0
Research Papers

Multidirectional In Vivo Characterization of Skin Using Wiener Nonlinear Stochastic System Identification Techniques

[+] Author and Article Information
Matthew D. Parker

Auckland Bioengineering Institute,
The University of Auckland,
Private Bag 92019,
Auckland 1142, New Zealand
e-mail: mpar145@aucklanduni.ac.nz

Lynette A. Jones

BioInstrumentation Laboratory,
Massachusetts Institute of Technology,
77 Massachusetts Avenue,
Cambridge, MA 02139
e-mail: ljones@mit.edu

Ian W. Hunter

BioInstrumentation Laboratory,
Massachusetts Institute of Technology,
77 Massachusetts Avenue,
Cambridge, MA 02139
e-mail: ihunter@mit.edu

A. J. Taberner

Department of Engineering Science,
Auckland Bioengineering Institute,
The University of Auckland,
Private Bag 92019,
Auckland 1142, New Zealand
e-mail: a.taberner@auckland.ac.nz

M. P. Nash

Department of Engineering Science,
Auckland Bioengineering Institute,
The University of Auckland,
Private Bag 92019,
Auckland 1142, New Zealand
e-mail: martyn.nash@auckland.ac.nz

P. M. F. Nielsen

Department of Engineering Science,
Auckland Bioengineering Institute,
The University of Auckland,
Private Bag 92019,
Auckland 1142, New Zealand
e-mail: p.nielsen@auckland.ac.nz

1Corresponding author.

Manuscript received May 24, 2016; final manuscript received October 7, 2016; published online November 4, 2016. Assoc. Editor: Kristen Billiar.

J Biomech Eng 139(1), 011004 (Nov 04, 2016) (11 pages) Paper No: BIO-16-1221; doi: 10.1115/1.4034993 History: Received May 24, 2016; Revised October 07, 2016

A triaxial force-sensitive microrobot was developed to dynamically perturb skin in multiple deformation modes, in vivo. Wiener static nonlinear identification was used to extract the linear dynamics and static nonlinearity of the force–displacement behavior of skin. Stochastic input forces were applied to the volar forearm and thenar eminence of the hand, producing probe tip perturbations in indentation and tangential extension. Wiener static nonlinear approaches reproduced the resulting displacements with variances accounted for (VAF) ranging 94–97%, indicating a good fit to the data. These approaches provided VAF improvements of 0.1–3.4% over linear models. Thenar eminence stiffness measures were approximately twice those measured on the forearm. Damping was shown to be significantly higher on the palm, whereas the perturbed mass typically was lower. Coefficients of variation (CVs) for nonlinear parameters were assessed within and across individuals. Individual CVs ranged from 2% to 11% for indentation and from 2% to 19% for extension. Stochastic perturbations with incrementally increasing mean amplitudes were applied to the same test areas. Differences between full-scale and incremental reduced-scale perturbations were investigated. Different incremental preloading schemes were investigated. However, no significant difference in parameters was found between different incremental preloading schemes. Incremental schemes provided depth-dependent estimates of stiffness and damping, ranging from 300 N/m and 2 Ns/m, respectively, at the surface to 5 kN/m and 50 Ns/m at greater depths. The device and techniques used in this research have potential applications in areas, such as evaluating skincare products, assessing skin hydration, or analyzing wound healing.

FIGURES IN THIS ARTICLE
<>
Copyright © 2017 by ASME
Your Session has timed out. Please sign back in to continue.

