Cognitive Performance Is Related to Central Sensitization and Health-related Quality of Life in Patients with Chronic Whiplash-Associated Disorders and Fibromyalgia

Pain Physician. May-Jun 2015;18(3):E389-401.

Abstract

Background: A growing body of research has demonstrated that impaired central pain modulation or central sensitization (CS) is a crucial mechanism for the development of persistent pain in chronic whiplash-associated disorders (WAD) and fibromyalgia (FM) patients. Furthermore, there is increasing evidence for cognitive dysfunctions among these patients. In addition, chronic WAD and FM patients often report problems with health-related quality of life (QoL). Yet, there is limited research concerning the interrelations between cognitive performance, indices of CS, and health-related QoL in these patients.

Objectives: (1) Examining the presence of cognitive impairment, CS, and limitations on health-related QoL in patients with chronic WAD and FM compared to healthy controls. (2) Examining interrelations between performance-based cognitive functioning, CS, and self-reported health-related QoL in these 3 study groups.

Study design: A case-control study was conducted.

Setting: The present study took place at the University Hospital Brussels, the University of Brussels, and the University of Antwerp.

Methods: Fifty-nine patients (16 chronic WAD patients, 21 FM patients, and 22 pain-free volunteers) filled out the Short Form 36 item Health Survey (SF-36), a self-reported psychosocial questionnaire, to assess health-related QoL. Next, they were subjected to various pain measurements (pressure hyperalgesia, deep-tissue hyperalgesia, temporal summation [TS], and conditioned pain modulation [CPM]). Finally, participants completed a battery of performance-based cognitive tests (Stroop task, psychomotor vigilance task [PVT], and operation span task [OSPAN]).

Results: Significant cognitive impairment, bottom-up sensitization, and decreased health-related QoL were demonstrated in patients with chronic WAD and FM compared to healthy controls (P < 0.017). CPM was comparable between the 3 groups. Cognitive performance was significantly related to central pain modulation (deep-tissue hyperalgesia, TS, CPM) as well as to self-reported health-related QoL (P < 0.05). Decreased cognitive performance was related to deficient central pain modulation in healthy controls. Further, significant correlations between decreased cognitive performance and reduced health-related QoL were revealed among all study groups. Additionally, FM patients showed correlations between cognitive impairment and increased health-related QoL. Remarkably, impaired selective attention and working memory were related to less TS, whereas impaired sustained attention was correlated with dysfunctional CPM in FM patients.

Limitations: Based on the current cross-sectional study no firm conclusions can be drawn on the causality of the relations.

Conclusion: In conclusion, this paper has demonstrated significant cognitive deficits, signs of CS, and reduced health-related QoL in chronic WAD and FM patients compared to healthy individuals. Significant relations between cognitive performance and CS as well as health-related QoL were demonstrated. These results provide preliminary evidence for the clinical importance of objectively measured cognitive deficits in patients with chronic WAD and FM.

Key words: Chronic pain, fibromyalgia, whiplash, central sensitization, conditioned pain modulation, temporal summation, cognition, quality of life.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Case-Control Studies
  • Central Nervous System Sensitization*
  • Cognition Disorders / etiology
  • Cognition Disorders / psychology
  • Cognition*
  • Female
  • Fibromyalgia / complications*
  • Fibromyalgia / psychology*
  • Humans
  • Hyperalgesia / etiology
  • Hyperalgesia / therapy
  • Male
  • Middle Aged
  • Neuropsychological Tests
  • Pain Management / methods
  • Psychomotor Performance / physiology*
  • Quality of Life
  • Stroop Test
  • Whiplash Injuries / complications*
  • Whiplash Injuries / psychology*
  • Young Adult