Discussion: Using the Walden Library

Journal of Affective Disorders 202 (2016) 10–15

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Research paper

Significantly improved neurocognitive function in major depressive disorders 6 weeks after ECT

Christine Mohn a,n, Bjørn Rishovd Rund a,b

a Research Department, Vestre Viken Hospital Trust, Drammen, Norway b Department of Psychology, University of Oslo, Oslo, Norway

a r t i c l e i n f o

Article history: Received 18 November 2015 Received in revised form 2 February 2016 Accepted 12 March 2016 Available online 20 May 2016

Keywords: Cognition Depression ECT MCCB Memory Neuropsychology

x.doi.org/10.1016/j.jad.2016.03.062 27/& 2016 Elsevier B.V. All rights reserved.

esponding author. ail address: [email protected] (C. Mo

a b s t r a c t

Background: Cognitive side effects may occur after electroconvulsive treatment (ECT) in depressive disorder patients. Previous studies have been limited by small numbers of cognitive functions assessed. The present study reports the first results from a prospective project monitoring cognitive effects of ECT using a comprehensive neuropsychological test battery and subjective report of everyday cognitive function. Methods: Thirty-one patients with major depressive disorder were assessed with the MATRICS Con- sensus Cognitive Battery (MCCB). Subjective cognitive complaints were described with the Everyday Memory Questionnaire (EMQ). Severity of depression symptoms were assessed with the Montgomery- Åsberg Depression Rating Scale (MADRS). These assessments were performed prior to and 6 weeks after non-standardized ECT. Results:: Compared to baseline, the mean depression severity level was nearly halved and there were significant improvements in mean levels of Speed of Processing, Attention/Vigilance, and Visual Learning 6 weeks after ECT. The other cognitive domains were not altered from baseline. There was no significant change in subjective cognitive complaints. At baseline, there were several significant correlations be- tween the MADRS and MCCB scores. There was no strong association between the EMQ and MCCB scores at either assessment point, but the post-ECT EMQ score was significantly correlated with depression severity. Limitations: Major limitations were low N and lack of uniform ECT procedure. Conclusions: There was significant improvement in Speed of Processing, Attention/Vigilance, and Visual Learning 6 weeks after ECT. Cognitive tests scores were related to severity of depression, but not to subjective memory complaints.

& 2016 Elsevier B.V. All rights reserved.

1. Introduction

Electroconvulsive therapy (ECT) is a life-saving intervention in treatment-resistant depression, and often results in rapid symp- tom relief. However, fear of memory loss is often cited as the main reason for not consenting to this type of treatment (Fraser et al., 2008). The precise nature, severity, and persistence of such side- effects have been the subject of intense debate.

A meta-analysis found that a sizable minority of patients report reduced cognitive function, mostly affecting speed of processing, executive function, and episodic memory during the first week after treatment (Semkovska and McLoughlin, 2010). However, 15 days after treatment, these functions were recovered or even im- proved. In the largest and longest-lasting investigation to date, a

hn).

multi-center study of attention, learning, short-term memory, and retrograde amnesia for biographical events in 260 patients, Sack- eim et al. (2007) reported that most cognitive parameters were significantly improved 6 months post ECT relative to pre ECT le- vels. However, reaction time/speed of processing was still com- promised at follow-up. Sustained adverse cognitive effects at fol- low-up were associated with demographic factors such as ad- vanced age, female gender, and lower baseline intellectual function.

Methodological aspects of ECT may contribute to post-treat- ment cognitive dysfunction. For this reason, sinus wave stimula- tion is no longer recommended, as square pulses result in less cognitive side-effects (Payne and Prudic, 2009). For the same reason, unilateral electrode placement is preferred over bilateral placement (Sackeim et al., 2000; 2007), although clinical char- acteristics of the patient may overrule the attempt to minimize cognitive side effects. Brief pulses usually have a stronger anti- depressive effect compared to ultra-brief stimulation, and recent

Table 1. Demographic characteristics of the participants (N¼31).

Age (years) 46.1 (SD 10.6)

Gender n¼10 (32.2%) men n¼21 (67.7%) women

Education Elementary school n¼9 (29.0%) High school n¼12 (38.7%) BA/BA þ n¼10 (32.2%) Years since first onset of depression 20.6 (SD 11.2, range 5–40)

Age and Years since onset in mean.

