Clin Rheumatol. 2013 Jun 5. [Epub ahead of print]
Cognitive performance is of clinical importance, but is unrelated to
pain severity in women with chronic fatigue syndrome.
Ickmans K, Meeus M, Kos D, Clarys P, Meersdom G, Lambrecht L, Pattyn N, Nijs J.
Pain in Motion Research Group (PIM), Department of Human Physiology,
Faculty of Physical Education and Physiotherapy, Vrije Universiteit
Brussel, Building L, Pleinlaan 2, 1050, Brussels, Belgium.
In various chronic pain populations, decreased cognitive performance
is known to be related to pain severity. Yet, this relationship has
not been investigated in patients with chronic fatigue syndrome (CFS).
This study investigated the relationship between cognitive performance
and (1) pain severity, (2) level of fatigue, and (3) self-reported
symptoms and health status in women with CFS. Examining the latter
relationships is important for clinical practice, since people with
CFS are often suspected to exaggerate their symptoms. A sample of 29
female CFS patients and 17 healthy controls aged 18 to 45 years filled
out three questionnaires (Medical Outcomes Study 36-Item Short-Form
Health Survey, Checklist Individual Strength (CIS), and CFS Symptom
List) and performed three performance-based cognitive tests
(psychomotor vigilance task, Stroop task, and operation span task),
respectively. In both groups, pain severity was not associated with
cognitive performance. In CFS patients, the level of fatigue measured
with the CFS Symptom List, but not with the CIS, was significantly
correlated with sustained attention. Self-reported mental health was
negatively correlated with all investigated cognitive domains in the
CFS group. These results provide evidence for the clinical importance
of objectively measured cognitive problems in female CFS patients.
Furthermore, a state-like measure (CFS Symptom List) appears to be
superior over a trait-like measure (CIS) in representing cognitive
fatigue in people with CFS. Finally, the lack of a significant
relationship between cognitive performance and self-reported pain
severity suggests that pain in CFS might be unique.
PMID: 23737111 [PubMed - as supplied by publisher]