RPSGT common mistakes
RPSGT · Understand the traps and how to avoid them.
Places EOG and chin EMG electrodes from a memorized list rather than from anatomical landmarks - swapping left/right eye channels, placing eye electrodes on the brow, or putting the chin electrodes on the jawline instead of the submental/mentalis area - and then can't recognize the resulting out-of-phase or attenuated signals.
Candidates memorize channel names as abbreviations (LOC, ROC, Chin1/2) without ever anchoring them to bony landmarks, so a stem that describes placement in words (rather than showing a picture) exposes the gap.
What to do instead
Rebuild placement from landmarks every time you study: left eye electrode roughly 1 cm above and 1 cm lateral to the left outer canthus, right eye electrode 1 cm below and 1 cm lateral to the right outer canthus (so the eyes move in opposite directions on the tracing), and chin EMG electrodes under the lower lip along the midline on the mentalis, with a second chin channel offset a couple of centimeters for a bipolar pair. Quiz yourself by describing placements aloud without notes.
Skips or rushes the pre-study patient assessment - no medication and substance history (benzodiazepines, SSRIs, opioids, alcohol, caffeine), no review of prior studies or PAP use, no documentation of presenting symptoms - and then cannot interpret an unusual night or answer a question about how a drug would change the record.
Setup is treated as a purely technical task, and under time pressure the interview is the first thing dropped.
What to do instead
Use a fixed intake checklist every time: medications and timing, caffeine/alcohol/nicotine, sleep schedule and naps, prior PSG/MSLT results, PAP or oral appliance use, comorbidities, and current symptoms. Practice stating, for a given drug class, which stage or event type it is likely to shift.
Accepts whatever signal appears - failing to measure and correct electrode impedance, and skipping or faking the biocalibration (asking the patient to blink, look up/down/left/right, clench, sniff, breathe, move each leg) before lights out.
The tracing 'looks fine' on screen, so the step feels optional; candidates also underestimate how many exam items hinge on recognizing a technically invalid record.
What to do instead
Make impedance measurement and biocalibration non-negotiable and know the acceptance criteria cold (keep impedances low and balanced; high impedance drives artifact and baseline sway). Learn the purpose of each biocalibration maneuver - which channel it should deflect and in which polarity - so you can spot a misconnected or dead channel before the study starts.
Sees artifact on the tracing (60 Hz interference, sweat/sway, electrode pop, pulse or ECG artifact in the EEG, snore vibration in the chin) but neither corrects it nor documents what was done, and cannot name a likely cause when asked.
Pattern recognition without a troubleshooting loop: candidates learn what artifact looks like but never practice 'identify → likely cause → action → document.'
What to do instead
Build a two-column table you can recite: artifact signature → cause and corrective action (check/replace the electrode and its impedance, re-prep the skin, reposition the wire away from movement, adjust the patient's position, verify reference and ground). Always timestamp a tech note when you intervene, so the record shows why the data changed.
Misapplies recording parameters - wrong filter settings for the channel type, wrong derivations for the EEG montage, or failure to verify that the intended channels are actually being acquired - and then misreads the resulting tracing.
Parameters are treated as default settings that 'someone else' configured, so the candidate never learns why a low-frequency or high-frequency filter setting changes the appearance of slow waves, sweat artifact, or EMG.
What to do instead
Learn the standard settings as a matched set (EEG and EOG recorded with a low-frequency filter around 0.3 Hz and a high-frequency filter around 35 Hz; EMG with a wider high-frequency band; ECG filtered separately) and learn the consequence of moving each one. For montages, be able to state which electrode is the active and which is the reference in each derivation and what a reversed connection would look like.
Scores arousals on the strength of a brief EEG speed-up alone - not confirming a sustained abrupt shift of at least 3 seconds, not requiring a stretch of stable sleep beforehand, and not requiring a concurrent increase in chin EMG when the shift occurs in REM.
The '3 seconds' number is the only part that gets memorized; the conditional REM rule and the stable-sleep prerequisite are forgotten because they only appear in edge cases.
What to do instead
Score arousals with a three-question checklist every time: (1) is there an abrupt frequency shift lasting at least 3 seconds? (2) was there adequate stable sleep immediately before it? (3) if this is REM, is there a simultaneous chin EMG rise? Only then count it and mark it.
Botches stage-continuation and stage-transition rules - scoring N2 in an epoch with no K-complex or spindle and no qualifying continuation, keeping a patient in REM through an arousal or a stretch of elevated chin EMG, or ending N2/N3 at the wrong boundary.
Stage rules are conditional and order-dependent, so candidates who memorize single facts rather than a decision sequence misapply them at transitions, which is exactly where exam items cluster.
What to do instead
Write out a decision tree per stage and run epochs through it in order (wake rules first, then N1/N2/N3/REM entry and continuation tests). Specifically drill the continuation clauses: what keeps a patient in N2 when no spindle or K-complex appears, and what keeps a patient in REM when rapid eye movements are absent.
Computes summary indices against the wrong denominator or conflates them - dividing events by total recording time instead of total sleep time, treating AHI and RDI as the same number, or reporting an oxygen desaturation index as if it were an apnea-hypopnea index.
The formulas look interchangeable on paper, and candidates rarely practice computing them from a stripped-down data set.
What to do instead
Fix the definitions by hand once: apnea-hypopnea index = apneas plus hypopneas divided by hours of sleep; respiratory disturbance index adds respiratory effort-related arousals to that numerator; desaturation index comes from oximetry events alone. Then practice with a made-up night's totals (events, sleep time, recording time) and compute all three from the same numbers.
Titrates positive airway pressure by reflex - bumping pressure for every event on the screen without separating obstructive from central events, without checking whether the events occurred in REM or supine, and without stating the endpoints that define a completed titration.
The mechanics of changing pressure are easy to learn, so the decision logic and stopping criteria get skipped.
What to do instead
Memorize the titration goal as a list you can recite: abolish apneas, hypopneas, respiratory effort-related arousals, and snoring; keep oxyhemoglobin saturation at or above the accepted target; ensure the endpoints are met in REM and in the supine position. Separately learn what to do when events persist despite pressure or when the events are central rather than obstructive - that is a different clinical path, not a higher pressure.
Treats the safety and professionalism content as filler and cannot answer scenario items - what to do in a medical emergency in the lab, how to handle oxygen and fire risk, how to protect patient confidentiality and study data, or when a finding is critical enough to escalate to the physician rather than wait for the morning report.
This domain is broad and non-technical, so it gets deferred to 'later' and never systematically reviewed.
What to do instead
Study these as short, testable protocols: the lab's emergency response sequence and how to summon help without abandoning the patient; oxygen handling and ignition-source rules; infection control and equipment cleaning between patients; confidentiality rules for records and images; and a clear list of critical findings (significant arrhythmia, severe desaturation, seizure, behavioral emergency) that require immediate notification rather than documentation alone.