C. Mohn, B.R. Rund / Journal of Affective Disorders 202 (2016) 10–15 11

research demonstrates no differences in cognitive side effects between these two methods (Spaans et al., 2013; Verwijk et al., 2015).

Lack of systematic monitoring has made it impossible to elu- cidate the cognitive side effects of ECT with respect to precise characteristics, severity, and duration (Rasmussen, 2015). There is a large number of studies of cognitive effects of ECT, but they are often limited by the small number of cognitive domains assessed (e.g., Falconer et al., 2010; Porter et al., 2008). A recent post ECT study investigated a broad range of cognitive functions employed participants up to 82 years of age, risking contamination of the results due to early stages of dementia (Bodnar et al., 2015). Thus, there is a need for post ECT studies using comprehensive test batteries assessing a broad range of cognitive functions in younger samples.

The MATRICS Consensus Cognitive Battery (MCCB) (Nuechter- lein and Green, 2006) consists of 10 tests assessing 7 cognitive domains – Speed of Processing, Attention/Vigilance, Working Memory, Verbal Learning, Visual Learning, Reasoning/Problem Solving, and Social Cognition. The MCCB has very good psycho- metric properties, and is well suited for use in a clinical setting with severely ill respondents (Nuechterlein and Green, 2006). It was developed for the schizophrenia population, but is also used with bipolar disorder (Burdick et al., 2011; Kessler et al., 2014; Lee et al., 2013; van Rheenen and Rossell, 2014), and major depressive disorder (MDD) patients (Murrough et al., 2015). In a baseline article from the current project, we have recently demonstrated that the MCCB is able to separate cognitive functioning of MDD patients and healthy controls, and that the scores of the depres- sion group were generally significantly lower than those of the control group (Mohn and Rund, 2016).

Although subjective complaints of cognitive impairments may occur after ECT, these subjective reports are not necessarily sup- ported by objective neuropsychological test results (Coleman et al., 1996; Prudic et al., 2000). In general, there is a well-known dis- crepancy between subjective cognitive complaints and objective test performance, both in individuals suffering from mental illness (Moritz et al., 2004) and healthy individuals (van der Elst et al., 2008; Stenfors et al., 2014). We are aware of only one study of the relationship between subjective memory report and neu- ropsychological test scores (Brakemeier et al., 2011). That study found a discrepancy between subjective and objective cognitive function, but was limited by the low number of neuropsycholo- gical tests employed.

In ill individuals, the above discrepancy may partly be ex- plained by the severity of the depressive symptoms, as depression intensity is correlated with subjective memory failure (Coleman et al., 1996; Prudic et al., 2000). In this study, we will describe the relationship between depression severity, subjective cognitive complaints and MCCB performance.

As previous findings of cognitive changes after ECT are con- flicting, no specific hypotheses were formulated. The following research questions were asked: (1) Is there a change in cognitive function, as assessed with a comprehensive test battery, 6 weeks after ECT? (2) Are the cognitive test scores related to depression severity and subjective memory complaints?

2. Method

This paper is the first follow-up report issued from a 2-year longitudinal project on cognitive effects of ECT for major depres- sion in South-Eastern Norway. We aim to monitor the cognitive status of the participants at regular intervals, using a compre- hensive neuropsychological test battery with good psychometric properties. This first paper presents results from the first follow-

up assessment, 6 weeks after the ECT was completed.

2.1. Participants

Demographic data are presented in Table 1. The patient group consisted of 31 White participants with a major depression dis- order recruited from the ECT clinical sections at Vestre Viken Hospital Trust and Vestfold Hospital Trust in South-Eastern Nor- way. All patients set to undergo ECT and fulfilling the inclusion criteria of the project were invited to participate. Two eligible patients could not be tested for lack of time before the start of ECT, while two others gave initial consent to project participation, but changed their minds due to fatigue the day of testing. Finally, one patient withdrew from the project due to confusion and lack of motivation after completing the initial two subtests. The remain- ing sample consists of 31 patients, who were included from March 2011 to November 2014.

