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Evidence record

Where does anaesthesia take you?

Every sentence on the exploration belongs to at least one claim below. Each says what kind of statement it is, what it rests on, what the evidence does not establish, and how far it was checked. Nothing here is a score, and none of it is a verdict on a belief or a theory.

Last checked 24 September 2026.

  • Partly checked: 8
  • A judgement, not a fact: 12
  • Source checked: 40
  • Presented as open: 1

If something here is wrong, misquoted, out of date or unfair, write to support@unknownoceans.com and give the claim number, which does not change.

What the question takes for granted

A scientific question with a philosophical floor. What can be measured is responsiveness, reports and brain responses; whether experience continues when all three are absent is what the page leaves open.

  • Anaesthesia takes a person somewhere, or nowhere, and one of the two is true

    Open

    The question assumes there is a fact about what the interval contains. The page reports that the evidence for its being empty rests on the absence of later reports, which memory loss would also produce.

  • A person who does not respond is not conscious

    Contested

    The working assumption the page argues against. Studies of the isolated forearm technique find some patients responding to command while otherwise unresponsive; how often depends on the study.

  • A report on waking is a reliable record of whether there was experience

    Contested

    Reports are the standard that measures of consciousness are calibrated against, and the authors of the complexity index say themselves that people can be conscious and forget.

How the question is labelled

Claim: The interval

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: Anaesthesia

Kind
Framing. Signposting. It asserts nothing a source could check.

The question

Claim: Millions of people a year are switched off and back on,

Kind
Present-day figure. A count, survey or report finding, as the named source gives it.
Review
Partly checked. Only part of the source could be read. What was not read is listed.

What this does not establish

The figure is the authors’ working assumption for the United States in 2004, not a count, and it is for anaesthetics rather than people. Only the abstract was read.

Later work looked for

Crossref, 2016 on, "incidence awareness general anaesthesia": nothing that revises the scale; "millions" holds on the United States figure alone.

Claim 3 · checked 24 September 2026 · AI-assisted audit

Claim: and the difference between not responding and not being there is measurable but not routinely measured.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The page’s summary of claims 18 to 34: response to command and the complexity index can each separate the two in studies, and neither is how depth is monitored in routine surgery.

  • Context

    Unresponsiveness is not the same as unconsciousnessDepth of Anesthesia monitors: Limitations and future directions

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: However before it can be routinely employed in the operating room this technology will have to significantly refined and simplified.

Claim 4 · checked 24 September 2026 · AI-assisted audit

Claim: General anaesthesia is reliable, common

Kind
Present-day figure. A count, survey or report finding, as the named source gives it.
Review
Partly checked. Only part of the source could be read. What was not read is listed.

What this does not establish

“Reliable” here means that remembered awareness is rare, which is what these studies measure. Both were read as abstracts only.

Later work looked for

Crossref, 2016 on, "incidence awareness general anaesthesia": later work reports higher rates in obstetrics, nothing that makes remembered awareness common.

Claim 5 · checked 24 September 2026 · AI-assisted audit

Claim: and not understood at the level of consciousness.

Kind
What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

Crossref, 2019 on, "mechanisms of general anesthesia consciousness": reviews continue to describe it as unresolved; nothing that changes it.

Claim 6 · checked 24 September 2026 · AI-assisted audit

Claim: A person who cannot respond is not necessarily absent,

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Unresponsiveness is not the same as unconsciousnessConclusions

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: Anesthesiologists must remain cognizant that unresponsiveness ≠ unconsciousness

Claim 7 · checked 24 September 2026 · AI-assisted audit

Claim: and the index that can tell the difference in a laboratory is not what operating theatres use.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Unresponsiveness is not the same as unconsciousnessDepth of Anesthesia monitors: Limitations and future directions

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: For detecting consciousness the use of transcranial magnetic stimulation and high density electroencephalogram under anesthesia appears particularly promising ... However before it can be routinely employed in the operating room this technology will have to significantly refined and simplified.

  • Supports

    A Theoretically Based Index of Consciousness Independent of Sensory Processing and BehaviorDiscussion

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Experiment

    The source reads: methods that aim to quantify the information or spectral content of brain signals ... and the bispectral index

What this does not establish

The index was tested in research settings on healthy volunteers and brain-injured patients, not during surgery.

