The ethics of neuromodulation for anorexia nervosa: a focus on rTMS

'My dad was like "it's your brain, what are you doing?"': Participant experiences of repetitive transcranial magnetic stimulation treatment in severe enduring anorexia nervosa

Objective

Repetitive transcranial magnetic stimulation (rTMS) is a promising emerging treatment for anorexia nervosa (AN). However, to date, patients' views and experiences of this treatment have not been fully explored. To assess these, we integrated a qualitative study into a feasibility randomised controlled trial of rTMS in individuals with severe enduring AN.

Method

Twenty‐nine (of 34) trial participants contributed to this study. Semi‐structured interviews were conducted 3‐months following the completion of rTMS treatment (4‐months post‐randomisation), prior to unblinding. Transcripts were analysed using content analysis.

Results

rTMS was deemed an acceptable but time‐consuming treatment. Many emphasised how their lives had changed to some extent during, but mainly after treatment by making them more positive, open‐minded, flexible and willing to try new things in relation to their AN and other aspects of their lives.

Conclusions

These qualitative data will be valuable in shaping participant information, recruitment and planning of future large‐scale trials of rTMS in AN.

Trial Registration

ISRCTN14329415, registered 23rd July 2015, https://www.isrctn.com/ISRCTN14329415

This study is the first to systematically explore participants' experiences of repetitive transcranial magnetic stimulation (rTMS) treatment for severe enduring anorexia nervosa (AN), as part of a randomised controlled feasibility trial.

Participants expressed that rTMS was an acceptable but time‐consuming treatment. Many participants who received real rTMS described positive changes in relation to AN and quality of life.

Findings from this qualitative study will help to shape future research of rTMS treatment for AN.

Participants' experience of approach bias modification training with transcranial Direct Current Stimulation as a combination treatment for binge eating disorder

OBJECTIVE

This study explored participants' experience of approach bias modification training (ABM) with transcranial Direct Current Stimulation (tDCS) for binge eating disorder (BED) within a randomised controlled trial (RCT). A subset of participants who completed the RCT were interviewed to attain feedback on treatment experience and outcomes.

METHOD

15 participants with BED who completed the RCT were recruited, using purposive sampling. Participants received six sessions of concurrent ABM training with either real or sham tDCS. Semi-structured interviews relating to study experience and treatment outcomes were conducted and data were analysed thematically.

RESULTS

The combined ABM and tDCS intervention was deemed acceptable and worthwhile by participants interviewed across both intervention groups. Negative preconceptions of tDCS were an initial deterrent to study participation for some, yet the brain stimulation experience was found to be tolerable. Minor and transient sensations and side effects attributed to tDCS were reported by most participants during and after stimulation, in addition to less pleasant aspects of ABM training, with no significant adverse effects reported by interviewees. Positive outcomes were described by participants across both intervention groups, relating to changes in BED symptoms and to broader beneficial effects on associated cognitive and emotional factors. Two participants experienced a shift in autonomy, attributed to tDCS and the combined intervention respectively.

CONCLUSIONS

Adults with symptoms of BED found concurrent ABM and tDCS sessions to be acceptable, despite initial apprehension about the safety of tDCS. Findings are relevant to the neuroethics literature and may inform science communication strategies on neuromodulation treatments.

Neurostimulation in Clinical and Sub-clinical Eating Disorders: A Systematic Update of the Literature

INTRODUCTION

Whilst psychological therapies are the main approach to treatment of eating disorders (EDs), advances in aetiological research suggest the need for the development of more targeted, brain-focused treatments. A range of neurostimulation approaches, most prominently repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation (tDCS) and deep brain stimulation (DBS), are rapidly emerging as potential novel interventions. We have previously reviewed these techniques as potential treatments of EDs.

AIM

To provide an update of the literature examining the effects of DBS, rTMS and tDCS on eating behaviours, body weight and associated symptoms in people with EDs and relevant analogue populations.

METHODS

Using PRISMA guidelines, we reviewed articles in PubMed, Web of Science, and PsycINFO from 1st January 2013 until 14th August 2017, to update our earlier search. Studies assessing the effects of neurostimulation techniques on eating and weight-related outcomes in people with EDs and relevant analogue populations were included. Data from both searches were combined.

RESULTS

We included a total of 32 studies (526 participants); of these, 18 were newly identified by our update search. Whilst findings are somewhat mixed for bulimia nervosa, neurostimulation techniques have shown potential in the treatment of other EDs, in terms of reduction of ED and associated symptoms. Studies exploring cognitive, neural, and hormonal correlates of these techniques are also beginning to appear.

CONCLUSIONS

Neurostimulation approaches show promise as treatments for EDs. As yet, large wellconducted randomised controlled trials are lacking. More information is needed about treatment targets, stimulation parameters and mechanisms of action.

Neuromodulation and neurofeedback treatments in eating disorders and obesity

PURPOSE OF REVIEW

Psychological interventions are the treatment of choice for most eating disorders; however, significant proportions of patients do not recover with these. Advances in understanding of the neurobiology of eating disorders have led to the development of targeted treatments, such as deep brain stimulation (DBS), noninvasive brain stimulation (NIBS), and neurofeedback. We review the emerging clinical evidence for the use of these interventions in eating disorders and obesity, together with their theoretical rationale. Finally, we reflect on future developments.

RECENT FINDINGS

During the last 20 months, seven case studies/series and seven randomized controlled trials (RCTs) of NIBS or neurofeedback in different eating disorders, obesity, or food craving have appeared. These have largely had promising results. One NIBS trial, using a multisession protocol, was negative. A case series of subcallosal DBS in anorexia nervosa has also shown promise. A search of trial registries identified a further 21 neuromodulation/feedback studies in progress, indicating that neuromodulation/feedback is an area of growing interest.

SUMMARY

At present, neuromodulation and neurofeedback are largely experimental interventions; however, growing understanding of the mechanisms involved, together with the rising number of studies in this area, means that the clinical utility of these interventions is likely to become clearer soon.