ASET – The Neurodiagnostic Society presents this document to provide national criteria for evaluating competencies for performing Evoked Potential (EP) studies. This document was developed by the ASET Standards and Practice Committee with input from modality-specific subject matter experts (SMEs) and approved by the ASET Board of Trustees.
The technical components included here are defined in the American Clinical Neurophysiology Society (ACNS) Guidelines on Evoked Potentials. 1–4 EP testing should be performed in compliance with all applicable institutional policies, regulatory requirements, and professional standards. International audiences may choose to use these competency standards with the understanding that parameter settings, waveform nomenclature, electrode placement, and montages may vary depending on testing variables, equipment specifications, and system configurations in their respective countries.
The competencies listed below represent the best practices and delineate the skills and knowledge required in performing visual, auditory, and somatosensory EP procedures. This document excludes EPs performed in the operating room (refer to the National Competency Skill Standards for Performing Intraoperative Neurophysiologic Monitoring).8
The Neurodiagnostic Technologist referred to in this document aligns with the ASET job descriptions and the descriptions defined in the Guidelines for Qualifications of Neurodiagnostic Personnel position statement.5 Successful completion of the ABRET Evoked Potential board examination, resulting in the R. EP T. credential, is recommended.
Competencies can be assessed by observation of clinical skills and/or by verbal, written, or computer-based proficiency testing.
Section I: EP Core Knowledge Recommendations
The EP Technologist demonstrates knowledge of:
1.1 Fundamental Knowledge of Evoked Potentials
- Medical terminology
- Accepted abbreviations and acronyms
- Standard and transmission-based infection prevention methods
- Best practices for preventing EP-related skin injuries6,7
- Neuroanatomy and neurophysiology relevant to EPs
- Indications for EP testing
- Recording concepts for visual, somatosensory and auditory EPs
- Normative age- and lab-specific data normal variants and standard deviations
- Critical care EPs with effects of medications and physiological variables associated with hypothermia protocols, neuromuscular blockades, and dialysis treatment, etc.
- Patient state e.g., Glasgow coma scale
- Digital recording concepts:
- Appropriate sampling rates (e.g., sampling rates for invasive versus routine monitoring)
- Vertical resolution (voltage range, bit capacity)
- Horizontal resolution (aliasing, Nyquist frequency, analysis time, sampling skew)
- Analog to digital conversion
- Differential amplifiers (input impedance, common mode rejection, polarity convention, gain)
- Effects of stimulus (rate, intensity, duration) and recording parameters (filters, gain/sensitivity) on waveforms
- Electrode impedance test
- Signal-to-noise ratio (e.g., increasing the number of sweeps)
- The meaning and significance of artifact rejection (establishing rejection parameters)
- Basic IT and computer hardware and software components (e.g., network, storage, operating systems)
- EP system integration with EMR
Section II: EP Technical Skills and Proficiency
The EP Technologist demonstrates competency in performing the following tasks:
2.1 EP Technology and Instrumentation
- Ensures that equipment is cleared as safe prior to use; identifies and tags malfunctioning equipment. Communicates technical issues with appropriate personnel.
- Follows institutional processes for troubleshooting network, hardware, data server storage and remote access.
- Selects recommended equipment settings for procedure.1-4
- Applies electrical safety concepts to patient care (e.g., grounding, patient isolation transformer, biomedical safety checks, and facility policies for malfunctioning equipment).
- Recognizes, eliminates, or mitigates physiologic and non-physiologic artifact.
2.2 EP Preprocedural Preparation
- Reviews medical records (e.g., patient demographics, patient history, neurological assessments, medications, procedures, previous EP studies).
- Collaborates with the patient care team (e.g., referring physician, reading physician, nursing staff).
- Determines and provides accommodation according to the patient’s needs in context (e.g., preferences, age, preferred language, communication, and ability).
- Interviews the patient and/or family /caretaker, provides education and instructions regarding EP, and answers questions of patients and caretakers.
- Collects supplies appropriate for each patient according to diagnostic needs.
- Customizes setup and recording protocols including appropriate montage derivations.
2.3 Performing EP Procedures
- Assesses the patient’s risk for skin breakdown and collaborates with care team as needed to mitigate risk.6,7
- Prepares patient’s skin to lower impedance prior to electrode application.
