Does cognitive functioning predict chronic pain? Results from a prospective surgical cohort.

It is well established that chronic pain impairs cognition, particularly memory, attention and mental flexibility. Overlaps have been found between the brain regions involved in pain modulation and cognition, including in particular the prefrontal cortex and the anterior cingulate cortex, which are involved in executive function, attention and memory. However, whether cognitive function may predict chronic pain has not been investigated. We addressed this question in surgical patients, because such patients can be followed prospectively and may have no pain before surgery. In this prospective longitudinal study, we investigated the links between executive function, visual memory and attention, as assessed by clinical measurements and the development of chronic pain, its severity and neuropathic symptoms (based on the 'Douleur Neuropathique 4' questionnaire), 6 and 12 months after surgery (total knee arthroplasty for osteoarthritis or breast surgery for cancer). Neuropsychological tests included the Trail-Making Test A and B, and the Rey-Osterrieth Complex Figure copy and immediate recall, which assess cognitive flexibility, visuospatial processing and visual memory. Anxiety, depression and coping strategies were also evaluated. In total, we investigated 189 patients before surgery: 96% were re-evaluated at 6 months, and 88% at 12 months. Multivariate logistic regression (stepwise selection) for the total group of patients indicated that the presence of clinical meaningful pain at 6 and 12 months (pain intensity ≥ 3/10) was predicted by poorer cognitive performance in the Trail Making Test B (P = 0.0009 and 0.02 for pain at 6 and 12 months, respectively), Rey-Osterrieth Complex Figure copy (P = 0.015 and 0.006 for pain at 6 and 12 months, respectively) and recall (P = 0.016 for pain at 12 months), independently of affective variables. Linear regression analyses indicated that impaired scores on these tests predicted pain intensity (P < 0.01) and neuropathic symptoms in patients with pain (P < 0.05), although the strength of the association was less robust for neuropathic symptoms. These results were not affected by the type of surgery or presurgical pain, similar findings being obtained specifically for patients who initially had no pain. In conclusion, these findings support, for the first time, the notion that premorbid limited cognitive flexibility and memory capacities may be linked to the mechanisms of pain chronicity and probably also to its neuropathic quality. This may imply that patients with deficits in executive functioning or memory because of cerebral conditions have a greater risk of pain chronicity after a painful event.

Effect of Alexithymia and Emotional Repression on Postsurgical Pain in Women With Breast Cancer: A Prospective Longitudinal 12-Month Study.

UNLABELLED: Alexithymia, the inability to identify and express emotions, and emotional repression, a defensive mechanism used to avoid unpleasant emotional experience, have been associated with chronic pain and medical illness including breast cancer, but whether these constructs might predict pain after breast cancer surgery has not been assessed. The present study was conducted to assess the predictive value of alexithymia and emotional repression in postoperative pain. Anxiety, depression, catastrophizing, and psychological adjustment were also assessed. Data were collected before surgery, and then at 2 days and 2, 3, 6, and 12 months after surgery. We included 100 pain-free women, 96% of whom were followed for up to 12 months. Separate multivariate analyses identified anxiety as a significant predictor of postsurgical pain at 3 months, alexithymia at 3, 6, and 12 months, and body image and catastrophizing predicted acute or subacute pain at 2 months. In contrast, emotional repression was not predictive of pain. The generalized estimating equation approach was used and identified alexithymia as the only significant predictor of pain during the 12-month period after surgery. Alexithymia, but not emotional repression, predicted the development of persistent pain after breast surgery independently of anxiety and depression. Thus, alexithymia might be involved in mechanisms of pain chronicity. PERSPECTIVE: This prospective study, conducted in women with breast cancer surgery, showed that alexithymia but not emotional repression predicted postsurgical pain. These results highlight the role of dysfunction in emotional processing in the development of postsurgical pain.

Are psychological predictors of chronic postsurgical pain dependent on the surgical model? A comparison of total knee arthroplasty and breast surgery for cancer.

UNLABELLED: Anxiety, depression, and catastrophizing are generally considered to be predictive of chronic postoperative pain, but this may not be the case after all types of surgery, raising the possibility that the results depend on the surgical model. We assessed the predictive value of these factors for chronic postsurgical pain in 2 different surgical models: total knee arthroplasty for osteoarthritis (89 patients, 65% women, age = 69 ± 9 years, baseline pain intensity = 4.7 ± 2.1) and breast surgery for cancer (100 patients, 100% women, age = 55 ± 12 years, no preoperative pain). Data were collected before surgery, then 2 days and 3 months after surgery. Anxiety, depression, and catastrophizing were measured with the Spielberger State-Trait Anxiety Inventory, Beck Depression Inventory, and Pain Catastrophizing Scale, respectively. Pain was assessed with the Brief Pain Inventory. Neuropathic pain was detected with the DN4 questionnaire. Multivariate logistic regression analyses for the total knee arthroplasty and breast surgery models considered together indicated that the presence of clinically meaningful chronic pain at 3 months (pain intensity ≥3/10) was predicted independently by age (P = .04), pain intensity on day 2 (P = .009), and state anxiety (P = .001). Linear regression models also showed that pain magnification, one of the dimensions of catastrophizing, independently predicted chronic pain intensity (P = .04). These results were not affected by the surgical model or by the neuropathic characteristics of the pain. Thus, state anxiety and pain magnification seem to constitute psychological risk factors for chronic postsurgical pain relevant in all surgical models. PERSPECTIVE: This prospective study performed in patients with total knee arthroplasty or breast surgery for cancer shows that state anxiety, amplification of pain, and acute postoperative pain independently predict postsurgical pain at 3 months and that this does not depend on the surgical model.