I have been getting bouts of confusion, dizziness (when looking up and sometimes when getting up), headaches, pulses, and pressure in my head and what I can only explain as brain fog (during these episodes, I find that my problem solving and my cognitive function is diminished). The episodes have been happening on and off for the last year, in which I have had three MRIs, a full cognitive function test, a full set of blood tests, a count, liver, kidney, cardiac panel, arthritis, and sleep apnea test. I have also had a cardiac stress test, 24-hour Holter monitor, 5-day event monitor, and echocardiogram, and these were all negative (no abnormalities were picked up). However, of late, I have found that these episodes have been getting more frequent. Could you advise if this could be intracranial pressure, a tumor, seizures, epilepsy, or some neurodegenerative disease?