Assessment of subtle cognitive impairment in stroke-free patients with carotid disease.

Carotid disease is a known risk factor for stroke and stroke is a known risk factor for cognitive impairment, but relation between carotid artery stenosis and cognitive function in asymptomatic individuals is less clear. Most patients have only minor complaints of cognitive dysfunction and assessment with usual tests is not sensitive enough. The study included 26 stroke-free patients (15 male and 11 female), mean age 66.3 +/- 8.7 years, with advanced internal carotid artery stenosis or/and occlusion (ICAs/o). Left ICAs/o was present in 11, right ICAs/o in eight, and bilateral ICAs/o in seven patients. History was taken and assessment of risk factors, brain CT scan and neurologic examination were performed. Cognitive functions were tested by use of Mini Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA). All patients were asymptomatic, except for two patients that presented with repeated transient ischemic attack (TIA). In all subjects median MMSE scores were within the normal range (27.5; IQ range 25-29), while mean MoCA scores were abnormal (22.6 +/- 3.4). Patients with left ICAs/o scored slightly better on MoCA (22.9 +/- 3.3) than patients with right ICAs/o (22.4 +/- 4.0). Delayed recall MoCA subtest was impaired in 22/26 patients and visuospatial subtest in 23/26 patients; however, there was no statistically significant difference according to the side of ICAs/o. Patients with the presence of one or two risk factors scored lower on visuospatial/executive MoCA subtests (P = 0.018) as compared with patients with multiple risk factors. MoCA proved to be a sensitive tool for assessment of mild cognitive changes in stroke-free patients with advanced ICAs/o. Decline was most pronounced in visuospatial, executive and short-memory functions.