Synonymes: Vertex sharp transient or V wave
- Maximum at the vertex (like K complex)
- Amplitude: 50-150 microV
- Presence in non-REM 1 and to a lesser extent in non-REM 2
- Narrower and more focal than K complex
- Unlike K complex vertex waves are not associated with sleep spindles
- In children and young adult vertex waves could be sharp and in a repetitive run, not to be confused with an epileptic discharge.