The event-related P300 potential approach to cognitive functions of nondemented patients with cerebral and peripheral arteriosclerosis

Abstract

Objectives: To detect subtle cognitive dysfunction in non-demented patients with either cerebral (cAD) or peripheral (pAD) arteriosclerotic disease, and to evaluate in these patients the effects on cognitive functions of carotid endarterectomy and bypass surgery, respectively.

Design: Case-control study.

Setting: Tertiary care referral center.

Participants: Eighty consecutive patients with moderate to high-grade stenosis of the internal carotid artery (ICA) (mean age +/- SD, 62 +/- 8 years), 53 patients with stenoses of the peripheral arteries (60 +/- 10 years), and 80 healthy volunteers (58 +/- 15 years) enrolled in a study on healthy aging. Cerebral and peripheral arteriosclerotic disease was verified by digital subtraction angiography, and all patients were screened for confounding effects of concomitant diseases.

Main outcome measures: Cognitive functions by event-related visual P300 potentials.

Results: Patients with cAD showed prolonged P300 latencies and reduced P300 amplitudes, whereas pAD patients had reduced P300 amplitudes only. On an individual scale, 25% of cAD patients, but only 6% of pAD patients, revealed P300 abnormalities. In the cAD, but not in the pAD patients, the P300 latencies were especially prolonged in the older patients, but other factors such as sex, cerebral symptoms, degree of ICA stenosis, and premorbid intelligence did not play any role in either group. Within 1 to 2 weeks of surgery, the P300 latencies shortened in both cAD and pAD patients with high initial values.

Conclusions: As demonstrated by P300 potentials, even nondemented arteriosclerotic patients reveal signs of subtle cognitive dysfunction affecting especially the older cAD patient. In the short-term, carotid endarterectomy presumably improves cognitive functions unspecifically in nondemented patients with a higher initial degree of P300 abnormality.