Silent Stroke

Abstract

Background and Purpose— The prevalence of silent brain infarcts varies from 8% to 28% in the general elderly population. Silent brain infarcts are associated with increased risk of subsequent stroke and cognitive dysfunction. By definition, silent strokes lack clinically overt stroke-like symptoms and fail to come to clinical attention; however, impaired recall of symptoms may be a potential confounder. Our aim is to report a series of patients with incidentally detected acute and subacute strokes and examine whether they were truly asymptomatic. Methods— Subjects included in this study were drawn from ongoing dementia research studies at the Memory Ageing and Cognition Center, in which all participants underwent a cranial MRI. Incidental hyperintense lesions on diffusion-weighted imaging with corresponding apparent diffusion coefficient defects indicative of acute/subacute silent stroke were identified. Clinical data for individuals with incidental hyperintense lesions on diffusion-weighted imaging were collated. Results— Six of 649 subjects had incidental hyperintense lesions on diffusion-weighted imaging; on retrospective questioning, 3 recalled symptoms temporally correlated with MRI lesions, which had been reported to but ignored by family members. Two subjects had focal neurological signs. A majority of the subjects with incidental hyperintense lesions on diffusion-weighted imaging had significant cognitive impairment. Conclusions— A significant number of strokes may be “silent” due to lack of awareness of stroke-like symptoms in the elderly and their families. Enhanced stroke prevention education strategies are needed for the elderly population and, in particular, for their families.

Prevalence and Risk Factors of Acute Incidental Infarcts

“…8 Moreover, 0.92% (6/649) of subjects undergoing MRI scans for research studies in cognitive impairment had AII. 9 By contrast, the communitybased Prospective Urban Rural Epidemiological (PURE) Mind substudy recently reported no AII among 793 participants.…”

Isolated, subtle, neurological abnormalities in neurologically and cognitively healthy aging subjects

“…These signs, however, are not benign at all since they are independently associated with WMH, lacunae, and subcortical atrophy, may partly be the consequence of silent strokes ''not listened to'' by both patients and physicians [59], thus probably constituting a red flag for future cognitive decline. Therefore, it is of paramount importance that these signs are not underestimated but assessed in combination with an accurate history and exhaustive imaging evaluation to prevent progression of cerebrovascular disease and future neurological and cognitive disabilities.…”

Association of sleep apnea with clinically silent microvascular brain tissue changes in acute cerebral ischemia

“…Also, the "silence" of chronic microvascular brain tissue changes may be due to various reasons: lesions in non-eloquent brain areas like the frontal lobes, small lesions causing minor symptoms not recognized as stroke symptoms, the sensitivity and memory of the patient. Particularly the latter reason may have introduced a recall bias [40]. Third, as we reviewed both hemispheres (including the affected side) on brain imaging, acute ischemic lesions may have obscured chronic microvascular brain tissue changes potentially resulting in an underestimation of the extent of these lesions.…”