Journal of behavioral medicine
-
Randomized Controlled Trial Clinical Trial
Parafunctional clenching, pain, and effort in temporomandibular disorders.
This study tested the hypotheses that (1) parafunctional clenching increases pain and can lead to a diagnosis of temporomandibular disorder (TMD) pain and (2) electromyographic (EMG) activity during parafunctional clenching is significantly and positively correlated with reports of pain. Fourteen individuals without TMD participated in 5 consecutive days of 20-min long EMG biofeedback training sessions of the left and right temporalis and masseter muscles. Subjects were randomly assigned to either a Decrease or Increase group and were instructed to maintain EMG activity below 2 microV or above 10 microV during training, respectively. ⋯ Masseter EMG activity was strongly correlated with pain. Parafunctional clenching increases pain and can lead to a diagnosis of TMD in otherwise pain-free individuals. Pain reports are positively correlated with the activity of the masseter muscle.
-
This study evaluated the relation of particular aspects of pain-related anxiety to characteristics of chronic pain distress in a sample of 76 individuals with low-back pain. Consistent with contemporary cognitive-behavioral models of chronic pain, the cognitive dimension of the Pain Anxiety Symptoms Scale (PASS; McCracken, Zayfert, and Gross, 1992, Pain 50:67-73) was uniquely predictive of cognitive-affective aspects of chronic pain, including affective distress, perceived lack of control, and pain severity. In contrast, the escape and avoidance dimension of the PASS was more predictive of behavioral interference in life activities. Overall, the findings are discussed within the context of identifying particular pain-related anxiety mechanisms contributing to differential aspects of pain-related distress and clinical impairment.