ABPN Clinical Neurophysiology common mistakes
ABPN Clinical Neurophysiology · Understand the traps and how to avoid them.
Calling a waveform epileptiform because it is sharply contoured, without first checking whether it is broad-based, has a physiologic field, and appears in a state-dependent distribution (e.g., vertex waves, POSTS, wicket spikes, breach rhythm).
Sharply contoured normal transients are visually salient and pattern-match to the 'spike' template learned from textbooks, so candidates classify by shape rather than by context, field, and state reactivity.
What to do instead
Apply a fixed checklist to every sharp transient before naming it: duration, field and polarity, reactivity to eye opening/alerting, state dependence, and symmetry. If it does not survive the checklist, call it a normal variant and justify why.
Describing the background as 'generalized slowing' without grading it, specifying whether it is continuous or intermittent, or stating whether it is reactive to eye opening or alerting.
Candidates treat background as a preamble to the 'real' question about spikes, so they write a generic descriptor that conveys no localizing or prognostic information.
What to do instead
Use a structured background sentence every time: dominant posterior frequency in Hz, symmetry, continuity, reactivity, and presence of focal or generalized slowing. Practice writing it in one line for 20 consecutive EEGs.
Reading a montage only in its default display and failing to re-montage (or reformat) to resolve a focal finding, then reporting a localization the montage cannot support.
Candidates memorize findings from a single referential or bipolar view and do not practice the habit of confirming a phase reversal or field in a second montage.
What to do instead
For every focal abnormality, force yourself to confirm it in at least one bipolar and one referential montage, and state the montage basis for the localization in your report.
Reporting an NCS amplitude or conduction velocity without verifying limb temperature, and without documenting temperature correction.
Temperature effects on latency and amplitude are taught as a footnote, so candidates chase a diagnosis of demyelination or axonal loss that is really a cool limb.
What to do instead
Before interpreting any NCS, check and record limb temperature; if below the laboratory threshold, warm the limb and repeat, or apply the lab's temperature correction and say so explicitly in the interpretation.
Diagnosing demyelination from a single prolonged distal latency or a single slowed conduction velocity without checking for dispersion, conduction block, or an alternative explanation such as a short segment or anomalous innervation.
Criteria are memorized as isolated numbers rather than as a pattern requiring more than one supporting feature, and candidates apply them to one nerve in isolation.
What to do instead
Apply formal demyelinating criteria across multiple nerves and require the specified number of abnormalities; explicitly look for temporal dispersion and conduction block, and exclude technical causes before committing to a demyelinating label.
Interpreting needle EMG spontaneous activity as definite denervation without distinguishing it from endplate noise, endplate spikes, or fasciculation, and without confirming the needle is in the right muscle.
Fibrillation potentials and positive sharp waves are taught as the marker of denervation, and candidates over-read benign endplate activity or mislocalize the needle.
What to do instead
Confirm needle placement by voluntary recruitment and audio, then classify spontaneous activity by its waveform and firing pattern; treat endplate noise and endplate spikes as normal and state the reasoning for calling true fibrillation potentials.
Reporting SEP or VEP latencies without specifying the stimulation and recording parameters, the normative comparison, and whether the abnormality is unilateral, absent, or merely prolonged.
Candidates focus on the number and omit the conditions that make the number interpretable, so a prolonged latency is reported without a defensible reference.
What to do instead
State stimulation site and rate, recording montage, the normative limit used, and the side-to-side comparison in every EP report; if the waveform is absent, say absent rather than prolonged.
Interpreting an abnormal evoked potential as a diagnosis rather than as a localizing test, e.g., calling a prolonged VEP 'demyelinating disease' or a prolonged SEP 'cord compression'.
EPs are taught alongside specific diseases, so candidates invert the logic and treat a supportive test as confirmatory.
What to do instead
Phrase every EP conclusion as an anatomic/physiologic statement (e.g., 'delayed conduction in the visual pathway, left greater than right') and list the differential it supports, not a single disease.
Scoring sleep stages from a single channel or a single epoch without applying the rules for epoch majority, arousal, and transitions, and without verifying the montage is adequate (EOG, chin EMG, appropriate EEG derivations).
Candidates focus on spotting spindles or slow waves and skip the rule-based process of assigning stage to a 30-second epoch by majority and transition criteria.
What to do instead
Score every epoch using the full rule set and the required channels; for each epoch, explicitly identify the stage-defining feature and its duration before assigning the stage, and re-score a set of epochs against published criteria.
Interpreting autonomic testing (e.g., tilt table, QSART, heart rate variability) without controlling for medications, hydration, time of day, and recent meals, and without distinguishing a positive test from a nonspecific or technically limited study.
Autonomic results are highly state-dependent, but candidates treat the numbers as fixed thresholds and skip the pre-test conditions that determine validity.
What to do instead
Document medication, hydration, and timing before testing, apply the laboratory's controlled protocol, and in the report separate technically adequate findings from those limited by confounders rather than issuing a bare positive or negative.