Electromyography

Author(s):  
Erik Stålberg

Electromyography (EMG) has been used since the 1940s in the diagnosis of neuromuscular disorders. It has particularly developed with the advent of computers and recording equipment with integrated software. This has made methods of analysis fast, robust, and precise, helping to deal with increasing numbers of patients. Indications have changed dynamically over the years, with the development of new EMG methods themselves and complementary methods used in this field for diagnosis such as histochemistry, genetics, and imaging techniques. This chapter focuses mainly on the routine methods based on recordings with concentric or monopolar needle electrodes, but will also briefly review some of the other EMG methods. There is an increasing understanding of the relationship between the generators (muscle fibres) and the recorded signal that helps interpretation of the recordings. The parameters used for quantitation of the EMG signal are discussed. The findings in pathological conditions are discussed and some practical hints on EMG studies given.

BMC Neurology ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
George Umemoto ◽  
Shinsuke Fujioka ◽  
Hajime Arahata ◽  
Nobutaka Sakae ◽  
Naokazu Sasagasako ◽  
...  

Abstract Background Swallowing dysfunction is related to major cause of adverse events and an indicator of shorter survival among patients with neuromuscular disorders (NMD). It is critical to assess the swallowing function during disease progression, however, there are limited tools that can easily evaluate swallowing function without using videofluoroscopic or videoendoscopic examination. Here, we evaluated the longitudinal changes in tongue thickness (TT) and maximum tongue pressure (MTP) among patients with amyotrophic lateral sclerosis (ALS), myotonic dystrophy type 1 (DM1), and Duchenne muscular dystrophy (DMD). Methods Between 2010 and 2020, TT and MTP were measured from 21 ALS, 30 DM1, and 14 DMD patients (mean ages of 66.9, 44.5, and 21.4 years, respectively) at intervals of more than half a year. TT was measured, by ultrasonography, as the distance from the mylohyoid muscle raphe to the tongue dorsum, and MTP was determined by measuring the maximum compression on a small balloon when pressing the tongue against the palate. Then we examined the relationship between these evaluations and patient background and swallowing function. Results Mean follow-up periods were 24.0 months in the ALS group, 47.2 months in the DM1group, and 61.1 months in the DMD group. The DMD group demonstrated larger first TT than the other groups, while the DM1 group had lower first MTP than the ALS group. The ALS group showed a greater average monthly reduction in mean TT than the DM1 group and greater monthly reductions in mean body weight (BW) and MTP than the other groups. Significant differences between the first and last BW, TT, and MTP measures were found only in the ALS group. Conclusions This study suggests that ALS is associated with more rapid degeneration of tongue function over several years compared to DMD and DM1.


It was shown in an earlier paper (7) that if maximal stimulation of either of two different afferent nerves can reflexly excite fractions of a given flexor muscle, there are generally, within the aggregate of neurones which innervate that muscle, motoneurones which can be caused to discharge by either afferent (i. e., motoneurones common to both fractions). The relationship which two such afferents bear to a common motoneurone was shown, by the isometric method of recording contraction, to be such that the activation of one afferent, at a speed sufficient to cause a maximal motor tetanus when trans­mitted to the muscle fibres, caused exclusion of any added mechanical effect when the other afferent was excited concurrently. This default in mechanical effect was called “occlusion.” Occlusion may conceivably be due to total exclusion of the effect of one afferent pathway on the common motoneurone by the activity of the other; but facilitation of the effect of one path by the activation of the other when the stimuli were minimal suggests that, in some circumstances at least, the effect of each could augment and summate with th at of the other at the place of convergence of two afferent pathways. Further investigation, using the action currents of the muscle as indication of the nerve impulses discharged by the motoneurone units, has now given some information regarding the effect of impulses arriving at the locus of convergence by one afferent path when the unit common to both is already discharging in response to impulses arriving by the other afferent path. Our method has been to excite both afferent nerves in overlapping sequence by series of break shocks at a rapid rate and to examine the action currents of the resulting reflex for evidence of the appearance of the rhythm of the second series in the discharge caused by the first when the two series are both reaching the motoneurone.


Blood ◽  
1968 ◽  
Vol 31 (1) ◽  
pp. 93-98 ◽  
Author(s):  
SAMIH Y. ALAMI ◽  
JAMES W. HAMPTON ◽  
GEORGE J. RACE ◽  
ROBERT SPEER

Abstract The relationship of fibrinogen concentration to Factor XIII activity in the plasmas of 110 subjects (90 patients and 20 healthy volunteers) was studied. No definite, consistent, predictable relationship could be established. However, in certain pathological conditions, with hyper- or hypofibrinogenemia, a moderate reduction in Factor XIII activity may be present, and usually occurs without hemorrhagic manifestations. On the other hand, examination of normal plasmas artificially enriched with large amounts of bovine fibrinogen revealed no changes in Factor XIII activity. In the light of these observations, the suggestion is made that reduced Factor XIII activity may be encountered in certain disease conditions without simultaneous changes in fibrinogen concentration. The site of synthesis of these two proteins, although most likely the liver, would appear to not influence their plasma concentrations simultaneously.


