Prospective study of nocebo effects related to symptoms of idiopathic environmental intolerance attributed to electromagnetic fields, 2020, Brascher

[Andy]

The exact causes of Idiopathic Environmental Intolerance Attributed to Electromagnetic Fields (IEI-EMF, i.e., experience of somatic symptoms attributed to low-level electromagnetic fields) are still unknown. Psychological causation such as nocebo effects seem plausible. This study aimed to experimentally induce a nocebo effect for somatic symptom perception and examined whether it was reproducible after one week. We also examined whether these effects were associated with increased sympathetic activity and whether interoceptive accuracy (IAcc) moderated these relationships.

Participants were recruited from the general population and instructed that electromagnetic exposure can enhance somatosensory perception. They participated twice in a cued exposure experiment with tactile stimulation and sham WiFi exposure in 50% of trials. The two sessions were scheduled one week apart (session 1: N = 65, session 2: N = 63). Before session 1, participants watched either a 6-minute film on adverse health effects of EMF or a neutral film on trade of mobile phones. IAcc was assessed with the heartbeat detection paradigm. Electrodermal activity served as a measure of sympathetic activation. Evidence for a nocebo effect (i.e., increased self-reported intensity and aversiveness and electrodermal activity) during sham WiFi exposure was observed in both sessions. IAcc moderated the nocebo effect, depending on stimulus intensity. Contrary to previous findings, no difference emerged between the health-related EMF and the neutral films.

Based on negative instructions, somatic perception and physiological responding can be altered. This is consistent with the assumption that IEI-EMF could be due to nocebo effects, suggesting an important role for psychological interventions.

Paywall, https://www.sciencedirect.com/science/article/abs/pii/S0013935120309166
Sci hub, https://sci-hub.tw/10.1016/j.envres.2020.110019

 

[Hutan]

Although the prevalence of IEI-EMF is considerable (on average 6 % across nine countries; Huang et al., 2018) and the strain on affected individuals is severe

Oh please - 6% of people severely affected by thinking EMF affected their health? Sure, 6% of people might think EMF can affect health, but I very much doubt that the strain on those 6% of people is severe.

experience of symptoms can emerge as a result of imprecise bodily sensations interacting with highly precise prior beliefs about symptoms. In extreme cases, sensory input may not be present at all

This is the core idea - one that is used to explain ME/CFS by some.

Several personality characteristics have been proposed as potential moderators of symptom generation, including interoceptive accuracy, trait negative affectivity, and gender.

Adding gender (female vs. male) as an additional factor was waived in the presented analyses since it did not change the observed pattern of results

So, despite it being hypothesised that gender was important in determining who feels symptoms when there is no real reason for them, this study didn't find that.

 

[Hutan]

Interoceptive accuracy

Participants were instructed to silently count their heartbeats by concentrating on bodily sensations that might be associated with heart activity. They were not allowed to take their pulse or attempt any other manipulations to facilitate the discrimination of their heartbeats (Schandry, 1981).

There were no significant correlations between the perception score (assessed at the first session) and self-reported intensity and aversiveness of the first session. Significant correlations between the perception score and self-reports of the second session emerged (Tab. 4). Correlations were negative for trials with low tactile stimuli and medium tactile stimuli, but positive for trials with high tactile stimuli. This means that higher interoceptive accuracy (IAcc) was related to smaller nocebo effects (i.e., the difference in the subjectively perceived intensity and aversiveness of WiFi ON and WiFi OFF trial) for weak and medium intense tactile stimuli. In the case of strong tactile stimuli, higher IAcc was positively associated with stronger nocebo effects in self-reported aversiveness and by trend self-reported intensity.

Consistent with predictive processing accounts, we hypothesized that higher interoceptive accuracy would lead to more reliable sensory input to the brain and thus reduce the impact of prior beliefs on the eventual conscious perception (Van den Bergh et al., 2017a; Van den Bergh et al., 2017b). Results show that interoceptive accuracy at session 1 predicted the nocebo effect in the second session. As expected, better interoceptive accuracy was related to a smaller nocebo effect with weak and medium stimuli. However, in strong tactile stimuli, higher interoceptive accuracy was related to a greater nocebo effect suggesting a larger influence of the prior in this context.

So, they expected that accuracy when estimating one's own heart beats was a sign of interoceptive accuracy, which they expected to be a good thing i.e. to prevent a nocebo effect. I'm not sure about that - there are a range of reasons why someone might be able to sense their heart beat. I would have thought being stressed might make your heart pound. Anyway.

In session 1, they found that people who estimated their heart rate accurately were no more or less likely to over-estimate the strength of a tactile stimulus. So their expectation was not borne out.

In session 2 a week later, they found that people who had estimated their heart rate accurately were less likely to over-estimate the strength of the weak and moderate intensity stimuli. But they were more likely to over-estimate the strength of the higher intensity stimuli. That is sounding all very random to me.

Nevertheless, the authors claim that interoceptive accuracy predicts the nocebo effect. If they found anything at all (which I strongly doubt), it was the opposite of what they expected - interoperative accuracy predicted a higher impact of prior beliefs on conscious perception.

No actual data for all this is presented of course.

 

[Hutan]

I have to stop looking at the study for now.

But, of note is that showing groups a film about the dangers of EMF vs a neutral film about trade in mobile phones had no impact on the nocebo response.

 

[James Morris-Lent]

This study is not ethical by it's own premises. By their own admission they are risking causing subjects to develop a serious illness with no reliable treatment:


1) The authors believe that 'psychological causation such as nocebo effect' could plausibly cause IEI-EMF.

2) The authors consider IEI-EMF to be a serious problem for sufferers (my bold below):

Individuals with idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF) experience various medically unexplained symptoms (e.g., paresthesia, headache, dizziness), which they attribute to exposure to weak electromagnetic fields emitted by electrical devices like mobile phones, WiFi routers, and similar devices (Baliatsas et al., 2012). Although the prevalence of IEI-EMF is considerable (on average 6 % across nine countries; Huang et al., 2018) and the strain on affected individuals is severe

3) According to the authors, there is no reliable cure or treatment for IEI-EMF:

treatment options remain limited, since the underlying cause of the condition has not been conclusively determined.

The authors explicitly state:

This study aimed to experimentally induce a nocebo effect

Again, they believe that this nocebo could cause a severely distressing and debilitating disease state. So they are exposing subjects to what they consider a plausible trigger for a serious disease state. Thus by their own admission they are risking causing subjects to develop a serious illness with no reliable treatment.

You can't do that.

@dave30th