Cognitive dysfunction in patients with asymptomatic ischaemic disturbances of the cerebral circulation and carotid stenosis

BACKGROUND: Impairment of cognitive function is often present in patients with carotid artery stenosis but the details of this dysfunction have rarely been reported.Our purpose was to elucidate the cognitive dysfunction in patients with Asymptomatic Ischaemic Disturbances of the Cerebral Circulation and unilateral asymptomatic severe carotid stenosis using comprehensive neuropsychological testing, and also to identify the specific underlying clinical and neuroimaging factors.METHODS: We analyzed the results of neuro-psy chological testing, the clinical history, and MR findings in 10 patients with Asymptomatic Ischaemic Disturbances of the Cerebral Circulation and severe (70-99%) stenosis of the extra cranial internal carotid artery (ICA) on Doppler sonography.Cognitive functions were examined.We excluded patients with Asymptomatic Ischaemic Disturbances of the Cerebral Circulation with contra lateral ICA occlusion or severe stenosis.RESULTS: Our neuropsychological testing revealed obvious cognitive deficits in all patients with Asymptomatic Ischaemic Disturbances of the Cerebral Circulation and unilateral asymptomatic severe ICA stenosis.The mean cognitive score on the memory test was also significantly lower in patients with asymptomatic ICA stenosis and score 3 lesions on MRI than in asymptomatic patients and lesions score 1 on MRI (p<0.05).CONCLUSIONS: Cognitive deficits are common in patients with Asymptomatic Ischaemic Disturbances of the Cerebral Circulation and unilateral asymptomatic severe ICA stenosis.Our findings suggest that an additional mechanism beyond the structural lesion such as chronic hypoperfusion may affect cognitive function in patients with high-grade ICA stenosis. Key words: asymptomatic ischaemic disturbances of the cerebral circulation, ICA stenosis, neuropsychological testCarotid stenosis is an important risk factor for stroke.The major cause of cerebral ischemia in patients with stenosis of the internal carotid artery (ICA) is intracranial arterial obstruction due to thromboembolism.Recent studies have also demonstrated the importance of hemodynamic factors to predicting the risk of ischemic stroke after ICA stenosis.Impairment of cognitive function has often been reported in patients with carotid artery stenosis.This study analyzed the reduced neuropsychological test performance with the aim of identifying the specific clinical and neuroimaging factors that influence the effects of asymptomatic carotid stenosis on cognitive function.