Inclusion criteria were age above 18 and below 70 years, ca- pacity for giving informed consent to both ECT and participation in this project, ability to understand spoken and written Norwegian, and a diagnosis of a treatment resistant major depressive episode. The diagnosis of “treatment resistant depression” was made by the clinicians based on previous lack of response to antidepressant medication in combination with psychotherapy. Exclusion criteria were ongoing alcohol or drug abuse, ongoing neurological illness, and ECT within the last two years.

2.2. Clinical assessment

The diagnosis of a major depressive episode (F 32.1, F 32. 2, F 32.3) was established by clinical interviews by hospital staff ac- cording to the ICD-10 criteria (WHO, 1993). Several different clinicians were involved in the diagnostic process. The patients were severely ill, and the decision to commence ECT was some- times made so rapidly that the diagnostic process could not be undertaken by one and the same clinician. We did, however, rely on comprehensive information from the patients’ journals to support the diagnosis made according to the ICD-10 system.

Severity of depression was assessed with the Montgomery- Åsberg Depression Rating Scale (MADRS, Montgomery and Åsberg, 1979) at the start of the neuropsychological assessment session. Twenty-three of the patients were diagnosed with recurrent uni- polar depression (F 33) and 10 with bipolar disorder type II (F 31). Seven had experienced psychotic symptoms during depressive episodes, 9 had moderate anxiety symptoms, and 4 partially ful- filled the criteria for a personality disorder (emotionally unstable personality disorder, F 60.3, and anxious personality disorder, F 60.6). Five of the patients had been treated with 1–2 series of ECT more than 2 years previously. All patients had discontinued their psychotropic medication 1–7 days before baseline testing. Five patients did not use any regular medication at baseline, and 6 were medicine free at 6 weeks follow-up. At both assessment points, medication for anxiety and/or insomnia had been

Table 2. Medication (CDD) before and 6 weeks after ECT (N¼31).

Pre ECT Post ECT

Antidepressants 2.5 2.4 Antipsychotics 1.1 1.3 Lithium .8 .8 Anticonvulsants .6 .2

CDD: Calculated dose of medication based on the prescribed dosage divided by the defined daily dosage.

Table 3. Raw scores of the MADRS, the MCCB tests, and EMQ before and 6 weeks after ECT (N¼22–31).

Pre ECT Post ECT F η2

MADRS 33.4 (7.7) 17.7 (8.1) 60.17nnn .67 Speed of processing TMT-A 49.6 (25.5) 39.7 (20.7) 6.01n .17 Symbol coding 40.4 (13.0) 44.9 (11.7) 8.74nn .23 Fluency 21.3 (8.4) 21.9 (6.3) .36 ns .01 Attention/Vigilance (CPT-IP) (n¼22)

2.48 (0.5) 2.77 (0.4) 7.61n .29

Working memory SS-WMS 12.9 (3.1) 13.6 (3.3) 2.34 ns .07 LNS 12.1 (3.9) 12.4 (3.7) .46 ns .02 Verbal learning (HVLT-R) 22.7 (5.9) 23.1 (6.0) .23 ns .01 Visual learning (BVMT-R) 21.2 (8.6) 23.3 (7.8) 7.32n .20 Reasoning/Problem solving (Mazes)

12.3 (8.0) 13.6 (7.8) 2.53 ns .08

Social cognition (MSCEIT) (n¼27) 93.5 (8.9) 95.0 (10.3) .74 ns .03 EMQ 105.7 (37.6) 109.4 (43.1) .21 ns .01

Scores in mean (SD). F: Significance test of time differences. ns: non significant. η2: effect size. Abbreviations: MADRS: Montgomery-Åsberg Depression Rating Scale, TMT-A: Trail Making Test A, CPT-IP: Continuous Perfor- mance Test-Identical Pairs, SS-WMS: Spatial Span-Wechsler Memory Scale, LNS: Letter Number Span, HVLT-R: Hopkins Verbal Learning Test Revised, BVMT-R: Brief Visuospatial Memory Test Revised, MSCEIT: Mayer-Salovey -Caruso Emotional In- telligence Test, EMQ: Everyday Memory Questionnaire.

nnn po .001. nn po .01. n po .05.

C. Mohn, B.R. Rund / Journal of Affective Disorders 202 (2016) 10–1512

permitted the evening before. See Table 2 for information on the daily defined doses of medication (WHO, 2010).

