Can medical audit change electromyographic practice?

Considerable variation in EMG practice has been described previously. Since 1992, 7 clinical neurophysiologists from 6 European countries prospectively collected electromyographic (EMG) examinations. The aim of this study was to examine whether several years of mutual influence among physicians using medical audit resulted in a more uniform EMG practice. We studied whether there was a change in the number of examinations per patient and the techniques used from the first 12 to the last 12 EMG examinations on patients with polyneuropathy. For F-wave studies and motor nerve studies, there was a clear change towards a more uniform practice. For sensory nerve conduction studies and muscle studies, there were only minor changes. With regard to examination techniques, there was a reduction in the use of more time-consuming examination techniques (near-nerve sensory studies and quantitative muscle studies). It seems possible to change the EMG practice of individual physicians by international collaboration and medical audit. However, until now most changes have been minor and large differences in European EMG practices persist. The diversity of practices suggests a need for studies on the optimal application of existing examination techniques.     

Interrater reliability of the needle examination in lumbosacral radiculopathy

Low back pain and lumbar radiculopathy are among the most common painful disorders affecting the adult population. This study hypothesizes that there is good correlation between the diagnostic impression of an unblinded electromyographer, using clinical and electromyographic information, and an independent electromyographer, who uses the needle examination only to assess for lumbar radiculopathy. This is a prospective, single-blinded, observational pilot study. The needle examination was electronically recorded, reproduced, and shown to a second examiner, blinded to all clinical data. Diagnostic impressions from both examiners were recorded and evaluated for agreement. Six recorded cases were reviewed by 66 blinded examiners. Overall diagnostic agreement was 46.9% (60.5% faculty level, 28.5% resident level). Logistic regression shows a strong association between training level and agreement on diagnostic impression (odds ratio, 1.9; 95% confidence interval, 1.12-3.22; P = 0.019). This study shows that there is fair interrater reliability between faculty-level examiners and poor reliability among resident-level examiners when the needle examination is used to evaluate patients with lumbar radiculopathy.     

Diagnostic value of electromyography in children and adolescents.

The diagnostic accuracy in pediatric neurology has been considerably improved by new methods such as magnetic resonance imaging and molecular genetic analysis. However, standard diagnostic techniques continue to play an important role. The authors analyzed the diagnostic value of electromyography (EMG) and nerve conduction studies (NCS) in a retrospective study of 498 pediatric patients. The overall consistency between EMG results and the final clinical diagnosis in all children examined was 98%. In myogenic diseases, the concordance between EMG and clinical findings was lower (80%), because some patients with congenital myopathies showed normal EMG findings in this group. Peripheral neurogenic diseases were in all but one of the cases diagnosed correctly (99.5%). No decrease in diagnostic reliability was found in the younger age group. EMG and NCS examinations have to be adapted to the needs of children by an experienced examiner, but continue to be valuable diagnostic methods in pediatric neurology.     

Electromyography and magnetic resonance imaging in the evaluation of radiculopathy

Electromyography (EMG) and magnetic resonance imaging (MRI) are commonly used in the diagnosis of cervical and lumbosacral radiculopathy, but the agreement between the two studies is unknown. We retrospectively studied 47 patients with a clinical history compatible with either cervical or lumbosacral radiculopathy who were evaluated with both an EMG and a spine MRI within 2 months of each other. Among these patients, 55% had an EMG abnormality and 57% had an MRI abnormality that correlated with the clinically estimated level of radiculopathy. The two studies agreed in a majority (60%) of patients, with both normal in 11 and both abnormal in 17; however, only one study was abnormal in a significant minority (40%), suggesting that the two studies remain complementary diagnostic modalities. The agreement was higher in patients with abnormal findings on neurologic examination, underscoring the difficulty of confirming the diagnosis in mild radiculopathy.     

