Natus & Persyst Instructions

Open Patient Study

Navigate to the Patient Studies list or use the search function to locate a record. Then select the desired EEG study. Confirm two patient identifiers, study date, and recording start time before interpreting or reporting.

Configure Display

Select the bipolar montage Bipolar LT over RT and begin with display sensitivity 7 μV/mm, time base 30 mm/sec, HFF 70 Hz, and LFF 1 Hz. These are starting display settings, not fixed interpretation settings; adjust the montage, sensitivity, time base, and filters to answer the clinical question while avoiding waveform distortion. See the same knobs on a 10-second page in EEG Fundamentals.

Calibrate the Screen

Go to Edit → Calibrate… On the Screen tab, set Monitor to Custom and enter the screen dimensions in millimeters using the actual measured display area, not a copied example value. Set Type to Auto (Primary), then click Apply. Calibration makes the on-screen millimeter scale physically accurate, so sensitivity (μV/mm) and time base (mm/sec) mean what they say.

Analyze the EEG

Read the raw EEG systematically: background, symmetry and reactivity, sleep features, artifacts, interictal abnormalities, and events. Change montage to check a suspected field; use video and ECG to test artifact explanations. Measure frequency and duration before assigning a pattern name.

Annotate Events

Place event markers by clicking the designated buttons at the top of the screen.

Create EEG Report

After review, open Epic's reporting interface, generate a new report, and pend the note for review.

Template Types (EPIC Smart Phrases)

These smartphrases are institution-specific — they exist in this institution's Epic build and will not be available at other sites.

Launch Persyst

Once your EEG study is open go to Analysis and ensure Persyst (toolbar) is checked

Persyst (toolbar)

Locate the Persyst toolbar as pictured below. If using two screens, grab the toolbar and drag it to the second screen.

Configure Panel Size

Check that "Comprehensive" is selected. Adjust display size by grabbing the bottom right corner to expand the panel.

Rhythmicity Spectrogram

The rhythmicity spectrogram highlights sustained rhythmic activity across frequencies and channels. It is a screening display: seizures, rhythmic/periodic patterns, artifact, and normal rhythms can all produce conspicuous trends, so every candidate event must be confirmed on raw EEG.

FFT Spectrogram

The FFT spectrogram displays frequency power over time. Warm colors indicate relatively greater power and cool colors lower power on the selected scale; color alone does not distinguish seizure from artifact, sleep, medication effect, or other cerebral activity. Confirm meaningful changes on raw EEG.

Asymmetry and aEEG

The Asymmetry panel in Persyst uses color contrasts (left blue and right red) to reveal lateral differences in EEG power between hemispheres sorted from delta to gamma frequency on the Y axis. The aEEG panel compresses long-term amplitude trends into a waveform, together providing a quick visual summary of lateral power differences and amplitude trends. Check the displayed color legend and scale for the selected template. An asymmetry does not identify its cause; confirm it on raw EEG and inspect electrode quality.

ADR

The alpha/delta ratio (ADR) trends relative alpha and delta power. A sustained regional decline can provide an early warning of delayed cerebral ischemia after subarachnoid hemorrhage, but an isolated value is neither “normal” nor diagnostic. Review baseline, raw EEG, asymmetry, sleep, sedation, artifact, systemic physiology, and the clinical examination.