EMDR protocol for urge to reduce scratching behaviour in prurigo nodularis

Prurigo nodularis (PN) is a chronic, inflammatory skin condition characterized
by intensely itchy nodules. PN (lit. *itchy bumps*) is, as the name suggests,
accompanied by severe itching. Compared to other dermatosis, PN shows the
highest values for itch intensity and frequency [1]. Itch is associated to
significant morbidities, such as suicidal ideations and sleeping problems [2].
PN is also associated with anxiety and depression, and quality of life
impairment [1, 3-5].
Scratching of the skin, as a response to the itch, is rewarding in the short
term, but may perpetuate the skin condition in the long run. In this way the
itch-scratch cycle is maintained [6], resulting in more itch.

Besides pharmacological treatment, psychological interventions that target
scratching behaviour show significant ameliorating effects on itching intensity
and scratching [7]. Psychological treatments for scratching behaviour are based
on *self-control procedures* and *habit reversal*. Habit reversal has been
shown to be effective in treating unwanted habits, such as thumb-sucking,
eyelash-picking, and scratching [8-11]. Habit reversal applies an 'incompatible
response': an activity that is incompatible with performing the unwanted habit
(i.e. wearing cotton gloves that make scratching impossible). Beside
self-control procedures and habit reversal, self-monitoring or registration of
habitual behaviour is a common component of effective cognitive-behavioural
treatments, which often leads to a decrease in the frequency of this behaviour
[12, 13].

The psychological intervention to be investigated in this study is the EMDR
protocol for urge (Drang EMD Protocol, DEP; Doeksen, 2018) [14], which draws on
elements of Eye Movement Desensitization and Reprocessing (EMDR) therapy,
cognitive behavioral therapy, and hypnotherapy. In the current treatment, not
the full EMDR procedure is applied, but only the EMD-part - that is the
desensitization part. Desensitization aims at the *fading out* or *losing
appetite* for behavior that is longed for, in this case the scratching [15].
Patients are allowed to perform the scratching in imagination, which
corresponds with the EMDR-technique of *cognitive interweaves*. Furthermore,
the treatment protocol draws on elements of cognitive behavior therapy, as
self-registration of behavior and homework assignments are core elements of
treatment. Finally, elements of hypnotherapy are incorporated in this
treatment, with respect to the interpretation to perceive the treated skin
spots - that does (no longer) evokes the urge to scratch - as *calm and white*.
This protocol, turned out to be successful in a number of individual treatments
[14]. The results of the first study to scientifically investigated this
intervention in patients with atopic dermatitis seem promising in that they
show a decrease in scratching behaviour. However, the effect of DEP on
scratching behaviour of patients with PN is unknown. Therefore, we aim to
replicate this previous study to investigate the effects of this intervention
in PN patients in a controlled study.

1. Steinke, S., et al., Humanistic burden of chronic pruritus in patients with
inflammatory dermatoses: Results of the European Academy of Dermatology and
Venereology Network on Assessment of Severity and Burden of Pruritus (PruNet)
cross-sectional trial. Journal of the American Academy of Dermatology, 2018.
79(3): p. 457-463. e5.
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prurigo nodularis. Journal of the European Academy of Dermatology and
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prurigo nodularis. Journal of the American Academy of Dermatology, 2022. 86(3):
p. 573-580.
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life: a systematic review and meta-analysis. Arch Dermatol Res, 2021. 313(8):
p. 669-677.
6. Kwatra, S.G., Breaking the itch-scratch cycle in prurigo nodularis. 2020,
Mass Medical Soc. p. 757-758.
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atopic dermatitis: a review. Br J Dermatol, 2016. 174(3): p. 657-9.
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outcome and quality of life in patients with chronic eczema: a prospective
observational study in the UK. Br J Dermatol, 2017. 177(2): p. 554-556.
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chronic skin picking: a pilot investigation. Behavior modification, 2006.
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research in assessment and treatment. Psychological Assessment, 1999. 11(4): p.
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overt change also imply implicit change? Journal of Behavior Therapy and
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drie patiënten met excessief krabben en tricotrillomanie, in EMDR Magazine.
2009. p. 5-9.
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Primary Objective:
To investigate if treatment according to the EMDR protocol for urge reduce
daily scratching behaviour in PN patients

Hypothesis: Treatment according to the EMDR protocol for urge leads to a
statistically significant reduction of daily scratching behaviour in PN
patients.

Secondary Objective(s):
2.1 To investigate if treatment according to the EMDR protocol for urge improve
the skin condition in PN patient.
2.2 To investigate if treatment according to the EMDR protocol for urge improve
quality of life in PN patients.
2.3 To investigate if treatment according to the EMDR protocol for urge improve
perceived self-control in PN patients.
2.4 To investigate if treatment according to the EMDR protocol for urge improve
sleep quality in PN patients.

Hypotheses:
2.1 H1: Treatment according to the EMDR protocol for urge leads to a clinically
relevant improvement in skin condition in PN patients.
2.2 H1: Treatment according to the EMDR protocol for urge leads to a clinically
relevant improvement in quality of life in PN patients.
2.3 H1: Treatment according to the EMDR protocol for urge leads to a clinically
relevant improvement in perceived self-control in PN patients.
2.4 H1: Treatment according to the EMDR protocol for urge leads to a clinically
relevant improvement in sleep quality in PN patients.

