Cognition

Abstract

Disorders of cognition (neurocognitive disorders) following stroke occur between 7% in population-based studies of first-ever stroke patients and 41% in hospital-based studies which included recurrent strokes. Milder forms of cognitive deterioration following stroke were found between 22% and 84% depending on definition, testing, and time of investigation. Incidence rates are 2-3% increasing annually at linear rates. Importantly, milder forms can also be quite disabling and hinder rehabilitation and reuptake of occupational and social roles. Probably all stroke patients are at risk of suffering from cognitive deterioration but some risk factors are important such as location of stroke, initial stroke severity, previous strokes, level of pre-stroke cognition and presence of vascular risk factors. Genetic and inflammatory biomarkers are under investigation but observational data suggest that high levels of interleukins and C-reactive protein have predictive value. Cognitive and brain reserve can protect against cognitive deterioration and depends on education, leisure activities and social interactions. Diagnosis of post-stroke cognitive deterioration (mild neurocognitive disorder) varies according to test instruments used. Usually, a short bedside test is used and an extended neuropsychological test battery is applied later. Variations also result from speech disturbances, emotional disorders such as depression. CT and MRI confirm the diagnosis and provide additional information on location and size of infarct, previous infarcts, white matter lesions, microbleeds, and brain atrophy. Management focuses on prevention and includes cognitive training and modification of risk factors. Life-style modifications have been shown to be beneficial in preventing cognitive decline in persons at risk of dementia. To date, smaller trials have not shown similar interventions to be effective in stroke patients. New studies on molecular changes invoked by social support and environmental enrichment strategies to preserve cognition are ongoing.