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Updated: Jun 3, 2026

Tilt Testing with Combined Lower Body Negative Pressure: a "Gold Standard" for Measuring Orthostatic Tolerance
Published on: March 21, 2013
Amnesia for loss of consciousness is common in vasovagal syncope
Clodagh O'Dwyer1, Kathleen Bennett, Yvonne Langan
1Falls and Blackout Unit, Department of Medical Gerontology, St James's Hospital, James' St, Dublin 8, Ireland. odwyercl@tcd.ie
Aims:
The aim of this study was to determine the prevalence of amnesia for loss of consciousness (A-LOC) in those who have a history suggestive of vasovagal syncope (VVS) and who develop syncope on head-up tilt (HUT) table testing. Furthermore, we wished to determine if A-LOC is an age-dependent phenomenon in VVS and whether haemodynamic parameters on tilting can predict for A-LOC.
Methods And Results:
Patients were recruited in a dedicated syncope unit and underwent neurocardiovascular evaluation as indicated under European Society of Cardiology guidelines to illicit a diagnosis of VVS. A set protocol of questioning occurred following induced syncope to determine the presence of A-LOC. The prevalence of A-LOC following syncope on tilting was 28% (44/159). Forty-two per cent of those≥60 years of age vs. 20%<60 years of age experienced amnesia post-induced syncope (P=0.003). However, regression analysis did not show age to be an independent predictor for A-LOC. Blood pressure change between those without amnesia and those with amnesia showed no significant difference (P=0.687). There was a significant difference in heart rate response; those experiencing amnesia had reduced bradycardic response on HUT compared with those without amnesia (P=0.001).
Conclusion:
Amnesia for loss of consciousness is common in VVS. Although more prevalent, it is not unique to older age-groups. Absence of syncope associated bradycardia during HUT testing predicts for A-LOC.
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