References

Hendriks, F. M. , Brokken, D. , Oomens, C. W. J. , Bader, D. L. , and Baaijens, F. P. T. , 2006, “ The Relative Contributions of Different Skin Layers to the Mechanical Behavior of Human Skin In Vivo Using Suction Experiments,” Med. Eng. Phys., 28(3), pp. 259–266. [CrossRef] [PubMed]
Delalleau, A. , Josse, G. , Lagarde, J.-M. , Zahouani, H. , and Bergheau, J.-M. , 2008, “ A Nonlinear Elastic Behavior to Identify the Mechanical Parameters of Human Skin In Vivo,” Skin Res. Technol., 14(2), pp. 152–164. [CrossRef] [PubMed]
Delalleau, A. , Josse, G. , George, J. , Yassine, M. , Ossant, F. , and Lagarde, J.-M. , 2009, “ A Human Skin Ultrasonic Imaging to Analyse Its Mechanical Properties,” Eur. J. Comput. Mech., 18(1), pp. 105–116.
Krueger, N. , Luebberding, S. , Oltmer, M. , Streker, M. , and Kerscher, M. , 2011, “ Age-Related Changes in Skin Mechanical Properties: A Quantitative Evaluation of 120 Female Subjects,” Skin Res. Technol., 17(2), pp. 141–148. [CrossRef] [PubMed]
Sutradhar, A. , and Miller, M. J. , 2012, “ In Vivo Measurement of Breast Skin Elasticity and Breast Skin Thickness,” Skin Res. Technol., (11), pp. 1–9.
Escoffier, C. , de Rigal, J. , Rochefort, A. , Vasselet, R. , Leveque, J. L. , and Agache, P. , 1989, “ Age-Related Mechanical Properties of Human Skin: An In Vivo Study,” J. Invest. Dermatol., 93(3), pp. 353–357. [CrossRef] [PubMed]
Leveque, J. L. , Corcuff, P. , de Rigal, J. , and Agache, P. , 1984, “ In Vivo Studies of the Evolution of Physical Properties of the Human Skin With Age,” Int. J. Dermatol., 23(5), pp. 322–329. [CrossRef] [PubMed]
Zahouani, H. , Pailler-Mattei, C. , Sohm, B. , Vargiolu, R. , Cenizo, V. , and Debret, R. , 2009, “ Characterization of the Mechanical Properties of a Dermal Equivalent Compared With Human Skin In Vivo by Indentation and Static Friction Tests,” Skin Res. Technol., 15(1), pp. 68–76. [CrossRef] [PubMed]
Flynn, C. , Taberner, A. J. , Nielsen, P. M. F. , and Fels, S. , 2013, “ Simulating the Three-Dimensional Deformation of In Vivo Facial Skin,” J. Mech. Behav. Biomed. Mater., 28, pp. 484–494. [CrossRef] [PubMed]
Pailler-Mattéi, C. , Bec, S. , and Zahouani, H. , 2008, “ In Vivo Measurements of the Elastic Mechanical Properties of Human Skin by Indentation Tests,” Med. Eng. Phys., 30(5), pp. 599–606. [CrossRef] [PubMed]
Delalleau, A. , Josse, G. , Lagarde, J. M. , Zahouani, H. , and Bergheau, J. M. , 2008, “ Characterization of the Mechanical Properties of Skin by Inverse Analysis Combined With an Extensometry Test,” Wear, 264(5–6), pp. 405–410. [CrossRef]
Woo, M. S. , Moon, K. J. , Jung, H. Y. , Park, S. R. , Moon, T. K. , Kim, N. S. , and Lee, B. C. , 2014, “ Comparison of Skin Elasticity Test Results From the Ballistometer® and Cutometer®,” Skin Res. Technol., 20(4), pp. 422–428. [CrossRef] [PubMed]
Sandrin, L. , Tanter, M. , Gennisson, J.-L. , Catheline, S. , and Fink, M. , 2002, “ Shear Elasticity Probe for Soft Tissues With 1-D Transient Elastography,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, 49(4), pp. 436–446. [CrossRef] [PubMed]
Zhang, X. , and Greenleaf, J. F. , 2007, “ Estimation of Tissue's Elasticity With Surface Wave Speed,” J. Acoust. Soc. Am., 122(5), pp. 2522–2525. [CrossRef] [PubMed]
Verhaegen, P. D. H. M. , Res, E. M. , van Engelen, A. , Middelkoop, E. , and van Zuijlen, P. P. M. , 2010, “ A Reliable, Non-Invasive Measurement Tool for Anisotropy in Normal Skin and Scar Tissue,” Skin Res. Technol., 16(3), pp. 325–331. [PubMed]