Claim 8 · checked 24 September 2026 · AI-assisted audit

Claim: The patient is told to count backwards and does not finish. Hours pass in no time at all.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

An illustrative scene, not a finding. The second sentence describes how the interval seems afterwards, which the rest of the page examines.

Claim 9 · checked 24 September 2026 · AI-assisted audit

Claim: What happened in between is the clearest natural experiment on consciousness anybody has,

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The page’s judgement. The review it rests beside treats anaesthesia as a tool for studying consciousness; “clearest” is the page’s own word.

Claim 10 · checked 24 September 2026 · AI-assisted audit

Claim: and it is performed tens of thousands of times a day in the United States alone, for other reasons.

Kind
Present-day figure. A count, survey or report finding, as the named source gives it.
Review
Partly checked. Only part of the source could be read. What was not read is listed.

What this does not establish

Twenty million a year is about 55,000 a day. The figure is the authors’ assumption, not a count, and the abstract alone was read.

Later work looked for

Crossref, 2016 on, anaesthetic volume: found estimates of operations worldwide, not of general anaesthetics; nothing that gives a better figure for the page to use.

Corrected

24 September 2026. Previously: “and it is performed hundreds of thousands of times a day for other reasons.” No cited source gave a worldwide daily count of general anaesthetics. The only figure on the page’s sources is Sebel and colleagues’ 20 million a year in the United States, which is tens of thousands a day.

Claim 11 · checked 24 September 2026 · AI-assisted audit

What is established

Claim: What is established

Kind
Framing. Signposting. It asserts nothing a source could check.

Unresponsive is not the same as unconscious

Claim: Unresponsive is not the same as unconscious

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

The heading is the paper’s own title in words.

  • Supports

    Unresponsiveness is not the same as unconsciousnessabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: Review of the isolated forearm technique demonstrates that consciousness, connectedness and responsiveness uncouple during anesthesia

Claim 13 · checked 24 September 2026 · AI-assisted audit

Claim: Anaesthetic agents act on movement, memory and awareness through partly separate routes.

Kind
What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Towards a comprehensive understanding of anesthetic mechanisms of action: a decade of discoverysection on extrasynaptic GABAA receptors and amnesia

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: Amnesia is one of the most sensitive behavioral endpoints of anesthetic action, with memory blockade occurring at plasma concentrations that are considerably lower than those required for unconsciousness and immobility

  • Supports

    Unresponsiveness is not the same as unconsciousnessMechanisms of Unresponsiveness

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: Furthermore actions in the ventral horn of the spinal cord prevent reflex motor responses

Later work looked for

Crossref, 2019 on, "mechanisms of general anesthesia": nothing that changes the separation of endpoints.

Claim 14 · checked 24 September 2026 · AI-assisted audit

Claim: A patient can be immobile and amnesic while some form of experience continues.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Unresponsiveness is not the same as unconsciousnessConnected consciousness is dissociable from spontaneous responsiveness

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: An advantage of the IFT is that it is not dependent on memory, indeed explicit recall of intraoperative events is usually absent

What this does not establish

The experience is inferred from a hand moving to command, which is the standard reading but still an inference (see claim 67).

Later work looked for

Europe PMC, 2013 on, "isolated forearm" and "connected consciousness": the 2017 and 2023 multicentre studies (claims 19 and 20) again found responses without recall.

Claim 15 · checked 24 September 2026 · AI-assisted audit

Claim: Sleep shows the reverse: people who sleepwalk respond to their surroundings without being conscious.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Unresponsiveness is not the same as unconsciousnessConnected consciousness is dissociable from spontaneous responsiveness

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: subjects who sleepwalk are spontaneously responsive but are unconscious and do not follow commands

Corrected

24 September 2026. Previously: “A patient can be immobile and amnesic while some form of experience continues, and can be experiencing nothing while showing reflexes.” None of the cited sources shows an anaesthetised patient experiencing nothing while showing reflexes. The reverse dissociation they do describe is sleepwalking, so the example now comes from sleep and says so.