2.3. Electroconvulsive therapy

From a scientific point of view, the ECT procedure should be uniform. However, the anti-depressive effect of ECT depends upon patient characteristics as well as stimulus type and strength. Therefore, it was considered unethical to refrain from providing treatment at individually effective doses, and no uniform ECT procedure was followed. Each treatment procedure was tailored to the individual patient. All patients received square wave, brief pulse (0.5 ms) stimulation from a Thymatron system machine 2 (n¼3) or 3 (n¼28) times a week. The stimulation was titrated according to the individual's seizure threshold. Mean number of applications per ECT series was 11.9 (SD 4.1, range 6–23). Right unilateral electrode placement was used in 23 cases, bifrontal placement in 1 case, and mixed placement (switching from right unilateral to bifrontal in mid-series) in 7 cases. Anesthetic agents were alfentanil, propofol, or thiopental. Succinylcholine was used as a muscle relaxant. These pharmacological agents were ad- ministered in dosages according to the physical characteristics of each individual participant.

After this first series, 7 patients received maintenance treat- ment with a mean 9.9 of applications (SD 6.7, range 1–18). Among these, 5 had right unilateral, 1 bifrontal, and 1 mixed electrode placement.

The participants were cognitively assessed 1–3 days before the start of ECT and 6 weeks after completion of ECT. For the 7 patients who received maintenance treatment, the follow-up cognitive assessment was performed 6 weeks after the final application of maintenance ECT.

At baseline, 36 patients were originally assessed. At follow-up 6 weeks later, 31 of them were available for testing, resulting in a drop-out rate of 14%. The reasons for dropping out were the fol- lowing: extended travelling/vacation (n¼2), lethal physical illness, unrelated to ECT or other depression treatment, requiring hospi- talization (n¼1), a depression level too severe to participate in testing (n¼1), and refusing further contact with tertiary health care (n¼1).

All participants signed an informed consent form before both testing sessions. These consents were given in addition to their consenting to ECT treatment, which was obtained by the clinical departments. The study was approved by the Regional Committee for Research Ethics for Health Region South-East (REK Sør-Øst).

2.4. Neuropsychological assessment

The cognitive assessment was carried out by a clinical psy- chologist with extensive neuropsychological training (CM). The participants were tested at their respective clinical wards.

The MCCB covers 7 cognitive domains using 10 subtests (Nuechterlein and Green, 2006; 2009):

Speed of Processing, consisting of the subtests Trail Making Test A (TMT-A; United States War Department, 1944), Symbol Coding

(Brief Assessment of Cognition in Schizophrenia, BACS; Keefe, 1999), and Fluency (Category Fluency; Blair and Spreen, 1989),

Attention/Vigilance, assessed by The Continuous Performance Test-Identical Pairs (CPT-IP; Cornblatt et al., 1988),

Working Memory, consisting of the subtests Spatial Span (The Wechsler Memory Scale, SS-WMS; Wechsler, 1997) and Letter Number Span (The University of Maryland Letter Number Span test, LNS; Gold et al., 1997),

Verbal Learning, assessed by the revised Hopkins Verbal Learning Test (HVLT-R, immediate recall; Brandt and Benedict, 2001),

Visual Learning, measured by the revised Brief Visuospatial Memory Test (BVMT-R; Benedict, 1997),

Reasoning/Problem Solving, assessed by the Mazes test (Neu- ropsychological Assessment Battery, NAB; White and Stern, 2003), and Social Cognition, measured by the Managing Emotions part of the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT; Mayer et al., 2002).

For a detailed description of the tests, see Mohn et al. (2012). The average time of completion of the MCCB is 45–60 min Due to excessive fatigue, 4 patients did not perform the MSCEIT test and 9 did not perform the CPT-IP test. This is indicated in Tables 3 and 4.

Norwegian T scores have been published for the 20–59 years age group (Mohn et al., 2012). As the current study includes par- ticipants above 60 years, the MCCB results are presented in raw scores.

After the completion of the MCCB, the patients filled in the Everyday Memory Questionnaire (EMQ, Sunderland et al., 1983), assessing practical attention and memory functions in 28 items.

2.5. Statistics

All statistical analyses were performed with IBM SpSS Statistics version 22. Time differences in neurocognitive function were analyzed with repeated-measures ANOVAs with effect sizes re- ported as partial eta squared (η2). The relationships between the

Table 4. Pearson's correlations of the relationship between subjective cognitive complaints (EMQ) and MCCB test scores before and 6 weeks after ECT (N¼22–31).

