The effect of adding biofeedback on heart rate variability to the treatment of
intimate partner violence perpetrators with cognitive behavioral therapy.

Meta-analyses of current treatments of intimate partner violence (IPV)
perpetrators show little to no effect in reducing violent behavior in intimate
relationships. Current practice in Europe is to treat risk factors with
cognitive behavioral therapy (CBT). An important therapy goal is to learn
self-control, which requires an early recognition of increasing arousal in
order to prevent escalation. However, the scientific literature on IPV shows
that perpetrators have difficulties in self-observing bodily signals that
accompany the build-up of arousal preceding IPV. A high level of emotional
arousal further hampers the ability to self-observe and subsequently to
self-control behavior. Because of this, we presume that IPV perpetrators can
not fully profit from *top down* CBT interventions aimed at developing
self-control.

With our newly developed smartphone application, GRIP-app, we aim to contribute
to the awareness of bodily signals that are associated with increased arousal
and subsequently contribute to the facilitation of reaching treatment goals of
IPV perpetrators. GRIP-app works in concordance with a wearable heart rate
sensor. It offers biofeedback on stress level (derived from heart rate
variability, a general marker of physiological arousal) and voice volume to
help perpetrators recognize increasing arousal. The smartphone will signal a
notification when a preset threshold is surpassed. We presume that by providing
biofeedback and supporting self-observation, perpetrators can practise
self-control before arousal becomes too high, thus preventing violence. This
presumption is built on prior research in other fields that shows that using
wearable technology contributes to achieving health-related goals by increasing
self-regulative abilities as well as increasing commitment to achieving these
goals.

The first objective is to investigate whether biofeedback on HRV and voice
volume will lead to a larger decrease of IPV compared to treatment as usual
(CBT only). Second, to test the premise that IPV perpetrators have trouble
self-observing bodily signals related to arousal, and whether adding
biofeedback to treatment increases awareness of bodily arousal signals. Third,
to explore whether HRV-values improve from pretest to posttest after using
biofeedback. Fourth, to gain an impression of the feasibility and practical
implications of using biofeedback with the newly developed GRIP-app and to
establish future research directions.

Randomized Controlled Trial (RCT) comparing treatment as usual (TAU) with CBT
to an experimental condition where biofeedback is added to CBT (EXP). After
obtaining informed consent, subjects will be randomly assigned to one of the
two treatment conditions, both with a 9-week duration. The primary outcome
measure will be administrated at T0 (before intervention period) and T1 (after
intervention period).

TAU consists of the CBT-based safety for partners treatment module, developed
by De Waag, which focuses on motivation, psycho-education and self-control.
Five out of eight weeks are aimed at self-control interventions. During this
time, subjects in the experimental condition (EXP) will be instructed to wear a
chest strap and use GRIP-app as often as possible and comfortable.

Regarding the burden, participants in the treatment as usual condition (TAU)
will receive regular treatment, and in addition fill out the outcome
questionnaires, and undergo a 5-minute baseline and posttreatment measurement
of HRV by wearing a heart rate sensor (see below).

Participants in the experimental biofeedback condition (EXP) will undergo these
same procedures and additionally wear a Polar H7 heart rate sensor during weeks
4-8, used in conjunction with GRIP-app on their smartphone. As for comfort,
participants might experience some physical discomfort by wearing the Polar H7,
because the device is worn on a soft chest strap which has to be made wet
before use. The chest strap also might feel tight or slightly painful to the
skin after prolonged wear. However, the strap is adjustable in size, addressing
tightness, and participants are free to limit their wearing time to the minimum
requirement or to leave the study and continue with regular treatment. We have
not found any risks or serious negative effects associated with wearing the
chest strap in literature. We will provide wearing instructions and therapists
will continually inquire into reasons that preclude wearing the strap, being
medical or otherwise.

As for data privacy, because Bluetooth is required, participants are exposed to
possible malevolent hacking attempts. However, we believe that the hardware and
software will primarily be used in the (relatively) safe home environment, and
that the Bluetooth requirement does not deviate from most people*s standard
usage of their smartphone. All data on physiological measures is handled
exclusively through secure network connections, accessing a server through a
cryptographic network protocol, where a therapist dashboard protected by hashed
passwords is coupled to GRIP-app with a unique code. No safety credentials are
hard-coded into the source code. Users have control over the data they share
with their therapist.

Participants referred by a probation officer might feel watched or controlled.
Data collection is limited to surpassings of the thresholds, only viewed before
the start of a therapy session and then discussed in-session with their
therapist. Participants are free to quit the study if they do feel watched,
without naming a reason. When quitting, we will ask whether their data might
still be used for data analysis or if they want to have it permanently removed.

Weighed against each other, we believe that the possible benefits of the
experimental condition * reduction of IPV - outweigh the possible burdens and
risks.