The settings in the MPA CTplus software are flexible and set by the user according to different applications (suction time, relaxation time, pressure/pressure rate, repetitions, etc.). The programme allows the calculation of a lot of interesting parameters from the different portions of the measurement curve during suction and recovery.
Most measurements in literature have been performed in mode 1 (full suction followed by complete relaxation).
Here a short overview:
(extremely well documented in literature for more than 30 years)
Area Parameters (F):
- R0: Uf pliability/firmness mm (amplitude at the end of the suction phase)
- R1/R4: ability of the skin to recover its initial state (residual deformation in mm at the end of recovery)
- R2: visco-elasticity in % (resistance to the mechanical force versus ability of recovery)
- R3/R9/R10: Tiring effects in mm (Fatigue) visible for repeated suction/recovery circles
- R5: net elasticity in %: Ur/Ue = elastic part of the suction phase vs. immediate recovery during relaxation phase
- R6: Uv/Ue Portion of the visco-elasticity of the curve during suction phase in %
- R7: Ur/Uf proportion of the immediate recovery compared to the amplitude after suction in %
- R8: Ua Total recovery after the pressure is cut off in mm
- F1: Area above the curve during suction phase. The more elastic, the less area there is.
- F2/F3/F4: “Fatigue” + “Skin Energy”
A set of parameters developed by the scientist Di Qu (Senior Research Scientist, R&D Skin Care, Amway Corporation, Ada, Michigan, USA) has been added, showing interesting correlations between skin age and the elastic and viscous recovery of the curves*:
- Q0: Maximum recovery area
- Q1: Total recovery (overall elasticity) - (QE + QR)/Q0
- Q2: Elastic recovery - QE / Q0
- Q3: Viscoelastic recovery - QR / Q0
*From: D. Qu, et al.: Correlating Age and Quantifying Product Efficacy on Human Skin Using Novel Viscoelastic Parameters
New interesting aging parameters for mode 2 and 3 (gradually decreasing pressure after suction):
Different from mode 1, in these modes at the end of the suction phase, the skin does not necessarily start to leave the probe. Depending on the loss of collagen, it may even go deeper inside the probe, even though the pressure already starts to decline as the collagen may not be strong enough to start to bring skin back into its original shape with the given power. R3 is the maximum amplitude in mm.
R4 = Maximum collagen power: Describes when the decreasing pressure is low enough so that the collagen can finally start to bring the skin out of the probe and begin the recovery. The corresponding distance in the pressure curve is expressed as proportion to the maximum pressure (in %). Young skin with high collagen power has a higher value for R4 than older skin with decreased collagen power.