TMT-A BACS Fluency CPT-IP SS-WMS LNS HVLT-R BVMT-R Mazes MSCEIT

Pre ECT EMQ � .04 � .07 � .18 .29 .08 .02 .04 .28 .10 .34 Post ECT EMQ .35 � .32 � .29 .10 � .47n � .29 � .55nn � .22 � .26 � .27

nn po .01. n po .05 (2-tailed).

C. Mohn, B.R. Rund / Journal of Affective Disorders 202 (2016) 10–15 13

EMQ score, the MADRS score, and the MCCB scores were in- vestigated with Pearson's correlations.

3. Results

The MADRS score was nearly halved post treatment, indicative of significant clinical effect of ECT (Table 3). There was no statis- tically significant change in the EMQ score (Table 3). Compared to baseline, tests assessing Speed of Processing, Attention/Vigilance, and Visual Learning showed significantly improved function after ECT, and the effect sizes were large (Table 3).

At baseline, there were no significant associations between subjective memory complaints (EMQ) and the cognitive test scores. After ECT, there were two such negative significant corre- lations, with Spatial Span and Verbal Learning (Table 4). This in- dicates a weak relationship between subjective and objective cognitive function assessments post treatment.

The relationship between the MADRS score and the cognitive function scores was strong at baseline, with 7 correlations reach- ing statistical significance. After ECT, only two correlations were significant - the EMQ and Verbal Learning (Table 5). Hence, sub- jective memory complaints after ECT seem related to depression severity and not to actual cognitive impairment, as measured with standard neuropsychological tests.

4. Discussion

Compared to the baseline assessment, our participants with major depressive disorder exhibited significantly improved cog- nitive function 6 weeks after cessation of ECT. The affected do- mains were Speed of Processing, Attention/Vigilance, and Visual Learning. No other MCCB scores were altered from baseline. Moreover, the cognitive test scores were strongly related to de- pression levels, but not to subjective memory complaints.

Our results correspond to the findings of the meta-analysis of Semkovska and McLoughlin (2010), who reported overall im- proved cognitive function 2 weeks after ECT. Moreover, in another Norwegian MCCB study, Kessler et al. (2014) found increased cognitive performance in bipolar disorder patients 3 weeks after

Table 5. Pearson's correlations of the relationship between depression severity (MADRS) and cog 31).

EMQ TMT-A BACS Fluency CPT-IP

Pre ECT MADRS � .25 .31 � .47nn � .47nn � .07 Post ECT MADRS .59nn .14 � .24 � .20 .24

nn po .01. n po .05 (2-tailed).

ECT, and no cognitive differences between patients treated with ECT and with anti-depressive medication. Ours is the first study documenting cognitive improvement after ECT in MDD patients using the comprehensive, standardized, and psychometrically strong MCCB assessment procedure.

The large post-ECT changes in Speed of Processing, Attention/ Vigilance, and Visual Learning is concordant with several studies reporting these domains to be strongly affected by depression (Egeland et al., 2003; Halvorsen et al., 2012; Lee et al., 2012; Murrough et al., 2015; Rund et al., 2006; Trivedi and Greer, 2014). Moreover, the same patients exhibited impaired levels of the same domains at baseline (Mohn and Rund, 2016). As the depression level is reduced, performance of these tests is likely to improve accordingly. As 9 of our participants did not perform the CPT-IP test, there is some uncertainty regarding the Attention/Vigilance finding in our study.

Improved Speed of Processing after ECT has been noted by others (Tsourtos et al., 2007). However, in the Sackeim et al. (2007), speed was still impaired 6 months after ECT. Possibly, methodological differences in terms of patient characteristics, technical aspects of ECT application, and cognitive assessment may explain these divergent results.

Our finding of improved Visual Learning is in accordance with the results of Bodnar et al. (2015) 3 months after ECT, and Maric et al. (2015) 1 month after ECT. However, Falconer et al. (2010) reported visuospatial decrements 1 month after ECT. Again, pa- tient characteristics and methodological aspects may be relevant explanations.

