Abstract Details

Efficacy of Hyperventilation in Short Video EEG (SVEEG)


Psychogenic non-epileptic attacks (PNEA) are distressing to patients and difficult to diagnose. Diagnostic delays negatively impact patients’ physical and mental health and increase healthcare costs. Prior to COVID-19, hyperventilation was considered an essential activation technique for the diagnosis of PNEA during SVEEG. ILAE and BSCN COVID-19 mitigation guidance called for its withdrawal from SVEEG protocols, leading to concern that patients would experience further delays to diagnosis and treatment.


This clinical audit determined whether removal of hyperventilation as an activation technique affected the number of PNEAs recorded during SVEEG. Its aim was to inform post COVID-19 decisions about the use of hyperventilation within the department. In particular, whether patients who cannot perform hyperventilation due to ability, preference, or contraindication are disadvantaged. These findings may also be considered if or when the guidelines are updated.


Records of 445 consecutive patients seen for SVEEG in the Clinical Neurophysiology department of Queen Elizabeth University Hospital (QEUH) from December 2017 to October 2022 were retrospectively audited. Patients were divided into two groups: those seen before the removal of hyperventilation (control group) and those seen after (experimental group). Reports were examined to determine patient and appointment characteristics and PNEA recording. Data were analysed and statistical tests performed to assess potential biases and determine the impact of removing hyperventilation from the protocol.


It was found that the removal of hyperventilation from the SVEEG protocol did not impact the yield of PNEA recorded and no differences in patient or appointment characteristics were identified that were likely to have biased the outcome.


This study confirms the continued efficacy of the SVEEG protocol despite the removal of the hyperventilation element and provides reassurance that patients attending for SVEEG without hyperventilation have not been disadvantaged.

TitleForenamesSurnameInstitutionLead AuthorPresenter
 Brooke MackenzieQueen Elizabeth University Hospital
DrVeronicaLeachQueen Elizabeth University Hospital
DrShonaLivingstonQueen Elizabeth University Hospital
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