Claim 16 · checked 24 September 2026 · AI-assisted audit

Claim: The isolated forearm technique keeps one arm free of the paralysing drug and asks the patient to squeeze a hand.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Unresponsiveness is not the same as unconsciousnessConnected consciousness is dissociable from spontaneous responsiveness

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: In the IFT, anesthesia is followed by inflation of a cuff on the arm before neuromuscular blockade is induced. The cuff prevents paralysis of the hand allowing the patient to communicate to an observer through predefined hand movements

Later work looked for

How the method works; not a finding later work revises.

Claim 17 · checked 24 September 2026 · AI-assisted audit

Claim: In the older studies that did this during surgery or laryngoscopy, a median of 37 per cent of patients responded. The range ran from none of them to all of them, and the review that collected them declined to pool them.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Unresponsiveness is not the same as unconsciousnessConnected consciousness is dissociable from spontaneous responsiveness; Table 2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: they did not test response to clinically relevant noxious external stimuli such as surgery or laryngoscopy (Table 2). Positive responses were observed in a median of 37% of patients (range 0 – 100%). The studies had heterogeneous methodology ... therefore meta-analysis has not been performed.

  • Supports

    Unresponsiveness is not the same as unconsciousnessConnected consciousness is dissociable from spontaneous responsiveness

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026

    The source reads: identifying 18 relevant studies. Five studies were excluded ... as they did not test response to clinically relevant noxious external stimuli such as surgery or laryngoscopy

What this does not establish

Thirteen studies from 1977 to 2008, of 12 to 184 patients each, with different drugs and methods. The median is a summary of heterogeneous studies, not an estimate of how often it happens now.

Later work looked for

Europe PMC, 2013 on, "isolated forearm" and "connected consciousness": two multicentre cohorts found 4.6 and 11 per cent after intubation, and a 2018 meta-analysis of 22 small studies of low methodological quality pooled 34.8 per cent; page updated with the cohorts.

Corrected

24 September 2026. Previously: “Across the studies that did this under surgical stimulation, a median of 37 per cent of patients squeezed. The range ran from none of them to all of them, and the authors declined to pool it.” The review’s criterion was surgery or laryngoscopy, not surgery alone, and larger studies since report much lower rates (claim 19), so the figure is now marked as the older literature’s.

Claim 18 · checked 24 September 2026 · AI-assisted audit

Claim: Two multicentre studies since have found fewer: 4.6 per cent of 260 adults after intubation in routine practice, and 11 per cent of 338 aged 18 to 40.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Partly checked. Only part of the source could be read. What was not read is listed.

What this does not establish

Both measured shortly after intubation, not across the whole operation, and the 2017 authors call their figure a conservative estimate. The 2023 study recruited only people aged 18 to 40, and women responded more often than men. The 2017 study was read as an abstract only; the 2023 study in full.

Later work looked for

Europe PMC, 2013 on, "isolated forearm" and "connected consciousness": these two are the largest prospective cohorts found; the 2018 meta-analysis (34.8 per cent across 22 small studies) is older data pooled.

Corrected

24 September 2026. Previously: “” The page gave only the 37 per cent median from older, heterogeneous studies. Later prospective multicentre cohorts, one led by the same first author, found rates up to ten times lower.

Claim 19 · checked 24 September 2026 · AI-assisted audit

Claim: In the first, none of the 253 asked after surgery recalled anything from during it.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Partly checked. Only part of the source could be read. What was not read is listed.

What this does not establish

Explicit recall only, as the abstract reports it. The abstract alone was read.

Later work looked for

Europe PMC, 2017 on, "connected consciousness": nothing that changes it.

Corrected

24 September 2026. Previously: “” Added with claim 19: it is the direct evidence for the page’s later point that memory, not experience, is what reports measure.

Claim 20 · checked 24 September 2026 · AI-assisted audit

Claim: Two anaesthetists, a psychiatrist and a neurologist made this argument in an anaesthesiology journal in 2012, against the assumption that a patient who does not respond is a patient who is not there.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

Sanders and Sleigh are in anaesthesia departments, Tononi in psychiatry and Laureys in neurology. The journal is Anesthesiology.

