Abstract
Background:
The memory-related side-effects rank among the strongest reasons for hostility against Modified Electroconvulsive Therapy (MECT). Most of the studies comparing the Unilateral v/s Bilateral Electrode placements on memory have been conducted on patients with depression while very few studies have been conducted on patients with psychosis in the Indian population.
Aim:
To compare the effects of right unilateral (RU/L) and bilateral (B/L) MECT on the severity of symptoms as well as memory in patients with psychosis after the fourth session and two weeks after the final session of the MECT.
Materials and Methods:
One hundred patients having a psychotic illness were randomized into either RU/L or B/L group. Comprehensive psychopathological rating scale (CPRS), clinical global impressions scale (CGI-S), and PGI-memory scale were applied before starting of MECT, after four sessions of MECT and two weeks after the last session of ECT.
Results:
The results show similar symptomatic improvement in patients receiving RU/L and B/L MECT and the results persisted beyond the therapy sessions. But, in the case of RU/L-MECT group, the deterioration in memory was less as compared to the B/L-MECT group. Both groups had no significant difference in psychopathology and its severity (CPRS and CGI). Both groups were significantly different in memory side effects after the fourth session and two weeks after the last session. Both groups showed a consistent downward trend in psychopathology and its severity. The consistent fall in the total PGI scores remained even after two weeks of the final session in the B/L group (total of six points as compared to baseline) while it came to baseline levels in the RU/L group. Both groups differed significantly in total PGI scores after the fourth session and two weeks after the final session.
Conclusion:
This study points toward a favorable outcome in the case of therapeutic response with MECT without any significant difference between both types of electrode placements and even after stopping MECT, the improvement appears to be stable over time. Although, there was a side-effect of memory impairment, it appears to be for a shorter duration and it improves with time. The side-effect profile of RU/L electrode placement is lower as compared to bilateral placement. In the post-MECT period, the patients receiving MECT with RU/L electrode placement showed better improvement in memory functions.
Keywords: Memory impairment, modified electroconvulsive therapy, right unilateral and bilateral electrode placement
Few treatments in modern-day clinical practice are as old as Electroconvulsive Therapy (ECT). Although it took birth before the introduction of modern drugs, ECT has not only survived the great strides in drug therapy post the 1950s, it has made significant progress and established its place in psychiatric practice. Electroconvulsive Therapy has evoked several debates; at one end is considered barbaric and at the other, the most potent antidepressant therapy. Human rights activists have also spoken against ECT; alleging that it was often used in the psychiatrically ill who were unable to provide consent.[1]
A significant challenge that remains is that the precise therapeutic mechanism of ECT is still unknown. The question remains as to whether the several mooted mechanisms are merely epiphenomena or true therapeutic mechanisms. This matter is compounded by our limited understanding of the pathophysiological basis of the mental disorders treated by ECT including depression, mania, and schizophrenia.[1] Modified Electroconvulsive therapy (MECT) is an effective treatment for patients with severe and medication-resistant psychiatric illnesses. There has been a longstanding controversy as to whether Right Unilateral (RU/L) ECT achieves the efficacy of Bilateral (B/L) ECT. However, ECT may have adverse effects on memory and other cognitive functions. Patients experience a variable period of disorientation after each treatment and may have difficulty remembering new information for several weeks after the treatment course (anterograde amnesia). Short-term cognitive deficits have been found to be greater with bilateral (B/L) than RU/L electrode placement.[2] This difference may extend to long-term cognitive effects.[3] There may also be persistent memory gaps for events that occurred before the treatment course (retrograde amnesia).
Data shows that almost all patients are back to their baseline cognition after six months. Some patients complain of persistent memory difficulties. Memory impairment and time to return to baseline cognitive functioning are directly proportional to the intensity of an electrical stimulus. No evidence has been found on the fact that whether ECT causes brain damage or not. While moderately suprathreshold stimulation (e.g. 1.5 × ST) is effective for bitemporal ECT (B/L),[4] substantially higher charges are required for RU/L ECT to approach the antidepressant effectiveness of B/L.[2,5] These higher charges of unilateral ECT may result in more deficits than lower charges.[6] A recent meta-analysis of cognitive outcomes following ECT confirmed that electrode placement is a significant moderator of performance, with unilateral ECT being associated with fewer cognitive side-effects of B/L treatments (e.g. U/L followed by B/L) in some cognitive domains.[7] From the time when ECT was blamed for its brain-damaging effects to ECT-induced neuroplasticity being touted as therapeutic, ECT has traversed a long and successful journey of 75 years.
