Adjunct Bifrontal Transcranial Direct Current Stimulation in Improving Cognitive Insight and Working Memory Deficits in Schizophrenia: A Single-blind,Randomised Sham-controlled Trial

Abstract

Background

Cognitive deficits are an integral part of schizophrenia. This is a single-centre, single-blind randomised sham-controlled study to evaluate the effect of bilateral transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex on cognitive deficits in schizophrenia, specifically targeting improvements in cognitive insight and working memory deficits.

Method

Thirty patients with schizophrenia were randomly allocated to receive 10 sessions of bilateral tDCS (anodal F3 and cathodal F4) into active and sham tDCS groups. A series of assessment tests were completed among patients having Schizophrenia, at baseline and after the 10 sessions, for instance, Beck Cognitive Insight Scale (BCIS), N-Back (0’ Back) task and Trail Making Test (TMT), Scale for Assessment of Positive Symptoms (SAPS), Scale for Assessment of Negative Symptoms (SANS) and Clinical Global Impression (CGI) scale.

Results

Out of a total of 30, twenty-seven participants (n = 13, Active and n = 14, Sham group) completed the study. However, an intention-to-treat analysis using Mixed model ANOVA was done on all the subjects. The study showed significant interaction effect (Time × Treatment) indicating that the active tDCS treatment had large effect on psychotic symptoms’ reduction (SAPS: F(1,28) = 12.55, p = .001, partial η2 = 0.31; SANS: F(1,28) = 10.43, p = .003, partial η2 = 0.27) and significantly improved cognitive performance (N-Back Accuracy percentage: F(1,28) = 27.66, p < .001, partial η2 = 0.45; N-Back Reaction Time (in seconds): F(1,28) = 57.41, p < .001, partial η2 = 0.67). Furthermore, for cognitive insight, there was improvement in cognitive confidence (BCIS-C: F(1,28) = 5.43, p = .03, partial η2 = 0.16) and composite index (BCIS R-C: F(1,28) = 1.97, p = .17; partial η2 = 0.06) in Active vs. Sham group. TMT scores reduced more in the Active (−18.8s) as compared to the Sham group, suggesting better cognitive functioning, especially in the areas of attention, speed and mental flexibility (F(1,28) = 6.15, p = .02, partial η2 = 0.18).

Conclusion

The study suggests that the adjunctive bifrontal tDCS over DLPFC helps improve cognitive insight and working memory deficits among patients having schizophrenia.

Keywords

tDCS DLPFC schizophrenia cognitive insight working memory

Introduction

Schizophrenia is a heterogeneous neuropsychiatric condition with positive symptoms, negative symptoms and a variety of neurocognitive deficits.¹ In 75%–85% of the patients, there are cognitive deficits, mainly including working memory disturbances.² Impaired insight is another core characteristic feature of schizophrenia and is prevalent throughout the illness. Cognitive insight is the capacity of a person to evaluate and correct distorted beliefs and misinterpretations.³ It has been suggested to be a prerequisite for clinical insight.⁴ Patients with cognitive deficits have poorer clinical insight⁴ and functional deficiencies.⁵ Medications and cognitive training show suboptimal improvements in cognitive impairments.⁵ People who have schizophrenia fail to activate their dorsolateral prefrontal cortex (DLPFC) when performing on working memory in comparison to healthier subjects.⁶

The application of transcranial direct current stimulation (tDCS) targeting the dorsolateral prefrontal cortex (DLPFC) has been investigated for its potential to enhance cognitive functions, mainly working memory and cognitive insight in schizophrenia.⁷ Several studies have focused on the electrode configuration involving anodal stimulation at F3 (left DLPFC) and cathodal stimulation at F4 (right DLPFC). Zhou et al. conducted a randomised, double-blind, sham-controlled trial that involved anodal stimulation of the left DLPFC (F3) and cathodal stimulation of the right DLPFC (F4) in patients with chronic schizophrenia; however, their findings indicated that tDCS could not improve cognitive functions in patients with chronic schizophrenia with tardive dyskinesia, contradicting their claim of cognitive enhancement.⁸ In a similar study, Salehinejad et al. found that patients suffering from major depression utilising the exact electrode placement showed enhancements in visual working memory and also improvements in the depressive symptoms, which informs on the utility of this method in cognitive enhancement on a larger scale.⁹

