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EEG seizure patterns during multiple unilateral and bilateral ECT
EEG Seizure Patterns During Multiple Unilateral and Bilateral ECT Richard
Abrams,
Jan Volavka,
and Max Fink
U
NILATERAL AND BILATERAL ECT (U/ECT, B/ECT) have different effects on clinical outcome 1,4 memory functions,7 and the interseizure EEG.“” These memory and EEG effects are readily attributed to differences in placement of treatment electrodes for the two methods, but as both methods induce generalized seizures the differences in therapeutic effect remain unaccounted for. A clinical study of multiple U/ECT and B/ECT3 provided an opportunity to examine the EEG seizure patterns for the two methods, and to assess the report of Blachly and Gowing (1966) on seizure characteristics during multiple ECT. The clinical effects of multiple ECT have been described;7 It is the purpose of this communication to characterize the seizure patterns elicited during multiple ECT with bilateral or unilateral treatment electrode placement. MATERIALS
AND
METHODS
The study was done at Gracie Square Hospital, a private institution in New York City. Patients with diagnoses of depressive psychosis or schizophrenia were referred for MECT by their attending psychiatrist, who chose the method of electrode placement (unilateral or bilateral). After premeditation with atropine, patients were anesthetized with methohexital, followed by succinylcholine relaxation, and given three or four consecutive electrically-induced convulsions spaced two to three minutes apart, with nondominant unilateral or bilateral electrode placement. Each treatment session lasted about 20 minutes. Seizures were recorded during treatment using a four channel Grass model 79 polygraph. Early in the study only a bifrontal derivation (F,-F,) was used. Later in the study, left and right frontocentral montages were recorded (F,-C,; F,-C,). There was some variation in recording technique, but most records were obtained at a paper speed of 15 cm/set, sensitivity of 15 mVolt/cm, and time constant of 0.3 seconds. During the passage of current the patient was isolated from the recording amplifiers by moving the selector switch from “use” to “Cal.” Nonetheless, the amplifiers remained blocked during the period of condenser discharge and the first 15 seconds of each seizure was obscured. R ESU LTS
Eighteen patients were treated, ranging in age from 24 to 82 years of age (mean, 55.1 years). There were 13 patients with depressive illness and five with schizophrenia. A total of 160 seizures were recorded during 45 sessions of MECT. Seizure
Duration
One hundred thirty-nine records were technically adequate for measuring seizure duration. Table 1 shows that seizures with B/ECT were about 10 seconds longer than those of U/ECT. From the Division of Biological Psychiatry, Department of Psychiatry, New York Medical College, 5 East IO2 Street, New York, N. Y. 10029 Richard Abrams, M.D.: Assistant Professor of Psychicltry; Jan Volavka, M.D.: Associate Professor of Psychiatry; Max Fink, M.D.: Professor of Psychiatry, Department of Psychiatry, New York Medical College, New York, N. Y. Supported in part by MH 15561 to the International Association for Psychiatric Research, Inc. 01973 by Crune & Stratton, Inc. Comprehensive
Psychiatry,
Vol. 14, No. 1 (January/February),
1973
25
26
ABRAMS,
Table 1. Seizure Duration
Electrode
for Unilateral
Placement
Number of Seizures 124
51.5 * 25.2
15
61.9 f 18.3
Bilateral d.f.=138;p
AND
FINK
ECT IN=1391
Mean Seizure Duration (set)
Unilateral
t=1.98;
and Bilateral
VOLAVKA,
< 0.025.
We also examined seizure duration with regard to the ordinal position of the seizure in the treatment session. There were 37 sessions of MECT containing at least three seizures in which accurate duration could be measured. We compared the duration of the first and the last seizure of each session, and found that in 25/37 sessions the last seizure was longer than the first (Xf = 3.88, d.f. = 1;~ < 0.05).