Coutts, L. , Bamber, J. , and Miller, N. , 2013, “ Multi-Directional In Vivo Tensile Skin Stiffness Measurement for the Design of a Reproducible Tensile Strain Elastography Protocol,” Skin Res. Technol., 19(1), pp. 37–44. [CrossRef]
Lim, K. H. , Chew, C. M. , Chen, P. C. Y. , Jeyapalina, S. , Ho, H. N. , Rappel, J. K. , and Lim, B. H. , 2008, “ New Extensometer to Measure In Vivo Uniaxial Mechanical Properties of Human Skin,” J. Biomech., 41(5), pp. 931–936. [CrossRef] [PubMed]
Jacquet, E. , Josse, G. , Khatyr, F. , and Garcin, C. , 2008, “ A New Experimental Method for Measuring Skin's Natural Tension,” Skin Res. Technol., 14(1), pp. 1–7. [PubMed]
Diridollou, S. , Berson, M. , Vabre, V. , Black, D. , Karlsson, B. , Auriol, F. , Gregoire, J. M. , Yvon, C. , Vaillant, L. , Gall, Y. , and Patat, F. , 1998, “ An In Vivo Method for Measuring the Mechanical Properties of the Skin Using Ultrasound,” Ultrasound Med. Biol., 24(2), pp. 215–224. [CrossRef] [PubMed]
Sandford, E. , Chen, Y. , Hunter, I. , Hillebrand, G. , and Jones, L. , 2012, “ Capturing Skin Properties From Dynamic Mechanical Analyses,” Skin Res. Technol., 19(1), pp. e339–48. [CrossRef] [PubMed]
Kennedy, B. F. , Hillman, T. R. , McLaughlin, R. A. , Quirk, B. C. , and Sampson, D. D. , 2009, “ In Vivo Dynamic Optical Coherence Elastography Using a Ring Actuator,” Opt. Express, 17(24), pp. 21762–21772. [CrossRef] [PubMed]
Boyer, G. , Zahouani, H. , Le Bot, A. , and Laquieze, L. , 2007, “ In Vivo Characterization of Viscoelastic Properties of Human Skin Using Dynamic Micro-Indentation,” 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBS 2007), Lyon, France, Aug. 22–26, pp. 4584–4587.
Boyer, G. , Laquièze, L. , Le Bot, A. , Laquièze, S. , and Zahouani, H. , 2009, “ Dynamic Indentation on Human Skin In Vivo: Ageing Effects,” Skin Res. Technol., 15(1), pp. 55–67. [CrossRef] [PubMed]
Chen, Y. , and Hunter, I. W. , 2013, “ Nonlinear Stochastic System Identification of Skin Using Volterra Kernels,” Ann. Biomed. Eng., 41(4), pp. 847–862. [CrossRef] [PubMed]
Chen, Y. , and Hunter, I. W. , 2012, “ Stochastic System Identification of Skin Properties: Linear and Wiener Static Nonlinear Methods,” Ann. Biomed. Eng., 40(10), pp. 2277–2291. [CrossRef] [PubMed]
Holzapfel, G. A. , and Ogden, R. W. , 2008, “ On Planar Biaxial Tests for Anisotropic Nonlinearly Elastic Solids. A Continuum Mechanical Framework,” Math. Mech. Solids, 14(5), pp. 474–489. [CrossRef]
Chen, Y. , and Hunter, I. W. , 2009, “ In Vivo Characterization of Skin Using a Weiner Nonlinear Stochastic System Identification Method,” Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC 2009), Minneapolis, MN, Sept. 3–6, pp. 6010–6013.
Flynn, C. , Taberner, A. , and Nielsen, P. , 2011, “ Mechanical Characterisation of In Vivo Human Skin Using a 3D Force-Sensitive Micro-Robot and Finite Element Analysis,” Biomech. Model. Mechanobiol., 10(1), pp. 27–38. [CrossRef] [PubMed]
Flynn, C. , Taberner, A. , and Nielsen, P. , 2011, “ Measurement of the Force–Displacement Response of In Vivo Human Skin Under a Rich Set of Deformations,” Med. Eng. Phys., 33(5), pp. 610–619. [CrossRef] [PubMed]
Sandford, E. , Chen, Y. , Hunter, I. , Hillebrand, G. , and Jones, L. , 2013, “ Capturing Skin Properties From Dynamic Mechanical Analyses,” Skin Res. Technol., 19(1), pp. e339–e348. [CrossRef] [PubMed]
Finlay, B. , 1970, “ Dynamic Mechanical Testing of Human Skin “In Vivo,” J. Biomech., 3(6), pp. 557–568. [CrossRef] [PubMed]
