title: Palpation force modulation strategies to identify hard regions in soft tissue organs.
abstract: This paper presents experimental evidence for the existence of a set of unique force modulation strategies during manual soft tissue palpation to locate hard abnormalities such as tumors. We explore the active probing strategies of defined local areas and outline the role of force control. In addition, we investigate whether the applied force depends on the non-homogeneity of the soft tissue. Experimental results on manual palpation of soft silicone phantoms show that humans have a well defined force control pattern of probing that is used independently of the non-homogeneity of the soft tissue. We observed that the modulations of lateral forces are distributed around the mean frequency of 22.3 Hz. Furthermore, we found that the applied normal pressure during probing can be modeled using a second order reactive autoregressive model. These mathematical abstractions were implemented and validated for the autonomous palpation for different stiffness parameters using a robotic probe with a rigid spherical indentation tip. The results show that the autonomous robotic palpation strategy abstracted from human demonstrations is capable of not only detecting the embedded nodules, but also enhancing the stiffness perception compared to static indentation of the probe.
authors.affiliation: School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom.
authors.forename: Jelizaveta
authors.initials: J
authors.lastname: Konstantinova
authors.affiliation: Department of Informatics, King's College London, London, United Kingdom.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Cotugno
authors.affiliation: AMRC Centre for Transplantation, DTIMB and NIHR BRC, King's College London, Guy's Hospital, London, United Kingdom.
authors.forename: Prokar
authors.initials: P
authors.lastname: Dasgupta
authors.affiliation: School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom.
authors.forename: Kaspar
authors.initials: K
authors.lastname: Althoefer
authors.affiliation: Dyson School of Engineering, Imperial College London, South Kensington Campus, London, United Kingdom.
authors.forename: Thrishantha
authors.initials: T
authors.lastname: Nanayakkara
mesh_terms: D000465:Algorithms; D055119:Elastic Modulus; D005385:Fingers / Q000502:physiology; D006801:Humans; D008390:Markov Chains; D008954:Models, Biological; D010173:Palpation / Q000379:methods*; D012371:Robotics; D014110:Touch