Pain
-
Multicenter Study Comparative Study
Comparison of pain syndromes associated with nervous or somatic lesions and development of a new neuropathic pain diagnostic questionnaire (DN4).
Few studies have directly compared the clinical features of neuropathic and non-neuropathic pains. For this purpose, the French Neuropathic Pain Group developed a clinician-administered questionnaire named DN4 consisting of both sensory descriptors and signs related to bedside sensory examination. This questionnaire was used in a prospective study of 160 patients presenting with pain associated with a definite neurological or somatic lesion. ⋯ The analysis of the psychometric properties of the DN4 questionnaire included: face validity, inter-rater reliability, factor analysis and logistic regression to identify the discriminant properties of items or combinations of items for the diagnosis of neuropathic pain. We found that a relatively small number of items are sufficient to discriminate neuropathic pain. The 10-item questionnaire developed in the present study constitutes a new diagnostic instrument, which might be helpful both in clinical research and daily practice.
-
Predictors of outcome following whiplash injury are limited to socio-demographic and symptomatic factors, which are not readily amenable to secondary and tertiary intervention. This prospective study investigated the predictive capacity of early measures of physical and psychological impairment on pain and disability 6 months following whiplash injury. Motor function (ROM; kinaesthetic sense; activity of the superficial neck flexors (EMG) during cranio-cervical flexion), quantitative sensory testing (pressure, thermal pain thresholds, brachial plexus provocation test), sympathetic vasoconstrictor responses and psychological distress (GHQ-28, TSK, IES) were measured in 76 acute whiplash participants. ⋯ Higher initial NDI score (1.03-1.28), greater psychological distress (GHQ-28) (1.04-1.28) and decreased ROM (1.03-1.25) predicted subjects with persistent milder symptoms from those who fully recovered. These results demonstrate that both physical and psychological factors play a role in recovery or non-recovery from whiplash injury. This may assist in the development of more relevant treatment methods for acute whiplash.
-
Comparative Study
Dot-probe evaluation of selective attentional processing of pain cues in patients with chronic headaches.
Evidence supporting the notion that patients with chronic pain are characterized by attentional biases for sensory and affect pain words, and that such biases are mediated by fear of pain, is mixed. The present investigation was an attempt to replicate and extend initial findings obtained with the dot-probe task. Thirty patients with chronic headache and 19 healthy controls were tested using a dot-probe task including affect pain, sensory pain, and neutral words. ⋯ These results do not provide convincing evidence that patients with chronic headache selectively attend to affect or sensory pain cues when compared to healthy controls. The significant cross-groups associations between anxiety sensitivity and current pain description and indices of selective attention are consistent with the notion that attentional biases may be influenced by fear propensity and current concerns. Implications of the findings and future research directions are discussed.
-
Comparative Study
Sensory and motor effects of experimental muscle pain in patients with lateral epicondylalgia and controls with delayed onset muscle soreness.
This study compares the effect of experimental muscle pain on deep tissue sensitivity and force attenuation in the wrist extensors of patients with lateral epicondylalgia (n=20), and healthy controls (n=20) with experimentally induced sensori-motor characteristics simulating lateral epicondylalgia. Delayed onset muscle soreness (DOMS) in wrist extensors of healthy controls was induced by eccentric exercise in one arm 24h prior to injection (Day 0). Saline-induced pain intensity (visual analogue scale, VAS), distribution, and quality were assessed quantitatively in both arms for both groups. ⋯ Patients demonstrated significant bilateral hyperalgesia at extensor carpi radialis brevis during and post saline-induced pain compared to pre-injection and healthy controls (P<0.04). The sore arm in patients and the DOMS arms in healthy subjects showed significantly reduced maximal force (P<0.0001), at all Day 1 times compared with the control arms. In patients, the bilateral increase in deep tissue sensitivity and enlarged referred pain areas during saline-induced pain might suggest involvement of central sensitisation.
-
Comparative Study
Brain processing during mechanical hyperalgesia in complex regional pain syndrome: a functional MRI study.
Complex Regional Pain Syndromes (CRPS) are characterized by a triad of sensory, motor and autonomic dysfunctions of still unknown origin. Pain and mechanical hyperalgesia are hallmarks of CRPS. There are several lines of evidence that central nervous system (CNS) changes are crucial for the development and maintenance of mechanical hyperalgesia. ⋯ The stimulation of the affected limb was painful (mechanical hyperalgesia) and led to a significantly increased activation of the S1 cortex (contralateral), S2 (bilateral), insula (bilateral), associative-somatosensory cortices (contralateral), frontal cortices and parts of the anterior cingulate cortex. The results of our study indicate a complex cortical network activated during pin-prick hyperalgesia in CRPS. The underlying neuronal matrix comprises areas not only involved in nociceptive, but also in cognitive and motor processing.