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 Table of Contents  
ORIGINAL ARTICLE
Year : 2022  |  Volume : 39  |  Issue : 2  |  Page : 74-78

Why electrophysiological reassessment is needed? The experience of our laboratory – A cross-sectional study


Department of Neurology, Istanbul University, Istanbul Faculty of Medicine, Istanbul, Turkey

Date of Submission12-Dec-2021
Date of Acceptance05-Feb-2022
Date of Web Publication29-Jun-2022

Correspondence Address:
Isil Yazici Gencdal
Department of Neurology, Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, 34093 Fatih, İstanbul
Turkey
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/nsn.nsn_233_21

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  Abstract 


Introduction: Requesting repetition of an electrodiagnostic examination (EDX) for follow-up and/or diagnostic verification is common in the daily practice of a reference center. Objective: This study aimed to evaluate demographical and electrophysiological characteristics of the patients who were referred to a reference electrophysiology laboratory for reassessment, to explore the underlying reasons, and motives for ordering a reassessment. Methods: Patients who had at least one EDX study within the last year in one of the two different time periods (winter and summer) were included in the study. Their demographical features, preliminary diagnosis, and electrophysiological findings were assessed and compared with their previous EDX interpretations. Results: Thirty-five (14 female, 21 male) patients (7,7%) out of 457 patients from the winter period (November 11, 2018‒December 12, 2018) and 38 (20 female, 18 male) patients (7,8%) out of 487 patients from the summer period (July 01, 2019‒August 08, 2019) were included in the study. Age, gender, preliminary diagnosis, and the number of previous electrophysiologic tests were statistically similar between the two groups. The most common reason for reassessment was to verify or to follow-up on a diagnosis of motor neuron disease or polyneuropathy. Compared to the summer group, the patients who had previous EDX in a different center were more common in the winter group, mean duration between EDX studies was also shorter. Conclusion: In this study, we have inspected the patients referred to our laboratory within two different time frames in a year for a repeat EDX study. It was observed that the number of patients who underwent a repeat EDX was relatively low, and there was no significant difference not only in the preliminary diagnosis but also in the electrophysiological findings.

Keywords: Electromyography, motor neuron disease, polyneuropathy, reassessment, repeat electromyography


How to cite this article:
Gencdal IY, Özdağ Acarlı AN, Elmalı AD, Emekli AS, Öge AE, Baslo MB, Orhan EK. Why electrophysiological reassessment is needed? The experience of our laboratory – A cross-sectional study. Neurol Sci Neurophysiol 2022;39:74-8

How to cite this URL:
Gencdal IY, Özdağ Acarlı AN, Elmalı AD, Emekli AS, Öge AE, Baslo MB, Orhan EK. Why electrophysiological reassessment is needed? The experience of our laboratory – A cross-sectional study. Neurol Sci Neurophysiol [serial online] 2022 [cited 2022 Dec 6];39:74-8. Available from: http://www.nsnjournal.org/text.asp?2022/39/2/74/348903




  Introduction Top


Electrophysiological evaluations are examination methods in which the bioelectrical activity of muscles and peripheral nerves is evaluated. It is used in the diagnosis and follow-up of many neurological and systemic diseases. It has an important role in the diagnosis of peripheral nerve, muscle, motor neuron, and neuromuscular junction diseases.[1],[2] A routine electrophysiological examination includes sensory and motor nerve conduction studies (electroneurography) and conventional needle electromyography (EMG).[3],[4] If necessary, other methods such as late responses, reflex studies, repetitive stimulation tests, sympathetic skin responses, R‒R interval analysis, single-fiber EMG, and macro-EMG may be also added to these examinations.[5],[6] Although electrophysiological examinations produce objective data, the interpretation of these data depends on the experience, knowledge, and skills of the physician performing and evaluating the examination. To evaluate the findings accurately, the physician should have sufficient knowledge and experience about the anatomy and physiology of the musculoskeletal system, as well as, the pathophysiology of neurological diseases.[7],[8]

Although it is not common in our daily practice, we occasionally encounter cases in which electrophysiological examinations are technically performed but not reported or the obtained findings and interpretations are not compatible. It may be necessary to repeat the electrophysiological examination due to reasons such as variability in the personal characteristics of the patients, technical failures, or inaccuracies during the examination, the necessity to follow the course of some diseases. In addition to all these reasons, it is observed that reevaluation may be performed to confirm the diagnosis obtained in the first examination.