Sackeim et al.[8] found the final remission rate, cognitive side effects, and memory deficits for ultrabrief UL-ECT better than ultrabrief BL-ECT, standard pulse-width BL-ECT, and standard pulse-width UL-ECT in patients having major depression. Rajagopalan et al.[9] studied the effect of MECT on cognitive functions and found no significant decline. Kessler et al.[10] found that general neurocognitive function was unaffected by RU/L brief-pulse ECT and positively related to improved mood in bipolar depression. Semkovska et al.[7] also found better results for U/L-ECT. But, most of these studies have been conducted on patients having depression. Many studies on other indications for ECT are lacking. This study was conceptualized to see the effects of U/L and B/L ECT on symptoms and memory in psychotic patients, and whether these effects are consistent even after stopping ECT. The present study aimed to compare the effects of unilateral and bilateral ECT on the symptoms and memory in different illnesses after the fourth session of ECT, and the reappearance of symptoms and improvement in memory after two weeks of the final session of ECT.
MATERIALS AND METHODS
The study was conducted at a tertiary referral center for psychiatric patients with a wide catchment area in eastern India. The study was approved by the Institutional Ethical Committee. All subjects gave informed consent.
Study design
The study was a prospective, hospital-based randomized, and double-blind study.
Sample size
The sample consisted of 100 psychotic patients who were randomly divided into two groups (50 in each group)—one receiving RU/L and the other group receiving bilateral ECT.
Sampling method
The study was done through purposive sampling which was followed by randomization into two groups—one receiving RU/L ECT and the other receiving Bilateral ECT.
Inclusion criteria
Patient of either sex.
Aged between 18 and 60 years.
Those having clinical indications for ECT.
Formal education up to fifth standard.
Those who give informed consent.
Exclusion criteria
Mental retardation.
Neurological diseases including epilepsy.
ECT within the past six months.
Severe medical illness.
Patients with contraindications for modified ECT.
Tools
Sociodemographic and clinical data sheet
It was a semi-structured proforma for recording demographic details like age, sex, marital status, religion, education, occupation, socioeconomic status, and residence as well as clinical data such as the age of onset, duration of ill, and past history as well as family history.
Comprehensive Psychopathological Rating Scale (CPRS)
The CPRS was used to assess the present psychiatric state, severity of symptoms, and change in symptoms over time.[11]
Clinical Global Impressions (CGI) Scale
The CGI scale was used to assess the severity of the illness.[12]
PGI-Memory Scale (PGI-MS)[13] was used as a comprehensive and simple scale to measure verbal and non-verbal memories based on neurological theory.
Mecta spectrum 5000q ECT machine
It offered maximum flexibility to treat with four individual parameter sets of pulse width, frequency, duration, and current. The treatment dosage was set using the four knobs beneath the LCD touchscreen so that the user could easily see and quickly choose the best treatment option to maximize efficacy and reduce side effects.
Procedure
The sample was drawn from patients admitted to the institute who had been diagnosed with any psychotic illness after a detailed history and mental status examination by the consultant or senior resident (both trained psychiatrists). Patients having indications for ECT were selected according to inclusion and exclusion criteria. Written informed consent from the patients was taken after explaining the objectives and procedure of the study in detail. Relevant sociodemographic and clinical data were collected from all the participants on the socio-demographic and clinical data sheet. The baseline severity of psychopathology in patients was evaluated by administering the Comprehensive Psychopathological Rating Scale.[11] The severity of the illness was assessed with the Clinical Global Improvement Severity Scale[12] and the memory functions were assessed using PGI-Memory Scale.[13] Recruited sample for the study was randomly allocated into one of the two groups—RU/L ECT or B/L ECT. The double blinding technique was used for removing the effect of bias.
Randomization, allocation concealment, and blinding
Patients were randomized using a random computer-generated number table, to receive either RU/L or bilateral MECT (see below for the whole MECT procedure that was used in the study). The assessor, patients, and their family members were kept strictly blind to the randomization status throughout the study. The assessor was not present in the ECT chamber during the procedure to ensure blinding and they also had no access to MECT records. The investigator who generated the random number sequence did not involve in the recruitment of the patients. The random sequence was kept concealed and the allotment status of the patients was revealed only to the junior resident posted in the MECT duty.
