Project Details
Abstract
Background: Carotid artery stenosis is an important risk factor of ischemic stroke. However, the
role of carotid artery stenosis in cognitive deficits remains controversial. In our existing project,
we elected a model of timed cognition in an attempt to tackle the limitations of commonly used
neuropsychological tests, and to address the relationship between cerebral hypoperfusion and
cognitive processing speed. Our preliminary data suggest that the occurrences of
procedural-related ischemic lesions and the laterality of carotid stenosis seem to play important
roles in moderating the effects of carotid stenosis and carotid angioplasty and stenting (CAS) on
cognitive changes.
Aims: The general purposes of this proposed project intend to extend the scope our existing
project to examine the effects of the patient-related (laterality) and procedure-related (peri-CAS
lesions) factors on the relationships between carotid artery stenosis, CAS, and cognitive functions.
Methods: A series of studies will be carried out to (a) validate the alternative forms of the tests
and test the applicability of these forms; (b) test if the occurrences of peri-CAS lesions can lead to
cognitive deficits and impede the beneficial effects of CAS on cognitive functions; (c) to examine
the role of unilateral carotid stenosis in moderating the effects on the cognitive changes produced
by CAS.
The research protocols and data analyses of the studies will be based on between-group or
mixed factorial designs. In this 3-year project, thirty volunteers (aged 18-30 years) and 50 older
volunteers (aged 50-75 years) will be recruited. They will serve as reference groups for deriving
measures of cognitive speed and validating the alternative forms of the tests used in the proposed
project. We also intend to recruit 160 participants with different grades of carotid stenosis from a
stroke unit. They will be allocated to three different groups: the revascularization group (n = 80),
the medication group (n = 40) and the control group (n = 40) based on their severity of stenosis
and choice of treatments. All participants will undergo three phases of neuropsychological
assessment, baseline (pre-CAS), 1 month, and 6 months after CAS or medications.
The revascularization group will undergo diffusion weighted magnetic resonance image (DWI)
in 3 phases (pre-CAS, 1 week and 6 months after CAS) for identifying and verifying new
peri-CAS lesions. The revascularization group will be divided into two subgroups based on the
presence or absence of new ischemic lesions on DWI performed at 1 week after CAS. The testing
data accumulated throughout the project will be analyzed by MANOVA or MANCOVA where
appropriate. The change scores across each phase will be used to derive reliable change index
and/or multiple regression equations based on the medication and control groups. The number of
cases falling in the ‘significant change’ range will be calculated and analyzed by 2 tests to
examine the group differences (with lesions versus without) according to specific cognitive
domains. To address the laterality effects, patients with significant stenosis will be further
regrouped based on the side of stenosis and operated carotid (left versus right). Thus, laterality
treatment will be used as independent variables, and the testing data will be analyzed by the same
methods described above.
Expected outcomes: We expect the presence of peri-CAS lesions may result in cognitive
impairments, which may further impede the beneficial effects of CAS on cognitive changes. We
also anticipate that the difference in the sidedness of carotid stenosis may reveal different levels of
performance on different cognitive domains that are predominantly regulated by the left and right
hemisphere, respectively. In addition, depending on which side of CAS is treated, we should expect to see more cognitive improvement in the performance corresponding to the hemispheric
functions in effect than that of its counterpart.
Project IDs
Project ID:PF10101-1994
External Project ID:NSC100-2410-H182-008-MY2
External Project ID:NSC100-2410-H182-008-MY2
Status | Finished |
---|---|
Effective start/end date | 01/08/12 → 31/07/13 |
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