Seizure Termination This was determined only for those technically adequate records with left and right (F,-C,; Fs-C,) derivations (N = 57). The seizure termination was judged precise or imprecise by visual estimation of the clarity with which seizure and postseizure activity could be differentiated. A precise end-point occurred when the typical 2-3 Hz spike and wave activity was abruptly replaced by the post-seizure pattern (either electrical silence, or mixed alpha/beta activity.) An imprecise end-point was seen when the seizure activity gradually diminished in amplitude and frequency, blending imperceptibly over many seconds with the post-seizure activity. U/ECT and B/ECT did not differ in the clarity of seizure end-point (Table 2). To assess the relation between the ordinal position of seizures in a session and the clarity of the seizure end-point, we examined all technically adequate recordings in which the first and last seizure of a session showed both sides ending in the same pattern (N = 31). Unlike Blachly and Gowing’ we found a strong trend toward an increase in end-point clarity for the fourth seizure compared with the first seizure each session (Table 3). Thus, in only six of 31 fits was the last (fourth) seizure less clearly terminated than the first.
Postseizure Activity For records with a clear seizure end-point the postseizure record was classed as either “flat” (isoelectric with very low voltage slow potentials) or predominantly mixed alpha/beta activity. Table 4 shows that such flat records occurred more often after B/ECT than U/ECT. When flat postseizure activity was seen only on one side of the head with unilateral ECT (N = 5), the flat record always occurred on the side of treatment electrode placement.
Table 2. Seizure End-Point
Clarity for Unilateral
and Bilateral
ECT (N = 57)
Method
Both Sides Precise
Neither Side Precise
Mixed
Unilateral Bilateral
30 13
4 1
8‘ 1
*Six of eight showed a precise end-point X2 = 1.4: d.f. = 2: n.s.
on the “treated”
side.
EEG SEIZURE
27
PATTERNS
Table 3.
Precision of Seizure End-Point Treatment
for the First and Fourth
Seizure of Each
Session (N = 31)
Precision of Seizure End-Point First > Fourth
First = Fourth
6
9
Fourth
> First
16
X,’ = 4.8; d.f. = 2; 0.1 > p > 0.05. Table 4.
Distribution
of “Flat”
and B/ECT
Post-ECT
EEGs for WECT
(N = 58)
“Flat”
Placement of Electrodes
Postseizure Activiry Neither Side or Mixed Both Sides
Unilateral
6
Bilateral
13
37 2
Xc’ = 26.8; d.f. = 1; /.I < 0.01.
DISCUSSION
We are unable to confirm the observation of Blachly and Cowing’ of a decrease in precision of seizure end-point with successive seizures. We found a trend in the opposite direction. We did confirm their observation of increased seizure duration within a treatment session for multiple ECT, and we believe this results from the diminishing cerebral effects over time of the short-acting barbiturate administered for anesthesia. Termination of bilateral-induced seizures in electrical silence may represent the pattern of a “fully developed” grand ma1 seizure; this pattern of termination is seen with spontaneous seizures, as well as those induced with pentylenetetrazol or flurothyl (Chatrian and Petersen, 1960). The tendency for unilateral-induced seizures to terminate in mixed alpha/beta activity was also observed by Small, Small, and Perez.g This pattern of termination may reflect a seizure for U/ECT which is somehow incomplete. Such a pattern was seen by Kirstein and Ottosson (1960) for lidocaine-modified seizures, which were also shorter in duration and less therapeutically effective than conventional seizures with bilateral electrode placement. The shorter duration of seizures with U/ECT is consonant with the postulated “incompleteness” of such fits, which may be related to the reported reduced therapeutic action of U/ECT compared to B/ECT. 3*4 This hypothesis remains to be tested, as we did not examine the relation of seizure duration to clinical outcome in the present study. SUMMARY
One hundred sixty electrically induced seizures were recorded by EEG during 45 treatment sessions in 18 patients. Patients received three to four seizures each session, with unilateral or bilateral electrode placement. Records were examined visually for seizure duration, pattern, and type of post-seizure activity. Seizures with U/ECT were shorter than for B/ECT, and were less frequently followed by a period of electrical silence, tending to end in alpha/beta activity. These observations for U/ECT are similar to those reported in the past for lidocainemodified seizures, which were noted to be less clinically effective than conventional bilateral-induced seizures.
28
ABRAMS,
It is postulated that seizures with U/ECT are “incomplete,” the reported reduced therapeutic efficacy for U/ECT.