  • Supports

    Unresponsiveness is not the same as unconsciousnessauthor affiliations; Introduction

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: Department of Anaesthetics, Intensive Care & Pain Medicine ... Professor, Department of Psychiatry, University of Wisconsin Madison ... Department of Neurology, University and University Hospital of Liège ... Professor, Department of Anaesthesia, University of Auckland

  • Supports

    Unresponsiveness is not the same as unconsciousnessIntroduction

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: both patients and anesthesiologists assume that general anesthesia is associated with unconsciousness similar to a dreamless sleep

Corrected

24 September 2026. Previously: “Anaesthesiologists have made this argument in print,” Two of the four authors of the cited paper are not anaesthesiologists: Tononi is in psychiatry and Laureys in neurology.

Claim 21 · checked 24 September 2026 · AI-assisted audit

Claim: Absence of response is absence of evidence about experience.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The page’s compression of the review’s conclusion.

  • Context

    Unresponsiveness is not the same as unconsciousnessConclusions

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: Lack of spontaneous responsiveness does not inform us that the patient is not experiencing surgery.

Claim 22 · checked 24 September 2026 · AI-assisted audit

There is a measurement

Claim: There is a measurement

Kind
Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

A research measurement validated against reports, which have their own limits (claim 65).

Later work looked for

Crossref, 2016 on, "perturbational complexity index": further studies in patients and in anaesthesia, nothing that withdraws it.

Claim 23 · checked 24 September 2026 · AI-assisted audit

Claim: A magnetic pulse delivered to the cortex produces a pattern of activity that echoes across the brain. In a conscious person the echo is complex: widespread, differentiated, long-lasting.

Kind
Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

Crossref, 2016 on, "perturbational complexity index": the 2016 validation (claim 31) reproduces it in a larger group.

Claim 24 · checked 24 September 2026 · AI-assisted audit

Claim: In dreamless sleep, or under propofol, midazolam or xenon, it either stays short and local or spreads as one stereotyped wave.

Kind
Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

Crossref, 2016 on, "perturbational complexity index": nothing that changes it.

Corrected

24 September 2026. Previously: “Under anaesthesia or in dreamless sleep it collapses into something short and local.” Casali and colleagues report two patterns of lost consciousness, local or global but stereotyped, not only a local one; and the agents they tested were propofol, midazolam and xenon. Ketamine behaves differently (claim 26).

Claim 25 · checked 24 September 2026 · AI-assisted audit

Claim: Under ketamine, after which people report vivid experiences, it stays complex.

Kind
Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

Six people were measured under ketamine.

Later work looked for

Crossref, 2016 on, "perturbational complexity index ketamine": nothing that changes it.

Corrected

24 September 2026. Previously: “” The page said the response collapses under anaesthesia. The 2016 benchmark included ketamine anaesthesia, which left people unresponsive but reporting experience, and scored in the conscious range.

Claim 26 · checked 24 September 2026 · AI-assisted audit

Claim: Compressing that response into a single number gives an index.

Kind
Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

How the method works; not a finding later work revises.

Claim 27 · checked 24 September 2026 · AI-assisted audit

Claim: In the 2013 study that introduced it, 32 healthy subjects were measured awake and 24 of them again asleep or anaesthetised: nothing unconscious scored above 0.31 and nothing awake below 0.44.

Kind
Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

Healthy volunteers in controlled conditions, and a clean gap between groups is not a threshold for a single patient.

Later work looked for

Crossref, 2016 on, "perturbational complexity index": the 2016 validation found the same cutoff in 150 people (claim 31).

Corrected

24 September 2026. Previously: “gives an index that separated waking from anaesthesia and dreamless sleep in all thirty-two healthy subjects tested, with nothing unconscious scoring above 0.31 and nothing awake below 0.44.” Thirty-two subjects were measured awake, but only 24 of them were also measured asleep or anaesthetised, so the separation was not tested in all thirty-two.

Claim 28 · checked 24 September 2026 · AI-assisted audit

Claim: Two locked-in patients, who could answer only by moving their eyes, scored in the waking range.

Kind
Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    A Theoretically Based Index of Consciousness Independent of Sensory Processing and BehaviorResults, brain-injured patients; Discussion

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Experiment

    The source reads: in two brain-injured patients who, at the time of recording, could communicate reliably only through vertical eye movements ... Conversely, PCI was as high as in healthy awake subjects in two brain-injured patients with LIS.

