Table 4: American Academy of Sleep Medicine Classification of Sleep Apnoea Evaluation.

Level	Level I: Standard Polysomnography	Level II: Comprehensive Portable Polysomnography	Level III: Modified Portable Sleepapnoea Testing	Level IV: Continuous (Single or Dual) Bioparameter Recording
Minimum recording channels	EEG, EOG, chin EMG, ECG, airflow, respiratory effort and oxygen saturation.	Same as for Level I except heart rate instead of ECG is acceptable.	Recording of ventilation (at least two channels of respiratory movement, or respiratory movement and airflow), ECG or heart rate and oxygen saturation.	Only one or two physiological variables need to be recorded.
Other characteristics	Body position must be documented or objectively measured. Leg movement recording (EMG or motion sensor) is desirable but optional.
Personnel and ability to intervene	Trained personnel must be in constant attendance and able to intervene.	Personnel are needed for preparation. Ability to intervene is not required for all studies.	Personnel are needed for preparation. Ability to intervene is not required for all studies.	Personnel are needed for preparation. Ability to intervene is not required for all studies.

EOG = electrooculogram; EMG = electromyogram.