Temporal Summation in Chronic Pelvic Pain

This study sought to characterize central sensitization further among women with chronic pelvic pain by identifying temporal summation using a cotton-tipped applicator test that can be used at the bedside.

A total of 36 women (18 with chronic pain and allodynia; 18 without pain) were recruited. Both groups were randomly assigned to receive 3 strokes of a benign stimulus on the abdomen at differing frequencies: 10, 30, or 100 seconds. Each group included 6 women. Pain was assessed using a rating scale of 1 to 10. Data were analyzed using the multivariate approach to repeated measures analysis of variance.

The pattern of pain scores differed significantly between women with and without chronic pain (P = 0.002). Women with chronic pelvic pain and allodynia showed a statistically significant increase in pain with successive strokes of the cotton-tipped applicator (P = 0.012 for stroke 1 vs. 2, P = 0.026 for stroke 2 vs. 3, and P = 0.005 for stroke 1 vs. 3).

Women with chronic pelvic pain and allodynia showed significant worsening of pain with successive strokes of a cotton-tipped applicator. This finding indicates that pain wind-up and central sensitization are present in women with chronic pelvic pain and allodynia. Identification of summation is further evidence of neuroplasticity, which is helpful in innovative therapies for chronic pelvic pain.