1980 ◽  
Vol 87 (1) ◽  
pp. 121-136 ◽  
Author(s):  
J. H. Koenig ◽  
K. Ikeda

Simultaneous intracellular recordings were made from the six ipsilateral dorsal longitudinal muscle fibres of Drosophila in stationary flight. The influence of the firing of one motor unit upon the firing of another was analysed by observing the relationship between the interspike interval of a unit and the relative firing times of the other motor units within that interval. The analysis suggests that the influence is insignificant except when one unit would have fired soon after another. Then, a neural interaction occurs that can cause a unit to fire either earlier or later, depending on its firing relationship with the other units. Thus, the observation that no DLM fibre fires soon after another is the result of both a delaying effect and an effect which causes a cell to fire earlier than it normally would have fired.


2020 ◽  
Author(s):  
George Umemoto ◽  
Shinsuke Fujioka ◽  
Hajime Arahata ◽  
Nobutaka Sakae ◽  
Naokazu Sasagasako ◽  
...  

Abstract Background: Swallowing dysfunction is related to major cause of adverse events and an indicator of shorter survival among patients with neuromuscular disorders (NMD). It is critical to assess the swallowing function during disease progression, however, there are limited tools that can easily evaluate swallowing function without using videofluoroscopic or videoendoscopic examination. Here, we evaluated the longitudinal changes in tongue thickness (TT) and maximum tongue pressure (MTP) among patients with amyotrophic lateral sclerosis (ALS), myotonic dystrophy type 1 (DM1), and Duchenne muscular dystrophy (DMD).Methods: Between 2010 and 2020, TT and MTP were measured from 21 ALS, 30 DM1, and 14 DMD patients (mean ages of 66.9, 44.5, and 21.4 years, respectively) at intervals of more than half a year. TT was measured, by ultrasonography, as the distance from the mylohyoid muscle raphe to the tongue dorsum, and MTP was determined by measuring the maximum compression on a small balloon when pressing the tongue against the palate. Then we examined the relationship between these evaluations and patient background and swallowing function.Results: Mean follow-up periods were 24.0 months in the ALS group, 47.2 months in the DM1group, and 61.1 months in the group. The DMD group demonstrated larger initial TT than the other groups, while the DM1 group had lower initial MTP than the ALS group. The ALS group showed a greater average monthly reduction in mean TT than the DM1 group and greater monthly reductions in mean BW and MTP than the other groups. Significant differences between the first and last BW, TT, and MTP measures were found only in the ALS group.Conclusions: This study suggests that ALS is associated with more rapid degeneration of tongue function over several years compared to DMD and DM1.


Crisis ◽  
2011 ◽  
Vol 32 (5) ◽  
pp. 246-253 ◽  
Author(s):  
Gretchen E. Ely ◽  
William R. Nugent ◽  
Julie Cerel ◽  
Mholi Vimbba

Background: The relationship between suicidal thinking and adolescent dating violence has not been previously explored in a sample of adolescent abortion patients. Aims: This paper highlights a study where the relationship between dating violence and severity of suicidal thinking was examined in a sample of 120 young women ages 14–21 seeking to terminate an unintended pregnancy. Methods: The Multidimensional Adolescent Assessment Scale and the Conflict in Adolescent Relationships Scale was used to gather information about psychosocial problems and dating violence so that the relationship between the two problems could be examined, while controlling for the other psychosocial problems. Results: The results suggest that dating violence was related to severity of suicidal thinking, and that the magnitude of this relationship was moderated by the severity of problems with aggression. Conclusions: Specifically, as the severity of participant’s general problems with aggression increased, the magnitude of the relationship between dating violence and severity of suicidal thinking increased. Limitations of the study and implications for practice are discussed.


Author(s):  
Melanie K. T. Takarangi ◽  
Deryn Strange

When people are told that their negative memories are worse than other people’s, do they later remember those events differently? We asked participants to recall a recent negative memory then, 24 h later, we gave some participants feedback about the emotional impact of their event – stating it was more or less negative compared to other people’s experiences. One week later, participants recalled the event again. We predicted that if feedback affected how participants remembered their negative experiences, their ratings of the memory’s characteristics should change over time. That is, when participants are told that their negative event is extremely negative, their memories should be more vivid, recollected strongly, and remembered from a personal perspective, compared to participants in the other conditions. Our results provide support for this hypothesis. We suggest that external feedback might be a potential mechanism in the relationship between negative memories and psychological well-being.


