How to Score Sleep Studies Brett Miller RPSGT, RST Scoring sleep studies can be divided into 6 steps: 1. Sleep staging 2. Arousals 3. Respiratory events and desaturations 4. Periodic limb movements 5. Arrythmias 6. Snoring Scoring definitions and Background: ● Hertz (Hz): cycles per second of a waveform. ○ ● Electroencephalogram (EEG): The recording of electrical activity along the scalp. Acquired by surface electrodes on the scalp at standardized locations called the 10-20 system in reference to to the distance of placement between electrodes based on 10 and 20% of the circumference of the head. See chart below ○ ○ Recommended derivations for EEG ■ F4-M1 ■ C4-M1 ■ O2-M1 ○ Alternate derivations for EEG ■ F3-M2 ■ C3-M2 ■ O1-M2 ● Electrooculogram (EOG): The recording of voltage changes caused by eye How to Score Sleep Studies Brett Miller RPSGT, RST ● ● ● ● ● ● ● ● ● ● ● ● ● movements. Acquired by surface electrodes placed 1cm above and 1cm away from the outer canthus of the right eye and 1cm below and 1cm away from the outer canthus of the left eye. ○ Recommended derivations for EOG ■ E1-M2 ■ E2-M2 Electromyogram (EMG): Acquired by surface muscles placed on the sub-mental or chin muscle and and by electrodes placed on the tibialis muscle of each leg. Sawtooth waves: Present in Stage R. Serrated waveforms. 2-6Hz Slow rolling eye movements (SREM): Present in Stage N1 and Sleep onset. Also called reading eye movements. Rapid eye movement (REM): Present in Stage R and Wakefulness Alpha waves: Present in Wake and Sleep onset. 8-13 Hz Beta waves: 13-30Hz waveforms Delta waves: Present in Stage N3. 1-4Hz waveforms with amplitudes greater than 75 micro-volts Theta waves: Present in Stage N1. 4-8Hz waveforms Sleep Spindle: Present in Stage N2. 11-16Hz waveforms. ≥ 0.5 seconds Vertex Sharp waves: Present in Stage N1. Sharp negative (upward) deflection followed by a positive (downward) deflection. <0.5 seconds K-complexes: Present in Stage N2. Sharp negative (upward) deflection followed by a positive (downward) deflection. ≥0.5 seconds Low amplitude mixed frequency waveforms: Predominately 4-7Hz waveforms. Also called Theta waves Epoch: Defined as a 30 second increment of a sleep study. Epochs begin immediately following “lights out” How to Score Sleep Studies Brett Miller RPSGT, RST Stage W 1. Characteristics a. EEG - Alpha b. EOG - Eye blinks or slow rolling eye movements (SREM) present in EOG electrodes (E1 & E2) c. EMG - Normal to high tone in submental EEG 2. Scoring Stage W a. Alpha or faster ≥50% of epoch b. Eye blinks c. Normal to high Submental EMG activity High submental EMG activity, Alpha waves present in O1 & O2 Slow rolling eye movements, Alpha waves present in O1 & O2 How to Score Sleep Studies Brett Miller RPSGT, RST Stage N1 1. Characteristics a. EEG - Theta, Alpha, Vertex sharp, Low amplitude mixed frequency b. EOG - Slow rolling eye movements (SREM) present in EOG electrodes (E1 & E2) c. EMG - Variable in amplitude but usually lower amplitude than Stage W d. Comprises ~5% of Total Sleep Time 2. Scoring a. Slow rolling eye movements are present b. Vertex sharp waves are present c. Low amplitude mixed frequency waveforms are present in O1 & O2 and comprise ≥50% of epoch Vertex sharp waves are present. Slow rolling eye movements, Alpha waves have attenuated and been replaced by low amplitude mixed frequency waves How to Score Sleep Studies Brett Miller RPSGT, RST Stage N2 1. Characteristics a. EEG - Theta waves with K complexes & Sleep spindles b. EOG - Similar to EEG activity in amplitude and frequency c. EMG - Variable in amplitude but usually lower amplitude than Stage W d. Comprises ~45% of Total Sleep Time 2. Scoring a. K complexes and sleep spindles are present for >50% of the epoch K complexes and sleep spindles are present throughout epoch How to Score Sleep Studies Brett Miller RPSGT, RST Stage N3 1. Characteristics a. EEG - Delta waves b. EOG - Similar to EEG activity in amplitude and frequency c. EMG - Variable in amplitude. most likely lower than in N1 & N2 and can be as low as in Stage R. d. Comprises ~25% of Total Sleep Time 2. Scoring a. Delta waves total 20% or greater of epoch (cumulative) Delta waves How to Score Sleep Studies Brett Miller RPSGT, RST Stage R 3. Characteristics a. EEG - Theta waves with sawtooth waves. Alpha waves may be present but will 1-2Hz slower than alpha waves found during wake b. EOG - Similar to EEG activity in amplitude and frequency with rapid eye movements c. EMG - Significantly reduced amplitude d. Comprises ~25% of Total Sleep Time e. Usually preceded by Stage N3 sleep. May be preceded by a short period of Stage N1 or N2. 4. Scoring a. Stage R - Phasic How to Score Sleep Studies Brett Miller RPSGT, RST Stage R - Tonic Stage R - Tonic transition to Phasic