What this does not establish

Two patients.

Later work looked for

Crossref, 2016 on: the 2016 benchmark included five locked-in patients among its conscious group; nothing that changes it.

Claim 29 · checked 24 September 2026 · AI-assisted audit

Claim: That study called itself hypothesis-generating.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

Corrected

24 September 2026. Previously: “” The page presented a study of 32 healthy subjects and 20 patients as settled; its authors describe it as hypothesis-generating.

Claim 30 · checked 24 September 2026 · AI-assisted audit

Claim: In 2016 a benchmark of 150 people, each able to report at the time or afterwards, gave a cutoff, again 0.31, that separated reported experience from its absence without an error in either direction, and it detected 94.7 per cent of minimally conscious patients.

Kind
Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

The cutoff was set and tested on the same benchmark, from each person’s highest value; 13 of 461 single measurements in waking people fell in the unconscious range. The reports it was calibrated on can themselves be wrong (claim 65).

Later work looked for

Crossref, 2016 on, "perturbational complexity index": later work applies it in more patients; nothing that replaces this validation.

Corrected

24 September 2026. Previously: “” The page rested on the 2013 study alone. The larger 2016 validation is the result the index’s standing depends on.

Claim 31 · checked 24 September 2026 · AI-assisted audit

Claim: It is a research instrument, not a monitor.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Unresponsiveness is not the same as unconsciousnessDepth of Anesthesia monitors: Limitations and future directions

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: However before it can be routinely employed in the operating room this technology will have to significantly refined and simplified.

  • Supports

    A Theoretically Based Index of Consciousness Independent of Sensory Processing and BehaviorEditor’s summary

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Experiment

    The source reads: The validity of PCI for clinical application will need to be assessed in prospective trials

Later work looked for

Crossref, 2016 on, "perturbational complexity index": studies remain research uses in patients with brain injury and in anaesthesia; nothing reporting it as an operating-theatre monitor.

Claim 32 · checked 24 September 2026 · AI-assisted audit

Claim: The depth gauges used in surgery read the spectral content of the EEG, which is a related quantity and not the same one.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

Claim 33 · checked 24 September 2026 · AI-assisted audit

Claim: They vary between people and between agents, and they have not reliably told a conscious brain-injured patient from an unconscious one.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

Casali and colleagues cite earlier studies for both points rather than testing them.

  • Supports

    A Theoretically Based Index of Consciousness Independent of Sensory Processing and BehaviorDiscussion

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Experiment

    The source reads: the bispectral index is widely ... among subjects and anesthetic agents (36) and cannot reliably discriminate between conscious and ... brain-injured individuals

  • Supports

    Unresponsiveness is not the same as unconsciousnessConnected consciousness is dissociable from spontaneous responsiveness

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: the Bispectral Index (BIS) cannot reliably distinguish between responders and non-responders to the IFT

Claim 34 · checked 24 September 2026 · AI-assisted audit

Claim: What the perturbation shows

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: A pulse produces a long, spatially differentiated response.

Kind
Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

Crossref, 2016 on, "perturbational complexity index": nothing that changes it.

Claim 36 · checked 24 September 2026 · AI-assisted audit

Claim: The cortex is integrating across regions.

Kind
Hypothesis. A proposed explanation, not an established one.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

This is how the index’s authors read a complex response, drawing on a theory of consciousness. The measurement is of complexity; integration is the interpretation.

Claim 37 · checked 24 September 2026 · AI-assisted audit

Claim: Every awake subject tested looks like this.

Kind
Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

True of each person’s highest value. Thirteen of 461 single measurements in waking people fell in the unconscious range.

Later work looked for

Crossref, 2016 on, "perturbational complexity index": nothing that changes it.

Claim 38 · checked 24 September 2026 · AI-assisted audit

Claim: The same pulse produces a brief, local response, or one stereotyped wave.

Kind
Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

Crossref, 2016 on, "perturbational complexity index": nothing that changes it.

Corrected

24 September 2026. Previously: “The same pulse produces a brief, local response.” As claim 25: the source reports two patterns, not one.

