RESUMO
Background: Body image disturbance and anxiety are core features of anorexia nervosa (AN), a psychiatric disorder with one of the highest mortality rates. This study examined the efficacy of a novel non-pharmacological treatment, floatation-REST (Reduced Environmental Stimulation Therapy) on body image disturbance and anxiety in inpatients with AN. Methods: This parallel group randomised controlled trial compared floatation-REST vs. care as usual in women and girls hospitalised for treatment of AN in Tulsa, Oklahoma, USA. Participants were randomised on a 2:1 ratio to receive eight, twice-weekly, 60-min floatation-REST sessions for 4 weeks, in addition to care as usual, or to receive care as usual. The primary outcome was the average change in body dissatisfaction from pre- to post-float as measured by the Photographic Figure Rating Scale. The secondary outcome was the average change in anxiety from pre- to post-float as measured by the state version of the State Trait Anxiety Inventory. Longitudinal effects of floatation-REST on body dissatisfaction were also examined. All analyses were conducted using the intention-to-treat principle. Planned linear mixed models tested the effect of floatation-REST vs. care as usual. The trial was preregistered (clinicaltrials.govNCT03610451). Findings: Between March 16, 2018 and February 25, 2021, 133 participants were screened for eligibility, and 86 were consented. Eighteen were excluded after consent, for a final randomisation sample of 68 participants (45 floatation-REST; 23 care as usual). There were two session by condition interactions on body dissatisfaction (p = 0.00026) and state anxiety (p < 0.0001), such that the floatation-REST group exhibited acute (i.e., pre- to post-session) reductions in body dissatisfaction (floatation-REST group mean change (Δm) = -0.43; 95% CI -0.56 to -0.30, p < 0.0001, Cohen's d = 0.23), and acute reductions in anxiety (floatation-REST group Δm = -15.75; 95% CI -17.95 to -13.56, p < 0.0001, Cohen's d = 1.52); however, the care as usual group exhibited no significant changes. With regard to longitudinal results, there was a significant time by treatment interaction between baseline and immediately post intervention (p = 0.012) and baseline and six-month follow up (p = 0.0019). At immediately post intervention, there was a trending reduction in body dissatisfaction for the floatation-REST group (Δm = -0.41, 95% CI -0.86 to 0.03, p = 0.068) and care as usual group (Δm = 0.61; 95% CI -0.04 to 1.27, p = 0.070). At six-months post-intervention, the floatation-REST group exhibited lower body dissatisfaction (Δm = -0.91; 95% CI -1.37 to -0.45, p = 0.0020, Cohen's d = 0.53) whereas the care as usual group reported no change in body dissatisfaction (Δm = 0.35; 95% CI -0.28 to 0.98, p = 0.96) relative to baseline. There were no adverse events related to the trial during the study. Interpretation: Our findings suggest that Floatation-REST decreased body dissatisfaction compared to care as usual acutely after each float session and at six-month follow-up. Floatation-REST has potential utility for the treatment of body image disturbance and anxiety in AN. These results may be limited by some generalisability concerns given the recruitment of a modest sample receiving inpatient treatment at a single site. Funding: The William K. Warren Foundation.
RESUMO
Understanding the neural processes governing the human gut-brain connection has been challenging due to the inaccessibility of the body's interior. Here, we investigated neural responses to gastrointestinal sensation using a minimally invasive mechanosensory probe by quantifying brain, stomach, and perceptual responses following the ingestion of a vibrating capsule. Participants successfully perceived capsule stimulation under two vibration conditions (normal and enhanced), as evidenced by above chance accuracy scores. Perceptual accuracy improved significantly during the enhanced relative to normal stimulation, which was associated with faster stimulation detection and reduced reaction time variability. Capsule stimulation induced late neural responses in parieto-occipital electrodes near the midline. Moreover, these 'gastric evoked potentials' showed intensity-dependent increases in amplitude and were significantly correlated with perceptual accuracy. Our results replicated in a separate experiment, and abdominal X-ray imaging localized most capsule stimulations to the gastroduodenal segments. Combined with our prior observation that a Bayesian model is capable of estimating computational parameters of gut-brain mechanosensation, these findings highlight a unique form of enterically-focused sensory monitoring within the human brain, with implications for understanding gut feelings and gut-brain interactions in healthy and clinical populations.
