In patients with disorder of consciousness (DOC), awareness preservation is related
to a better outcome prognosis (34). The dissociation of identified signs of awareness
by laboratory assessment while undetected by bedside behavioural examination, is
defined as cognitive motor dissociation (CMD) (1, 22-27). The rate of misdiagnosis is
about 30% (18-21). Current researches emphasize enlarged bedside evaluation as it
is easily administered and more economical (26). The Motor Behavioural Tool (MBT)
had provided accurate insight into the content of consciousness, and had improved
significantly the correlation with the outcome prediction during the acute stage, while
the CRS-R sub-scores per se did not (1). We propose to further the exploration of
supplementary motor behavioural signs by studying the predictability of the emergence
defined by the CRS-R as well as the ability to detect CMD of the clinical items of three
existing scales: The FOUR, the GCS and the NCS.
We enrolled 35 patients with first CRS-R, MBT and the 3 aforementioned scales
evaluation performed within 28 days post-injury. One evaluation of each scale was
selected for every patient. The FOUR has 4 items, the GCS 3, and the NCS 4, that
means 11 items, all rated with a sub-score which were the analysed variables.
A first class of 8 group and 4 comparisons were made depending on the first and last
CRS-R assessment, the latter defining the emergence: DOC patient emerging (1a) vs
not emerged (1b), UWS (1c) and MCS (1e) emerging vs not emerged (1d) and (1f),
and patients showing no CRS-R change (1g) vs those showing upper class of CRS-R
(1h).
A second class of 5 groups with 3 comparisons were made according to the MBT
assessment at the admission and the last CRS-R evaluation : CMD patients (2a) vs
true DOC (2b) at the entry in the unit, true DOC with DOC at last CRS-R (2c) vs CMD
with emergence at last CRS-R (2e), and CMD with DOC at last CRS-R (2d) vs CMD
with emergence at last CRS-R (2e).
The statistical testing was based on a non-parametric Mann-Whitney U test to see
whether there is a difference of sub-scores when comparing two groups for the same
item.
The p-value was > 0.05 for all comparisons; in other word, none item enables to predict
the outcome defined by the last CRS-S classification or to make the CMD diagnosis
according to the MBT.
Moreover, 26% of CMD patients were classified as DOC on the last CRS-R which can
be related to the rate of misdiagnosis found in the literature.
Those findings address explicitly the issue of how performing the clinical evaluation to
overcome this underestimation of the degree and level of consciousness, and how
essential it is to develop and render more accurate the bedside evaluation of
awareness.