Claim 39 · checked 24 September 2026 · AI-assisted audit

Claim: Dreamless sleep, or anaesthesia with propofol, midazolam or xenon.

Kind
Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

Crossref, 2016 on, "perturbational complexity index": nothing that changes it.

Corrected

24 September 2026. Previously: “Anaesthesia, or dreamless sleep.” Not every anaesthetic: under ketamine the response stays complex (claim 26).

Claim 40 · checked 24 September 2026 · AI-assisted audit

Claim: The parts either stop talking to one another or all say the same thing.

Kind
Hypothesis. A proposed explanation, not an established one.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

The authors’ reading of the two patterns, in the site’s words: “suggesting” is theirs. The response is what is measured.

Corrected

24 September 2026. Previously: “Parts are working; they are not working together.” The source gives two readings, a loss of integration and a loss of differentiation; the page gave only the first.

Claim 41 · checked 24 September 2026 · AI-assisted audit

Claim: A patient who cannot respond produces the complex response.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

Crossref, 2016 on, "perturbational complexity index": nothing that changes it.

Corrected

24 September 2026. Previously: “A behaviourally unresponsive patient produces the complex response.” The page cited only the 2013 study, whose high-scoring patients were locked-in and could answer with their eyes. The unresponsive patients with high scores are in the 2016 study, now cited.

Claim 42 · checked 24 September 2026 · AI-assisted audit

Claim: Perhaps someone is there: 9 of 43 patients in a vegetative state did this, and the authors say they may keep a capacity for consciousness.

Kind
Hypothesis. A proposed explanation, not an established one.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

Whether these patients were conscious could not be checked: they could not report, which is why they were not used to set the cutoff.

Corrected

24 September 2026. Previously: “Someone is there.” The source says these patients may retain a capacity for consciousness; the page stated it as a fact.

Claim 43 · checked 24 September 2026 · AI-assisted audit

Claim: This is the case behaviour alone could get wrong, and it is the reason the index exists.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    A Theoretically Based Index of Consciousness Independent of Sensory Processing and Behaviorabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Experiment

    The source reads: One challenging aspect of the clinical assessment of brain-injured, unresponsive patients is the lack of an objective measure of consciousness that is independent of the subject’s ability to interact with the external environment.

Corrected

24 September 2026. Previously: “This is the case behaviour alone gets wrong,” Follows claim 43: that behaviour got these patients wrong is not established.

Claim 44 · checked 24 September 2026 · AI-assisted audit

What is not measured in practice

Claim: What is not measured in practice

Kind
Framing. Signposting. It asserts nothing a source could check.

How often awareness happens anyway

Claim: How often awareness happens anyway

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: Reported awareness during general anaesthesia is rare,

Kind
Present-day figure. A count, survey or report finding, as the named source gives it.
Review
Partly checked. Only part of the source could be read. What was not read is listed.

What this does not establish

Much higher in some settings: the British audit found about one in 670 during Caesarean section. Both read as abstracts.

Later work looked for

Crossref, 2016 on, "incidence awareness general anaesthesia": a 2021 obstetric cohort and reviews; nothing that makes it common.

Claim 47 · checked 24 September 2026 · AI-assisted audit

Claim: and how rare depends on how the question is asked.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Follows from claims 49 and 50: a structured interview and a count of reports differ about 25-fold.

Other readings

The two studies also differ in country, year and practice, so method is not the only difference between them.

Claim 48 · checked 24 September 2026 · AI-assisted audit

Claim: A structured interview of 19,575 patients at seven American academic centres found 25 cases, roughly one in 800.

Kind
Present-day figure. A count, survey or report finding, as the named source gives it.
Review
Partly checked. Only part of the source could be read. What was not read is listed.

  • Supports

    The incidence of awareness during anesthesia: a multicenter United States studyabstract

    Cited · Link answered, 19 October 2026 · Abstract only, 24 September 2026 · Research in people · Observational study: associations, not causes

    The source reads: conducted at seven academic medical centers in the United States ... by using a structured interview. Data from 19,575 patients are presented. A total of 25 awareness cases were identified (0.13% incidence).