Furthermore, the study by Palm et al. stressed the effects of anodal tDCS on F3 with an extra-cephalic anode, although the study did focus on the right DLPFC.¹⁰ Mylius et al.’s work has also established the anodal F3 and cathodal F4 to enhance working memory performance, following other studies emphasising the importance of this specific montage.¹¹ Also, the configuration described by Nikolin et al. was substantiated by the outcomes of the studied participants, which showed significant effects on working memory performance among healthy participants.¹² Narmashiri and colleagues, in their recent systematic review and meta-analysis, reported that application of tDCS can effectively increase the cognitive task performance.¹³ Blay et al., in a systematic review, found that while some studies reported improvements in cognitive insight, others did not observe significant results.¹⁴

There is clear evidence to suggest a rise in targeting left DLPFC in schizophrenia. The targeted configuration of anodal F3 stimulation and F4 cathodal stimulation on cognitive insight and working memory in schizophrenia needs to be further tested, as the available evidence is mixed; and some studies show no significant effects at all. The progress of studies in this area may clarify the necessary parameters of tDCS. Hence, the current study aimed to investigate the effect of tDCS in enhancing cognitive insight and ameliorating working memory deficits in individuals diagnosed with schizophrenia. The central hypothesis posits that anodal tDCS applied to the left DLPFC and cathodal stimulation at the right DLPFC will significantly improve cognitive insight and working memory performance compared to a sham stimulation condition.

Material and Methods

It was a longitudinal, randomised, single-blind, sham-controlled, single-centre and parallel-group trial to determine the effect of anodal tDCS at F3 and cathodal stimulation at F4 on cognitive insight and working memory among patients with schizophrenia. The permission to conduct the trial was obtained from the Institutional Ethics Committee and was subsequently registered with the Clinical Trials Registry of India (CTRI).

Participants

Eligible subjects had a diagnosis of schizophrenia, were between 18 and 60 years of age, were right-handed, had a duration of illness not exceeding 5 years, had the mental capacity to engage in the study and were willing to participate in the study voluntarily. It was also necessary that the individual could read and acknowledge English language alphabets. Those were excluded who had comorbid other psychiatric disorders, including substance use disorders (except tobacco), having a history of neurosurgery, seizures, substantial brain damage, brain aneurysm or any other significant neurocognitive conditions. Individuals who had received electroconvulsive therapy (ECT) or any other form of neuromodulation in the past 6 months were also excluded from the trial. Furthermore, patients with medical implants such as defibrillators, pacemakers or brain aneurysmal clips, as well as those for whom tDCS is contraindicated, such as pregnant women, migraineur or those with significant scalp lesions were ineligible for the study.

Intervention

Two sessions every day, separated by at least two hours, for ten sessions over 5 days, were carried out to provide the interventions. The anode was positioned at F3 and the cathode at F4 (using the 10-20 EEG electrode placement technique) for a bilateral stimulation method, and the current intensity was set at 2 mA. In the active treatment (group A), the current was increased gradually over 30 seconds to 2 mA, and it was then kept constant for 20 minutes. The same 30-second ramp-up duration was applied at the beginning of the sham stimulation (group S) and was ramped down to 0 mA through the remainder of the 20-minutes time.

Study Sampling Technique

The primary variables of interest were cognitive insight and working memory deficits, whereas the illness severity, clinical improvement and therapeutic response were the secondary outcome variables. For an effect size of 0.44,⁷ an α error probability of 0.05, power of study at 0.95 and for the Mixed model ANOVA, a total sample size of 30 (15 in each arm) was estimated.

Convenience sampling was used, and the eligible, consenting participants were assigned into two groups in a random non-stratified way. The participants were allocated in a ratio of 1:1 in two intervention arms, for instance, active and sham intervention groups. Simple randomisation technique was applied to assign the participants to the treatment groups without constraints. Another investigator, who was not involved in administering the interventions, generated two random number sequences using the website www.random.org.¹⁵ The generated number sequences were securely stored and, throughout the trial, this investigator enrolled participants into the active or sham groups based on matching their serial number with the corresponding random sequence number. The participants were blinded to the allocation and intervention.

