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Electroencephalography techniques in adult neurology clinics in south Iran: A survey of neurologists

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Introduction

EEG is a valuable tool in evaluating patients with paroxysmal events and epilepsy (Asadi-Pooya & Sperling 2014). Minimum technical standards are required for routine clinical recording of EEGs (Acharya et al 2016; Kuratani et al 2016; Sinha et al 2016); including, recording at least 16 channels, using all 21 electrodes in the 10-20 system, having logical montage designs, sensitivity in the range of 5 to 10 μV/mm, low-frequency filter (LFF) of no higher than 1 Hz and high-frequency filter (HFF) of no lower than 70 Hz. The record should also contain at least 20 minutes of technically satisfactory recording (Acharya et al 2016; Sinha et al 2016).

Epilepsy centers are rather new in Iran with only about 10 years of establishment and during these years, the suboptimal quality of the EEG recordings by many neurology centers has come to attention. The aim of this study was to determine the technical knowledge of the neurologists in performing EEGs in Fars province, Iran, in order to identify any pitfalls in the performance of the procedure and to provide evidence-based recommendations for the neurology community to improve the quality of their work.

Materials and Methods

In this survey, all neurologists who practice in the Fars province in south Iran were asked to participate. At the time of the study, there were a total of thirty neurologists in practice in this province. An anonymous questionnaire was prepared and included questions about EEG recording procedures utilized in their clinics (number of channels, montages, filters, duration, procedures, etc.). This study was conducted with the approval by Shiraz University of Medical Sciences Review Board.

Results

Eighteen neurologists participated in this survey. Six neurologists (33%) recorded EEGs at < 16 channels and twelve recorded at ≥ 16 channels. Seven physicians (39%) recorded one or two montages only and the other five recorded ≥ three. Eight neurologists (44%) recorded EEGs for < 20 minutes and ten recorded for ≥ 20 minutes. One of the neurologist participants did not use photic stimulation and two did not perform hyperventilation during EEG recordings. With regards to the low-frequency filter (LFF), eight neurologists did not answer the question and two used LFF > 1 Hz. With respect to the high-frequency filter (HFF), seven neurologists did not provide an answer and three used HFF < 70 Hz. With regards to adjustments made to equipment for recording EEGs, the manufacturer salesperson was responsible for settings changes for seven neurology clinics (39%) without involvement of the neurologist in the process. Six neurologists (33%) reviewed printed copies of EEG recordings (post-recording, settings fixed) and the other twelve reviewed EEG recordings digitally. All the participants agreed that participating in EEG workshops and training classes would be beneficial to their practice.

Discussion

In this survey of neurologists in Fars province, Iran, we observed that a significant number of the neurologist participants did not have a good knowledge of the technical aspects of EEG recording and as a result recorded EEGs sub-optimally. For example, an LFF setting of > 1-Hz attenuates slow-wave activity; hence, important information may be missed by the neurologists who used > 1-Hz setting if pathological delta activity was present. Also, an HFF setting < 70-Hz may distort or attenuate pathological spikes and may also cause muscle artifact to look like pathological spikes (Sinha et al 2016), but several neurologists who participated in the survey use this HFF setting.

One of the challenges for neurologists who are trained and practicing in Iran is the lack of appropriate EEG training during their residency; in particular, lack of training on technique and practice standards for EEG recording. As a result, if a neurologist lacks understanding of the basic fundamentals of EEG recording, they may not recognize a suboptimal montage setting designed by an inexperienced equipment salesperson, or filters set to incorrectly demonstrate artifact-free EEG (both of which were observed by participants in this study and also the author’s personal experience). Since EEG is one of the main ancillary tests in the daily practice for any neurologist, a course on the fundamentals of EEG technology in the clinical setting seems necessary as a part of any neurology residency program. Unfortunately, over-interpretation of EEGs is a common practice and is an important contributor to misdiagnosis and mismanagement of patients who suffer from paroxysmal events (Benbadis & Tatum 2003; Benbadis & Lin 2008; Asadi-Pooya et al. 2013). A knowledgeable and competent electroencephalographer should be able to design logical EEG montages and should have the knowledge of the important technical aspects and EEG settings in order to provide the best possible interpretation of the EEG findings.

Another important shortcoming in Iran that has a significant impact on the quality of EEG recordings is the lack of officially trained EEG technologists and the lack of a certified educational program to train such professionals in the nation.  In many developed nations, EEG technologists typically hold an associate’s degree and during their education, technologists often receive training that includes neuroanatomy and neurophysiology, neurodiagnostic technology, and basic instrument methodology, among other important topics. The significant role of EEG technologists is undeniable. While establishing certified educational programs to train knowledgeable EEG technologists is a must for any healthcare system world-wide, professionals living in developing countries may have limited access to resources.

In conclusion, we should bear in mind that EEG is only an ancillary tool, and its helpfulness largely depends on the skill and knowledge of the EEG technologist who performs it and the neurologist who interprets it. However, in knowledgeable and skillful hands, EEG may provide valuable information in many patients with paroxysmal events (Pillai & Sperling 2006).

Acknowledgment

We would like to thank the Neuroscience Research Center, Shiraz University of Medical Sciences for supporting this study.

References

Acharya JN, Hani AJ, Thirumala P, Tsuchida TN. 2016. American Clinical Neurophysiology Society Guideline 3: A Proposal for Standard Montages to Be Used in Clinical EEG. Neurodiagn J; 56: 253-260.

Asadi-Pooya AA & Sperling MR. 2014. Atlas of EEG reports. 1st Edition. Shiraz; Shiraz University of Medical Sciences Publications.

Asadi-Pooya AA, Emami M, Ashjazadeh N, Nikseresht A, Shariat A, Petramfar P, Yousefipour G, Borhani-Haghighi A, Izadi S, Rahimi-Jaberi A. 2013. Reasons for uncontrolled seizures in adults; the impact of pseudointractability. Seizure; 22: 271-274.

Benbadis SR, Tatum WO. 203. Overinterpretation of EEGs and misdiagnosis of epilepsy. J Clin Neurophysiol; 20: 42-44.

Benbadis SR, Lin K. 2008. Errors in EEG interpretation and misdiagnosis of epilepsy. Which EEG patterns are overread? Eur Neurol; 59: 267-271.

Kuratani J, Pearl PL, Sullivan LR, Riel-Romero RMS, Cheek J, Stecker MM, Orta DSJ, Selioutski O, Sinha SR, Drislane FW, et al. 2016. American Clinical Neurophysiology Society Guideline 5: Minimum Technical Standards for Pediatric Electroencephalography. Neurodiagn J; 56: 266-275.

Pillai J, Sperling MR. 2006. Interictal EEG and the diagnosis of epilepsy. Epilepsia; 47 Suppl 1: 14-22.

Sinha SR, Sullivan LR, Sabau D, Orta DSJ, Dombrowski KE, Halford JJ, Hani AJ, Drislane FW, Stecker MM. 2016. American Clinical Neurophysiology Society Guideline 1: Minimum Technical Requirements for Performing Clinical Electroencephalography. Neurodiagn J; 56: 235-244.

Article by:
Ali A. Asadi-Pooya, M.D. 1, 2 Maryam Homayoun, M.D. 1

1. Neuroscience Research Center, Shiraz Medical School, Shiraz University of Medical Sciences, Shiraz, Iran.

2. Jefferson Comprehensive Epilepsy Center, Department of Neurology, Thomas Jefferson University, Philadelphia, USA.

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