H567/02 Section A - Chaney et al. (2004): Funhaler study

Reinforcement, sample and design

Prescribed medication cannot have its intended effect if using the delivery device is difficult or avoided. The researchers developed the Funhaler, a spacer with a spinner and whistle designed to give enjoyable feedback during effective breathing. The psychological principle is positive reinforcement: a rewarding consequence of a behaviour can increase the likelihood of repeating it. The intended reward was the play feedback, rather than the delayed health benefit, which a preschool child may not readily understand. Demonstrating an attractive device is not itself proof that reinforcement caused a lasting change.

The pilot recruited 32 children using prescribed inhaled asthma medication and a spacer from seven clinics in Perth, Western Australia. The original report describes random recruitment across clinics covering differing geographical and socioeconomic areas. There were 22 boys and 10 girls, aged 1.5–6 years, with a mean age of 3.2 years and an average asthma duration of 2.2 years. Parents supplied information and permission. Random recruitment within a clinical setting does not make this a representative sample of every child, and does not mean random allocation to device order.

This was a home-based field investigation with repeated measures: parents reported on their child's existing spacer, then on the Funhaler after two weeks. OCR describes it as a field experiment; the original report describes a matched questionnaire survey of the same caregivers at two interviews. Both descriptions recognise that the device changed while each child acted as their own comparison. Stable differences such as age and temperament were therefore less likely to explain the before-and-after difference. However, conventional-device use always came first. Device and order were linked, so practice, novelty or greater parental attention during the trial could contribute to improvement.

The device and the procedure

The Funhaler separated the spinner and whistle from the principal drug-delivery pathway, placing the incentive toys in a branch associated with the expiratory valve. This aimed to reward useful breathing without obstructing delivery or contaminating the medication path. The design allowed incentive components to be changed to help maintain interest. A laboratory aerosol-output comparison with a conventional small-volume spacer found no significant difference in the tested delivery characteristics. That check supports the feasibility of the device design, not proof of improved clinical health.

Parents were approached at home and interviewed about the existing spacer before the Funhaler was introduced, reducing the chance that initial ratings were simply comparisons with the appealing new device. The same interviewer conducted two matched questionnaire interviews: baseline and after two weeks of Funhaler use. Questions covered ease of use, success medicating the child, willingness, breathing technique, and parental attitudes. Parents were also telephoned at random on one occasion to ask about medication on the previous day. The random timing of a call was a reporting check; it did not counterbalance the device conditions.

The dependent measures were primarily parent reports, including previous-day medication and whether the child achieved at least four breathing cycles per aerosol delivery. They were not direct measurements of drug doses absorbed or long-term asthma symptoms. Parents observed home use, making their reports practically relevant, but the researchers could not independently verify every reported attempt or breath.

Reported results and their limits

The number of valid responses differed between questions; 32 recruits does not mean every percentage used 32 as its denominator.

The breathing-cycle difference was 30 percentage points, calculated as $80-50=30$. There were nine more children meeting that criterion among the 30 valid comparisons. A relative increase would be $(80-50)/50\times100=60\%$; that is a different calculation. Do not call a 30-percentage-point difference a 30% relative increase. For previous-day medication, rounded percentages differ by 22 points; calculating directly from counts gives $(22-16)/27\times100\approx22.22$ percentage points.