Primary cerebral autoregulatory failure (pCAF, (b)). HR and BP were normal at supine and during the tilt. CBFv was markedly reduced at the supine position and was further reduced during the tilt. Data from 47-year-old man. Patient was referred for evaluation of chronic fatigue, difficulites with attention, and chronic dizziness that was both supine and postural. For comparison, a healthy 80-year-old woman has normal CBFv (a).