. This chapter reviews the clinical application of neurophysiological tests, particularly nerve conduction studies and needle EMG, in the assessment of patients with a variety of neuromuscular complaints.
Somatosensory Evoked Potentials
Authors: Watson James C. , Carter Jonathan L.
Published: June 2016

Somatosensory evoked potentials (SEPs) provide a non-invasive, sensitive, and quantitative way of assessing the functional integrity of the peripheral and central proprioceptive, dorsal column–medial lemniscus somatosensory conduction pathways. SEPs can be used to localize lesions in the nervous system, to identify objectively abnormalities in patients with few sensory manifestations or none at all, to determine whether a process potentially affecting the spinal cord is functionally impairing, and to provide prognostic information in the context of post-anoxic coma. This chapter discusses the technical aspects, limitations, and roles of SEPs in the evaluation of neurologic symptoms, and provides examples of SEPs in different diseases.
Visual Evoked Potentials
Authors: Carter Jonathan L.
Published: June 2016

Visual evoked potentials (VEPs) have a role in evaluating patients with neurologic disease affecting the optic pathway. In patients with lesions involving the optic nerve and anterior chiasm, VEPs have several important advantages: (1) they are objective and reproducible and may demonstrate a functional abnormality that is not evident on physical examination or with neuroimaging studies; (2) abnormalities may persist over time even when there is clinical resolution of visual symptoms; (3) they may be a more reliable indicator of disease than MRI, (4) they may be more sensitive than MRI for detecting abnormalities in optic nerves; and (5) they are less expensive than MRI studies and can be used in situations where MRI studies are contraindicated (i.e., pacemakers, aneurysm clips, etc). This chapter discusses the technical aspects, limitations, and roles of VEPs in the evaluation of neurologic symptoms.
Brainstem Auditory Evoked Potentials in Central Disorders
Authors: Carter Jonathan L.
Published: June 2016

Brain stem auditory evoked potential (BAEPs) is a neurophysiological technique used to detect brain stem lesions from a variety of causes, most commonly acoustic neuromas or multiple sclerosis. BAEPs are electrical potentials generated from structures in the acoustic nerve and lower pons to midbrain as a result of an auditory stimulus. They are very low in amplitude, requiring averaging a large number of responses to ensure reproducible waveforms. As with other evoked potentials, rigorous attention to technical parameters is important to assure that reproducible, reliable responses are obtained. The greatest technical challenge is sensorineural hearing loss, which can cause loss or delay of wave I. BAEPs can detect lesions not seen on brain stem MRI imaging or in cases where MRI is contraindicated due to implanted devices. Due to their resistance to drugs or anesthesia, BAEPs are also useful in monitoring patients during coma or surgery.
Motor Evoked Potentials
Authors: Strommen Jeffrey A. , Boon Andrea J.
Published: June 2016

Motor evoked potentials (MEP) may be used in the diagnosis of central and peripheral neurological disorders and have become the standard of care in many operative procedures as a means to monitor the motor pathways.In the awake patient, transcranial magnetic stimulation (TMS) can be utilized with surface or subcutaneous muscle recordings to identify central conduction abnormalities, as well as assist with prognosis, in conditions such as multiple sclerosis, stroke, spinal cord injury, Parkinson’s disease, hereditary spastic paraplegia, or ALS. In the operating theater, transcranial electrical stimulation with recording from the spinal cord, root, peripheral nerve, or muscle can be used to prevent spinal cord damage, determine continuity of roots or peripheral nerves, and assist with surgical planning. MEP are significantly affected by many physiological variables and pharmacological agents. Various techniques in regards to simulation sites, stimulation parameters, and recording techniques and sites need to be modified to enhance the reproducibility and reliability of these responses.
Cardiovagal Reflexes
Authors: Cheshire William P.
Published: June 2016

