Abstract
BackgroundSevere stenosis of the internal carotid artery (ICA) has been associated with impaired cognition in patients, but its effect on rapid-onset cortical plasticity is not known. Carotid endarterectomy (CEA) in patients with severe ICA stenosis reduces stroke risk, but the impact on cognition or physiology of the respective hemisphere remains controversial.Methods/Results16 patients with severe stenosis of the ICA and 16 age and sex matched controls were included. Rapid-onset cortical plasticity was assessed using the paired-associative stimulation (PAS) protocol. PAS models long-term synaptic potentiation in human motor cortex, combining repetitive stimulation of the peripheral ulnar nerve with transcranial magnetic stimulation of the contralateral motor cortex. Cognitive status was assessed with a neuropsychological test battery. In patients, verbal learning and rapid-onset cortical plasticity were significantly reduced as compared to controls. Identical follow-up tests in 9 of the 16 patients six months after CEA revealed no improvement of cognitive parameters or cortical plasticity.ConclusionsDecreased rapid-onset cortical plasticity in patients with severe stenosis of the ICA was not improved by reperfusion. Thus, other strategies known to increase plasticity should be tested for their potential to improve cortical plasticity and subsequently cognition in these patients.
Highlights
Stenosis of the internal carotid artery (ICA) is responsible for about 15 to 20% of all ischemic strokes [1]
Decreased rapid-onset cortical plasticity in patients with severe stenosis of the ICA was not improved by reperfusion
Cognition was determined by a neuropsychological test battery, rapid-onset cortical plasticity by paired associative stimulation (PAS) [9], a non-invasive brain stimulation paradigm used as a model of Hebbian associative long-term potentiation (LTP) of synaptic efficacy in humans [10,11]
Summary
Stenosis of the internal carotid artery (ICA) is responsible for about 15 to 20% of all ischemic strokes [1]. Carotid endarterectomy (CEA) in patients with severe ICA-stenosis can reduce stroke risk [2]. While stroke clearly increases the odds for developing dementia [3|, severe ICA-stenosis even in the absence of stroke seems to be associated with cognitive impairment [4]. Previous studies have shown reduced LTP-like plasticity in patients with impaired cognitive function and learning ability, like Alzheimer’s disease [14]. Severe stenosis of the internal carotid artery (ICA) has been associated with impaired cognition in patients, but its effect on rapid-onset cortical plasticity is not known. Carotid endarterectomy (CEA) in patients with severe ICA stenosis reduces stroke risk, but the impact on cognition or physiology of the respective hemisphere remains controversial
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