MECT PROCEDURE: After doing a detailed Pre-MECT evaluation, the patient was kept nil per oral for six hours before ECT. Benzodiazepines and other seizure threshold-increasing drugs were deferred until after the ECT session. The patient was encouraged to pass urine to prevent bladder rupture during MECT. Hair was kept dry and clean. After ensuring that the patient had been prepared adequately for the procedure, an IV cannula was inserted, preferably in the left upper limb. Injection Glycopyrrolate and Metoclopropamide were then given. The anaesthetic agent, thiopentone was injected slowly intravenously. The muscle relaxant, succinylcholine was administered, after isolating a right foot by applying a cuff. Pulse oximetry was used to guide ventilation, and vitals were monitored. Ultrabrief pulse was used for ECT. The threshold was assessed by gradual titration in the first session and the stimulus provided at the desired intensity in subsequent sessions. As the cerebral oxygen demand markedly increases during the seizure, oxygenation was commenced during the seizure and stopped only when the patient had resumed spontaneous and regular respirations. Seizure duration was measured after giving the stimulus. In case of missed seizure, a stimulus of higher intensity was given after ensuring that the patient was still under anaesthesia. Once the patient started breathing spontaneously, routine post-ictal care was initiated with monitoring of the airway, breathing, and circulation. Sessions were given thrice weekly. After the fourth session of ECT, all the scales were applied again to see the change through the treatment. The decision for stopping ECT was taken by the treating team according to the desired outcome. Scales were applied for the third time after two weeks of the last ECT session to see for results sustainment after stopping ECT.
Statistical analysis
The results obtained were analyzed by using the computer software program, Statistical Package for Social Sciences version 25.0 (SPSS-25.0) for Windows®, with different parametric, and non-parametric measures being used. Description of sample characteristics was done with descriptive statistics—percentage, mean, and standard deviation. Group differences for baseline sample characteristics were examined with an independent t-test for continuous data and a Chi-square test for nominal data. The Kolmogorov–Smirnov test was applied to check for the normal distribution of the data. The data did not fulfill the assumptions for parametric tests. For comparison between the two groups, Mann–Whitney U test was applied and for in-between group differences over time, Freedman’s test was applied. The post hoc test for both unilateral and bilateral groups for four parameters (CPRS, Clinical Global Improvement (CGI-S), total PGI memory score) using Wilcoxon Signed Ranks Test and Bonferroni correction[14] (as there were three subgroup analyzes, therefore significance level was kept at 0.017).
RESULTS
The two groups that received MECT had no differences in sociodemographic factors [Table 1]. The two groups were matched while doing the randomization along with allocation concealment to remove the bias on results that can arise due to differences in age, socioeconomic strata, religion, gender, living conditions, psychiatric diagnosis, family history, and mean years of schooling. The mean age in the unilateral MECT (U/L) group was 28.44 years, while the mean age in the bilateral MECT (B/L) group was 30.6 years [Table 1]. The difference in the mean age and age of onset of the participants (21.78 years in U/L v/s 22.60 years in B/L) was statistically insignificant. The difference in other variables didn’t reach a statistically significant level. Both groups were similar in their baseline characteristics [Table 1]. The difference in CPRS scores in all three groups at baseline, after the fourth session, and two weeks after the last MECT session was statistically insignificant. Psychopathological scores were lower in the B/L MECT group, but the difference was statistically insignificant [Table 2]. Although intra-group comparison at all the three points reached statistically significant levels with Bonferroni correction, The ratings on the CPRS scale fell significantly as compared to the baseline (UL group = 28.2 vs. B/L group = 29.4). [Table 3; Freedman statistic = 100; P value = 0.000]. A post hoc test revealed sequential benefit as the CPRS rating fell by 68 points, pointing towards the benefit of the full course of MECT (Wilcoxon signed rank test = -6.158 U/L vs. 6.157; P = 0.000) [Table 4]. Clinical Global Improvement was applied for the assessment of the severity of the illness, and the two groups didn’t differ significantly across all assessment points in time [Table 2]. The intragroup comparison revealed a significant decrease in CGI-S scores in both groups (UL vs. B/L), with maximum benefit after the full course of the treatment [Table 3]. The post hoc test also revealed the maximum difference between the two groups at two weeks after the last MECT session [Table 5]. The total PGI memory scores reached baseline levels in the U/L group [Table 3], while there was a constant significant drop in total scores in the B/L group [Table 3]. A post hoc test revealed that the greatest drop in total PGI scores was at the fourth session in both groups (UL vs. B/L) [Table 6]. The scores came to the baseline levels after two weeks of the last session in the U/L group, but there was a six-point drop in the total PGI memory scale score in the B/L group [Table 6].