What this does not establish

Awareness with recall, from interviews in recovery and a week or more later. A further 46 cases were classed as possible. Abstract only.

Later work looked for

Crossref, 2016 on, "incidence awareness general anaesthesia": nothing that replaces it as the United States interview figure.

Corrected

24 September 2026. Previously: “A structured interview of 19,575 patients in the United States” The sample was seven academic centres, not the United States at large.

Claim 49 · checked 24 September 2026 · AI-assisted audit

Claim: A British national audit that counted the reports made to it found about one in 19,600.

Kind
Present-day figure. A count, survey or report finding, as the named source gives it.
Review
Partly checked. Only part of the source could be read. What was not read is listed.

What this does not establish

95 per cent confidence interval 1 in 16,700 to 1 in 23,450. Abstract only.

Later work looked for

Crossref, 2016 on, "accidental awareness general anaesthesia": reviews still cite NAP5 as the national figure; nothing that changes it.

Corrected

24 September 2026. Previously: “A British audit that counted the reports arriving on their own” The abstract says reports were the numerator; how they arrived is not in what could be read, so the page now says only that.

Claim 50 · checked 24 September 2026 · AI-assisted audit

Claim: Memory is the confounder.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The page’s summary of claims 52 and 53.

Claim 51 · checked 24 September 2026 · AI-assisted audit

Claim: An agent that prevents encoding produces a patient who reports nothing regardless of what occurred,

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Unresponsiveness is not the same as unconsciousnessDisconnected Consciousness: Dreaming in Sleep & Anesthesia

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: Given the amnesic effects of anesthetic agents, these data likely underestimate the true prevalence of dreaming since the reports required the recall of dreams.

  • Supports

    Towards a comprehensive understanding of anesthetic mechanisms of action: a decade of discoverysection on extrasynaptic GABAA receptors and amnesia

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: memory blockade occurring at plasma concentrations that are considerably lower than those required for unconsciousness and immobility

Claim 52 · checked 24 September 2026 · AI-assisted audit

Claim: which means the honest quantity being measured is remembered awareness.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The studies themselves define what they count as awareness with recall.

  • Context

    The incidence of awareness during anesthesia: a multicenter United States studyabstract

    Cited · Link answered, 19 October 2026 · Abstract only, 24 September 2026 · Research in people · Observational study: associations, not causes

    The source reads: We, therefore, undertook a prospective study to determine the incidence of awareness with recall during general anesthesia in the United States.

Claim 53 · checked 24 September 2026 · AI-assisted audit

What the drugs actually do

Claim: What the drugs actually do

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: The molecular targets are known in some detail, down to anaesthetic binding sites resolved by structural biology.

Kind
What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

Much of the structural work is on bacterial homologues of human receptors, which the review says lack their subunit complexity.

Later work looked for

Crossref, 2019 on, "anesthetic binding site structure": further structures of human receptors with anaesthetics bound; the claim stands.

Claim 55 · checked 24 September 2026 · AI-assisted audit

Claim: The step from a receptor to the disappearance of experience is not,

Kind
What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

Crossref, 2019 on, "mechanisms of general anesthesia consciousness": nothing that closes the gap.

Claim 56 · checked 24 September 2026 · AI-assisted audit

Claim: and different agents reach the same endpoint by different routes.

Kind
What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Towards a comprehensive understanding of anesthetic mechanisms of action: a decade of discoverysections on sleep circuits and on information transfer

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: Propofol and dexmedetomidine, however, utilize two distinct mechanisms to indirectly excite these neurons ... the Φ and EEG relationships associated with anesthetic-induced unconsciousness/responsiveness are not identical across anesthetics

Later work looked for

Crossref, 2019 on: nothing that changes it.

Claim 57 · checked 24 September 2026 · AI-assisted audit

Claim: That gap is the reason anaesthesia is interesting rather than merely useful.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The page’s judgement, following claims 55 and 56.

Claim 58 · checked 24 September 2026 · AI-assisted audit

Claim: It is a switch whose mechanism nobody can yet describe in full.

Kind
What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

Crossref, 2019 on, "mechanisms of general anesthesia consciousness": nothing that gives a full account.