The current study applies a multiple baseline across subjects design, in which
participants will be randomly allocated to different baseline lengths. All
patients will start their daily registration at the same time, at day 1
(Monday) of week 1. After a minimum of three weeks baseline registration, pairs
of two patients were randomly selected and were assigned to one of three
possible starting weeks, with a randomly selected weekday for each patient to
start treatment. The intervention phase starts when the first DEP treatment is
applied and ends on the last day of week eight. During the intervention phase a
total of two DEP sessions take place in the setting of the of the psychiatry
outpatient clinic of the Erasmus MC. The total study duration, consisting of
the baseline and intervention phase is 8 weeks and is equal for all
participants.

Eye Movement and Desensitization Reprocessing (EMDR) therapy is an
evidence-based psychological treatment that is recommended by national
guidelines for the treatment of PTSD [18]. Since then, it has been shown to be
effective for a variety of anxiety and somatic complaints [19-21]. In the
current study, the EMDR protocol for urge (DEP) is tested. This protocol has
recently been developed and applied and clinical results so far have been
positive [14]. However, scientific research on its effectivity so far is
scarce. For this reason, we aim to conduct the current study.
Working-memory theory offers an explanation for how EMDR might work [22, 23].
The theory states that the short-term or working memory can perform various
tasks at the same time. However, the working memory has a limited attention
capacity. As a result, by performing one task, performance on another task
comes under pressure. In DEP, the patient is asked to focus on the distracting
stimulus, but at the same time also to focus on the urge to scratch his/her
skin. So, the attention, which is focused on the urge to scratch, is distracted
by the eye movements. The hypothesis is that as a result, 'decay'
(desensitization) of the urge to scratch takes place and the urge loses more
and more of its urgency.
In this study the DEP consists of two sessions of 90 minutes divided over two
weeks (so one session in week 1, and one in week 2 of the intervention phase).
An important part of DEP consists of homework exercises. These homework
exercises comprise to practice/apply the intervention as learned during the
sessions with the therapist, in those situations wherein the urge to scratch
their skin is present. In the text below, we will explain in more detail what
the treatment protocol entails.

In the DEP sessions, the patient is asked to focus on the spot on his/her skin
where the urge to scratch is highest. The patient then is asked to rate the
level of urge to scratch this spot on a 10-point scale and to imagine that they
scratch this spot as they would like. At the same time eye movements are
offered for 30 seconds. Then, the level of urge is rated again and the
procedure is repeated until the level of urge to scratch that particular spot
has become nihil. After that the patient is asked to imagine that this spot had
become *white*, that is calm and quiet. Next, this procedure is repeated for
all other skin parts where the patient experiences an urge to scratch, until
there are no skin parts left that the patient wishes to scratch during the
session. As a homework assignment straight after the first session, the patient
is instructed and encouraged to practice the same intervention at home. That
is, each time that the patient experiences the urge to scratch his skin, he has
to imagine that he is actually scratching in the way he would like to do and at
the same time focus on a distracting stimulus that taxes working memory. This
distracting stimulus is either the following of one*s own finger moving from
left to right, or playing Tetris on one*s mobile phone. Within three days after
each of the face-to-face sessions, the patient is called by the therapist to
ask for their experiences with the practicing at home. In case the patient
experiences difficulties in practicing at home, these difficulties are
discussed and patient and therapist together try to find a solution to enable
practicing at home.

18. Balkom, A.v., et al., Multidisciplinaire richtlijn Angststoornissen.
Richtlijn voor de diagnostiek, behandeling en begeleiding van volwassen
patiënten met een angststoornis. 3th revision ed. Utrecht: Trimbos-instituut,
2013.
19. Logie, R. and A. De Jongh, The *Flashforward procedure*: Confronting the
catastrophe. Journal of EMDR Practice and Research, 2014. 8(1): p. 25-32.
20. Dautovic, E., et al., Pediatric seizure-related posttraumatic stress and
anxiety symptoms treated with EMDR: a case series. European Journal of
Psychotraumatology, 2016. 7(1): p. 30123.
21. van Rood, Y.R. and C. de Roos, EMDR in the treatment of medically
unexplained symptoms: A systematic review. Journal of EMDR practice and
Research, 2009. 3(4): p. 248-263.
22. Engelhard, I.M., et al., Reducing vividness and emotional intensity of
recurrent *flashforwards* by taxing working memory: An analogue study. Journal
of anxiety disorders, 2011. 25(4): p. 599-603.
23. de Jongh, A., et al., The impact of eye movements and tones on disturbing
memories involving PTSD and other mental disorders. Journal of behavior therapy
and experimental psychiatry, 2013. 44(4): p. 477-483.

We expect that the intervention will reduce unwanted behaviour, that is the
scratching worsening the skin condition in patients with PN. Apart from the
time investment (to attend two therapy sessions and to fill out the
questionnaires), no disadvantages are expected to participate in the study.
However, participants may be disappointment in case the experimental treatment
may not bring what the patients had hoped for. However, this is no other than
the risk any patient faces in undergoing experimental treatment.