Chronic pain experience in adults with Down syndrome, with and without dementia, and the relationship with cognitive functioning.

Only a few studies have been published about a clinical very relevant symptom
with probably a high prevalence in intellectual disabilities: chronic pain.
Compared to the healthy population, people with intellectual disabilities have
a higher risk of developing musculoskeletal disorders. This is alarming,
because adults without intellectual disabilities rate musculoskeletal disorders
as very or extremely painful. Moreover, medical interventions for physical
conditions such as surgery or physiotherapy are often painful. An effective
treatment of these painful conditions requires a reliable pain assessment,
which is hampered in intellectual disabilities due to communicative
limitations, especially in those suffering from dementia. Impaired cognitive
performances have been observed in chronic pain patients. This is important in
intellectual disabilities, because the relationship between chronic pain and
cognition has not been examined in this syndrome.

First, we will focus on adults with Down syndrome, because the neuropathology
of this syndrome is familiar among which the brain areas that are involved in
pain processing.

The first aim of the present study is to examine whether the pain experience in
adults with Down syndrome (without dementia) differs from the pain experience
in adults without intellectual disability, after correction for mentale age,
comorbidity and medication. Furthermore, we will examine whether the pain
experience in adults with Down syndrome without dementia differs from the pain
experience in adults with both Down syndrome and dementia, after correction for
mentale age, comorbidity and medication

The second aim of the present study is to examine within the group persons with
Down syndrome whether a relationship exists between chronic pain experience and
cognitive functioning, and whether the presence of dementia changes the pain
experience.

The ultimate aim of the project is implimentation of daily pain diagnostics in
Dutch institutions for people with an intellectual disability, which we will
realise by training the nursing staff in execution of this diagnostics and by
developing a computer test in such way that people with intellectual
disabilities can regularly and independently indicate their pain.

Invasive, observational study.

Burden for subjects control group: in total 1.5 hours per subject

Burden for subjects with Down syndrome: in total 1.5 hours per subject
- The ApoE genotype will be determined by collecting saliva in the cheek
pouches with Orogene sponge sticks (and subsequently analyse these swabs in the
laboratory).
- The pain experience will be assessed in the subjects by means of 3 visual
analogue scales and 3 tests for tactile perception. In the test for tactile
perception, the subjects has to judge with eyes closed whether he/she feels on
the inside of his/her forearms the blunt or sharp side of a Neuropen, a cold
mental instrument and warm a warm mental instrument and when he/she feels 'von
Frey hairs' with differential thickness. This whole procedure will be executed
with greatest care. The measurements are standardised and quanitative, for
example 25 degrees Celcius for the cold stimulus and 40 degrees Celcius for the
warm stimulus.
- The cognitive functioning will be assessed by means of a test battery, which
is developed for adults with intellectual disabilities. Furthermore, the
nursing staff will complete a questionnaire for executive functions, because
these functions are difficult to test on the subjects themselves.

Burden for Down syndrome subjects Computer Test: in total 1 hour per subject
- Questions are answered by means of a touch screen, keypad buttons, or mouse.
It is investigated what works best. After a brief introduction about pain, the
subject answers a few questions about the location of body parts, numbersona a
ruler, and faces that express pain. This is the assessment of understanding.
Then the subject answer whether he / she has any pain today (answer YES and
NO). When "NO" is answered, then the test is automatically completed. When
"YES" is answered, then the pain experience is further explored. The test
automatically includes only the images that are understood in the comprehension
test. The test ends automatically with a pain score as a percentage of the
maximum score depending on the number of questions that are asked.
- In the test for understanding of sentences, the subject choose the
accompanying picture of each sentence that is read aloud. In the test for
vocabulary, he / she is asked to give the meaning of words. In the test for
block patterns, he / she makes patterns with colored blocks during which the
time is recorded. The tests for vocabulary and block patterns are increasingly
difficult until a cut-off point is reached.

Burden for nursing staff: 60 minutes per subject in total
- Completing an observation list for pain behaviour (by prefer 2x: after test
session and again 3 months later)
- Completing 3 questionnaires (executive functions, mental level, dementia)

Risks for subjects and nursing staff: none (a pin prick at the most).