Screening for Stroke and Cognitive Impairment Chapter 2: Background

Vascular Cognitive Impairment “Vascular Cognitive Impairment (VCI) includes the cognitive and behavioural disorders associated with cerebrovascular disease and risk factors, from mild cognitive deficits to frank dementia.” 1 “VCI is a syndrome with cognitive impairment affecting at least one cognitive domain (e.g., attention, memory, language, perception or executive function) and with evidence of clinical stroke or subclinical vascular brain injury.” 1 “VCI encompasses a large range of cognitive deficits, from relatively mild cognitive impairment of vascular origin (VaMCI) to Vascular Dementia (VaD) the most severe form of VCI.” 1 “VCI also plays a role in patients with Alzheimer’s disease pathology who have coexisting vascular lesions.” 1

Vascular Cognitive Impairment The first step for health care providers in Taking Action for cognitive changes is to understand the frequency of occurrence for VCI in patients. 1 “VCI affects up to 60% of stroke survivors and is associated with poorer recovery and decreased function in activities of daily living and instrumental activities of daily living.” 1 “Cognitive abilities in the areas of executive function, attention and memory appear important in predicting functional status at discharge.” 1 “Cognitive impairment increases long-term dependence and is associated with increased mortality rates (61% versus 25%)” 1,4

Vascular Cognitive Impairment “Cognitive impairment can be chronic and progressive after stroke; post stroke dementia is estimated to occur in 26% of stroke patients by 3 months and adversely affects recovery.” 1 Classification and Diagnostic Criteria for Vascular Cognitive Impairment and Dementia can be found at: 1

Covert Strokes Cognitive impairment due to covert vascular pathology is becoming more prevalent 1. Covert strokes, e.g., lacunes are common (23% of community elderly) and are associated with cognitive decline, dementia, and stroke 1. For every clinically evident stroke there could be as many as 10 previous “covert” strokes 1. Signs of covert stroke can often present as signs and symptoms of cognitive impairment 1.

Incidence of Cognitive Impairment in a Stroke Prevention Clinic In this study two-thirds of stroke prevention clinic patients demonstrated evidence for cognitive impairment irrespective of their final diagnosis or the presence of white matter changes, which further supports the need for cognitive screening in a secondary stroke prevention clinic setting 10.

Dementia Stroke and dementia are interconnected, sharing common risk factors and each increases the risk of the other 4. About 10% of patients hospitalized with their first stroke have pre-stroke dementia, and an additional 10% will have new dementia as a consequence of the stroke 4. Approximately 25% of hospitalized stroke patients will have dementia when evaluated during the first year post stroke 4. In stroke patients with recurrent stroke the rates of dementia can be greater than 30% 4.

Dementia Vascular dementia is the second most common cause of dementia after Alzheimer Disease 1. The combination of Alzheimer disease and vascular disease results in the most common type of dementia in the elderly 1. “A single macroscopic hemispheric infarct is sufficient to cause dementia in people with intermediate Alzheimer pathology.” 1

Dementia Approximately one in three persons will develop stroke, dementia, or both, and the incidence for both increases exponentially with age 4. Increasing age, lower education level, cerebral atrophy, white matter disease, premorbid disability, and diminished cognition pre-stroke are non-stroke factors associated with post-stroke dementia 4.

Post-stroke Dementia Incidence in Inpatients Chart shows incidence (linear regression –solid line, 95% CI –dashed lines) of post-stroke dementia in hospital pts of either first or recurrent stroke, and excludes pre-stroke dementia. There is a rapid rise in dementia incidence in the immediate post-stroke period. Incidence of dementia increases linearly at a rate of 3.0% ( %) per year above the initial post-stroke incidence of approximately 20% at three to six months 4.