For carpal tunnel syndrome sufferers, itching and throbbing are pain qualities most responsible for impaired functioning and sleep disruption, according to new research reported in The Journal of Pain.
Researchers from the University of Washington examined how pain-quality measures, not pain intensity, are associated with how pain interferes with normal function. No previous study had examined the associations between pain quality (sharp, sensitive, deep, surface, etc.) and changes in patient functioning and quality of life. The researchers hypothesized that ratings of pain quality would show significant independent associations with function interference and sleep disruption. They anticipated that deep pain would be would be a pain quality with strong associations to impaired functioning.
Subjects for the study were participants in a clinical trial comparing lidocaine patch 5% to naproxen 500 mg. in 100 patients with carpel tunnel syndrome. All participants were given the Brief Pain Inventory questionnaire and sleep quality was assessed using a five point rating scale.
Results showed, for the first time, that measures of specific pain qualities were associated with changes in patient functioning over and above pain intensity and other global pain measures. Among the carpel tunnel patients, itch and throbbing were the pain qualities most highly associated with impaired function and sleep disruption. This finding, according to the authors, underscores the significance of assessing pain quality as a major variable for thorough pain assessments.
For the carpel tunnel patients, throbbing was a unique individual predictor for pain interference and itching had the most significant impact on sleep quality.
"Pain is much more than just intensity and unpleasantness," said lead author Mark P. Jensen, PhD. "Knowledge of pain quality, as well as pain intensity, provides additional clues for understanding the impact of pain on patient's life."