Cardiovagal reflexes assess the parasympathetic control of heart rate. Vagal nerve traffic’s final effect on heart rate is accessible by electrocardiography (ECG). Cardiovagal physiology has a complex basis; therefore, testing cardiovagal reflexes should be performed under controlled conditions, analyzed by a standardized method, and interpreted in light of potentially confounding variables, such as medications, sympathetic tone, and respiratory and heart rates that can alter the response. The most sensitive test is the magnitude of respiratory sinus arrhythmia in response to cyclical deep breathing. Another test of cardiovagal function is the Valsalva ratio, which is the ratio of the greatest to the least heart rate in response to respiratory straining. This ratio should always be measured in conjunction with beat-to-beat blood pressure recordings. Power spectral analysis is useful in assessing spontaneous heart rate variability. A number of less frequently utilized tests of cardiovagal function are also discussed.
Electrophysiology of Pain
Authors: Sandroni Paola
Published: June 2016

The diagnosis of neuropathic pain is a challenge for physicians.The incompletely understood and complex mechanisms of neuropathic pain contribute to the difficulty. As pain is a subjective experience, there is no test that can assess it.. However various neurophysiological tests can assess the integrity, or lack of thereof, of the somatosensory pathways. Although some tests are used routinely (i.e., the quantitative sensory test and the autonomic testing), others have failed to reach widespread use in clinical practice, although they have provided very interesting data in the research field. This chapter reviews various neurophysiologic techniques used to study the function and dysfunction of the nociceptive system in humans, including quantitative sensory tests (QSTs), autonomic tests, microneurography (MCNG), laser evoked potentials (LEPs) and contact heat evoked potential stimulator (CHEPS).
Movement-Related Potentials and Event-Related Potentials
Authors: Utianski Rene L. , Caviness John N.
Published: June 2016

Movement-related cortical potentials (MRCPs) are EEG potentials that occur with movement and are recorded using surface scalp electrodes. A technique termed “EEG-EMG back-averaging” is used to obtain MRCPs. The earliest recordable MRCP is the Bereitschaftspotential or readiness potential. Special EEG averaging techniques may also be used to study the cortical processes underlying cognition. Event-related potentials (ERPs) record the cortical activity evoked by a stimulus charged with cognitive significance. The P300 is the most commonly recorded ERP, elicited in an oddball technique of auditory stimulation; the subject is instructed to attend to a rare stimulus presented among a string of frequent stimuli. Only trials triggered by this rare event are averaged. The P300 may be the electrophysiological correlate of selected attention. The N400, another ERP, is assessed during semantic comprehension of language. The chapter discusses normal variants of MRCPs and ERPs, as well as disruptions secondary to neurological disease.
Cerebral Function Monitoring
Authors: So Elson L.
Published: June 2016

This chapter covers the pitfalls and benefits of recording electrophysiological data in challenging environments such the operating room or intensive care unit. The usefulness of such recordings depends on the knowledge and skills of the technologist and the neurophysiologist, who should be able to correct technical problems and recognize electrophysiological changes indicating nervous system injury. Parameters of actionable EEG changes are discussed, because the degree of EEG change encountered during surgery varies widely. EEG monitoring during carotid artery surgery is compared with other methods of monitoring, such as evoked potentials or neurological examination during wakefulness. This chapter also discusses the pharmacological effects of anesthesia on the EEG. These effects constitute the background EEG activity from which the critical EEG changes appear. It is important that these anesthesia effects on the EEG not be mistaken for pathological changes due to the surgical procedure.
Brain Stem and Cranial Nerve Monitoring
Authors: Crum Brian A.
Published: June 2016

