July 30, 2019

expert reaction to study looking at ‘tickling’ the ear with a small electric current and various measures of wellbeing

A study, published in the journal Aging, reports that ‘tickling’ the ear with a small electric current could potentially slow down some of the effects of ageing. 

Dr David Clancy, Lecturer, Lancaster University, said:

“There is a shift toward sympathetic nervous system activity (fight/flight) with age which may be associated with declines in heart function, blood pressure control, mood and emotion and gut function that occur as we age, though there is clearly an unresolved cause versus effect question here.

“But vagal nerve stimulation is known to help shift the balance in the autonomic nervous system back toward the parasympathetic.

“Here the researchers used a simple non-invasive method of stimulating the vagus nerve using an electrode attached to part of the external ear, and measured many cardiovascular parameters as well as aspects of mood and quality of life.

“Although study 1, with a small sample size of 14 people, tested stimulation versus sham in the same subjects and found benefit, the other two studies had more subjects but had no controls, instead comparing treatment responses to measures at baseline.  In study 2, it would have been useful to measure responses to treatment versus sham here, because the people who took part were sat in a quiet, temperature controlled (21 ± 2°C) room, and were reclined semi-supine on a couch for the duration of each experiment – I suspect many of us may have found our relaxation and wellbeing improved under such conditions!  In study 3, participants first received the treatment in these conditions and were trained how to use it, and after that they did it themselves at home every day for two weeks.  This is better and more convincing, but still lacks a control group – the participants presumably knew the aims of the experiment and knew what they were doing to themselves so the potential for placebo effect is significant.

“People with higher resting or baseline sympathetic tone seemed to respond most.  The ability of the heart to respond to changes in blood pressure decreases with age and seems to be associated with cardiovascular as well as all-cause mortality.  This measure and measures related to it seemed to change most in those with poorer baseline states so the treatment might usefully be tried on this group.

“However to be sure we would want to see a controlled study using a cohort who received sham vagal nerve stimulation.”

‘Effects of transcutaneous vagus nerve stimulation in individuals aged 55 years or above: potential benefits of daily stimulation’ by Beatrice Bretherton et al. was published in Aging at 05:00 UK time on Tuesday 30 July 2019. 

DOI: 10.18632/aging.102074

Declared interests

Dr David Clancy: “I have no competing interests to declare.”