- Measures, marks, and applies electrodes.1–4
- Adjusts electrode placement for anatomical defects or anomalies.
- Uses appropriate electrode type for procedure.
- Verifies that impedances are low and balanced.4
- Practices safe infection prevention methods.
- Applies the appropriate stimulator type (e.g., stimulator bar, bipolar, tiptrode, headphone, goggles, monitor, etc.).
- Determines the correct polarity for stimulation (e.g., anode, cathode, rarefaction, etc.).
- Applies additional electrode derivations and other techniques as needed to enhance waveforms.
- Selects appropriate analysis time, sensitivity, and bandpass settings.
- Uses appropriate recording and stimulus parameters.
- Resolves waveforms adequately.
- Collects adequate number of acceptable responses (e.g., non-rejected) for each replication.
- Records at least two replications1 demonstrating consistency of latency and amplitude measurements.
- Uses additional techniques that clarify the abnormal responses (e.g., warming limb temperature, changing stimulus duration, varying intensity, increasing number of averages, extending analysis time, etc.).
- Documents administration of neuromuscular blockade if used in the critical care setting.
2.4 EP Postprocedural Process
- Removes all electrodes, cleans skin, and follows process for skin breakdown.
- Uses proper disinfecting techniques for all diagnostic equipment.
- Replenishes and maintains supplies.
- Ensures that equipment is operational for the next procedure.
- Saves and prepares data for interpretation.
Section III: Specific EP Procedures
3.1 Visual Evoked Potentials (Pattern Reversal [PVEP], Flash [FVEP])
- Obtains relevant ophthalmologic and neurologic history and/or neurosurgical history or any other relevant pathway-specific information such as the presence of eye trauma, optic neuritis, visual field defect, or other disorders affecting visual acuity.
- Assesses the patient’s visual acuity.
- Employs appropriate montages and derivations utilizing Queen’s Square or the International 10–20 System of electrode placement.
- Calculates and selects an adequate check size and positions the patient at a distance from the pattern stimulator appropriate for the desired visual angle.
- Closely monitors the patient’s attention during the test.
- Performs the study with the same parameters and conditions used for normative studies, including ambient light, pattern luminance, and contrast.
- Adequately resolves waveforms:
- PVEP: P100, N75, N145 and N100
- FVEP: I-VI
- Marks waveforms and calculates the absolute latencies, amplitudes and interpeak intervals of the obligate components.
- Extends analysis times as needed to accommodate absent or delayed responses.
- Performs additional testing as indicated by critical findings or diagnoses (e.g. hemifields).
- Correlates VEP Findings with:
- Generator sites
- Obligate peaks
- Near and far field potentials
- Related disease processes and criteria for clinically significant abnormalities
- Recognizes medication effects on VEPs.
- Addresses physiologic and non-physiologic artifacts affecting VEPs.
3.2 Somatosensory Evoked Potentials (SSEPs)
- Obtains relevant neurologic, orthopedic, and/or neurosurgical history or any other relevant pathway-specific information such as the presence of peripheral neuropathy.
- Obtains and documents limb temperature and length prior to procedure.
- Applies the appropriate stimulating electrodes: active cathode over the nerve and anode placed 2–3 centimeters distal to the cathode.
- Properly grounds the patient to reduce stimulus artifact; ground placed between point of stimulation and the first recording electrode.
- Selects sufficient intensity and duration to elicit a motor twitch from the appropriate areas of stimulation.
- Uses a montage that records responses from multiple levels of the pathway such as peripheral nerve, spinal cord, subcortical, and cortical responses.
- Adequately resolves the obligate components of Erb’s Point, N13, P14, N18, and N20 of the median nerve SSEP, ensuring reproducibility.
- Adequately resolves the obligate components of lumbar (LP), N34, and P37 of the posterior tibial nerve SSEP, ensuring reproducibility.
- Records a popliteal fossa (PF) potential to confirm adequate stimulation of the tibial nerve in the absence of a recordable LP potential.
- Extends analysis times as needed to accommodate absent or delayed responses.
- Marks waveforms and calculates the absolute latencies, amplitudes and interpeak intervals of the obligate components.