Cranial nerves can be injured during surgical procedures performed in the middle and posterior cranial fossae as well as in the head and neck region. Damage results from compression, stretch, abrasion, or ischemia of the nerve. If axonal disruption occurs, recovery is limited, resulting in significant clinical deficits. Cranial nerve function can be monitored during anesthesia by recording spontaneous or stimulus-evoked electrical activity directly from the nerve or the cranial muscles. Activity in other pathways in the brain stem can be monitored by following changes in evoked potentials of sensory and motor pathways. These methods can detect damage to either the intra-axial or the extra-axial portion of cranial nerves and can localize cranial nerves during an operation when normal anatomy is altered, making accurate identification of nerves difficult. Finally, information from intraoperative cranial nerve monitoring may lead to an altered surgical plan to preserve neurological function.
Spinal Cord Monitoring
Authors: Strommen Jeffrey A. , Boon Andrea J.
Published: June 2016

Intraoperative neurophysiological monitoring is a valuable tool to preserve spinal cord and spinal root integrity during surgical procedures. A monitoring plan may include somatosensory evoked potentials (SEP), motor evoked potentials (MEP), compound muscle action potentials (CMAP), and electromyography (EMG). Such monitoring is individualized depending on the preoperative clinical deficit, the structures most at risk, and the surgical and anesthesia plan. The most common use of these techniques is in primary spine disease, where the spinal cord pathways will typically be monitored with both MEP and SEP. In cervical or lumbar spine surgeries, EMG monitoring will help protect the nerve root either during decompression or during pedicle screw placement. Monitoring during spinal cord tumor resection or vascular procedures (such as aortic aneurysm repair) not only helps prevent deficit, but also allows the surgeon to proceed with confidence and not unnecessarily terminate the procedure.
Peripheral Nervous System Monitoring
Authors: Strommen Jeffrey A. , Harper C. Michel
Published: June 2016

Routine nerve conduction studies and needle electromyography can be useful in the intraoperative setting, and may play a critical role in surgical decision-making. They may be used to determine continuity of the axons. In brachial plexus injuries, they will help determine whether surgical nerve repair is possible, as an avulsed root is not amenable to grafting techniques. Monitoring of the peripheral nerves may prevent further axon injury during removal of mass lesions and may be necessary to identify nerve structure that can easily be confused with other tissue. In surgical procedures such as hip arthroplasty, joint disarticulation, or other pelvic and shoulder surgeries, intraoperative monitoring will help prevent inadvertent nerve trauma. Finally, they are useful in conditions where identification of specific fascicles is necessary for diagnostic biopsy. These techniques are modified to allow direct intraoperative nerve stimulation, which is not possible with routine electrodiagnostic techniques.
Audiogram, Acoustic Reflexes, and Evoked Otoacoustic Emissions
Authors: Bauch Christopher D. , Olsen Wayne O.
Published: June 2016

Pure-tone air-conduction and bone-conduction evaluations separate hearing loss into conductive, sensorineural, or mixed categories, and also indicate the degree of hearing loss and attendant communication difficulties. The inclusion of specific types of speech tests assess the ability of the patient to hear and understand speech. Acoustic reflex threshold and reflex decay evaluations evaluate a complex neural network, including afferent pathways to and through the lower brainstem, decussating brainstem pathways, and efferent innervation of CN VII to the stapedius muscle in the middle ear. Evoked otoacoustic emissions provide objective measurement of the peripheral auditory system coursing from the external canal to the cochlear outer hair cells. They are implemented widely in screening tests for hearing in infants, for patients suspected of auditory neuropathy spectrum disorder, and for patients suspected of pseudohypacusis; that is, feigning or exaggerated hearing loss.
Vertigo and Imbalance
Authors: Zapala David A.
Published: June 2016

Electrophysiologic testsests can be used to evaluate the function of each of the five vestibular sensory receptors in the labyrinth, in patients with dizziness and imbalance. Tests of semicircular canal function concentrate on vestibular ocular reflex behavior and include the bilateral, bi-thermal caloric test, video head impulse tests (vHIT), and rotary chair tests. Otolith function tests focus on changes in muscle tone and include the cervical and ocular vestibular evoked myogenic potentials (cVEMP and oVEMP). Interpreting vestibular tests requires an understanding of the underlying anatomy and physiology, and an appreciation of central compensation processes and their effects on each test. This chapter reviews the techniques and interpretation of vestibular testing to assess semicircular canal and otolith function and postural control.
Clinical Phenotyping of Youth With New-Onset Musculoskeletal Pain
Authors: Lewandowski Holley Amy , Wilson Anna C. , Cho Elise , Palermo Tonya M.
Published: June 2016