Table 1.
Comparison of sociodemographic variables between the two groups
| Characteristics | Right Unilateral ECT (n=50) | Bilateral ECT (n=50) | t-test/Chi-square test (c)/fisher’s exact (f) | df | P |
|---|---|---|---|---|---|
| Age (years) | |||||
| Mean±SD | 28.44±9.16 | 30.60±9.93 | -1.13 | 98 | 0.261 |
| Family income (Rupees/month) | |||||
| Mean±SD | 10020.00±6610.11 | 10560.00±8114.38 | -0.36 | 98 | 0.176 |
| Age of Onset (years) | |||||
| Mean±SD | 21.78±6.29 | 22.60±7.42 | -0.59 | 98 | 0.553 |
| Mean years of schooling (in years) | |||||
| Mean±SD | 10.48 | 9.72 | 1.14 | 98 | 0.253 |
| Sex | |||||
| Male | 36 (72%) | 37 (74%) | 0.51 (c) | 1 | 1.000 |
| Female | 14 (28%) | 13 (26%) | |||
| Marital status | |||||
| Married | 21 (42%) | 27 (54%) | 1.44 (c) | 1 | 0.317 |
| Unmarried | 29 (58%) | 23 (46%) | |||
| Religion | |||||
| Hindu | 41 (82%) | 43 (86%) | 0.29 (c) | 1 | 0.786 |
| Others | 9 (18%) | 7 (14%) | |||
| Residence | |||||
| Rural | 33 (66%) | 40 (80%) | 2.48 (c) | 1 | 0.176 |
| Urban | 17 (34%) | 10 (20%) | |||
| Occupation | |||||
| Employed | 19 (38%) | 21 (42%) | 0.16 (c) | 1 | 0.838 |
| Unemployed | 31 (62%) | 29 (58%) | |||
| Diagnosis | |||||
| Affective | 24 (48%) | 29 (58%) | 1.01 (c) | 1 | 0.423 |
| Non-Affective | 26 (52%) | 21 (42%) | |||
| Family history of Psychiatric Illness | |||||
| Present | 4 (8%) | 3 (6%) | 0.15 (f) | 1 | 1.000 |
| Absent | 46 (92%) | 47 (94%) |
Table 2.
Comparison of CPRS, CGI, and Total PGI scores across time in both groups (Unilateral v/s Bilateral MECT)
| Groups across time | Unilateral MECT group (n=50) Mean Rank | Bilateral MECT group (n=50) Mean Rank | Mann–Whitney U test | P |
|---|---|---|---|---|
| CPRS scores | ||||
| Baseline | 45.48 | 55.52 | 999 | (0.08) |
| After fourth session | 46.46 | 54.54 | 1048 | (0.16) |
| Two weeks after the last session | 51.80 | 49.20 | 1185 | (0.62) |
| CGI score | ||||
| Baseline | 51.20 | 49.80 | 1215 | (0.78) |
| After fourth session | 50.08 | 50.92 | 1229 | (0.87) |
| Two weeks after the last session | 52.09 | 48.91 | 1170 | (0.52) |
| Total PGI memory battery score | ||||
| Baseline | 55.22 | 45.78 | 1014 | (0.103) |
| After fourth session | 58.46 | 42.54 | 852 | (0.006) |
| Two weeks after the last session | 63.07 | 37.93 | 621 | (0.000) |
Table 3.
