Cuff algometry for estimation of hyperalgesia and pain summation

Objective. Cuff algometry is useful to assess pain sensitivity mechanisms, but effects of cuff position and stimulation pattern are not clear. Methods. In 20 healthy volunteers, cuff pain detection threshold (PDT) and pain tolerance (PTT) were recorded with cuffs accommodating two individual chambers at four locations (eight positions) along the leg, using ramp inflation (1kPa/s) until subjects indicated PDT and PTT. Repeated stimulations (1-s stimulation, 4-s break) with a staircase increase in stimulus intensity (5 kPa/step) were used to assess PDT and PTT on a single location. Spatial pain summation was calculated as the ratio between PTTs recorded with one chamber or simultaneously with two neighbor chambers. Temporal pain summation was assessed by repeated cuff stimulations (1-s stimulation, 1-s break) and the pain intensity was recorded on a visual analog scale (VAS); the PTT from ramp and staircase assessments were used as stimulus intensity. Results. For the most distal cuff position, the PTT was higher compared with other leg positions except when in proximity to the knee (P< 0.01). The PDT was higher for the distal part compared with the mid-portions of the lower and upper leg (P< 0.01). Compared with other leg locations, the spatial summation ratio was highest at the proximal lower leg (P< 0.02). The staircase versus ramp pattern revealed higher PDT and PTT (P < 0.01), as well as pronounced temporal pain summation (P< 0.01). Conclusion. The mid-portion of the lower leg is recommended for cuff placement, and the staircase paradigm provides relevant stimulus intensity for assessment of temporal pain summation.