Procedure

All consecutive patients who had schizophrenia and attended the department of psychiatry of a tertiary care teaching-training hospital were screened for recruitment in the present study. As per the inclusion and exclusion criteria, those found eligible were explained the study’s rationale and requested to participate. Each participant received a written patient information sheet, and informed consent was obtained before commencement. Baseline socio-demographic and clinical data were collected using a semi-structured proforma. The participants’ handedness was determined beforehand using the Edinburgh Handedness Inventory (Short-Form).¹⁶ Beck Cognitive Insight Scale (BCIS)¹⁷ was applied to measure cognitive insight. The N-Back (0’ Back) task was performed through Psychopy¹⁸ and the Trail Making Test - part A¹⁹ was used to measure the attention and cognitive performance. Scale for the Assessment of Positive Symptoms (SAPS) and Scale for the Assessment of Negative Symptoms (SANS)^{20, 21} were scored for positive and negative symptoms of schizophrenia, respectively. To determine the severity of the illness and global improvement/change, the Clinical Global Impression (CGI) Scale was employed.²² All participants were given the treatment interventions, that is, ten sessions of active or sham tDCS twice a day over five consecutive days. All tools were applied at baseline (pre-intervention) and at least 2 hours after the completion of tDCS on day 5 (post-intervention) in both A and S treatment arms. A side effect checklist for tDCS was used to record adverse events after each tDCS session. Throughout the trial, treatment as usual was continued in both intervention arms.

Data Analysis

Analysis was done using SPSS version 21.0. Socio-demographic and clinical variables were tabulated, and central tendencies were computed, presenting the data as mean ± standard deviation for quantitative variables and frequencies (percentage) for categorical variables. Data was assessed for normal distribution using Skewness and Kurtosis values, Histogram and Shapiro-Wilk test. Descriptive statistics were applied to compare inter-group socio-demographic and clinical profiles using the Chi-square test for categorical variables, Student’s independent t-test and Mann Whitney for continuous variables, depending on the distribution. Mixed model ANOVA was used to calculate the difference in the mean scores of various scales, such as the BCIS scale, N-back task, etc., in the groups. The level of significance used is p < .05 (95% CI).

Results

Figure 1 illustrates the flow of the participants during the trial. Eighty-one participants with a diagnosis of schizophrenia were approached and screened based on inclusion and exclusion criteria for the study, and 21 did not give consent for the study. Thirty participants were finally enrolled in the trial and were randomly allocated into active (A; n = 15) and sham (S; n = 15) treatment groups. Among those excluded (n = 30), 19 had comorbid substance use disorder, 4 of them had comorbid neurological disorder, 6 had received ECT in the last year and 1 patient had a history of chronic migraine. A total of 27 patients completed the study (A; n = 13 and S; n = 14); however, to conclude our results, we did an intention-to-treat analysis.

Figure 1.

Consort Flow Diagram.

Baseline Parameters of Participants

Table 1 depicts the socio-demographic and clinical characteristics of the participants in active (A) and sham (S) tDCS groups at baseline. Most participants were males (A: n = 9; S: n = 11) and had a mean age of 32.37 ± 8.10 years. The average duration of illness among the participants was 3.31 ± 0.35 years. At baseline, both groups matched in their symptomatology and the illness severity [SAPS: u = 138.50; p = .285; SANS: u = 132.50; p = .406 and CGI: u = 110.00; p = .904).

Table 1.

Baseline Characteristics of Participants.

