Objective
To assess differences in vulvar and peripheral sensitivity between women with and without vulvodynia.
Methods
Women with vulvodynia (N=41) and age-matched controls (N=43) seen in the outpatient setting were evaluated via surveys, clinical examination, and multimodal sensory testing (pressure, heat, cold, vibration, and electrical stimulation). The relationship between sensitivity to various sensory modalities and case/control status, as well as by vulvodynia subgroups, were assessed using logistic regression.
Results
Women with vulvodynia were more sensitive to pressure and to electrical stimuli than were control women at the vulva (Median 22 vs 230 grams and 0.495 vs 0.769 mA, respectively, p <0.001 for each) and at the thumb (Median 2500 vs 4250 grams and 0.578 vs 0764 mA, respectively, p=0.006 for pressure, p<0.001 for electrical stimulation). Heat, cold, and vibration detection thresholds did not differ significantly between these groups (p>0.025). Those reporting spontaneous pain versus provoked pain had greater pressure sensitivity to the thumb (Median 1850 vs 2690 grams, p=0.020) and greater electrical sensitivity at the introitus (0.450 vs 0.608 mA, p=0.011), and those with primary versus secondary vulvodynia, had substantially greater pressure sensitivity to the thumb (Median 2438 vs 3125 grams, p=0.004). However, having localized versus generalized vulvodynia was not associated with differences in pressure or electrical sensitivity.
Conclusions
Sensitivity to pressure and electrical stimuli is greater among vulvodynia cases than among controls, and supports two previously defined subgroups -- those reporting spontaneous pain versus those whose pain only occurred when provoked, and those with primary versus secondary vulvodynia.