Liang, X. , and Boppart, S. A. , 2010, “ Biomechanical Properties of In Vivo Human Skin From Dynamic Optical Coherence Elastography,” IEEE Trans. Biomed. Eng., 57(4), pp. 953–959. [CrossRef] [PubMed]
Kearney, S. P. , Khan, A. , Dai, Z. , and Royston, T. J. , 2015, “ Dynamic Viscoelastic Models of Human Skin Using Optical Elastography,” Phys. Med. Biol., 60(17), pp. 6975–6990. [CrossRef] [PubMed]
Khatyr, F. , and Imberdis, C. , 2004, “ Model of the Viscoelastic Behaviour of Skin In Vivo and Study of Anisotropy,” Skin Res. Technol., 10(2), pp. 96–103. [CrossRef] [PubMed]
Weickenmeier, J. , Jabareen, M. , and Mazza, E. , 2015, “ Suction Based Mechanical Characterization of Superficial Facial Soft Tissues,” J. Biomech., 48(16), pp. 4279–4286. [CrossRef] [PubMed]
Jemec, G. B. E. , Selvaag, E. , Agren, M. , and Wulf, H. C. , 2001, “ Measurement of the Mechanical Properties of Skin With Ballistometer and Suction Cup,” Skin Res. Technol., 7(2), pp. 122–126. [CrossRef] [PubMed]
Li, C. , Guan, G. , Reif, R. , Huang, Z. , and Wang, R. K. , 2012, “ Determining Elastic Properties of Skin by Measuring Surface Waves From an Impulse Mechanical Stimulus Using Phase-Sensitive Optical Coherence Tomography,” J. R. Soc. Interface, 9(70), pp. 831–841. [CrossRef] [PubMed]
Raveh Tilleman, T. , Tilleman, M. M. , and Neumann, M. H. A. , 2004, “ The Elastic Properties of Cancerous Skin: Poisson's Ratio and Young's Modulus,” Isreal Med. Assoc. J., 6(12), pp. 753–755. http://www.ima.org.il/FilesUpload/IMAJ/0/52/26480.pdf
Hendriks, F. M. , Brokken, D. , van Eemeren, J. T. W. M. , Oomens, C. W. J. , Baaijens, F. P. T. , and Horsten, J. B. A. M. , 2003, “ A Numerical–Experimental Method to Characterize the Non-Linear Mechanical Behaviour of Human Skin,” Skin Res. Technol., 9(3), pp. 274–283. [CrossRef] [PubMed]
Tran, H. V. , Charleux, F. , Rachik, M. , Ehrlacher, A. , and Ho Ba Tho, M. C. , 2007, “ In Vivo Characterization of the Mechanical Properties of Human Skin Derived From MRI and Indentation Techniques,” Comput. Methods Biomech. Biomed. Eng., 10(6), pp. 401–407. [CrossRef]
Geerligs, M. , van Breemen, L. , Peters, G. , Ackermans, P. , Baaijens, F. , and Oomens, C. , 2011, “ In Vitro Indentation to Determine the Mechanical Properties of Epidermis,” J. Biomech., 44(6), pp. 1176–1181. [CrossRef] [PubMed]
Hatefi, A. , and Amsden, B. , 2002, “ Biodegradable Injectable In Situ Forming Drug Delivery Systems,” J. Controlled Release, 80(1–3), pp. 9–28. [CrossRef]
Sanders, R. , 1973, “ Torsional Elasticity of Human Skin In Vivo,” Pflugers Arch., 342(3), pp. 255–260. [CrossRef] [PubMed]
Grahame, R. , and Holt, P. J. L. , 1969, “ The Influence of Ageing on the In Vivo Elasticity of Human Skin,” Gerontology, 15(2–3), pp. 121–139. [CrossRef]
Khatyr, F. , Imberdis, C. , Vescovo, P. , Varchon, D. , and Lagarde, J.-M. , 2004, “ Model of the Viscoelastic Behaviour of Skin In Vivo and Study of Anisotropy,” Skin Res. Technol., 10(2), pp. 96–103. [CrossRef] [PubMed]
Langer, K. , 1978, “ On the Anatomy and Physiology of the Skin—I: The Cleavability of the Cutis,” Br. J. Plast. Surg., 31(1), pp. 3–8. [CrossRef] [PubMed]
Nizet, J. L. , Piérard-Franchimont, C. , and Piérard, G. E. , 2001, “ Influence of Body Posture and Gravitational Forces on Shear Wave Propagation in the Skin,” Dermatology, 202(2), pp. 177–180. [CrossRef] [PubMed]
Fung, Y. , 1993, Biomechanics: Mechanical Properties of Living Tissues, Springer-Verlag, New York.