VOLAVKA,
AND
FINK
accounting
in part, for
ACKNOWLEDGMENT We are grateful to the Director and Staff of Gracie Square Hospital in New York for their cooperation in making this study possible. REFERENCES 1. Abrams, R., Volavka, J., Roubicek, J., Dornbush, R., and Fink, M.: Lateralized EEG changes after unilateral and bilateral electroconvulsive therapy. Dis. Nerv. Syst. (GWAN Suppl.) 31:28, 1970. 2. -: Recent clinical studies of ECT. Sem. Psychiat. 4:3, 1972. 3. -, and Fink, M.: Clinical experiences with multiple electroconvulsive treatments. Compr. Psychiat. 13:115, 1972. 4. -, -, Dornbush, R., Feldstein, S., Volavka, J., and Roubicek, J.: Unilateral and bilateral ECT: effects on depression, memory and the electroencephalogram. Arch. Gen. Psychiat. (In press). 5. Blachly, P. H., and Gowing, D.: Multiple monitored electroconvulsive treatment. Compr. Psychiat. 7: 100, 1966. 6. Chatrian, G. E., and Petersen, M. C.: The convulsive patterns provoked by Indoklon, Metrazol and electroshock: some depth electro-
graphic observations in human patients. Electroencephalogr. Clin. Neurophysiol. 12:715, 1960. 7. Dornbush, R., Abrams, R., and Fink, M.: Memory changes after unilateral and bilateral convulsive therapy (ECT). Br. J. Psychiat. 119:75,1971. 8. Kirstein, L., and Ottosson, J. 0.: Experimental studies of electroencephalographic changes following electroconvulsive therapy. Acta. Psychiat. Neurol. Stand. (Suppl.) 145:7, 1960. 9. Small, J. G., Small, I. F., and Perez, H. C.: Electroencephalographic (EEG) and neurophysiological studies of electrically induced seizures. J. Nerv. Ment. Dis. 150:479, 1970. 10. Volavka, J., Feldstein, S., Abrams, R., Dornbush, R., and Fink, M.: EEG and clinical change after bilateral and unilateral electroconvulsive therapy. Electroencephalogr. Clin. Neurophysiol. 32:631, 1972.
Abrams,
Jan Volavka,
and Max Fink
U
NILATERAL AND BILATERAL ECT (U/ECT, B/ECT) have different effects on clinical outcome 1,4 memory functions,7 and the interseizure EEG.“” These memory and EEG effects are readily attributed to differences in placement of treatment electrodes for the two methods, but as both methods induce generalized seizures the differences in therapeutic effect remain unaccounted for. A clinical study of multiple U/ECT and B/ECT3 provided an opportunity to examine the EEG seizure patterns for the two methods, and to assess the report of Blachly and Gowing (1966) on seizure characteristics during multiple ECT. The clinical effects of multiple ECT have been described;7 It is the purpose of this communication to characterize the seizure patterns elicited during multiple ECT with bilateral or unilateral treatment electrode placement. MATERIALS
AND
METHODS
The study was done at Gracie Square Hospital, a private institution in New York City. Patients with diagnoses of depressive psychosis or schizophrenia were referred for MECT by their attending psychiatrist, who chose the method of electrode placement (unilateral or bilateral). After premeditation with atropine, patients were anesthetized with methohexital, followed by succinylcholine relaxation, and given three or four consecutive electrically-induced convulsions spaced two to three minutes apart, with nondominant unilateral or bilateral electrode placement. Each treatment session lasted about 20 minutes. Seizures were recorded during treatment using a four channel Grass model 79 polygraph. Early in the study only a bifrontal derivation (F,-F,) was used. Later in the study, left and right frontocentral montages were recorded (F,-C,; F,-C,). There was some variation in recording technique, but most records were obtained at a paper speed of 15 cm/set, sensitivity of 15 mVolt/cm, and time constant of 0.3 seconds. During the passage of current the patient was isolated from the recording amplifiers by moving the selector switch from “use” to “Cal.” Nonetheless, the amplifiers remained blocked during the period of condenser discharge and the first 15 seconds of each seizure was obscured. R ESU LTS