Comparison of CPRS, CGI, and Total PGI scores across time in unilateral and bilateral MECT groups
| Comparison of | Mean (SD) | Mean Rank | Friedman test statistic |
|---|---|---|---|
| CPRS scores across time in unilateral MECT group | |||
| CPRS at baseline | 72.26 (13.73) | 3 | Friedman test (Chi-Square statistic) = 100, Df=2, P=0.000 |
| CPRS after fourth session | 44.06 (11.0) | 2 | |
| CPRS two weeks after the last session | 9.06 (7.57) | 1 | |
| CPRS scores across time in bilateral MECT group | |||
| CPRS at baseline | 76.48 (12.21) | 3 | Friedman test (Chi-Square statistic) = 100, df=2, P=0.000 |
| CPRSafter furth session | 47.08 (7.69) | 2 | |
| CPRS score: two weeks after the last session | 9.06 (8.20) | 1 | |
| CGI scores across time in unilateral MECT group | |||
| CGI score at baseline | 5.42 (0.54) | 3 | Friedman test (Chi-Square statistic) = 100, Df=2, P=0.000 |
| After fourth session | 3.58 (0.61) | 2 | |
| After two weeks after the last session | 1.62 (0.88) | 1 | |
| CGI scores across time in bilateral MECT group | |||
| CGI score at baseline | 5.40 (0.495) | 3 | Friedman test (Chi-Square statistic) = 99.5, Degree of freedom=2, P=0.000 |
| After fourth session | 3.58 (0.54) | 1.99 | |
| After two weeks after the last session | 1.52 (0.84) | 1.01 | |
| Comparison of Total PGI scores across time in unilateral MECT group | |||
| Total PGI score at baseline | 74.92 (6.70) | 2.70 | Friedman test (Chi-Square statistic) = 84, Degree of freedom=2, P=0.000 |
| After fourth session | 63.48 (6.95) | 1.02 | |
| After two weeks after the last session | 74.24 (6.38) | 2.28 | |
| Comparison of Total PGI scores across time in bilateral MECT group | |||
| Total PGI score at baseline | 73.74 (6.002) | 2.85 | Friedman test (Chi-Square statistic) = 86.28, Degree of freedom=2, P=0.000 |
| After fourth session | 60.08 (5.59) | 1.02 | |
| After two weeks after the last session | 67.78 (6.73) | 2.13 |
Table 4.
Post hoc test for CPRS in Unilateral vs Bilateral MECT groups
| Test across time (n=100) | Unilateral MECT | Bilateral MECT | Mean rank (U/L) | Mean rank (B/L) | Wilcoxon signed-rank test statistic (P) U/L | Wilcoxon signed-rank test statistic (P) B/L |
|---|---|---|---|---|---|---|
| CPRS score baseline vs CPRS score after fourth session | Baseline (B) = 72.26 (SD=13.733) | 76.48 (12.21) | 25.50 | 25.50 | -6.158 (0.000) | -6.157 (0.000) |
| After the fourth session=44.06 (11.00) | 47.08 (7.69) | |||||
| CPRS Score baseline vs CPRS score two weeks after the last session | B-72.26 (13.733) | 76.48 (12.21) | 25.50 | 25.50 | -6.155 (0.000) | -6.155 (0.000) |
| two weeks afterward=9.06 (7.57) | 9.06 (8.20) | |||||
| CPRS score after fourth session vs CPRS score two weeks after the last session | After the fourth session=44.06 (11.00) | 47.08 (7.690) | 25.50 | 25.50 | -6.156 (0.000) | -6.156 (0.000) |
| Two weeks after the last session=9.06 (7.54) | 9.06 (8.20) |
Table 5.
Post hoc test for CGI in Unilateral vs Bilateral MECT groups
| Test across time (n=100) | Unilateral MECT | Bilateral MECT | Mean Rank (U/L) | Mean Rank (B/L) | Wilcoxon signed-rank test statistic (P) U/L | Wilcoxon signed-rank test statistic (P) B/L |
|---|---|---|---|---|---|---|
| CGI score at baseline vs CGI score after fourth session | Baseline (B) = 5.42 (SD=0.538) | 5.40 (0.495) | Mean negative rank=25.50 | Mean negative rank=25.50 | -6.41 (0.000) | -6.44 (0.000) |
| After the fourth session=3.58 (0.609) | 3.58 (0.538) | |||||
| CGI Score baseline vs CGI score two weeks after the last session | Baseline=5.42 (0.538) | 5.40 (0.495) | Mean negative rank=25.50 | Mean negative rank=25.50 | -6.29 (0.000) | -6.29 (0.000) |
| Two weeks afterward=1.62 (0.87) | 1.52 (0.84) | |||||
| CGI score after fourth session vs CGI score two weeks after the last session | After fourth session=3.58 (0.609) | 3.58 (0.538) | Mean negative rank=25.50 | Mean negative rank=25 | -6.33 (0.000) | -6.25 (0.000) |
| 2 weeks after the last session=1.62 (0.87) | 1.52 (0.839) |
Table 6.