When diagnostic agreement is high, but reliability is low: some paradoxes occurring in joint independent neuropsychology assessments

Two paradoxes can occur when neuropsychologists attempt to assess the reliability of a dichotomous diagnostic instrument (e.g., one measuring the presence or absence of Dyslexia or Autism). The first paradox occurs when two pairs of examiners both produce the same high level of agreement (e.g., 85%). Nonetheless, the level of chance-corrected agreement is relatively high for one pair (e.g., 70) and quite low for the other (e.g., .32). To illustrate the second paradox, consider two examiners who are in 80% agreement in their overall diagnosis of Dyslexia. Assume, further, that they are in 100% agreement in the proportion of cases they both diagnose as Dyslexic (20%) and as Non-Dyslexic (80%). Somewhat paradoxically, the level of chance-corrected interexaminer agreement for this pair of examiners calculates to only .37. In distinct contrast, a second set of examiners also in 80% overall agreement, is in appreciable disagreement with respect to diagnostic assignments. Thus, the first neuropsychologist: (a) classifies 65% of the cases as Non-Dyslexic, as opposed to 45% so diagnosed by the second neuropsychologist; and (b) classifies the remaining 35% as Dyslexic, as compared to the 55% so classified by the second examiner. Despite these phenomena, this second pair of examiners produces a much higher level of chance-corrected agreement than did the first pair, that is, a value of .61. The underlying reasons for both of these paradoxes, as well as their resolution, are presented.     

Muscle ultrasonography and electromyography correlation for evaluation of floppy infants

Floppiness in an infant may have a number of different etiologies from disorders of the brain to spinal cord lesions, neuropathies, neuromuscular junction disorders and myopathies.In this study we aimed to investigate the correlation of muscle ultrasonography (US) and electromyography (EMG) in the diagnosis of floppy infants.The study encompassed 41 floppy infants aged 2-24 months. The muscle US and EMG examinations were performed without awareness of the clinical diagnosis. The final diagnosis was established by molecular genetic tests or muscle/nerve biopsy. The neurogenic group consisted of 16 infants according to their US and EMG findings. Fifteen of them had spinal muscular atrophy proven by genetic analysis and one had polyneuropathy diagnosed by nerve biopsy. Six infants were in the myopathic group according to their muscle US and EMG results. All of them underwent muscle biopsy and microscopic examination revealed five congenital muscular dystrophy and one glycogen storage disease. In two infants the US and EMG data conflicted. Their biopsies were also insufficient for the diagnosis. Seventeen infants had normal US and EMG findings but pathologic cranial magnetic resonance imaging or metabolic/genetic tests. They were considered in the group of central hypotonia.Our results suggest a high concordance of US and EMG findings in the diagnostic work-up of neurogenic and myopathic disorders.     

Electrodiagnosis of polyneuropathy

Electrodiagnostic studies comprising electromyography (EMG) and nerve conduction studies (NCS) are well-established objective methods for the diagnosis, quantification and classification of polyneuropathies (PNP). This paper reviews examination techniques, their pathophysiological interpretation, examination strategies and diagnostic criteria for the diagnosis and classification of a PNP. The routine electrodiagnostic evaluation includes sensory NCSs performed with surface or needle electrodes, motor NCSs, F-wave studies and EMG by qualitative or quantitative techniques. Sensory NCSs and F-wave studies have a high sensitivity in PNPs and the different techniques complement each other. The distinction between a PNP with predominantly axonal loss and a PNP with predominantly demyelination is one of the major aims of the electrophysiological examination. There are, however, large variation in suggested criteria for predominantly demyelination. The degree of slowing in conduction taken to indicate demyelination varies between a decrease of 50 to 30% from mean of controls, distal latency prolongation criteria vary from 35% to 70% of mean of controls, F-wave latency prolongation criteria vary from 120% to 150% of upper limit of controls, and criteria for partial motor conduction block vary from 11 to 50% reduction of CMAP amplitude and/or area between proximal and distal stimulation. Needle EMG studies may be valuable in order to detect and quantify denervation activity, to assess chronicity by an evaluation of the extent of reinnervation, and to evaluate the topographical distribution of changes. It is concluded that electrodiagnostic studies are valuable in patients with suspected PNP and the results may have consequences for prognosis and therapy of individual patients. Large variation in examination techniques, strategies, interpretations and diagnostic criteria have been found among electromyographers and it is suggested that the value of electrodiagnostic studies may be further improved by international standardisation.     