Eighteen patients were treated, ranging in age from 24 to 82 years of age (mean, 55.1 years). There were 13 patients with depressive illness and five with schizophrenia. A total of 160 seizures were recorded during 45 sessions of MECT. Seizure
Duration
One hundred thirty-nine records were technically adequate for measuring seizure duration. Table 1 shows that seizures with B/ECT were about 10 seconds longer than those of U/ECT. From the Division of Biological Psychiatry, Department of Psychiatry, New York Medical College, 5 East IO2 Street, New York, N. Y. 10029 Richard Abrams, M.D.: Assistant Professor of Psychicltry; Jan Volavka, M.D.: Associate Professor of Psychiatry; Max Fink, M.D.: Professor of Psychiatry, Department of Psychiatry, New York Medical College, New York, N. Y. Supported in part by MH 15561 to the International Association for Psychiatric Research, Inc. 01973 by Crune & Stratton, Inc. Comprehensive
Psychiatry,
Vol. 14, No. 1 (January/February),
1973
25
26
ABRAMS,
Table 1. Seizure Duration
Electrode
for Unilateral
Placement
Number of Seizures 124
51.5 * 25.2
15
61.9 f 18.3
Bilateral d.f.=138;p
AND
FINK
ECT IN=1391
Mean Seizure Duration (set)
Unilateral
t=1.98;
and Bilateral
VOLAVKA,
< 0.025.
We also examined seizure duration with regard to the ordinal position of the seizure in the treatment session. There were 37 sessions of MECT containing at least three seizures in which accurate duration could be measured. We compared the duration of the first and the last seizure of each session, and found that in 25/37 sessions the last seizure was longer than the first (Xf = 3.88, d.f. = 1;~ < 0.05).
Seizure Termination This was determined only for those technically adequate records with left and right (F,-C,; Fs-C,) derivations (N = 57). The seizure termination was judged precise or imprecise by visual estimation of the clarity with which seizure and postseizure activity could be differentiated. A precise end-point occurred when the typical 2-3 Hz spike and wave activity was abruptly replaced by the post-seizure pattern (either electrical silence, or mixed alpha/beta activity.) An imprecise end-point was seen when the seizure activity gradually diminished in amplitude and frequency, blending imperceptibly over many seconds with the post-seizure activity. U/ECT and B/ECT did not differ in the clarity of seizure end-point (Table 2). To assess the relation between the ordinal position of seizures in a session and the clarity of the seizure end-point, we examined all technically adequate recordings in which the first and last seizure of a session showed both sides ending in the same pattern (N = 31). Unlike Blachly and Gowing’ we found a strong trend toward an increase in end-point clarity for the fourth seizure compared with the first seizure each session (Table 3). Thus, in only six of 31 fits was the last (fourth) seizure less clearly terminated than the first.
Postseizure Activity For records with a clear seizure end-point the postseizure record was classed as either “flat” (isoelectric with very low voltage slow potentials) or predominantly mixed alpha/beta activity. Table 4 shows that such flat records occurred more often after B/ECT than U/ECT. When flat postseizure activity was seen only on one side of the head with unilateral ECT (N = 5), the flat record always occurred on the side of treatment electrode placement.
Table 2. Seizure End-Point
Clarity for Unilateral
and Bilateral
ECT (N = 57)
Method
Both Sides Precise
Neither Side Precise
Mixed
Unilateral Bilateral
30 13
4 1
8‘ 1
*Six of eight showed a precise end-point X2 = 1.4: d.f. = 2: n.s.
on the “treated”
side.
EEG SEIZURE
27
PATTERNS
Table 3.
Precision of Seizure End-Point Treatment
for the First and Fourth
Seizure of Each
Session (N = 31)
Precision of Seizure End-Point First > Fourth
First = Fourth
6
9
Fourth
> First
16
X,’ = 4.8; d.f. = 2; 0.1 > p > 0.05. Table 4.
Distribution
of “Flat”
and B/ECT
Post-ECT
EEGs for WECT
(N = 58)
“Flat”
Placement of Electrodes
Postseizure Activiry Neither Side or Mixed Both Sides
Unilateral
6
Bilateral
13
37 2
Xc’ = 26.8; d.f. = 1; /.I < 0.01.