Figures

Grahic Jump Location
Fig. 1

Microrobot device used to perturb skin in vivo. (a) A close-up of the robot components. (b) A potential skin site positioned on the aluminum-acrylic support structure prior to testing. Note that the relative positions of the robot and subject's arm are chosen for demonstrative purposes and do not reflect exact test conditions presented in this study.

Grahic Jump Location
Fig. 2

Schematic system diagram. The system refers exclusively to the combination of the robot and tissue.

Grahic Jump Location
Fig. 3

Stochastic input with stepwise increase in mean, referred to as “protocol B.” Preconditioning at each step was performed by holding the mean value. The first 10 s show a full-scale preconditioning step where the maximum output force is held for demonstrative purposes and do not reflect exact test conditions presented in this study.

Grahic Jump Location
Fig. 4

Location, direction, and order of applied tangential stretches. Dashed line indicates approximate proximal–distal axis that intersects the test site.

Grahic Jump Location
Fig. 5

Representative experimental results from nonlinear stochastic system identification on the volar forearm. The measured input force (a) is used to generate the linear impulse response function (b), shown blue in measured form and red in parameterized form. The linear dynamics are then passed through the Wiener nonlinearity, as shown in blue in (c). The nonlinearity has been parameterized, shown by the red line. The output of the Wiener nonlinearity is shown in (d), where the Wiener-predicted output (red) is shown against the potentiometer-measured output (blue).

Grahic Jump Location
Fig. 6

Representative static nonlinearity plot for a volar forearm using incremental loading schemes, protocols A and B under (a) normal indentation and (b) extension

Grahic Jump Location
Fig. 7

Representative experimental results from linear stochastic system identification on a forearm using incremental loading, under normal indentation and across-surface extension. (a) The tissue stiffness estimated at various stretches is shown. (b) The perturbed mass estimated as various stretches is shown, after the actuator mass is subtracted. (c) The tissue damping at various stretches is shown after the actuator damping is subtracted. (d) The VAF for each site is plotted against actuator tip position.

Grahic Jump Location
Fig. 8

Representative experimental results from linear incremental stochastic system identification of a volar forearm and thenar eminence test are shown. Each plot shows a different linear output property as produced by an incremental loading scheme, in different perturbation directions and/or sites. (a) The tissue stiffness estimated at various stretches is shown. (b) The perturbed mass estimated at various stretches is shown, after the actuator mass is subtracted. (c) The tissue damping at various stretches is shown, after the actuator damping is subtracted. (d) The VAF for each site is plotted against actuator tip position.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In