Post hoc test for PGIMS scores in Unilateral vs Bilateral MECT groups
| Test across time (n=100) | Unilateral MECT | Bilateral MECT | Mean Rank (U/L) | Mean Rank (B/L) | Wilcoxon signed-rank test statistic (P) U/L | Wilcoxon signed-rank test statistic (P) B/L |
|---|---|---|---|---|---|---|
| Total PGIMS score at baseline vs PGIMS score after fourth session | Baseline=74.92 (SD=6.70) | 73.34 (6.00) | Negative Mean Rank=24.50 Positive Mean rank=0 |
Negative Mean Rank=25.50 Positive Mean rank=0 |
-6.04 (0.000) | -6.17 (0.000) |
| After fourth session=63.48 (6.95) | 60.08 (5.59) | |||||
| Total PGIMSScore baseline v/s PGIMS score two weeks after the last session | Baseline=74.92 (6.70) | 73.34 (6.0) | Negative Mean Rank=16.46 Positive Mean rank=22.33 |
Negative Mean Rank=25.91 Positive Mean rank=10.92 |
-2.81 (0.005) | -5.29 (0.000) |
| Twoweeks afterwards=74.24 (6.36) | 67.78 (6.74) | |||||
| Total PGIMS score after fourth session vs PGIMS score two weeks after the last session | After fourth session=63.48 (6.95) | 60.08 (5.59) | Negative Mean Rank=0 Positive Mean rank=25.50 |
Negative Mean Rank=0 Positive Mean rank=26 |
-6.16 (0.000) | -6.16 (0.000) |
| Two weeks after the last session=74.24 (6.36) | 67.78 (6.73) |
Intergroup comparisons
Table 1 shows the age (years), family income per month (in rupees), and the age of onset (in years) between the two groups along with baseline characteristics like gender, marital status, religion, occupation, residence, and family history of psychiatric illness of the patients in the RU/L ECT and B/L ECT. The scores of CPRS, CGI, and PGI memory scales were compared between the two groups using a Mann–Whitney U test while Chi-square was used for the categorical data. The majority of the patients in the RU/L group were male (72%), unmarried (58%), Hindu (82%), unemployed (62%) from rural areas (66%), and with an absence of a family psychiatric history (92%). In the B/L group, males were 74%, with married status (54%), Hindu (86%), unemployed (58%), from rural areas (80%) and with the absence of family psychiatric history in 94%. There was no significant difference between the two groups concerning these parameters.
The age (years), family income per month (in rupees), mean years of schooling, and age of onset (years) of symptoms between the two groups using a student t-test. The mean age (in years) of the RU/L ECT group was 28.44 ± 9.16, with an age of onset of 21.78 ± 6.29 years and the family income was 10020.00 ± 6610.11 rupees. In the Bilateral ECT group, the mean age (in years) was 30.60 ± 9.93, the age of onset was 22.60 ± 7.42, and the family income was 10560.00 ± 8114.38. There was no significant difference between the two groups concerning these parameters. The mean years of schooling were 10.48 years in the RU/L MECT group, while it was 9.72 years in the bilateral group MECT group, but the difference between both groups was statistically insignificant.
Apart from these baseline characteristics, an intergroup comparison between RU/L vs B/L MECT group was conducted. Mann–Whitney U test was applied for the comparison of CPRS, CGI, and total PGI scores at all three points (baseline, after the fourth session, and two weeks after the last session) and the results have been summarized in Table 2. The total PGI scores both differed between two groups at two points (at the fourth session and after two weeks after the last session) [Table 2].
Intragroup comparison
The intragroup comparison was conducted at three points across time for CPRS, CGI, and the total PGI score. The mean ranks were calculated and the Friedman test was applied to assess all of these parameters. They differed significantly at all points across time [Table 3]. Post hoc test (Wilcoxon signed rank test) revealed the differences within the groups [refer to Tables 4-6].
DISCUSSION
The present study was of a large sample size (n = 100), and both groups, the RU/L and B/L were very similar in terms of various sociodemographic and clinical parameters. Patients diagnosed with any psychotic illness, both affective and non-affective, and who were having clinical indications for ECT were recruited for the study followed by random allocation to either group for which both the patient and rater were blinded. The study was of naturalistic design where the number of sessions given to a patient was decided according to the clinical response and there was no interference by the researcher in this respect.
