Pain
-
The objective was to investigate the relationship between pain relief scores produced by placebo and by active interventions in randomised controlled trials (RCTs). Individual patient categorical pain relief scores from 5 placebo-controlled single-dose parallel-group RCTs in acute postoperative pain were used to calculate the percentage of the maximum possible pain relief score (%maxTOTPAR) for the different treatments. One hundred and thirty of the 525 patients in the 5 trials had a placebo. ⋯ In double-blind, randomised parallel-group studies of high quality placebo scores should not vary. Despite these conditions being met the placebo scores did vary. The previous explanation, of a relationship between the mean placebo scores and the mean scores for the active treatments was not supported.
-
Clinical Trial
Concerning the homology of painful experiences and pain descriptors: a multidimensional scaling analysis.
How is the sensory (or other) experience of pain related to the words used to describe such experiences? Answering this question would not only improve our general understanding of the relationship between the experience of pain and the report of pain, but also would allow one to quantify inaccuracies or idiosyncracies in this regard. A continuous multidimensional scaling model was used to examine the similarity between noxious electrocutaneous stimuli and the words used to describe them. If these two types of stimulus objects were homologous, one would expect that physical and verbal stimuli with the same meaning would be scaled with similar values along a single dimension; if not, the two types of stimuli would be scaled at opposite poles of a dimension which distinguished between them. ⋯ A single dimension in the group stimulus space scaled both physical and verbal stimulus objects from least to greatest intensity. Since this (or any higher) dimension failed to segregate verbal from physical stimuli, the words appear to be homologous with experience. While conclusions are limited to these specific stimuli, results suggest that the INDSCAL model offers a valuable method for exploring the relationship between pain report and pain experience.
-
Randomized Controlled Trial Clinical Trial
A new method of recording somatosensory evoked potentials by randomized electrical tooth stimulation with 6 levels of intensity.
Dental somatosensory evoked potentials (SEPs) corresponding to the stimulus intensity levels were recorded at 6 different levels of intensity presented in a randomized order. The relationships between the amplitude of the late SEP component with latency between 150 and 300 msec and each stimulus intensity level were also compared in conditions of randomized intensity and constant intensity. The amplitude of the late component increased significantly with the increased stimulus intensity both in the randomized and constant intensity stimulation. ⋯ The latency of the late positive component significantly increased with the randomized stimulation with a 3-sec ISI. This phenomenon might be attributable to the psychological contamination. SEP recording in the randomized dental stimulation with a 1-sec ISI may have applications in neuropharmacological research or physiological research on pain and evaluation of the effects of analgesics, anesthetics, acupuncture and transcutaneous electrical nerve stimulation (TENS).
-
Clinical Trial
Mechanisms of spontaneous tension-type headaches: an analysis of tenderness, pain thresholds and EMG.
Pericranial muscle tenderness, EMG levels and thermal and mechanical pain thresholds were studied in 28 patients with tension-type headache and in 30 healthy controls. Each patient was studied during as well as outside a spontaneous episode of tension-type headache. Outside of headache, muscle tenderness and EMG levels were significantly increased compared to values in controls subjects, while mechanical and thermal pain thresholds were largely normal. ⋯ EMG levels were unchanged during headache. It is concluded that one of the primary sources of pain in tension-type headache may be a local and reversible sensitization of nociceptors in the pericranial muscles. In addition, a segmental central sensitization may contribute to the pain in frequent sufferers of tension-type headache.
-
Randomized Controlled Trial Clinical Trial
The influence of low back pain on muscle activity and coordination during gait: a clinical and experimental study.
Chronic low back pain (CLBP) is a major clinical problem with a substantial socio-economical impact. Today, diagnosis and therapy are insufficient, and knowledge concerning interaction between musculoskeletal pain and motor performance is lacking. Most studies in this field have been performed under static conditions which may not represent CLBP patients' daily-life routines. ⋯ The clinical and experimental findings indicate that musculoskeletal pain modulates motor performance during gait probably via reflex pathways. Initially, these EMG changes may be interpreted as a functional adaptation to muscle pain, but the consequences of chronic altered muscle performance are not known. New possibilities to monitor and investigate altered motor performance may help to develop more rational therapies for CLBP patients.