Neurogenic orthostatic hypotension impairs information processing speed and attention

Neurogenic orthostatic hypotension (NOH) is characterized by a drop in systolic blood pressure (SBP) ≥20 mmHg or diastolic blood pressure (DBP) ≥10 mmHg within three minutes of upright posture. NOH is common in the elderly population. This group of individuals is at an increased risk for deficits in multiple cognitive domains such as information processing speed (IPS) and attention. The objective of the current study was to investigate the change in IPS and attention during head-up tilt (HUT) in patients with NOH compared to controls. Cognitive function was assessed in the supine and HUT positions using the symbol digit modalities test (SDMT) which assesses IPS and the Stroop Test which measures attention. 40 participants completed the study, 20 controls (age 64.50 ± 9.25) and 20 NOH patients (age 69.55 ± 7.43) with associated conditions of Parkinson's disease (n = 11), multiple systems atrophy (n = 3), early Lewy body dementia (n = 1) and idiopathic NOH (n = 5). NOH patients had no difference in IPS between supine (43.20 ± 15.26) and HUT (42.90 ± 14.33; p = .77). Controls had significantly faster IPS in the HUT position (69.90 ± 12.02) compared to supine (63.55 ± 9.96; p < .001). NOH patients had significantly slower IPS in both the supine and HUT position compared to controls (p < .001). Attention in the HUT position was significantly worse in NOH patients (-14.86 ± 8.96) compared to controls (-8.68 ± 7.13; p = .029). During HUT, NOH patients experienced a significant decrease in mean SBP by -64.11 ± 18.96 from baseline, whereas controls only had a mean decrease of -5.69 ± 7.65. It is evident that NOH patients have impaired IPS and attention compared to controls and likely plays an important role in the morbidity of these individuals.