Retrograde amnesia for personal events is one of the most consistently reported side effects of ECT (Fraser et al., 2008). We did not assess this function. The main reasons were the wish to spare a severely ill and fatigued group of participants another time consuming test, and lack of psychometrically strong assessment tools of retrograde cognitive function in depressed individuals (Söderlund et al., 2014). Retrograde cognitive function may be impaired in patients who have been treated with ECT even in the face of unimpaired or improved anterograde function (Coleman et al., 1996; Kessler et al., 2014; Prudic et al., 2000). Therefore, cannot conclude that our participants did not display any cognitive side effects of ECT.

There was a strong relationship between depression severity and cognitive function at baseline, but not 6 weeks after ECT. This

nitive variables (EMQ and MCCB test scores) before and 6 weeks after ECT (N¼22–

SS-WMS LNS HVLT-R BVMT-R Mazes MSCEIT

� .38n � .60nn � .53nn � .43n � .28 � .44n

� .26 � .28 � .42n � .02 � .05 � .32

C. Mohn, B.R. Rund / Journal of Affective Disorders 202 (2016) 10–1514

is probably explained by the significant reduction in depression symptoms after treatment. However, the significant correlation between the MADRS score and the EMQ score at this time point is interesting, as it is supported by a similar finding by Brakemeier et al. (2011). In combination with our report of no strong relation between subjective (EMQ) and objective (MCCB) cognitive func- tion, we suggest that the memory complaints often reported by depression patients after ECT is related to the level of depression and not to actual cognitive performance.

4.1. Limitations and strengths

The first major limitation is the relatively small sample. Con- sequently, we were not able to compare the patients with MDD alone to those with symptoms of bipolar disorder II or psychosis, or to analyze gender effects. However, our heterogeneous patient group is a typical naturalistic sample, and our findings are prob- ably clinically valid. Nevertheless, some of the statistical results with small effect sizes should be interpreted with caution.

Second, the ECT procedure was not uniform, but tailored to meet each individual patient's clinical needs. Again, however, this renders our sample naturalistic and clinically valid.

Third, the MCCB was originally developed for assessment of schizophrenia patients, and has not been validated for other clin- ical populations. However, it is increasingly used in depression research (Kessler et al., 2014; Murrough et al., 2015), and in a baseline study of the present patients, this battery was able to differentiate between the depression group and the healthy con- trol group (Mohn and Rund, 2016). Cleary, this battery may be employed in depressive disorder populations, although formal validation studies from these patient groups are still lacking.

Fourth, it may be argued that the relatively short time span between baseline and follow-up cognitive assessment facilitates learning effects. However, one of the explicit aims behind the MCCB test selection and standardization procedure was the de- velopment of a battery that allows repeated assessments at rela- tively short intervals, and alternate forms of the tests are used when appropriate (Nuechterlein et al., 2008). Moreover, other re- levant studies have employed shorter follow-up periods than ours, with no reports of practice effects (Murrough et al., 2015; Rose- berry and Hill, 2014).

The major strengths of this study are the low drop-out rate and the use of a comprehensive, internationally validated neurocog- nitive test battery with strong psychometric properties in combi- nation with subjective reports of memory complaints.

5. Conclusion

Six weeks after ECT, cognitive function was either significantly improved or unaltered from baseline in MDD patients. Depression severity was associated with cognitive test scores at baseline, but not at follow-up. There was a discrepancy between cognitive test scores and subjective report of memory problems, and the latter were related to depression severity. The clinical implication is that complaints of cognitive problems after ECT could be the result of the depressive illness and not a side effect of ECT.

Conflict of interest No conflict of interest declared.

Role of funding source This study was supported by grants to Dr. Rund (no. 2009044 and no. 2011/125)

from the Helse Sør-Øst (Health South East) Regional Hospital Trust and Vestre Viken Hospital Trust. The funding source has not contributed to the performance of

the study or preparation of this article.

Contributors

Dr. Mohn designed the study, performed the neurocognitive assessments and the statistical analyses, and drafted the paper. Dr. Rund participated in the design of the study, the interpretation of the results, and in the drafting of the paper.

Acknowledgements Hilde Jakobsen, RN, Gro Liebeck, RN, and Drs Jovan Randjelovic, John E. Berg,

Phelix Blayvas, and Arne Thorvik are gratefully acknowledged for recruiting the patients for this study. Statistical advice was provided by Ms. Cathrine Brunborg, Oslo University Hospital.

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