Characteristic	Active t-DCS (A; n = 15)	Sham t-DCS (S; n = 15)	t/U or χ²/ Fisher Exact	p Value
Female [n (%)] Male	6 (40) 9 (60)	4 (26.66) 11 (73.33)	.600^x	.439
Age (in years)	31.73 ± 8.33	33.07 ± 8.40	−0.436^u	.66
BMI (in kg/m²)	23.20 ± 3.61	22.93 ± 1.96	0.251^t	.804
Duration of illness (in years)	3.73 ± 0.34	3.03 ± 0.36	86.50^u	.285
Family history of MI; [n (%)]
None	12 (80)	13 (86.66)	1.040^x	.792
Anxiety disorder	1 (6.66)	1 (6.66)
Mood disorder	1 (6.66)	1 (6.66)
Psychotic disorder	1 (6.66)	0 (0)
Medications use; [n (%)]
SGA	11 (73.33)	11 (73.33)	1.200^x	.753
SGA + FGA	2 (13.33)	3 (20)
FGA + others	1 (6.66)	1 (6.66)
SGA + others	1 (6.66)	0 (0)
Medical comorbidity; [n (%)]	3 (20)	2 (13)	0.240^x	1.00
Tobacco use; [n (%)]	4 (26)	7 (46)	1.292^x	.256
Marital status; [n (%)]
Single	5 (60)	7 (46.66)	1.942^x	.379
Married	5 (33.33)	7 (53.33)
divorced	1 (6.66)	0 (0)
SAPS	28.60 ± 12.62	32.13 ± 10.06	138.50^u	.285
SANS	28.73 ± 16.67	35.13 ± 20.31	132.50^u	.406
BCIS-R	12.73 ± 4.07	11.47 ± 1.45	73.00^u	.095
BCIS-C	7.40 ± 1.95	7.93 ± 1.22	−0.895^t	.378
BCIS-RC	5.33 ± 3.45	3.53 ± 1.846	61.50^u	.030^*
N-Back Task (0-Back) avg correct	42.79 ± 17.23	35.64 ± 11.01	1.30^t	.200
N-Back Task (0-Back) RT	0.99 ± 0.06	0.98 ± 0.03	82.50^u	.211
CGI	3.67 ± 0.48	3.67 ± 0.61	110.00^u	.904
TMT-A	71.00 ± 33.86	81.33 ± 34.04	143.50^u	.191

Notes: *p value significant at < .05; Data presented as mean ± sd, unless otherwise stated; BMI: body mass index; MI: mental illness; t: Student independent test; U: Mann Whitney; x/χ²: Chi Square; SGA: second generation antipsychotics; FGA: first generation antipsychotics; SAPS: Schedule for the assessment of positive symptoms; SANS: Schedule for the assessment of negative symptoms; BCIS: Beck Cognitive Insight Scale; R: self-reflectiveness; C: self-certainty; RC: Reflectiveness-Certainty Index; avg: average; RT: Response Time; CGI: Clinical global impression; TMT-A: Trail making task (Part A).

Overall Multivariate Effects

Both treatment and time independently influenced outcomes, and their interaction suggests that treatment (tDCS intervention) efficacy over time differs between the two (Active vs. Sham) groups. There was a significant overall effect of treatment on the dependent variables (SAPS, SANS, BCIS, TMT, N-Back and CGI scores), with the Wilks’ Lambda = 0.41, F(9,20) = 3.151, p = .016, partial η² = 0.586. The time effect (Pre vs. Post) was also found to be strongly significant across all dependent variables (Wilks’ Lambda = 0.05, F(9,20) = 41.97, p < .001, partial η² = 0.950). Furthermore, the interaction effect (time × treatment) was also found significant (Wilks’ Lambda = 0.108, F(9,20) = 18.312, p < .001, partial η² = 0.892).

Time × Treatment Interaction Effect

The large improvements with treatment over time were seen in SAPS [F(1,28) = 12.55, p < .001, partial η² = 0.31], SANS [F(1,28) = 10.43, p < .003, partial η² = 0.27], N-Back Reaction time [F(1,28) = 57.41, p < .001, partial η² = 0.67], N-Back Accuracy% [F(1,28) = 27.66, p < .001, partial η² = 0.45]. There were moderate interaction effects in BCIS-C (Self-certainty) [F(1,28) = 5.43, p < .02, partial η² = 0.16], CGI [F(1,28) = 4.49, p < .04, partial η² = 0.13], TMT-A [F(1,28) = 6.15, p < .02, partial η² = 0.18]. However, no significant interaction effect for BCIS-R (self-reflectiveness) and BCIS R-C (composite index) (p = .86, 0.17, respectively) was seen.

Between-groups (Treatment Only) Effects

Active group showed better scores than Sham especially on N-Back [N-Back-RT: F(1,28) = 14.88, p = .001, partial η² = 0.34; N-Back Accuracy 5: F(1,28) = 10.44, p = .33, partial η² = 0.27 ] and CGI [F(1,28) = 4.30, p = .04, partial η² = 0.13], supporting the efficacy of the treatment.

Table 2 illustrates the comparison of scores on various clinical scales (Pre vs. Post) after 5 days of tDCS treatment.

Table 2.

Comparison of Scores on Clinical Scales (Pre vs. Post) After 5 Days of tDCS Treatment.

