Background variability and reactivity

Criteria & assessment

• A qualifying response is a conspicuous change in frequency, continuity, or voltage.
• Record each feature as yes, no, or unclear/unknown/not applicable.
• Variability first appears near 25 weeks PMA, increases by 28 weeks, and is well established around 30-31 weeks.
• Reactivity first appears around 30-32 weeks PMA; record stimulus type and strength.
• Separate cerebral change from movement, EMG, crying, and respiratory artifacts; arousal-related voltage attenuation is not automatically discontinuity.