Influence of medical audit on electrodiagnostic evaluation of polyneuropathy. A multicentre study.

OBJECTIVE: Since 1992, 7 European neurophysiologists have participated in the ESTEEM project concerned with improvements in electrodiagnostic medicine. This study assesses whether the collaboration that includes peer review medical audit has influenced the involved physicians' electrodiagnostic criteria for polyneuropathy (PNP) diagnosing and classification. METHODS: Two sets of each physician's PNP examinations performed early and late in the study were examined for changes in (1) number of studies with abnormal electrophysiological findings required for diagnosing PNP, and (2) agreement between the classifications given by the individual physicians and the peer review group. RESULTS: The average number of abnormal motor nerve segments per patient increased from 4.6 to 6.4 during the study. Although most individual changes were minor, the second set of examinations showed an increased homogeneity among the physicians in the number of abnormal motor nerve segments and abnormal F wave studies, and a tendency towards increased homogeneity in the number of abnormal sensory nerve segments. There was also an increased agreement on pathophysiological PNP classification in the second set of examinations compared to the first set. CONCLUSIONS: The participation in the ESTEEM project seems to have impacted the physicians' clinical routine, possibly as they have accustomed themselves to apply criteria more strictly. SIGNIFICANCE: This study support that international collaboration is a useful step towards improvements in electrodiagnostic medicine.     

腰椎间盘突出症肌电图检查的独特价值

目的探讨肌电图在腰椎间盘突出症定位诊断方面的独特价值。方法99例腰椎间盘突出病人,用常规针极肌电图及H反射记录方法,将其结果与CT、椎管造影、临床症状体征及手术所见相比较。结果肌电图、CT、椎管造影、临床等四种方法定位与手术所见的符合率分别为72．7％、87．5％、78．6％、83．8％。CT（椎管造影）、EMG、临床、手术所见四者定位完全一致占56．6％;EMG、临床、手术所见三者定位一致占60．6％;三者所见不尽一致占39．4％。结论肌电图定位准确率稍逊于其他方法,但是其特殊发现能很好补正其他检查的不足,对定位诊断和术式选择有重要意义。     

Diagnosis of functional psychoses

Summary The results of a comparison between the clinical diagnoses of 115 probands with functional psychoses, made on the basis of careful clinical history-taking, interviewing and examinations, and those made by computerized evaluation (CATEGO) on the basis of the present state examination (PSE) were presented. The clinical diagnoses of the project psychiatrist and the provisional classification resulting from the application of the CATEGO program to the PSE symptom profiles were in an overall concordance of 82%. In a second step the 20 cases with differences in diagnoses were reevaluated on the basis of the full history and psychopathology and a syndrome checklist was completed. This reevaluation led to a practically full diagnostic agreement.     

Comparaison de l’échographie et de l’électroneurographie pour le diagnostic du syndrome du canal carpien en pratique courante

Introduction

Many studies had been performed in the last years to prove the usefulness of ultrasonographic measurements of the median nerve in the diagnosis of carpal tunnel syndrome (CTS). We wanted to determine its reliability and to compare this technology with electromyography (EMG) in ordinary diagnostic conditions.

Methods

The study involved 90 wrists with suspected CTS, 35 controlateral wrists and 52 control wrists. The diagnosis of CTS was confirmed in 81 cases by the hand symptom diagram and the Tinnel and Phalen sign. The EMG examination evaluated medianulnar sensory latency difference to the ring finger and wrist-to-palm sensory conduction velocity. For the ultrasound diagnosis, the cross sectional area of the median nerve at the level of the pisiform bone, was considered. The sensitivity and specificity of the two techniques was calculated.

Results

Sensitive electroneurographic parameters showed a sensibility and specificity respectively of 79 and 80%. The cut-off point for ultrasound sensibility and specificity using ROC analysis was 11 mm² for mean cross-sectional area. Sensitivity and specificity found in this way were 72% and 56%. Reliability was good with intra- and inter-reader intraclass correlation coefficients of 0.99, and interobserver coefficient of 0.88. Sonography found seven CTS among the 17 clinical CTS with normal electrophysiological findings. A statistically correlation was found between the cross-sectional section and the sensitive electrophysiologic parameters (r = 0.43, p < 0.001).

