The Neurobiological Basis of the Patient-Practitioner Interaction: A PET Proof of Principle Study

Recent advances within the field of placebo effect research have demonstrated
that the patient-practitioner interaction is an important component in the
generation of these multi-facetted neuropsychobiological effects. The
neurotransmitters dopamine and opioids have been established as the neural
substrates involved affecting the psychological mechanisms of expectancy,
reward and motivation, and it is these mechanisms which are inherently involved
in patient-practitioner communication. Research has shown that certain aspects
of the patient-practitioner communication, such as physician empathy, are
important elements of medical care with regard to patient outcomes. A warm,
empathic, interaction in which a positive outcome is voiced influences
patients* expectancies and outcomes in a positive way; a cold, unempathic
interaction in which an uncertain outcome is voiced negatively impacts
patients* expectancies and outcomes. These two different communication styles
have also been found to have a direct influence on physiological correlates of
skin conductance and heart rate. However, the impact of these two communication
styles on neurotransmitter release in the brain regions involved with
expectancy, reward and motivation has not been explored.

To measure the impact of the two opposite communication styles (warm, empathic
and cold, formal) on the neurophysiological changes (endogenous dopamine
release) in the human brain using positron emission tomography (PET)
neuroimaging. This is an extension of our recent findings of affective- and
expectancy-oriented communication effects on analogue patients.

This proof of principle study uses a between subject design. In the
recruitment, screening and selection phase, interested participants (N>=36) fill
in a battery of psychological tests. On the basis of these, the twelve with the
highest interpersonal reactivity index (empathy) rating and menstrual pain
experience will be invited to participate in the PET scanning experiment. Each
volunteer (N=12) undergoes one PET scan using [11C]-raclopride as radiotracer.
During the PET scan, volunteers act as analogue patients and view a one-minute
video clip consultation of a general practitioner (N=6 cold, formal
communication style; N=6 warm, empathic communication style; random
assignment). The volunteers will be instructed to imagine that they are the
female patient in the video. On a separate day prior to the PET scan, each
subject with be required to undergo an MRI scan to establish brain anatomy
coordinates.

During a PET scan, participants will watch a video of a physician communicating
in an empathic and positive way or watching a video of a physician
communicating in an non-empathic way voicing uncertain outcome expectations.

In the recruitment, screening and selection section interested participants
have to complete questionnaires. There are no risks associated with
participation for this. The MRI and PET scans are to be carried out at the
Department of Nuclear Medicine & PET research of the VU Medical Center (VUmc).
The risks associated with PET scanning are limited, but the subjects will
receive tracer doses of radiation, which is estimated at 4 milli-Sievert (mSv)
(so less then 10 mSv). Minimal risks are associated with MRI acquisition.

No immediate benefits are to be expected for the individuals participating in
this study. No medical treatment is given.