Only evaluation and assessment NOT stroke protocols to correct such problems. Pretty much useless research.
Why would you want neurologists in this?
Are Neurologists Respected? Read and weep.
Have Stroke Neurologists Entered the Arena of Stroke-Related Cognitive Dysfunctions?
Not Yet, but They Should!
See related article, p 1539
In this issue of Stroke, Zamboni et al1
reported the results of a study that explored whether early cognitive
impairment was associated with the volume of white matter
hyperintensities and with white matter damage on diffusion-weighted
magnetic resonance imaging in patients with transient ischemic attack
(TIA) or minor stroke. Cognitive evaluation was performed with the 2
currently most widely used screening tools, the Montreal Cognitive
Assessment (MoCA) and the Mini Mental State Examination. Scores on both
tests, 1 month after the event, were significantly correlated with
volume of white matter hyperintensities and fractional anisotropy.
However, only the MoCA was independently correlated with white matter
hyperintensity volumes, average fractional anisotropy values, and
reduced fractional anisotropy in anterior tracts after controlling for
the Mini Mental State Examination.
This study reinforces
the idea that the MoCA is better suited than the Mini Mental State
Examination for the assessment of patients with cerebrovascular
diseases.2
These data are also in agreement with previous studies showing that the
MoCA is more specifically associated with microstructural damage in
white matter than the Mini Mental State Examination.3
Some
issues, such as the appropriate normality cutoffs for these tests,
remain open, but these studies, however, have the great merit of raising
a series of relevant points concerning the cognitive costs of
cerebrovascular diseases.
Cognition After Stroke: Magnitude of the Problem
Cognitive
dysfunction is among the most common and severe consequence of stroke.
For patients and their caregivers, cognition and related disturbances
are among the top 10 priorities related to life after stroke.4
In
hospital series, poststroke dementia prevalence can be as high as 40%
depending on inclusion of recurrent strokes, time of evaluation after
stroke, dementia criteria, and exclusion of aphasic patients.5
The magnitude of the problem is even larger considering that many
stroke patients develop cognitive deficits that do not meet criteria for
dementia (ie, mild cognitive impairment)6; this percentage can be as high as 80%.7 Finally, >90% of stroke survivors complain of subjective cognitive impairment.8 These complaints may benefit from objective testing.9
The
presence of cognitive deficits has several consequences after stroke.
Importantly, it may heavily affect rehabilitation strategies.10
Early poststroke cognitive dysfunction, together with stroke severity
and prestroke functionality, is a significant and independent predictor
of long-term functional poststroke outcome.11
In
this era where a great focus and vast efforts are placed on acute
stroke and on the treatments available in this phase, it is interesting
to compare the above-mentioned data with the figures of stroke patients
subjected to thrombolysis. Estimates of alteplase treatment range from
3% to 5%,12 with eligibility estimates approaching 10%. Optimistically, patients eligible for endovascular thrombectomy could be 7%,13
but current performance rates are significantly lower. Remarkably, all
stroke patients can clearly benefit from admission to a dedicated stroke
unit.
It is obvious that although the acute-phase
therapies(Where are they?) are cornerstones of our care of stroke patients and, on an
individual patient basis, they may change dramatically the outcome, the
bulk of stroke problems remain in the chronic phase.
Stroke Neurologist Are Called to Assess Cognition
Despite
the impressive data on the frequency of the stroke cognitive
consequences, this topic has received scarce attention to date. One
systematic review of published stroke trials pointed out that, out of
almost 9000 studies, <5% included a cognitive measure.14
The
evaluation of the patient’s cognitive abilities has always been part of
the neurological examination, and neurologists had been skilled in this
for years. However, this part of the neurological examination is
complex, requires experience, and takes time. Today, we are frequently
called to quickly visit stroke patients especially in specific settings
such as in the acute phase when time-dependent decisions need to be
made. Brief and time-convenient neurological scales have, therefore,
been developed, the best example being the National Institute of Health
Stroke Scale. The National Institute of Health Stroke Scale has great
advantages such as the implementation of a standardized scoring measure
and use of a common language among centers. These scales are so widely
used in the stroke setting that there is a tendency for them to entirely
replace the full neurological examination. There are clear hazards in
such oversimplification. One is that these scales are heavily weighted
on more easily evaluable deficits such as motor, whereas cognitive
evaluation, besides language items, is minimalized.
Tools for the Evaluation of Cognition After Stroke
Thus,
the evaluation of cognition should clearly become part of the
neurological assessment of all stroke patients. Some of the open issues
in this regard concern the time of the evaluation and the tools for it. A
thorough cognitive assessment requires time as cognitive domains are
various (language, memory, attention, executive function, visuospatial,
etc).
Many cognitive instruments have been proposed for the evaluation of stroke patients.15
These tools should be selected according to the different intervals of
assessment after stroke and the availability of time and personnel. In
any case, we need tools to systematically assess cognition in stroke
patients and instruments that are usable from the early phases.
The MoCA could be one of such tools.16
Its use for the assessment of cerebrovascular disease patients has been
advocated because it evaluates many of the cognitive domains affected
in these patients.17
The MoCA has been tested in several studies in the acute stroke setting
where it is applicable and predictive of long-term outcome. The MoCA
has advantages and limitations as does any other cognitive tool2
under investigation for use in acute stroke. More important than the
issue of the finding of the best tool (likely to be an impossible task)
is attention to the evaluation of cognition in stroke patients.
Is It a TIA or a Cognitive Stroke?
One last interesting issue raised by the study by Zamboni et al1
is the fact that some cognitive impairment was found in TIA patients 1
month after the event. TIA symptoms by definition must last <24
hours, so finding a clinical deficit at a time distant from onset could
challenge the concept of TIAs being transient.
There are
at least 2 possible explanations for such findings. The first is that
the vascular event clinically diagnosed as TIA induces a cerebral damage
that is transient in its noncognitive expression but that is sustained
for cognition. Indeed, it is well documented that some TIAs are
associated with permanent brain lesions.18
This damage might also happen at a microstructural level and be
invisible on conventional neuroimaging. Alternatively, one may
hypothesize that, in TIA patients, brain microstructural damage and
functional dysfunction are present before the event. White matter damage
as shown in the study by Zamboni et al could be one of the correlates
of this cognitive decline. The answer to this question can come from
longitudinal imaging studies, cognitively assessing subjects before the
cerebrovascular event and then afterward. However, these are not easy to
conduct.
Ten years after the call for vascular
neurologists to enter the arena of poststroke cognition to fight the
hard problem in daily life after a stroke,19
the consideration given to this aspect remains limited. We urge stroke
clinicians to increase their attention toward the cognitive and
long-term consequences of stroke.
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