DISCUSSION
We are unable to confirm the observation of Blachly and Cowing’ of a decrease in precision of seizure end-point with successive seizures. We found a trend in the opposite direction. We did confirm their observation of increased seizure duration within a treatment session for multiple ECT, and we believe this results from the diminishing cerebral effects over time of the short-acting barbiturate administered for anesthesia. Termination of bilateral-induced seizures in electrical silence may represent the pattern of a “fully developed” grand ma1 seizure; this pattern of termination is seen with spontaneous seizures, as well as those induced with pentylenetetrazol or flurothyl (Chatrian and Petersen, 1960). The tendency for unilateral-induced seizures to terminate in mixed alpha/beta activity was also observed by Small, Small, and Perez.g This pattern of termination may reflect a seizure for U/ECT which is somehow incomplete. Such a pattern was seen by Kirstein and Ottosson (1960) for lidocaine-modified seizures, which were also shorter in duration and less therapeutically effective than conventional seizures with bilateral electrode placement. The shorter duration of seizures with U/ECT is consonant with the postulated “incompleteness” of such fits, which may be related to the reported reduced therapeutic action of U/ECT compared to B/ECT. 3*4 This hypothesis remains to be tested, as we did not examine the relation of seizure duration to clinical outcome in the present study. SUMMARY
One hundred sixty electrically induced seizures were recorded by EEG during 45 treatment sessions in 18 patients. Patients received three to four seizures each session, with unilateral or bilateral electrode placement. Records were examined visually for seizure duration, pattern, and type of post-seizure activity. Seizures with U/ECT were shorter than for B/ECT, and were less frequently followed by a period of electrical silence, tending to end in alpha/beta activity. These observations for U/ECT are similar to those reported in the past for lidocainemodified seizures, which were noted to be less clinically effective than conventional bilateral-induced seizures.
28
ABRAMS,
It is postulated that seizures with U/ECT are “incomplete,” the reported reduced therapeutic efficacy for U/ECT.
VOLAVKA,
AND
FINK
accounting
in part, for
ACKNOWLEDGMENT We are grateful to the Director and Staff of Gracie Square Hospital in New York for their cooperation in making this study possible. REFERENCES 1. Abrams, R., Volavka, J., Roubicek, J., Dornbush, R., and Fink, M.: Lateralized EEG changes after unilateral and bilateral electroconvulsive therapy. Dis. Nerv. Syst. (GWAN Suppl.) 31:28, 1970. 2. -: Recent clinical studies of ECT. Sem. Psychiat. 4:3, 1972. 3. -, and Fink, M.: Clinical experiences with multiple electroconvulsive treatments. Compr. Psychiat. 13:115, 1972. 4. -, -, Dornbush, R., Feldstein, S., Volavka, J., and Roubicek, J.: Unilateral and bilateral ECT: effects on depression, memory and the electroencephalogram. Arch. Gen. Psychiat. (In press). 5. Blachly, P. H., and Gowing, D.: Multiple monitored electroconvulsive treatment. Compr. Psychiat. 7: 100, 1966. 6. Chatrian, G. E., and Petersen, M. C.: The convulsive patterns provoked by Indoklon, Metrazol and electroshock: some depth electro-
graphic observations in human patients. Electroencephalogr. Clin. Neurophysiol. 12:715, 1960. 7. Dornbush, R., Abrams, R., and Fink, M.: Memory changes after unilateral and bilateral convulsive therapy (ECT). Br. J. Psychiat. 119:75,1971. 8. Kirstein, L., and Ottosson, J. 0.: Experimental studies of electroencephalographic changes following electroconvulsive therapy. Acta. Psychiat. Neurol. Stand. (Suppl.) 145:7, 1960. 9. Small, J. G., Small, I. F., and Perez, H. C.: Electroencephalographic (EEG) and neurophysiological studies of electrically induced seizures. J. Nerv. Ment. Dis. 150:479, 1970. 10. Volavka, J., Feldstein, S., Abrams, R., Dornbush, R., and Fink, M.: EEG and clinical change after bilateral and unilateral electroconvulsive therapy. Electroencephalogr. Clin. Neurophysiol. 32:631, 1972.