BACKGROUND: Anaesthetic drugs act at sites within the brain that undergo profound changes during typical ageing. We postulated that anaesthesia-induced brain dynamics observed in the EEG change with age. METHODS: We analysed the EEG in 155 @entity1 aged 18-90 yr who received @entity1875 (n=60) or @entity2614 (n=95) as the primary anaesthetic. The EEG spectrum and coherence were estimated throughout a 2 min period of stable anaesthetic maintenance. Age-related effects were characterized by analysing power and coherence as a function of age using linear regression and by comparing the power spectrum and coherence in young (18- to 38-yr-old) and elderly (70- to 90-yr-old) @entity1 . RESULTS: Power across all frequency bands decreased significantly with age for both @entity1875 and @entity2614 ; elderly @entity1 showed EEG oscillations    2- to 3-fold smaller in amplitude than younger adults. The qualitative form of the EEG appeared similar regardless of age, showing prominent alpha (8-12 Hz) and slow (0.1-1 Hz) oscillations. However, alpha band dynamics showed specific age-related changes. In elderly compared with young @entity1 , alpha power decreased more than slow power, and alpha coherence and peak frequency were significantly lower. Older @entity1 were more likely to experience burst suppression. CONCLUSIONS: These profound age-related changes in the EEG are consistent with known neurobiological and neuroanatomical changes that occur during typical ageing. Commercial EEG-based depth-of-anaesthesia indices do not account for age and are therefore likely to be inaccurate in elderly @entity1 . In contrast, monitoring the unprocessed EEG and its spectrogram can account for age and individual @entity1 characteristics.

The Ageing Brain: Age-dependent changes in the electroencephalogram during @entity1875 and XXXX general anaesthesia.

@entity1 :: ('9606', 'Species') :: ['patients', 'patient'] @entity1875 :: ('MESH:D015742', 'Chemical') :: ['propofol'] @entity2614 :: ('MESH:C009250', 'Chemical') :: ['sevoflurane']
@entity2614 :: (MESH:C009250,Chemical) :: ['sevoflurane']