Conclusions

In our study, ultrasonographic diagnostic value are not as good as electrophysiological value, like found in recent literature, probably because of the composition of our group of patients which is including many causes of acroparesthesias. This can mean that in clinical practice, sonography is a complementary tool instead, for example in cases of equivocal EMG.     

Reliability of the Part II Board Certification Examination in Psychiatry: interexaminer consistency

OBJECTIVE: The aim of the study was to examine the reliability (interexaminer consistency) of the American Board of Psychiatry and Neurology (ABPN) Part II (oral) examination in psychiatry. METHOD: Grades were assigned independently by two examiners who observed the same examination in a 1-year cycle (1,422 candidates, two examinations each). The consistency between these pairs of grades (pass, condition, fail) was analyzed using a weighted kappa statistic. RESULTS: There was perfect agreement between examiners in 67% of examinations, minor disagreement in 26%, and major disagreement in 7% (weighted kappa = 0.54-0.56). CONCLUSIONS: The Part II ABPN examination demonstrates fair to good reliability as measured by interexaminer consistency. Development of more explicit grading criteria should further improve examiner agreement in future examinations.     

进行性脊肌萎缩症129例临床分析

目的探讨进行性脊肌萎缩症(PSMA)的临床特点、诊断与鉴别诊断。方法回顾性分析129例PSMA患者的临床资料。结果本组患者均隐袭起病,逐渐加重,男性多见,发病年龄65.9%患者>50岁。首发症状以单侧上肢无力和肌萎缩为多见(65.9%),均表现为下运动神经元损害的症状和体征,51.9%患者出现延髓麻痹症状;肌电图检查均提示神经源性损害;易误诊为颈或腰椎病。结论本病是一组慢性进行性下运动神经元疾病,病变可累及延髓。诊断主要依据临床表现和肌电图。     

Variation in diagnostic strategy of the EMG examination--a multicentre study.

OBJECTIVES: In order to improve the universal quality of the EMG examination, knowledge about the variation among physicians is needed. METHODS: The variation among physicians in diagnostic strategy or criteria for diagnosing was analysed from a multicentre database with 940 EMG examinations sampled by seven physicians from six laboratories in Europe. RESULTS: For the whole group of patients as well as for the subgroup of patients with polyneuropathy, variation among physicians in examination techniques, number of examined structures per patient and number of abnormal structures per patient required for a diagnosis was found. Some of the variation may be explained by use of different techniques, which showed differences in sensitivity, while some of the variation may be due to differences in diagnostic strategy and criteria for diagnosing. CONCLUSIONS: The study indicates a need for development and revision of international guidelines for EMG practice although implementation of standards requires caution.     

The diagnostic accuracy of selected neurological tests

The diagnostic value and reliability of selected neurological clinical tests was studied in control subjects with normal neuroimaging (n=42), and subjects with a focal brain lesion (n=38). The items were studied by two examiners blinded to group membership and using standardized protocols, and subsequently by a neurologist who was not blinded to diagnosis. The positive likelihood ratios ranged from 1.06 (pronator drift) to 22.11 (single leg stance with eyes open, while the negative likelihood ratios ranged from 0.47 (tandem gait) to 0.97 (pupil symmetry). Three items (single leg stance - eyes closed - firm surface; single leg stance - eyes open - foam surface; and tandem gait) successfully distinguished between the two groups (odds ratio p<0.05). The inter-rater reliability was generally poor, with only tandem gait showing excellent agreement (kappa [K]=0.92). Tandem gait was the only item to show noteworthy agreement (K=0.93) between the examiners and the neurologist. The tests varied considerably in their ability to detect radiologically demonstrated structural brain lesions, and several items were poorly reproducible, questioning their value as part of a routine neurological examination.     

Congenital hypotonia: is there an algorithm?