- Correlates SSEP findings with:
- Generator sites
- Obligate peaks
- Near and far field potentials
- Related disease processes and criteria for clinically significant abnormalities
- Recognizes medication effects on SSEPs.
- Addresses physiologic and non-physiologic artifacts affecting SSEPs.
3.3 Brainstem Auditory Evoked Potentials (BAEPs)
- Obtains relevant audiologic, neurologic, and/or neurosurgical history (e.g., hearing loss, ear infections, dizziness, tinnitus, etc.).
- Assesses the patient’s ear canals for blockages or any obstruction that could impact the procedure or test results.
- Establishes hearing thresholds.
- Correlates elevations in thresholds with any existing hearing loss or conditions of ear structures.
- Uses a montage derivation of vertex to ipsilateral ear and vertex to contralateral ears or alternate derivations.
- Chooses the appropriate analysis time, number of average stimulus rates, sensitivity, and bandpass settings.
- Obtains optimal waveforms (i.e., chooses the appropriate click polarity, rate and intensity).
- Expresses click intensity measures in equivalent units of dBSL, dBHL or dBSPL.
- Appropriately uses masking for contralateral ear.
- Measures and calculates the absolute latencies, amplitudes and interpeak intervals of obligate peaks, I, III, and V.
- Extends analysis times as needed to accommodate absent or delayed responses. Accounts for latency differences resulting from ear inserts.
- Correlates BAEP Findings with:
- Generator sites
- Obligate peaks
- Near and far field potentials
- Related disease processes and criteria for clinically significant abnormalities
- Recognizes medication effects on BAEPs.
- Addresses physiologic and non-physiologic artifacts affecting BAEPs.
Section IV: Continuing Education
To maintain and improve knowledge and skill, the EP technologist:
- Reviews EP records with an experienced mentor or clinical neurophysiologist on a regular basis.
- Reads journal articles.
- Studies textbooks related to the field.
- Attends continuing education courses, webinars, seminars, conferences, etc. in clinical neurophysiology.
- Participates in quality assurance/improvement reviews.
- Participates in professional organizations for neurodiagnostics.
- Achieves EP registry and meets recertification requirements.
- Serves as a clinical preceptor, educator, or mentor.
- Volunteers in neurodiagnostic organizations and committees.
References
- American Clinical Neurophysiology Society. 2006. Guideline 9A: guidelines on evoked potentials. J Clin Neurophysiol. 23(2): 125–127.
- American Clinical Neurophysiology Society. 2006. Guideline 9B: guidelines on visual evoked potentials. J Clin Neurophysiol. 23(2): 138–156.
- American Clinical Neurophysiology Society. 2006. Guideline 9C: guidelines on short-latency auditory evoked potentials. 2006. J Clin Neurophysiol. 23(2): 157–167.
- American Clinical Neurophysiology Society. 2006. Guideline 9D: guidelines on short-latency somatosensory evoked potentials. 2006. J Clin Neurophysiol. 23(2): 168–179.
- López JR, Ahn-Ewing J, Emerson R, Ford C, Gale C, Gertsch JH, Hewitt L, Husain A, Kelly L, Kincaid J, et al. 2023. Guidelines for qualifications of neurodiagnostic personnel: a joint position statement of the American Clinical Neurophysiology Society, the American Association of Neuromuscular & Electrodiagnostic Medicine, the American Society of Neurophysiological Monitoring, and ASET – The Neurodiagnostic Society, Neurodiagn J. 63(1): 14–46. doi: 10.1080/21646821.2023.2183008.
- ASET – The Neurodiagnostic Society. 2016. ASET position statement on skin safety during EEG
procedures – a guideline to improving outcome. https://www.aset.org/best-practices/ - ASET – The Neurodiagnostic Society. 2017. ASET position statement on skin safety during EEG procedures – a guideline to improving outcome addendum: neonatal continuous EEG. https://www.aset.org/best-practices/
- ASET — The Neurodiagnostic Society. 2021. National Competency Skill Standards for Performing Intraoperative Neurophysiologic Monitoring. https://www.aset.org/wp-content/uploads/2022/11/IONM_Competencies_FINAL.pdf