Brain fog in postural tachycardia syndrome: An objective cerebral blood flow and neurocognitive analysis

Background It remains unclear whether brain fog is related to impaired cerebral blood flow (CBF) in postural tachycardia syndrome (POTS) patients. Methods We assessed CBF in the posterior cerebral artery (PCA) using transcranial Doppler with visual stimuli in 11 POTS and 8 healthy subjects in the seated position, followed by neurocognitive testing. Results CBF parameters were similar between the two groups. POTS patients demonstrated significantly longer latency in delayed match to sample response time and greater errors in attention switching task. Conclusions Impaired short-term memory and alertness may underlie the symptom of brain fog in POTS patients, despite normal CBF.