Determinants of pain in patients with carpal tunnel syndrome

Carpal tunnel syndrome causes numbness, weakness, and atrophy. Pain without numbness is not characteristic of this disease.

We tested the hypothesis that among patients with carpal tunnel syndrome confirmed by electrophysiologic testing, pain catastrophizing and/or depression would be good predictors of pain intensity at the time of diagnosis, whereas nerve conduction velocity would not.

Fifty-four patients completed a measure of tendency to misinterpret pain, a measure of depressive symptoms, anxiety about pain, self-efficacy in response to pain, and a five-point Likert measure of pain intensity. One-tailed Spearman correlation was performed to find a correlation between pain and continuous variables. One-way ANOVA was performed to assess differences between categorical variables. For each group, all variables with significant correlations with pain intensity were included in a multiple linear regression analysis.

Sex, age, and electrophysiologic measures did not correlate with pain intensity. All measures of illness behavior correlated with pain intensity and were entered in a multiple linear regression model; only misinterpretation of nociception and depression were significantly associated and accounted for 39% of the variation in pain intensity.

Illness behavior (specifically depression and misinterpretation of nociception) predicts pain intensity in patients with carpal tunnel syndrome.