In our study, we aimed to question “why reevaluation is requested” and understand the reasons for these requests cross-sectionally. Patients who had another electrophysiological examination in the last year among patients referred to our electrophysiology laboratory are included. Demographic findings and older and new electrophysiological findings of the patients who were sent to our laboratory for reexamination during the winter and summer periods were compared.


  Methods Top


Patients who were referred from other clinics of Istanbul Faculty of Medicine or different centers for an electrodiagnostic examination (EDX) reassessment and who had at least one EDX study within the last year were included in the study. The patients were recruited in one of the two different time periods; the winter period was from November 2018 to December 2018 and the summer period was from July 2019 to August 2019. The demographical features, preliminary diagnosis, present, and previous EDX findings of the subjects were recorded. The patients' diagnosis was categorized as plexopathy, radiculopathy, polyneuropathy (PNP), myopathy, motor neuron disease (MND), neuromuscular junction disorder, facial neuropathy, and peripheral nerve injury according to their current EDX findings. Their present EDX findings and diagnosis were compared with previous ones.

The study was approved by the Ethics Committee of the Istanbul University, Istanbul Medical Faculty and each participant were enrolled after giving a written informed consent.

All findings were presented as mean, standard deviation, and P values where applicable. Analyses were performed using the SPSS 21.0. (IBM SPSS version 21.0, USA) Student's t-test was employed for comparisons when the data show normal distribution according to Shapiro‒Wilk and if the data were not normally distributed, Mann–Whitney U-test was performed. Nominal data were assessed by Chi-square test and by Fischer's exact test when it is appropriate. P < 0.05 were considered to be significant.


  Results Top


Thirty-five (14 female, 21 male) patients (7,7%) out of 457 patients from the winter period (November 26, 2018‒December 31, 2018) and 38 (20 female, 18 male) patients (7,8%) out of 487 patients from the summer period (July 01, 2019‒August 08, 2019) were included in the study. Demographical data of the subjects were summarized in [Table 1].
Table 1: Demographical and clinical features of patients

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The mean age of 35 patients (14 female, 21 male) of the winter group was 37.3 ± 20.2 years (range: 3 months– 73 years). Among 49 previous EDX of those subjects, 21 of them were performed within last 3 months, 11 were within last 6 months, and 17 were within last year. The subjects with EDX reassessment requests were directed from the clinics of neurology (18 patients), pediatrics (7 patients), neurosurgery (6 patients), orthopedics (3 patients), and plastic surgery (1 patient). Four patients had three past EDX within 1 year, 6 patients had two, and 25 patients had one. The most common reason for a reassessment request was to verify or to follow-up on a diagnosis of a MND or a PNP. Preliminary diagnosis of the subjects who was requested for repetition of an EDX was hereditary/acquired PNP (12 patients), MND/radiculopathy (7 patients), brachial plexopathy (3 patients), radiculopathy (3 patients), facial neuropathy (2 patients), Myasthenia Gravis (MG; 2 patients), and entrapment neuropathy (2 patients). Four patients were referred for a reassessment of an EDX performed for peripheral nerve injury. Previous and present EDX findings of the subjects were summarized in [Table 2].
Table 2: Comparison of prediagnosis and previous and subsequent examination results of the patients who were reevaluated electrophysiologically in the first period

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The mean age of 38 patients (20 female, 18 male) of the summer group was 41.8 ± 19.0 years (range: 12– 83 years). Among 41 previous EDX of those subjects, 13 of them were performed within last 3 months, 12 were within last 6 months, and 16 were within last year. The subjects, requested for EDX reassessment, were directed from the clinics of neurology (20 patients), pediatrics (7 patients), orthopedics (5 patients), neurosurgery (2 patients), rheumatology (2 patients), plastic surgery (1 patient), and physical medicine and rehabilitation (1 patient). Three patients had two past EDX within 1 year, whereas 35 patients had one. Preliminary diagnosis of the subjects who was requested for repetition of an EDX was hereditary/ acquired PNP (16 patients), radiculopathy (7 patients), MND/MMN (Multifocal Motor Neuropathy; 5 patients), MG (3 patients) entrapment neuropathy (2 patients), and myopathy (1 patient). Four patients were referred for a reassessment of an EDX performed for peripheral nerve injury. Previous and present EDX findings of the subjects were summarized in [Table 3].
Table 3: Comparison of prediagnosis and previous and subsequent examination results of the patients who were re-evaluated electrophysiologically in the second period

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Among 35 patients in the winter group, 23 of them were referred to our laboratory to verify their final diagnosis suggested in the previous EDX, which was performed in a different center, and 12 of them were for a follow-up. Among 38 patients in the summer group, 14 of them were referred to our laboratory to verify their final diagnosis, and 24 of them were for a follow-up.