This study was performed with the aim of determining the diagnostic profile of newborns with hypotonia and of analyzing the usefulness of different procedures in the diagnostic process. One hundred thirty-eight hypotonic newborns were identified through the search of hospital records in a 10-year period: 121 (88%) had central hypotonia and 13 (9%) had peripheral hypotonia, whereas 4 (3%) remained unclassified. Analysis of the contribution of clinical data and results of investigations led to the construction of an algorithm, by which all cases in the group were diagnosed. Step 1, which included clinical data and results of examinations, solved 50% of all diagnosed cases. Neuroimaging techniques made up step 2 and contributed to the diagnosis in 13%. Step 3 was accomplished by a search through Oxford Medical Databases, which yielded the final diagnosis in 9%, whereas karyotyping and fluorescent in situ hybridization for Prader-Willi syndrome comprised step 4 and contributed to the diagnosis in 6.5%. Biochemical tests formed step 5 and contributed to the diagnosis in 6%. Step 6, which included specific investigations of muscle and nerve, was diagnostic in 6%. The remaining cases (6.5%) were diagnosed only after several follow-up examinations. These results could assist the neonatologist when deciding the diagnostic approach to floppy newborns.     

Clinical utility of electrodiagnostic consultation in suspected polyneuropathy

Although paresthesias of the distal lower limbs are characteristic features of polyneuropathy, they may also herald the presence of a focal neuropathy, polyradiculopathy, or myelopathy. Electromyography and nerve conduction studies (EMG/NCS) are widely used in the evaluation of such symptoms, but their utility has not been subjected to vigorous scrutiny. We investigated the clinical impact of the electrodiagnostic consultation in assessing suspected polyneuropathy. When compared with the clinical impression, the result of the electrodiagnostic consultation was confirmatory in only 39% of all patients, and changed the diagnosis or uncovered an additional diagnosis in 43%. An alternative diagnosis was likely when either weakness was present (75%) or the Achilles stretch reflex was preserved (48%). These data support the use of EMG/NCS in the diagnostic evaluation of patients presenting with distal paresthesias, especially in those with preserved Achilles reflexes or motor deficits.     

Medical technology assessment. Electrodiagnosis in motor neuron diseases and amyotrophic lateral sclerosis.

In motor neuron diseases/amyotrophic lateral sclerosis (MND-ALS), electrodiagnostic techniques are essential in supporting the diagnosis and excluding other conditions that clinically resemble MND-ALS. Electrodiagnostic techniques can also monitor disease progression and provide prognostic information. Electromyography has an important role in the diagnosis of MND-ALS, but some drawbacks should be borne in mind. Although internationally accepted electrophysiological criteria have been defined to support MND-ALS diagnosis, differences in different laboratories can raise unexpected difficulties in application of diagnosis criteria. Much work needs to be done to increase standardisation of the electrodiagnosis of MND-ALS in order to improve quality. Differential diagnosis with motor axonal neuropathies may be particularly difficult. EMG is an essential tool for the early diagnosis of MND-ALS, which increases potential benefit of therapeutic interventions. A wide discussion among neurophysiologists from different schools could create a sound consensus on early diagnosis of MND-ALS.     

Pathomorphological evaluation in stereotactic brain tumor biopsy

The method is described of multistep pathomorphological examination of biopsy material obtained by stereotactic procedures from brain tumours. In the analysis of 260 biopsies the possibility was assessed of intraoperative cytological examinations confronting the results of these examinations with those of final histological and immunohistochemical investigations. Attention is called to the difficulties in the evaluation of material derived from stereotactic biopsies and to the cause of possible diagnostic errors. It is concluded that the combination of the results of cytological examination of smears and histological examination of paraffin slides makes possible establishing of full pathomorphological diagnosis with determination of tumour type and its malignancy degree in 90.7% of cases. On most cases cytological intraoperative examination had the greatest influence on therapeutic management. In the confrontation of these examinations with histological examinations a high proportion of correct cytological examinations was found (76.6%). Owing to the possibility of application of all techniques of morphological diagnosis, stereotactic biopsy is a reliable method in the diagnosis of brain tumours.