Variable	Group	Pre (Mean ± SD)	Post (Mean ± SD)	Change	p Value  (Within Group)	Interaction  p Value  (Between Groups)
SAPS	Sham	32.40 ± 10.23	31.20 ± 10.14	−1.20	< .001*	.001*
	Active	28.67 ± 12.36	25.93 ± 12.28	−2.74	< .001*	.001*
SANS	Sham	36.13 ± 21.38	35.40 ± 21.38	−0.73	< .001*	.003
	Active	27.47 ± 16.72	25.27 ± 16.17	−2.20	< .001*	.003
BCIS-R	Sham	11.33 ± 1.29	11.07 ± 1.39	−0.26	.239	.86
	Active	12.73 ± 4.18	12.40 ± 4.29	−0.33	.253	.86
BCIS-C	Sham	7.93 ± 1.22	7.47 ± 1.46	−0.46	< .001*	.027*
	Active	7.60 ± 1.96	6.27 ± 1.98	−1.33	< .001*	.027*
BCIS-RC	Sham	3.40 ± 1.64	3.60 ± 1.72	+0.20	.045	.172
	Active	5.13 ± 3.54	6.13 ± 4.00	+1.00	.066	.172
CGI	Sham	3.73 ± 0.70	3.60 ± 0.51	−0.13	< .001*	.043*
	Active	3.60 ± 0.74	3.07 ± 0.46	−0.53	< .001*	.043*
N-Back-avg. correct %	Sham	35.69 ± 10.99	36.51 ± 10.44	+0.82	< .001*	< .001*
	Active	43.11 ± 16.96	62.39 ± 17.97	+19.28	< .001*	< .001*
N-Back-RT	Sham	0.985 ± 0.033	0.962 ± 0.039	−0.023	< .001*	< .001*
	Active	1.001 ± 0.074	0.724 ± 0.169	−0.277	< .001*	< .001*
TMT-A	Sham	84.00 ± 34.65	76.00 ± 31.24	−8.00	< .001*	.019*
	Active	71.67 ± 33.63	52.87 ± 19.10	−18.80	< .001*	.019*

Notes: *p value significant at < .05; Pre: at baseline; Post: after 5 days of tDCS; SAPS: Schedule for the assessment of positive symptoms; SANS: Schedule for the assessment of negative symptoms; BCIS: Beck Cognitive Insight Scale; R: self-reflectiveness; C: self-certainty; RC: Reflectiveness-Certainty Index; avg: average; RT: Response Time; CGI: Clinical global impression; TMT-A: Trail making task (Part A).

Discussion

The current study aimed to determine and compare the effects of transcranial direct current stimulation (tDCS) on cognitive deficits (working memory and cognitive insight) among patients with schizophrenia. The study shows that there was a significant improvement in the active group as compared to sham tDCS group in the cognitive insight, working memory deficits and illness severity. These findings are similar to various other studies^23–26 while contradicting some similar studies’ results.^27–30 Earlier similar studies have also used N-back tasks to assess working memory.^{24, 31} A study by Schwippel and colleagues²⁴ used spatial N-back tasks with increasing load. It showed significant improvement in accuracy with a 2 mA current dose on right DLPFC stimulation compared to the current study. Several other recent studies also failed to show the difference in the working memory after tDCS sessions, when assessed immediately after completing the session, but have shown results when assessed after weeks²³ and months.³² Therefore, the outcome might have differed if we had assessed at a different point. The effects of tDCS on cognition in general are currently being debated,^{35, 36} particularly the improvement of cognition in schizophrenia.³³ In the effort to discover the effect of tDCS on cognition improvement in patients with schizophrenia, the recent systematic review reveals that the effect of tDCS on working memory and attention is superior to all other cognitive domains,^34–37 which is similar to our study findings. Similarly, other reviews have shown significant improvements in working memory and attention, comparable with those achieved by other neuromodulation techniques such as transcranial magnetic stimulation.³⁵

We found that both active and sham groups showed significant within-group improvement in cognitive insight, cognitive deficits and illness severity. According to a recent review by Fonteneau et al., non-specific placebo effects and some negative studies in the tDCS area could result from sham tDCS exerting neurobiological effects.³⁸ As per our sham stimulation protocol, the 2 mA current was turned on for 30 s and then was ramped down to 0 mA throughout the remainder of the 20-minute time. Research in healthy people found that 1.6 seconds of direct current stimulation improved verbal memory.^38–40 These finding of ours could also be primarily attributed to improved compliance, regular monitoring and other placebo effects such as the non-specific psychotherapeutic and halo effects.⁴¹ Additionally, we gave tDCS in addition to treatment-as-usual; and the within group effects could be explained to this.

