EEG Spectrogram, brain vulnerability and POD

• Research type

  Research Study

• Full title

  EEG spectrogram to assess brain vulnerability as a risk factor for postoperative delirium in older people – a feasibility study

• IRAS ID

  307354

• Contact name

  Iain Moppett

• Contact email

  iain.moppett@nottingham.ac.uk

• Sponsor organisation

  University of Nottingham

• Duration of Study in the UK

  0 years, 5 months, 30 days

• Research summary

  This is a feasibility study. The aim of this study is to assess the feasibility of acquiring and analysing electroencephalogram (pEEG) data from the Narcotrend Processed EEG monitor during the preoperative and intraoperative period to identify pre-specified EEG parameters.
  Our target population are people 65 years or older undergoing moderate or major surgery.
  The anaesthesia index of PEEG monitoring is often used to guide anaesthesia dose titration during surgery. The device however also gives other outputs derived from raw regional EEG data such as a density spectral array and spectral edge frequency.
  In people with Alzheimer's disease or Mild Cognitive Impairment, the power of different brain-waves on the spectrogram is altered. Given that symptomatic Alzheimer's disease is predated, by several years, by structural brain pathology, it is possible that some brain-wave abnormalities may be present in cognitively intact older people who already have preclinical neurodegeneration.
  Neurodegeneration is a risk factor for postoperative delirium. Identification of accessible and cheap methods of identifying intrinsic brain vulnerability such as neurodegeneration in the perioperative period may help with risk stratification of older people undergoing surgery and contribute to screening for future dementia.

  Lay summary of study results: With this study we assessed if it was possible to use a depth of anaesthesia monitor (used to guide dose of anaesthetic) to obtain EEG from the front (frontal) and back (occipital) of the brain. We also tried to see if the occipital EEG was different between people who developed postoperative delirium (POD) and those who did not.
  Thirty two participants were recruited to this study, however two were withdrawn because surgery was cancelled and a further two withdrawn due to devastating postoperative complications. Of the remaining 28, occipital EEG of good quality was obtained in 22 (79%).
  A comparison of the posterior total EEG power (eyes-open or eyes-closed) did not show a significant difference between POD and no POD groups although there was a trend.
  A comparison of the posterior alpha power (a specific frequency band in EEG) eyes-open or eyes-closed between POD and no POD was not significantly different although there was also a trend.
  Given that feasibility has been proven in this study and given the initial data provided in this study, a future study of an appropriate sample size to determine if there is a significant difference in posterior EEG power between POD and no POD is a next logical step

• REC name

  East of England - Essex Research Ethics Committee

• REC reference

  22/EE/0071

• Date of REC Opinion

  11 May 2022

• REC opinion

  Further Information Favourable Opinion