A 30-minute prolonged cognitive stress test caused a greater reduction in cerebral blood flow velocity in POTS patients compared to healthy controls (-7.8% vs -1.8%; P=0.038).
Case-Control (n=40)
Does prolonged cognitive stress reduce cerebral blood flow velocity and cognitive performance in patients with postural tachycardia syndrome compared to healthy controls?
Prolonged cognitive stress in POTS patients leads to reduced cerebral blood flow velocity and cognitive dysfunction even in the absence of orthostatic stress, providing a physiological basis for 'brain fog'.
Absolute Event Rate: -7.8% vs -1.8%
p-value: p=0.038
Background The physiology underlying "brain fog" in the absence of orthostatic stress in postural tachycardia syndrome (POTS) remains poorly understood. Methods and Results We evaluated cognitive and hemodynamic responses (cardiovascular and cerebral: heart rate, blood pressure, end‐tidal carbon dioxide, and cerebral blood flow velocity (CBFv) in the middle cerebral artery at baseline, after initial cognitive testing, and after (30‐minutes duration) prolonged cognitive stress test (PCST) whilst seated; as well as after 5‐minute standing in consecutively enrolled participants with POTS (n=22) and healthy controls (n=18). Symptom severity was quantified with orthostatic hypotensive questionnaire at baseline and end of study. Subjects in POTS and control groups were frequency age‐ and sex‐matched (29±11 versus 28±13 years; 86 versus 72% women, respectively; both P ≥0.4). The CBFv decreased in both groups (condition, P =0.04) following PCST, but a greater reduction in CBFv was observed in the POTS versus control group (−7.8% versus −1.8%; interaction, P =0.038). Notably, the reduced CBFv following PCST in the POTS group was similar to that seen during orthostatic stress (60.0±14.9 versus 60.4±14.8 cm/s). Further, PCST resulted in greater slowing in psychomotor speed (6.1% versus 1.4%, interaction, P =0.027) and a greater increase in symptom scores at study completion (interaction, P 0.05). Conclusions Reduced CBFv and cognitive dysfunction were evident in patients with POTS following prolonged cognitive stress even in the absence of orthostatic stress.
Wells et al. (Sat,) conducted a case-control in Postural tachycardia syndrome (POTS) (n=40). Prolonged cognitive stress test (PCST) vs. Healthy controls was evaluated on Change in cerebral blood flow velocity (CBFv) following PCST (p=0.038). A 30-minute prolonged cognitive stress test caused a greater reduction in cerebral blood flow velocity in POTS patients compared to healthy controls (-7.8% vs -1.8%; P=0.038).