Patients in both groups showed significant improvement in symptoms and the severity of illness. This finding was in accordance with previous studies that have shown the efficacy of ECT in various psychiatric disorders like major depression, bipolar illness, and schizophrenia.[15,16] On further assessments at follow-up after two weeks after the last session, the improvement was maintained in both groups and the patients did not show a relapse of symptoms. The review by Jelovac et al.[17] found that up to half of all patients who respond to ECT relapse within the first year, the period of highest risk being the first six months. In the current study, it appeared that in the short term, the relapse rate in patients receiving ECT was low in both placements.
Both placements resulted in a significant decline in PGIMS scores after fourth session. This was consistent with the earlier studies that have shown the cognitive side effects of ECT.[18,19] But the effects did not sustain for long, as exemplified when the reassessment was done after two weeks of the last session of ECT and this was also in accordance with previous studies on adverse effects of ECT.[19,20] It implied that although cognitive side effects were caused by ECT they were short-lived.
When the interaction of time and groups was assessed, it became obvious that both the electrode placements were equally efficacious in improving the psychopathology and the severity of illness, which was also demonstrated in the study by Kellner et al.[21] Moreover, the improvements were maintained even after two weeks of the last session of ECT and both the electrode placements did not differ significantly in this respect also. Although remission rates exceed those seen with other somatic treatments, high rates of relapse were observed and acknowledged as a major clinical problem with ECT.[22] Earlier and recent studies showed a relapse rate after a successful brief pulse ECT of 50% within six months, despite the continuation of pharmacotherapy.[5] But, it could be inferred from the current study that the improvement in symptoms persisted in the short term after the therapy was completed.
The decline in total PGIMS scores was significantly more in the case of B/L-ECT than RU/L-ECT, which pointed toward the better cognitive side effect profile with RU/L electrode placement. Some studies had also shown fewer cognitive side effects in the case of unilateral placement of electrodes while others found that there was no significant difference between unilateral and bilateral ECT in terms of cognitive side effects.[23] Neuroimaging studies had shown that verbal learning and semantic recall were largely lateralized to the dominant hemisphere (i.e. the left hemisphere in the majority of patients), specifically to regions of the frontal and temporal cortex.[24] Given the dual functional role of the left medial temporal structures in verbal learning and recall, and especially the role of the hippocampus in memory retrieval processes, greater stimulation of this region with BL relative to RUL ECT was therefore consistent with this profile of increased cognitive side effects.
After two weeks after the last session of ECT, PGIMS scores fared better in the RU/L group. Retrograde amnesia for personal events had been seen as one of the most consistently reported side effects of MECT,[25] while the anterograde function remained unimpaired. The studies by Sackiem, Semkovska et al.,[26] and Martin et al.[27] found that immediately after ECT, patients showed impairment on nearly all cognitive measures with bilateral electrode placement compared to unilateral, being associated with significantly higher impairment. At the six-month follow-up, there was a significant improvement relative to baseline on all tasks except reaction-time measures and autobiographical memory. It had already been shown that patients who manifest global cognitive impairment, as measured with the MMSE are more prone to autobiographical memory impairment.[28] Similarly, in the present study, memory functions remained impaired in the case of B/L electrode placement as compared to right U/L MECT.
Strengths and limitations
Our study included 100 patients and double blinding was used to ensure minimization of bias. These characteristics make the findings that can be generalized on a larger population. But due to the naturalistic design, the number of sessions was decided according to the clinical response. So, there can be confounding factors of the number of sessions as different patients would have showed improvement with different number of sessions. The effects of medications being given before, during, and after stopping ECT could have effects on symptoms, cognitive functions, and memory. So, it could not be established that the effects were solely due to ECT. Moreover, most of the population belonged to lower socioeconomic status and had less education which could have an impact on memory.
CONCLUSION
The present study showed similar symptomatic improvement in patients receiving RUL and BL-ECT and the results persisted beyond the therapy sessions. But, in the case of RUL-ECT, the deterioration in memory functions was lesser as compared to BL-ECT. In the subsequent two weeks after ECT, the patients receiving RUL-ECT performed better as was an improvement in memory functions. The study pointed toward a favorable outcome in the case of therapeutic response with ECT without any significant difference between both placements. After stopping the therapy, the symptoms didn’t show relapse and the improvement appeared to be stable over time. The side effect profile of RU/L placement was lower as compared to B/L placement. In the post-ECT period also, the patients receiving RU/L placement showed better improvement in memory functions.
Conflicts of interest
There are no conflicts of interest.
Funding Statement
Nil.
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