Another aim of the study was to assess the effect of tDCS on cognitive insight, which was assessed using the Beck Cognitive Insight Scale (BCIS). Our study showed no significant improvement in the BCIS-R and R-C index. However, BCIS-C has shown a significant improvement of cognitive insight in the Active group, suggesting cognitive enhancement by tDCS. The results from previous studies are also mixed. Chang et al., in 2019, have reported that frontotemporal stimulation had a significant effect on the ‘self-reflectiveness’ subscale of the BCIS, with moderate effect size and the composite score of R-C with mild effect size, but not on the ‘self-certainty’ subscale of the BCIS, after 5 days of tDCS (10 sessions). This effect was not consistent when assessed at one month, or when HD-tDCS was used for the trial purpose.²⁷ In a study by Kim et al.⁴² where tDCS 2mA current for 20 minutes was given, clinical and cognitive outcomes failed to improve significantly. A later study by same authors in 2020, where bi-anodal tDCS was given, failed to demonstrate significant improvement in cognitive insight. However, significant improvement was reported in clinical insight.⁴³

This study may have several limitations. Sample size was small and we used the conventional tDCS. We have assessed patients at baseline and after completion of ten sessions, which only speaks about immediate changes but not maintenance of effects. We recruited patients who would attend for 5 consecutive days, which may have caused a selection bias. There were no biomarkers assessed in our study. Furthermore, the tasks which were paper/pencil-based, might have reduced the accuracy of results. The results of this study would have been more pronounced if it had been conducted in multiple centres.

In conclusion, this study observed that adjuvant tDCS over left DLPFC improves working memory, sustained attention and cognitive insight in patients with schizophrenia. For replication of these findings and further exploration of tDCS in patients with schizophrenia, large sample sizes should be used in future research.

Authors’ Contribution

NB: Conceptualisation, Writing original draft, Methodology, Formal analysis, Writing review & Editing. VD: Supervision, Conceptualisation, Methodology, Formal analysis, Writing review & editing. JR: Writing, Reviewing and Editing. RV: Methodology, Formal analysis, Writing, Reviewing & Editing.

Statement of Ethics

Approved by Institutional Ethics Committee (IEC), All India Institute of Medical Sciences (AIIMS) Rishikesh, Uttarakhand, India with No. AIIMS/IEC/20/640 dtd. 12.09.2020. The study protocol was subsequently registered with the Clinical Trials Registry of India (CTRI) with the number CTRI/2020/11/028888. Written informed consent was obtained from all participants to participate in the study.

Footnotes

Declaration of Conflicting Interests

The authors declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article.

Declaration of Generative AI and  AI-assisted Technologies in the  Writing Process

No generative AI tools, AI-assisted technologies, or machine learning algorithms were used in the creation, writing, or editing of this manuscript.

Funding

The authors received no financial support for the research, authorship and/or publication of this article.

ORCID iDs

Vishal Dhiman

Jitendra Rohilla

Rohit Verma

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Adjunct Bifrontal Transcranial Direct Current Stimulation in Improving Cognitive Insight and Working Memory Deficits in Schizophrenia: A Single-blind,Randomised Sham-controlled Trial

Abstract

Background

Method

Results

Conclusion

Keywords

Introduction

Material and Methods

Participants

Intervention

Study Sampling Technique

Procedure

Data Analysis

Results

Consort Flow Diagram.

Baseline Parameters of Participants

Baseline Characteristics of Participants.

Overall Multivariate Effects

Time × Treatment Interaction Effect

Between-groups (Treatment Only) Effects

Comparison of Scores on Clinical Scales (Pre vs. Post) After 5 Days of tDCS Treatment.

Discussion

Authors’ Contribution

Statement of Ethics

Footnotes

Declaration of Conflicting Interests

Declaration of Generative AI and AI-assisted Technologies in the Writing Process

Funding

ORCID iDs

References

Declaration of Generative AI and  AI-assisted Technologies in the  Writing Process