What about β? Relationship between pain and EEG spindles during anaesthesia

Abstract

With the progressive ageing of the population, anaesthetists are increasingly faced with geriatric patients. As our patient population greys, there have been regular calls to limit anaesthetic exposure in older patients out of fear of overdose. The current concern regarding postoperative cognitive dysfunction weighs heavily on some patients' minds, while anaesthetists ponder the significance of the 'triple low' as a predictor of morbidity and mortality. 1 2 Anecdotally, elderly patients take a variable, but prolonged, amount of time to recover from anaesthesia relative to younger patients. The open question remains, how and Editorials | i5

Memory and awareness in anaesthesia

“…3 6 Thus, γ is of interest in how anaesthetics affect consciousness, or in other words, how anaesthetics 'work'. 7 In fact, the definition of γ has been extended to higher frequency bands to capture more of the EEG bandwidth as recording methods and capacity for data storage and analysis improve. 8 As with γ, β (α) has been subdivided into various frequency bands, with 'sigma' a less frequently used term basically analogous to 'sleep spindles'.…”

“…Some of the issues with using processed indices of the EEG rather than the raw waveform are addressed in the review by Hagihira, 6 along with editorial commentary by Veselis. 7 Purdon and colleagues 8 report profound age-dependent changes in the EEG that also have important implications for depth-of-anaesthesia monitors relying on processed EEG signals. Greater sensitivity to anaesthetics evident in the increased susceptibility to burst suppression in the elderly 7 is supported by animal studies that demonstrate delayed emergence and increased sensitivity to anaesthetics in old rats.…”

“…7 Purdon and colleagues 8 report profound age-dependent changes in the EEG that also have important implications for depth-of-anaesthesia monitors relying on processed EEG signals. Greater sensitivity to anaesthetics evident in the increased susceptibility to burst suppression in the elderly 7 is supported by animal studies that demonstrate delayed emergence and increased sensitivity to anaesthetics in old rats. 9 This is highlighted in an editorial by Hudson and Proekt.…”