The relationship between pain and cognitive functioning, of patients with neurodegenerative diseases such as Parkinson's disease, Multiple Sclerosis and Huntington's disease
Substudy: The relationship between pain, cognitive functioning, and motor activity in patients with multiple sclerosis

Parkinson*s disease, multiple sclerosis, and Huntington*s disease are
neurodegenerative disorders which are characterized by degeneration of the
white and grey matter. Besides sensory, motor, and cognitive disturbances, is
also pain a clinical hallmark of these disorders. Unfortunately, in these
specific disorders pain is not acknowledged as an important clinical symptom,
resulting in a less effective treatment of pain. However, in general the extent
in which people suffer from pain is crucial for the quality of life as it has a
large impact on for example work and personal relationships. Without an
effective pain treatment one can get isolated, anxious or depressive.

Various brain areas play a crucial role in both pain and cognition, supporting
the existence of a close relationship between pain and cognition. Consequently,
it is important to examine whether pain experience changes at the moment the
patient shows signs of a cognitive deterioration. A relationship between pain
experience and cognitive functioning has not been examined in the above
mentioned three neurodegenerative disorders so far. This is remarkable as
insight into this relationship is relevant for effective pain treatment. From a
theoretical point of view, one may assume that an increase in white matter
lesions coincides with an increase in the experience of pain. Due to an
increase in cognitive impairment, the patient may become less able to
communicate about his/her pain. Therefore, this study is of clinical relevance.

In patients with MS, also the relationship between pain, cognition, and motor
activity will be examined.

The total study (Parkinson, MS, Huntington) will include 284 patients and 170
controls without neurodegenerative disorders. In the past 10 years we performed
a number of studies in which we examined pain and cognition in patients with
dementia (Alzheimer's disease, vascular dementia). The power-analysis was based
on the results of these studies. Participants will be attracted through
outpatient clinics neurology, pateints'associations, and general practitioners.
Global cognitive functioning will be testen by means of the Mini-Mental State
Examination. More specific cognitive functions (attention, memory, executive
functions) will be tested by a neuropsychological testbattery. Motor activity
will be assessed by two scales. Pain experience will be assessed by means of a
number of pain scales that address pain intensity and the
motivational-affective aspects of pain.


In the MS-study, 40 new patients will be included. In these patients, motor
activity will be examined by two tests: the Expanded Disability Status Scale
(EDSS) and the Multiple Sclerosos Functional Composite (MFSC) (see protocol).

The total number of patients plus controls will amount: 454 (284 patiënts, 170
controls).


In patients with Huntington's disease also a pain observation scale will be
applied. In addition, the test Trailmaking will be replaced by the Key-Search
task of the Behavioural Assessment of Dysexecutive Disorders.

This study encompasses no risks for the patients. It is possible, however, that
the patients become tired during testing. We will address this point carefully
and extensively with the patients (and legal representatives) at the onset of
the examination. It will always be possible to complete the examination in two
or three sessions. This important aspect of the examination will have our full
attention.