Objectives:

The course of pediatric musculoskeletal pain from acute to chronic has not been well described and there is limited understanding of how to identify individuals with new-onset pain who may be predisposed to developing persisting symptoms. Thus, the purpose of this study was to describe the clinical phonotype of treatment-seeking youth with new-onset musculoskeletal pain compared with youth with and without chronic pain. Further, we tested predictors of pain-related disability and pain sensitivity in the new-onset pain sample.

Methods:

Participants were 191 youth, ages 10 to 17 years, representing 3 cohorts (new-onset musculoskeletal pain, chronic musculoskeletal pain, and a comparison group without chronic pain). Participants completed questionnaire measures of pain characteristics, psychological functioning, sleep, and pain-related disability. They also attended a laboratory visit to complete an experimental pain assessment using heat and cold stimuli to assess pain sensitivity and conditioned pain modulation.

Results:

Findings revealed youth with new-onset musculoskeletal pain had a distinct clinical phenotype where symptoms of pain and disability were in the mid-range between those of youth with diagnosed chronic musculoskeletal pain and youth in the community without chronic pain. Linear regressions within the new-onset pain sample demonstrated poorer sleep quality and higher pain fear predicted greater pain-related disability, and pain catastrophizing predicted cold pressor sensitivity.

Discussion:

Clinical phenotyping of youth with new-onset musculoskeletal pain highlights factors relevant to the pain experience. Future research can examine the roles of these variables in predicting longitudinal risk for chronic pain and disability.
Pregnancy-Associated Deaths in Rural, Nonrural, and Metropolitan Areas of Georgia
Authors: Platner Marissa , Loucks Tammy L. , Lindsay Michael K. , Ellis Jane E.
Published: June 2016

OBJECTIVE:

To characterize pregnancy-associated deaths and examine the relationship between area of residence and pregnancy-associated deaths and pregnancy-related mortality ratios in Georgia from 2010 to 2012.

METHODS:

The cohort of pregnancy-associated deaths was reviewed and categorized as pregnancy-related or resulting from other medical conditions not related to pregnancy, suicide, drug toxicity, homicide, or motor vehicle accident. Georgia Online Analytical Statistical Information System data were used to calculate pregnancy-related mortality ratio by rural, nonrural, and metropolitan Atlanta area and by race. Causes of death and pregnancy-related mortality ratio were compared by area of residence and race using χ2 tests; a P value <.05 was considered significant.

RESULTS:

There were 262 pregnancy-associated deaths; 40.1% (n=105) were pregnancy-related. The 2010–2012 pregnancy-related mortality ratio was 26.5 per 100,000 live births and the pregnancy-related mortality ratio did not differ statistically among rural (27.1), nonrural (24.4), and metropolitan Atlanta (27.7) areas (P=.845). Most pregnancy-related deaths were the result of hemorrhage and cardiovascular factors. In aggregate, the pregnancy-related mortality ratio for black women was 49.5 compared with 14.3 for white women (P<.001). The gap in pregnancy-related mortality ratio between black and white women was highest for metropolitan Atlanta (51.6 compared with 12.4, P<.001), less in nonrural areas (50.3 compared with 12.0, P<.001), and comparable in rural areas (39.4 compared with 22.4, P=.281).

CONCLUSION:

Although the pregnancy-related mortality ratio was similar for rural, nonrural, and metropolitan Atlanta areas, it was significantly higher for black compared with white women living outside of rural areas.