Executive dysfunction in patients with transient ischemic attack and minor stroke

A considerable number of patients with transient ischemic attack suffer from cognitive impairment, even after recovery of focal neurological deficits. In particular, executive functions such as working memory, abstraction, reasoning, verbal fluency and cognitive flexibility are impaired in these patients. The purpose of the present study was to explore the nature and prevalence of cognitive impairment in a series of patients with transient ischemic attack and minor stroke.

We included 140 patients (61% women) who presented with a focal cerebral ischemic event lasting less than 24h in the Urgent TIA outpatient clinic. All patients underwent a brief battery of neuropsychological tests, consisting of the Mini Mental State Examination (MMSE), Neurobehavioral Cognitive Status Examination-Judgment Subtest, Clock Drawing Test and Trail Making Test.

A majority of patients (57%) were impaired on one or more of these neuropsychological tests. Nearly one-third of individuals were impaired on two or more tests. Cognitive impairment was most frequently observed on the Trail Making Test Part A (31% of patients) and Part B (40%). The Trail Making Test examines executive functions, as it requires cognitive flexibility, ability to maintain a complex response set and speed of processing. By contrast, only 5% of patients were impaired on the MMSE, a widely used neuropsychological test insensitive to executive dysfunction.

Our results highlight the limitations of the MMSE as an independent cognitive screening instrument for patients with TIAs and minor stroke and the high prevalence of executive dysfunction in these patients.