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IVT
alpha intrusion
Abnormal presence of alpha frequency waves during NREM sleep, often associated with non-restorative sleep.
Full Definition
Alpha intrusion refers to the pathological appearance of alpha frequency brain waves (8-13 Hz) during NREM sleep stages where they should normally be absent. This phenomenon creates a pattern of alpha-delta sleep that prevents deep, restorative sleep despite adequate sleep duration. Alpha intrusion is commonly observed in fibromyalgia, chronic fatigue syndrome, and other conditions characterized by non-restorative sleep complaints.
Usage
Usage note: Distinguish from 'alpha wave intrusion' which is the broader category.
In Context
- "The polysomnogram revealed significant alpha intrusion throughout slow-wave sleep stages." — sleep study report
- "Alpha intrusion may explain the patient's complaints of unrefreshing sleep despite normal total sleep time." — clinical interpretation
Also known as
alpha-delta sleep
alpha contamination
Contrasted with
normal NREM sleep
Don't confuse with
alpha wave intrusion
sleep fragmentation