Distractions like films prevent inflated readings when measuring patients' lung function, say researchers after the first study into anxiety and electrical activity in rib muscles.
Inspiration for the study came when Dr Victoria MacBean, physiotherapy lecturer at Brunel University London, used to show the animated adventure film Finding Nemo to settle and distract children while taking EMGpara measurements.
This method uses electrodes on the skin to measure electrical activity in the intercostal muscles – which help form and move the chest wall – to give a better measurement of how hard an individual has to work to breathe. For children and for adults with lung disease, it's a less invasive and troublesome measurement than peak flow and similar tests, which requires them to exhale forcefully and fully.
"Mostly the measurements would only take about 45 minutes. But every now and then we'd have siblings to measure back to back, or a child took longer to settle, and we'd get to the scary bit in the film with the sharks," Dr MacBean said. "I kept thinking to myself whether it made a difference to my data, and whether anxiety in children or in adults could change the readings."
Dr MacBean teamed up with experimental psychology student Juliette Westbrook to take EMGpara, air flow and other lung function measurements from 22 adults under four different conditions. Each participant watched giraffes fighting in David Attenborough's Africa for tension and gentler sequences for calm, listened to music from the latest charts, and was also tested in a no-distraction condition – each time assessing how tense or relaxed they felt.
Results showed that being exposed to a tense external condition is associated with higher EMGpara readings, together with a faster breathing rate and a bigger volume of breath exhaled over a minute.
This is problematic, explains Dr MacBean: "In a clinical setting, such elevated readings could make the patient appear more tired or unwell, and possibly result in incorrect treatment."
With externally generated anxiety and internally generated anxiety having similar effects on the body – such as 'white coat hypertension' causing a blood pressure rise – a patient with lung disease's worries could result in incorrect lung function measurements.
"We think adults can just sit there and act predictably," said Dr MacBean (pictured above). "But they could be worried about being made breathless by the test, why the test is being done, what's about to come next, whether their disease is getting worse, and so on."
Their study suggests that careful consideration should be given to minimising participant anxiety before undertaking any respiratory measurements to make the results as reliable as possible.
"We certainly don't have any evidence that focussing on relaxation will have an adverse effect on the measurements," added Dr MacBean.
"So some form of distraction is probably beneficial in many situations, together with a longer settling-down period before testing. Individuals who are more anxious will also benefit from more detailed explanations and reassurance."
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