There was no significant difference in gender and age between the groups. The distribution of preliminary diagnosis of the subjects was similar between the groups. In the winter group, the mean number of previous EDX per patient was significantly higher compared to the summer group (1.4 ± 0.7 vs. 1.1 ± 0.3, P = 0.017). Compared to the summer group, the ratio of patients who had previous EDX in a different center was higher in the winter group (%66 vs %34, P = 0.010), and mean duration between EDX studies was shorter (4.7 ± 3.8 vs. 6.5 ± 3.7, P = 0.04). The ratio of patients who had at least one EDX within last 3 months was similar between the two groups (%51 vs. %32, P = 0.085). In the winter group, the ratio of subjects whose diagnosis and new EDX findings were different from the previous one was higher compared to the summer group (%26 vs. %8, P = 0.058).


  Discussion Top


Electrophysiological examinations are helpful methods in the diagnostic process, monitoring the effects of treatments, understanding, and monitoring the progression of diseases.[9],[10] In cases with a need to diagnosis confirmation or progression follow-up, electrophysiological evaluation may be performed repeatedly. In our laboratory, up to 5000 electrophysiological examinations are performed annually, and approximately 8% of these examinations are electrophysiological examinations repeated at different times for the same patient. We aimed to approach electrophysiological examinations from a different perspective and to understand the contribution of EDX to clinical evaluation.

The first striking point in our study, in which a cross-sectional evaluation in two different time periods was performed, is that the most common prediagnosis for the patients who was referred for a repeat study was PNP and MND. Although electrophysiological examination was performed in another center in the last 3 months, 18 patients in the winter period and 12 patients in the summer period were referred for reexamination. Of these patients, the working diagnosis was PNP in nine patients, radiculopathy in six, MND in five, MG in three, plexopathy in two, peripheral nerve injury in two, facial neuropathy in two, and entrapment neuropathy in one.

All four patients who had three electrophysiological examinations in the last year and were requested to be reexamined were referred during the winter period. Two of these four patients were referred to our laboratory for the confirmation of a preliminary diagnosis of MND, one for entrapment neuropathy, and one for electrophysiological follow-up due to brachial plexus injury.

In our study, we approached the electrophysiological methods repeated in the working order of a reference center in the prepandemic period with an overview, but after the COVID 19 pandemic was announced in March 2020, there were significant changes in the working system of our laboratory, and the content and number of patients examined. A different study evaluating electrophysiological examinations during the pandemic period and comparing it with the prepandemic period continues.

The limitations of our study are that a standard approach could not be applied because the initial examinations of the patients were made in different centers, possibly with different devices, and reports were written by various physicians. Another limitation of the study is the EDX evaluations performed based on the preliminary diagnosis of the clinician.

The strengths of the study are that; it is performed in a reference center, it is novel since there has not been such a cross-sectional study before, the number and diversity of the patients are adequate, and the evaluation of two different time periods such as summer and winter for sample selection provides a range and diversity.


  Conclusion Top


In this study, we have compared the patients who had repeating EDX studies in two different time periods. It was revealed that the number of patients who underwent repeat electrophysiological evaluation was relatively low compared to the total number of electrophysiological examinations performed. When the repeat electrophysiological examinations performed in two different periods of the year were considered as two groups, it was seen that they were mostly similar both in terms of numbers and content, but remarkable differences were revealed, especially in the diagnosis of MND and PNP. In the examinations made with preliminary diagnoses such as facial neuropathy, brachial plexopathy, entrapment neuropathy, and myopathy, it was observed that there was no significant difference in electrophysiological findings in a 1-year period. We think that this information may be helpful in timing the control electrophysiological examination during clinical follow-up of patients.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

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Preston DC, Shapiro BE. Electromyography and Neuromuscular Disorders E Book: Clinical Electrophysiologic Correlations (Expert Consult Online). 3rd Edition: Elsevier Health Sciences; 2012.  Back to cited text no. 7
    
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Kang PB. Pediatric nerve conduction studies and EMG. In: Blum AS, Rutkove SB, editors. The Clinical Neurophysiology, Primer. Totowa, NJ: Humana Press Inc.; 2007. p. 369-89.  Back to cited text no. 8
    
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Hellmann M, von Kleist-Retzow JC, Haupt WF, Herkenrath P, Schauseil-Zipf U. Diagnostic value of electromyography in children and adolescents. J Clin Neurophysiol 2005;22:43-8.  Back to cited text no. 9
    
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  [Table 1], [Table 2], [Table 3]



 

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