1994 ◽  
Vol 72 (01) ◽  
pp. 058-064 ◽  
Author(s):  
Goya Wannamethee ◽  
A Gerald Shaper

SummaryThe relationship between haematocrit and cardiovascular risk factors, particularly blood pressure and blood lipids, has been examined in detail in a large prospective study of 7735 middle-aged men drawn from general practices in 24 British towns. The analyses are restricted to the 5494 men free of any evidence of ischaemic heart disease at screening.Smoking, body mass index, physical activity, alcohol intake and lung function (FEV1) were factors strongly associated with haematocrit levels independent of each other. Age showed a significant but small independent association with haematocrit. Non-manual workers had slightly higher haematocrit levels than manual workers; this difference increased considerably and became significant after adjustment for the other risk factors. Diabetics showed significantly lower levels of haematocrit than non-diabetics. In the univariate analysis, haematocrit was significantly associated with total serum protein (r = 0*18), cholesterol (r = 0.16), triglyceride (r = 0.15), diastolic blood pressure (r = 0.17) and heart rate (r = 0.14); all at p <0.0001. A weaker but significant association was seen with systolic blood pressure (r = 0.09, p <0.001). These relationships remained significant even after adjustment for age, smoking, body mass index, physical activity, alcohol intake, lung function, presence of diabetes, social class and for each of the other biological variables; the relationship with systolic blood pressure was considerably weakened. No association was seen with blood glucose and HDL-cholesterol. This study has shown significant associations between several lifestyle characteristics and the haematocrit and supports the findings of a significant relationship between the haematocrit and blood lipids and blood pressure. It emphasises the role of the haematocrit in assessing the risk of ischaemic heart disease and stroke in individuals, and the need to take haematocrit levels into account in determining the importance of other cardiovascular risk factors.


2014 ◽  
pp. 147-153
Author(s):  
P. Orekhovsky

The review outlines the connection between E. Reinert’s book and the tradition of structural analysis. The latter allows for the heterogeneity of industries and sectors of the economy, as well as for the effects of increasing and decreasing returns. Unlike the static theory of international trade inherited from the Ricardian analysis of comparative advantage, this approach helps identify the relationship between trade, production, income and population growth. Reinert rehabilitates the “other canon” of economic theory associated with the mercantilist tradition, F. Liszt and the German historical school, as well as a reconside ration of A. Marshall’s analysis of increasing returns. Empirical illustrations given in the book reveal clear parallels with the path of Russian socio-economic development in the last twenty years.


2020 ◽  
Vol 7 (2) ◽  
pp. 291-317
Author(s):  
Burak Çavuş

Bu çalışmada, 1960-1990 yılları arasında yayınlanan ve Avrupa’ya işçi göçünü konu edinen romanlar izleksel bağlamda incelenmiştir. Romanlardaki temel izlekler çerçevesinde göç süreci irdelenmiş, inceleme, göçmenlerin tanımlanmasında ve adlandırılmasında kullanılan Gastarbeiter (konuk işçi) Auslander (yabancı) kavramları ve Almanlar tarafından Türk kimliğine atfedilen çağrışımlar üzerinden yürütülmüştür. Göçmenlere yönelik politikalarda ve yaklaşımlarda onların nasıl tanımlandığının etkili olduğuna ve yazınsal süreçte de bu politika ve yaklaşımların belirleyici olduğu savından hareket edilmiştir. Bu noktada adlandırmaların, tanımlamaların göç olayı çerçevesinde biz ve öteki ilişkisi üzerindeki etkisine odaklanılmış; toplum ve yazın ilişkisi temelinde incelenen romanlar üzerinden göç ve göçmenlik meselesine dair çıkarımlar yapılmıştır. Bunlar arasında, ayrımcılık, kötü çalışma koşulları, hak ihlalleri, ırkçılık ve ötekileştirme gibi başat sorunların bu eserlerde merkezi konumda olduğu tespit edilmiştir. Böylece çalışmanın amacı olan göç yazınını oluşturan temel izleklere ulaşılmış; sosyolojik ve tarihsel gerçekliğin yazınsal gerçekliğe aktarılmasında etkili olan unsurlar ön plana çıkarılmıştır. ABSTRACT IN ENGLISH Main Patterns in Migration Novels In this study, the novels published between 1960-1990 and dealing with the migration of workers to Europe were examined in a contextual context. The process of immigration has been examined within the framework of the basic lines in the novels, through the concepts of Gastarbeiter (guest worker), Auslander (foreigner) used in the identification and naming of immigrants and connotations attributed to Turkish identity was conducted. The argument is that how they are defined is effective in policies and approaches towards immigrants and that these policies and approaches are determinative in the literary process. At this point, the effect of naming definitions on us and the other relationship within the framework of migration has been focused; there are inferences about the issue of migration and immigration through the novels examined on the basis of the relationship between society and literature. Among these, it has been determined that dominant problems such as discrimination, poor working violations, racism and marginalization are central to these works. Thus, the basic themes that constitute the migration literature, which is the aim of the study have been reached and the factors that are effective in transferring the sociological and historical reality have been brought the fore.


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