Introduction 1 4 1 5 6 Some recent findings challenge this doctrine: reduced cognitive performance in hypotension has been demonstrated by neuropsychological testing, and EEG studies have revealed diminished cortical activity. Moreover, the assumption of unimpaired brain perfusion in hypotension no longer holds. In the present review the necessity of a reappraisal concerning hypotension is discussed in light of the relationship between blood pressure and cerebral functioning. Constitutional hypotension 4 1 6 1 7 3 8 9 10 11 14 15 16 13 1 1 17 18 19 20 21 22 23 24 Cognitive deficits in constitutional hypotension 1 Table 1 Studies on cognitive performance in hypotension (SBP, systolic blood pressure; DBP, diastolic blood pressure) Authors Main focus Samples Assessment instruments Main results 18 Attentional performance in  hypotension and hypertension 30 hypotensives (SBP < 106 mmHg);  40 hypertensives (SBP > 140 mmHg);  31 normotensive controls; age 16–40 years 25 Reduced attentional performance in the  case of both lowered and elevated  blood pressure 26 Attentional, memory and  arithmetic performance  in hypotension 17 female hypotensives (SBP < 100 mmHg);  19 normotensive controls; mean  age 23 years 27 28 Prolonged reaction times, poorer  performance on the verbal memory  and arithmetic tasks in hypotension,  no effect for digit span 29 Attentional and memory  performance in hypotension 26 female hypotensives (SBP < 105,  DBP < 65 mmHg), 22 normotensive  controls; mean age 29 years 30 31 28 Poorer attentional and memory  performance on each of the three  tests in hypotension 32 Relationship between blood  pressure and cognitive  performance in elderly  persons n 33 34 35 Weak U-shaped relationship between  blood pressure and cognitive  performance 22 Attentional performance in  hypotension 25 female hypotensives (mean  SBP = 102 mmHg); 25 normotensive  controls; age 19–44 years 36 Reduced performance on a subtest  assessing cognitive flexibility  in hypotension 37 Attentional performance in  moderate hypotension 26 borderline hypotensives (mean  SBP = 112 mmHg); 29 normotensive  controls; mean age 26 years 30 31 Prolonged reaction times and poorer  performance on the  “Aufmerksamkeits-Belastungs-Test” in  moderate hypotension, no effects  for the “Zahlen-Verbindungs-Test” 38 Attentional and working  memory performance in  hypotension with motor  performance and  mood controlled 40 hypotensives (SBP < 105 mmHg in  women, SBP < 110 mmHg in men);  40 normotensive controls; age  19–45 years 39 40 41 Poorer performance on six tests  assessing tonic and phasic alertness,  selective, divided and sustained  attention as well as working memory  in hypotensives with fine motor  performance and mood controlled 18 26 29 26 22 36 37 38 39 40 41 42 43 44 11 13 32 45 46 Neuroelectrophysiological correlates of hypotension-related cognitive deficits 22 29 47 4 1 Fig. 1 N N 47  48 49 50 51 52 47 47 53 54 47 55 57 23 58 59 60 42 59 61 62 Cerebral blood perfusion in constitutional hypotension 5 5 63 64 5 65 4 2 Fig. 2 N N 65  66 67 68 71 72 73 75 76 77 65 78 64 65 66 3 Fig. 3 N N 65  Final comments 26 29 38 22 29 47 65 1 17 1 20 21 79 30 4