Electroconvulsive Therapy: Seizure Monitoring

Electroconvulsive Therapy: Seizure Monitoring

Monitoring of Motor Response
Seizure monitoring has long been an integral component of ECT technique (Weiner et al. 1991). Traditionally, this monitoring has consisted of the detection of the presence and duration of the motor convulsive response. Because of the effects of muscle relaxation, it is usually necessary to prevent the flow of the muscle relaxant to a hand or foot, by means of a blood pressure cuff inflated above systolic pressure, just before infusion of the drug. Generally, it is best to place the cuff on the right ankle when RUL ECT is given, because monitoring on the right will help ensure that the seizure has generalized to both sides of the brain.

Monitoring of Electroencephalographic Response
The seizure produced with ECT involves the intense and highly synchronous discharge of neurons throughout the cerebral hemispheres. It is now recognized that the best way to monitor this process is the use of scalp-recorded electroencephalography (EEG) (American Psychiatric Association Committee on ECT 2000; Weiner et al. 1991). The EEG seizure is typically longer in duration than the ictal motor response. Although the mean difference is only 10-15 seconds, the difference in duration in certain individuals may be much greater, and prolonged seizures can easily be missed when EEG monitoring is not available. For these reasons, single- or double-channel EEG monitoring capability is now incorporated into most ECT devices made in the United States. For a single EEG channel, one recording electrode should be placed with its center located approximately an inch above the midpoint of the patient's left eyebrow, and the second electrode should be placed on the left upper mastoid region. This placement allows the practitioner to ensure that a RUL ECT seizure has generalized to both cerebral hemispheres. With two EEG channels, the additional two electrodes can be placed over the right hemisphere in an analogous fashion. Use of two channels allows seizure symmetry to be observed and provides backup in cases when there are substantial EEG artifacts.

Electroconvulsive Therapy Introduction Indications