3.3 Recording, Documentation & Special Populations

Running the Study & Technologist Documentation

Once calibrations pass and the lights go out, the technologist continuously monitors the recording, the patient, and the synchronized video. The technologist log (study notes) is a legal and clinical document that lets the scorer and interpreting physician understand what the raw signal alone cannot show. On the RPSGT exam, documentation questions reward the candidate who records objective, time-stamped facts and avoids anything resembling a diagnosis.

The log should capture, with time stamps:

• Lights out and lights on times — these define total recording time and the denominator for sleep efficiency
• Body position changes (supine, left, right, prone) — position drives event distribution; many patients are far worse supine
• Sensor events — which electrode/sensor failed, when, and the correction performed
• Patient behaviors — snoring, paradoxical breathing, coughing, leg jerks, parasomnia events, awakenings, sleep talking
• Interventions — bathroom breaks, supplemental oxygen added, positive airway pressure (PAP) titration changes, reassurance for anxiety
• Notable events — seizures, significant desaturations, arrhythmias, and any clinical concern escalated to nursing or the on-call physician

Why It Matters

Good documentation explains gaps and anomalies so the scorer does not misread a corrected electrode pop as a seizure, or a bathroom break as wake-after-sleep-onset artifact. Consider a 3:10 a.m. annotation: "Pt to bathroom, all leads disconnected at headbox; reconnected and bio-cal repeated 3:18 a.m." That single note tells the scorer to exclude eight minutes from sleep time and reassures them the post-break signals are valid. The technologist documents what happened; the physician decides what it means. Recording a diagnostic opinion is outside the technologist's scope of practice and is a frequent distractor on the exam.

Artifact Recognition & Correction

An artifact is any recorded signal that does not come from the physiologic source the channel is meant to measure. Recognizing the artifact and correcting the cause — not hiding it with filters — is a core RPSGT skill, and the exam presents these as scenario items.

Distinguishing Look-Alikes

Sweat artifact and a true slow-wave (delta) burst both occupy the low-frequency band, but sweat drift is slower than 0.5 Hz and wanders the baseline without the morphology of genuine delta; it also worsens through a warm night. ECG artifact in an EEG or chin EMG channel is unmistakable once you align it with the ECG trace — the spikes march in lockstep with the QRS complex. The fix is to reposition the offending reference, not to filter the heartbeat out.

Order of Operations

When an artifact appears, work outward from the patient: check the patient and electrode first, then the headbox/jackbox connection, then the amplifier and filter settings. Document every correction in the log. The recurring exam principle: fix the cause, never mask the symptom, and never delete or overwrite raw data.

Pediatric & Special-Population Considerations

Pediatric PSG is not simply a smaller adult study. The differences the exam tests:

• Carbon dioxide monitoring: children are prone to obstructive hypoventilation, so end-tidal CO2 (EtCO2) or transcutaneous CO2 (TcCO2) is added. The AASM defines pediatric hypoventilation as CO2 > 50 mmHg for more than 25% of total sleep time.
• Pediatric apnea rule: a pediatric obstructive apnea requires absent airflow lasting ≥2 respiratory cycles (event-duration based), not the adult fixed ≥10-second threshold.
• Pediatric hypopnea: scored on a ≥30% airflow drop lasting ≥2 breaths with an associated ≥3% desaturation or arousal.
• Sleep architecture: infants show more REM (active sleep) and a tracé alternant pattern; the AASM provides separate infant staging terms (Wake, REM, N1–N3, and "N" for indeterminate non-REM) for children under specified ages.
• Sensor adaptation: smaller electrodes, gentler skin prep, collodion avoidance in neonates, and a caregiver present at the bedside.

Other Special Populations

Every substitution — a relocated tibial electrode, an expanded montage, an added CO2 sensor — belongs in the technologist log so the scorer applies the correct rule set. Applying adult respiratory criteria to a child's study is a classic scoring error the exam probes, because the duration thresholds genuinely differ.

Equipment Troubleshooting During Acquisition

Problems during acquisition must be solved fast and quietly so the patient stays asleep and the data stays valid. A reliable, exam-favored order of operations:

1. Confirm the finding — is it one channel or many? One channel usually means a sensor/electrode; many channels suggest a ground, headbox, or amplifier problem.
2. Inspect the patient and electrode — look for a dislodged sensor, kinked CPAP tubing, or a disconnected oximeter probe.
3. Check the headbox/jackbox — reseat the lead in the correct input; a lead in the wrong jack mislabels the channel.
4. Check connections and ground — verify the patient ground and cable integrity; a lost ground often shows as global 60 Hz.
5. Check amplifier and software settings — confirm the channel is not muted, filtered incorrectly, or rescaled.
6. Document the problem, the corrective steps, and the time in the technologist log.

The One-Channel vs. Many-Channels Heuristic

This distinction is the fastest diagnostic shortcut. A single flat EEG channel while every other trace looks normal points to that electrode or its single input, so you inspect and reseat rather than tearing down the montage. Conversely, 60 Hz or dropout across many channels at once implicates a shared resource — the patient ground, the headbox, or mains interference — so you check those before touching individual electrodes.

Hard Rules

Never "fix" a physiologic problem by deleting or overwriting raw data, and never silently change a montage mid-study without logging it — the scorer must be able to reconstruct exactly what happened, channel by channel and minute by minute. Patient safety always outranks the recording: if a finding suggests a clinical emergency (a dangerous arrhythmia, profound sustained desaturation, or a seizure), the technologist intervenes and escalates per lab protocol first, then documents.