Electroencephalographic Changes Resulting From Carotid Artery Compression

Abstract

THE VALUE of electroencephalography in clinical work is reflected in the vast literature which has developed on this subject since Berger's original report in 1929. It has become apparent, however, that if the diagnostic value of electroencephalography is to be extended, activation techniques must be developed and assessed. One must alter the resting tracing by physiological or pharmacological means if one is to obtain additional information. Although this was appreciated in part at an early stage in the case of hyperventilation, other methods of activation have been investigated only within the past few years. Such techniques must be studied in a systematic fashion if their indications, potentialities, and limitations are to be fully understood.Among the various methods of activation being tried in our laboratory, cerebral hypoxia as produced by carotid artery compression has shown some promise, and it is the purpose of the present report to record our initial results with this technique. That cerebral function is greatly affected by acute anoxia is not surprising, con¬ sidering that the brain, although only 2% of the body weight, requires 14% of the total cardiac output and uses approximately 22% of the total oxygen consumption of the body.1 Numerous workers * have shown that cerebral hypoxia may be reflected in changes of the electroencephalogram. Engel and Romano 10 observed that the EEG ' improved when 100% oxygen was given to delirious patients with either heart or pulmonary failure, Cheyne-Stokes respiration, or anemia. Similarly, the EEG of patients with severe anemia was found to improve after blood transfusion. Engel, Webb, and Ferris 11 reported the significant changes in frequency distribution which occur at altitudes of 10,000 ft. (3,000 meters) and progressively increase at higher altitudes.There are several reports in the literature concerning EEG changes after carotid artery ligation.f Digital occlusion of the ipsilateral carotid artery in a case of carotidcavernous aneurysm 14 produced loss of consciousness, contralateral Jacksonian seizures, and marked delta activity over the ipsilateral hemisphere 8 to 10 seconds after the occlusion ; incomplete compression and carotid sinus massage produced no changes. Carotid compression repeatedly applied during a six-month period con¬ tinued to give the same results.

Assessment of the capacity of cerebral collateral circulation using ultrasonic Doppler technique.

“…The present study has also pointed out that there is a linear correlation between the per cent increase in both internal carotid and vertebral artery flows and the value of MABP. Skillicorn and Aird (1954) made clear that EEG abnormalities during carotid compression occurred more frequently in older patients than in the young. Meyer et al (1965) suggested that the capacity of cerebral collateral circulation appeared to decrease with advancing age and with cerebrovascular disease.…”