G266 – Electrophysiological assessment of movement disorders
OHIP Diagnostic & Therapeutic Procedures Code — DIAGNOSTIC AND THERAPEUTIC PROCEDURES · Schedule of Benefits
Electrophysiological assessment of movement disorders which includes multi-channel recording of EEG and EMG, rectification, averaging, back averaging, frequency analysis and cross correlation. This service requires a minimum duration of 3 hours, and the physician must be physically present throughout the entire assessment.
When to Use
- Use G266 for complex movement disorder investigations requiring multi-channel EEG/EMG analysis, such as differentiating psychogenic tremor from organic myoclonus.
- Select G266 when the diagnostic protocol necessitates advanced signal processing like back-averaging or cross-correlation that exceeds the scope of a standard G548 EMG study.
Common Pitfalls
- Billing G266 without explicitly recording the start and end times in the clinical notes, which is a mandatory requirement for all time-based codes under GP7.
- Attempting to bill G266 for assessments lasting less than 180 minutes, as the code strictly mandates a minimum 3-hour duration for the physician's physical presence.
- Failing to document the specific signal analysis techniques used, such as rectification or frequency analysis, which are required components of the G266 service definition.
Billing Tips
- Ensure the medical record clearly justifies the 3-hour duration by detailing the multi-channel recording and subsequent signal processing steps performed during the session.
- If subtemporal needle electrodes are required for the assessment, remember to add G417 to the claim as an eligible add-on code to maximize the procedural fee.
Effective: April 1, 2025
J. Diagnostic and Therapeutic Procedures
DIAGNOSTIC AND THERAPEUTIC PROCEDURES
Diagnostic
Diagnostic and Therapeutic Procedures
Physician must be physically present throughout assessment.
The assessment must have a minimum duration of 3 hours.
The start and end times of the service must be recorded in the patient's permanent medical record as per general requirements for services with a minimum time duration ().
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