Sounds like something useful to identify locked-in-syndrome. Are you positive your emergency department has this available and knows how to use it? What is your ER protocol to identify such patients?
http://www.alphagalileo.org/ViewItem.aspx?ItemId=166432&CultureCode=en
New research suggests that
an electroencephalogram (EEG) could be a strong indicator of the level
of awareness of patients in a vegetative state after a severe brain
injury.
Functional magnetic resonance imaging (fMRI) has repeatedly shown
that a significant minority of patients diagnosed as in the vegetative
state are actually aware, but unable to show it reliably with their
behaviour.
The new research findings, published in Annals of Neurology, suggest a
correspondence between a patient’s ability to generate an EEG marker of
attention to tactile stimulation, and their ability to produce the
critical clinical marker of awareness by following verbal commands.
Crucially, this relationship existed for patients who could only follow commands with the more expensive methods of fMRI.
The mental demands of the EEG task are lower than the demands of the
fMRI tasks. Furthermore, EEG is entirely portable, inexpensive, and
available in the majority of hospitals.
The researchers state that this more simple EEG assessment may be
capable of diagnosing a patient’s level of awareness without the need
for expensive and challenging fMRI scans, thereby increasing the number
of patients who may benefit from a more accurate diagnosis.
14 patients were selected for the study, across levels of awareness
and behavioural ability; seven in a vegetative state, four in a
minimally conscious state, two emerging from a minimally conscious
state, and one with locked in syndrome.
Each patient’s surrogate decision maker provided informed, written
consent for the patient’s participation in the study. As a scientific
control, a sample of fifteen healthy volunteers also participated in the
tasks.
The patients completed two sets of brain imaging tasks:
· Vibrating stimulators affixed to each wrist and the upper
back administered non-painful pulses five times per second while the
patients’ EEGs were recorded. 80% of these vibrations occurred on the
upper back. The relatively more infrequent vibrations on the wrists (20%
of the time) produce changes in a healthy individual’s EEG that reflect
attention being drawn toward the new location of stimulation.
· During separate fMRI scans, patients were asked to engage
in three established measures of a covert ability to follow commands –
imagining playing tennis, imagining walking around the house, and
counting target words in a stream of distractors.
All patients whose EEGs showed evidence of attention being directed
toward the infrequent tactile stimuli were also able to display evidence
of following commands in the fMRI tasks.
Similarly, most patients (five of six) who did not generate a
response to the EEG task did not generate evidence of command following.
Dr Damian Cruse, from the University of Birmingham, explained, “A
bedside EEG may work as a cost-efficient and portable way of improving
the accuracy of diagnosis in disorders of consciousness. While current
clinical diagnoses are accurate for many patients, recent reports
estimate that as many as 15% of patients considered to be in a
vegetative state could retain awareness that cannot be detected reliably
from their behaviour alone.”
“The ultimate aim is to provide more accurate diagnoses for all
patients, thus directing appropriate rehabilitation and therapy to those
most likely to benefit.”
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