“Independent study that utilized DANA to detect and measure cognitive impairment associated with orthostatic intolerance (OI) in patients with Long COVID and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Objectives : Determine whether a simple, standardized, office-based test of OI would aggravate symptoms associated with Long COVID and ME/CFS and produce objective hemodynamic and cognitive abnormalities, the latter being evaluated by DANA. Methods: 42 Long COVID patients, 26 ME/CFS patients, and 20 healthy control subjects participated in this study. Immediately before and after completing the 10-Minute NASA Lean Test (a simple, standardized test of OI), participants completed DANA cognitive testing and a symptom assessment. Participants’ blood pressure and heart rate were measured immediately before and after, and each minute during, the OI test. Participants completed subsequent DANA testing 2 days and 7 days after the OI test. Results: There was a significant worsening of symptoms during and immediately after the OI test only in the two patient groups, and not in the healthy control subjects. Both patient groups experienced increased diastolic blood pressure which caused a reduced pulse pressure and an abnormally narrowed blood pressure ratio. Finally, the DANA tests assessed before and after the OI test revealed that, immediately after completion of the OI test, cognitive efficiency dropped for both patient groups, whereas it rose in the healthy control subjects. The slowed reaction time observed is consistent with the subjective reports by people with Long COVID and with ME/CFS that orthostatic challenge leads to worsening in their cognitive function. Slowed reaction time is one of the most sensitive measures of impaired cognitive functioning and has been the most consistently measured objective finding in ME/CFS neurocognitive research. Sensitivity of DANA: The results of this study demonstrated the sensitivity of DANA and its ability to detect cognitive impairment associated with Long COVID and ME/CFS.”