THE EVENT-RELATED P300 POTENTIAL APPROACH TO COGNITIVE FUNCTIONS OF NONDEMENTED PATIENTS WITH CEREBRAL AND PERIPHERAL ARTERIOSCLEROSIS

OBJECTIVES: To detect subtle cognitive dysfunction in nondemented pati ents with either cerebral (cAD) or peripheral (pAD) arteriosclerotic d isease, and to evaluate in these patients the effects on cognitive fun ctions of carotid endarterectomy and bypass surgery, respectively. DES IGN: Case-control study. SETTING: Tertiary care referral center. PARTI CIPANTS: Eighty consecutive patients with moderate to high-grade steno sis of the internal carotid artery (ICA) (mean age +/- SD, 62 +/- 8 ye ars), 53 patients with stenoses of the peripheral arteries (60 +/- 10 years), and 80 healthy volunteers (58 +/- 15 years) enrolled in a stud y on healthy aging. Cerebral and peripheral arteriosclerotic disease w as 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 reduc ed P300 amplitudes, whereas pAD patients had reduced P300 amplitudes o nly. On an individual scale, 25% of cAD patients, but only 6% of pAD p atients, revealed P300 abnormalities. In the cAD, but not in the pAD p atients, the P300 latencies were especially prolonged in the older pat ients, 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 d emonstrated by P300 potentials, even nondemented arteriosclerotic pati ents reveal signs of subtle cognitive dysfunction affecting especially the older cAD patient. In the short-term, carotid endarterectomy pres umably improves cognitive functions unspecifically in nondemented pati ents with a higher initial degree of P300 abnormality.