Corrected

24 September 2026. Previously: “It is a switch whose mechanism nobody can describe.” Much of the mechanism has been described; the review calls unconsciousness unsolved but a full account within reach.

Claim 59 · checked 24 September 2026 · AI-assisted audit

The part reports cannot reach

Claim: The part reports cannot reach

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Section title; follows from claims 64 to 66.

Claim 60 · checked 24 September 2026 · AI-assisted audit

Claim: An hour with no memory of it and an hour with nothing in it produce the same report.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The page’s restatement of claims 52 and 64.

Claim 61 · checked 24 September 2026 · AI-assisted audit

Whether the interval is empty

Claim: Whether the interval is empty

Kind
Open question. Something the page says is not known.
Review
Presented as open. The page says this is unresolved, and the review found that it is.

Claim 62 · checked 24 September 2026 · AI-assisted audit

Claim: Dreamless sleep, anaesthesia and the gap between are usually described as nothing happening.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Unresponsiveness is not the same as unconsciousnessIntroduction

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: both patients and anesthesiologists assume that general anesthesia is associated with unconsciousness similar to a dreamless sleep

Claim 63 · checked 24 September 2026 · AI-assisted audit

Claim: The evidence for that rests on the absence of a report afterwards, which is exactly what an agent that blocks memory would produce.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Stratification of Unresponsive Patients by an Independently Validated Index of Brain ComplexityIntroduction

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes

    The source reads: no report = unconscious condition; immediate or delayed report = conscious condition

  • Supports

    Unresponsiveness is not the same as unconsciousnessDisconnected Consciousness: Dreaming in Sleep & Anesthesia

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: Given the amnesic effects of anesthetic agents, these data likely underestimate the true prevalence of dreaming since the reports required the recall of dreams.

Corrected

24 September 2026. Previously: “The only evidence for that is the absence of a report afterwards,” The page itself reports a brain measure that is low in these states; the correction keeps the point by saying what that measure rests on (claim 65).

Claim 64 · checked 24 September 2026 · AI-assisted audit

Claim: Even the complexity index was calibrated against those reports, and its authors warn that people can be conscious and then forget.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Stratification of Unresponsive Patients by an Independently Validated Index of Brain ComplexityDiscussion

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes

    The source reads: in certain situations people may be conscious but subsequently forget their experiences, or be unconscious and confabulate upon awakening. Accordingly, PCI* should not be interpreted as an absolute boundary between consciousness and unconsciousness

Corrected

24 September 2026. Previously: “” Without it the section contradicted the measurement section above. The index’s authors state the limit themselves.

Claim 65 · checked 24 September 2026 · AI-assisted audit

Claim: No report made afterwards can tell an experience that did not occur from one that left no trace, and that limit is permanent.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Follows from what a report is: it depends on memory, and claims 20 and 52 show memory failing while experience may continue.

Corrected

24 September 2026. Previously: “No method distinguishes an experience that did not occur from one that left no trace. This is a hard limit on the question and not a temporary one.” Too strong: the isolated forearm technique detects experience that leaves no memory (claims 15 and 20). What is permanent is the limit on reports; what no method yet does is rule experience out.

Claim 66 · checked 24 September 2026 · AI-assisted audit

Claim: A hand that squeezes shows that someone was there.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Unresponsiveness is not the same as unconsciousnessConnected consciousness is dissociable from spontaneous responsiveness

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Review of the field

    The source reads: we provide evidence of connected consciousness that is dissociated from spontaneous responsiveness during anesthesia

  • Qualifies

    Connected consciousness after tracheal intubation in young adults: an international multicentre cohort studyabstract, Results

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes

    The source reads: Responses were more likely to occur after a command to respond (and not to nonsense, 13 subjects) than after a nonsense statement (and not to command, four subjects, P=0.049).

What this does not establish

A movement is read as a response to meaning. In the 2023 study four people moved after a nonsense statement and not after the command, so not every movement is one.

Claim 67 · checked 24 September 2026 · AI-assisted audit

Claim: Nothing yet shows that no one was.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The page’s reading. The one measure calibrated to separate the two states is described by its authors as an operational threshold rather than a boundary.

Claim 68 · checked 24 September 2026 · AI-assisted audit

What was read