A
severe brain injury may be caused by an accident or other trauma (traumatic
brain injury) or a non-traumatic event such as a stroke or aneurysm. People may
lose consciousness for days or weeks after a severe brain injury. When emerging
from an unconscious or comatose state, many individuals may first enter a
vegetative state, also known as Unresponsive Wakefulness Syndrome (UWS), where
their eyes are open, but they show no signs of conscious awareness. Then, they
may gradually show signs of consciousness, such as visually tracking a moving
object, following simple commands, or answering yes/no questions. Over time,
these signs may appear more consistently and may progress to more complex
behaviors, such as handling familiar objects. Accurately detecting the first
signs of consciousness may improve rehabilitation planning and care for people
with severe brain injuries.
In
a recent NIDILRR-funded study, researchers looked at records from people with
severe brain injuries who transitioned from coma or UWS to a minimally
conscious state. They wanted to find out which signs of consciousness appeared
first in these individuals and how long it took for these signs to appear after
the brain injuries. They also wanted to find out whether people with traumatic
brain injuries (TBI) had different patterns of regaining consciousness compared
to people with non-traumatic brain injuries.
Researchers
at the Spaulding-Harvard Traumatic Brain Injury Model System
Center looked at records from 79 people with severe brain
injuries who were admitted to a specialized inpatient rehabilitation program
for people with disorders of consciousness. About half of these individuals had
a TBI, while the other half had brain injuries resulting from stroke, aneurysm,
or other non-traumatic causes. The individuals were in a coma or were diagnosed
with UWS on admission to the rehabilitation program, and then regained at least
minimal consciousness during their inpatient stay. During their stay, the
individuals were evaluated twice per week to determine whether or not they
displayed any of 13 behavioral signs of consciousness, according to a
standardized scale specifically designed for patients with altered states of
consciousness. These included visual signs, such as fixating the eyes on and
tracking a moving object; auditory signs, such as following simple verbal
commands to initiate movement; motor signs such as handling objects or
displaying automatic movement such as scratching or waving; and communication
signs, such as answering yes/no questions either gesturally or verbally. The
researchers looked at which behavioral signs of consciousness emerged first in
the individuals as well as the length of time between when the injury occurred
and the when first sign of consciousness was observed.
The
researchers found that the three most common first signs of consciousness were:
·
Visual pursuit: About
40% of the individuals first demonstrated conscious awareness by tracking a
moving mirror with one or both eyes at least twice in any direction.
·
Command following: 25%
of the individuals first demonstrated conscious awareness by following simple
movement commands, such as lifting an arm when asked to do so, at least three
times.
·
Automatic movement:
24% of the individuals, the first sign of conscious awareness was an
automatic movement such as scratching an itch.
The
researchers found that these first signs of conscious awareness tended to
emerge about 6 weeks after injury, with a quarter of the individuals showing
the first sign of conscious awareness at least 33 days after injury and
three-fourths 59 days after injury. In most of the individuals (72%), only one
sign of conscious awareness was detected during the first week of
consciousness.
When
the researchers compared the individuals with TBI to those with non-traumatic
injuries, they found that both groups showed the first signs of consciousness
at roughly the same length of time after injury. However, more of the
individuals with TBI showed motor signs of consciousness first, such as
following commands, compared with the individuals with non-traumatic injuries,
who were more likely to display visual signs such as visual pursuit. For
example, about 18% of those with TBI displayed automatic movement compared to
about 6% of those with non-traumatic injuries; while about 25% of those with
non-traumatic injuries displayed visual pursuit, compared to about 15% of those
with TBI.
The
authors noted that reliably detecting the first signs of consciousness may play
an important role in planning care and supports for people with severe brain
injuries. Based on the results of this study, clinicians may wish to develop
consciousness assessments that focus on visual pursuit, command-following, and
detection of automatic movements. In addition, because signs of consciousness
may emerge one at a time, and may not appear consistently at first, clinicians
may want to ensure that assessments are performed frequently and examine a
variety of different behaviors. Future research may be useful to further
investigate the possible differences in recovery trajectories between people
with TBI and non-traumatic brain injuries.
To Learn More
The
Model Systems Knowledge Translation Center (MSKTC) works with the Model System
centers to develop a diverse collection of research-based,
consumer-tested information resources on TBI. These include
factsheets on Severe TBI and Vegetative and Minimally Conscious States After TBI,
and Acute Inpatient Rehabilitation, among others.
The Brain Injury
Association of America offers a wealth of information and
support resources for brain injury survivors, families, and health
professionals. In addition, state affiliates can connect individuals to local
resources and support groups.
To Learn More About this Study
Martens,
G., Bodien, Y., Sheau, K., Christoforou, A., and Giacino, J.T. (2020) Which behaviours are first to emerge during recovery of
consciousness after severe brain injury? Annals of Physical and
Rehabilitation Medicine, 63(4), 263-269. This article is available from the
NARIC Collection under Accession Number J84128.
Date
published: 2020-08-26
Download
this article in PDF format:
What are the First Signs of Consciousness After a Severe
Brain Injury.pdf
Research
In Focus is a publication of the National Rehabilitation Information Center
(NARIC), a library and information center focusing on disability and
rehabilitation research, with a special focus on the research funded by
NIDILRR. NARIC provides information, referral, and document delivery on a wide
range of disability and rehabilitation topics. To learn more about this study
and the work of the greater NIDILRR grantee community, visit NARIC at http://www.naric.com or
call 800/346-2742 to speak to an information specialist.
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