title: Real-time, ultrasound-based control of a virtual hand by a trans-radial amputee.
abstract: Advancements in multiarticulate upper-limb prosthetics have outpaced the development of intuitive, non-invasive control mechanisms for implementing them. Surface electromyography is currently the most popular non-invasive control method, but presents a number of drawbacks including poor deep-muscle specificity. Previous research established the viability of ultrasound imaging as an alternative means of decoding movement intent, and demonstrated the ability to distinguish between complex grasps in able-bodied subjects via imaging of the anterior forearm musculature. In order to translate this work to clinical viability, able-bodied testing is insufficient. Amputation-induced changes in muscular geometry, dynamics, and imaging characteristics are all likely to influence the effectiveness of our existing techniques. In this work, we conducted preliminary trials with a transradial amputee participant to assess these effects, and potentially elucidate necessary refinements to our approach. Two trials were performed, the first using a set of three motion types, and the second using four. After a brief training period in each trial, the participant was able to control a virtual prosthetic hand in real-time; attempted grasps were successfully classified with a rate of 77% in trial 1, and 71% in trial 2. While the results are sub-optimal compared to our previous able-bodied testing, they are a promising step forward. More importantly, the data collected during these trials can provide valuable information for refining our image processing methods, especially via comparison to previously acquired data from able-bodied individuals. Ultimately, further work with amputees is a necessity for translation towards clinical application.
authors.forename: Clayton A
authors.initials: CA
authors.lastname: Baker
authors.forename: Nima
authors.initials: N
authors.lastname: Akhlaghi
authors.forename: Huzefa
authors.initials: H
authors.lastname: Rangwala
authors.forename: Jana
authors.initials: J
authors.lastname: Kosecka
authors.forename: Siddhartha
authors.initials: S
authors.lastname: Sikdar
mesh_terms: D000674:Amputees; D001186:Artificial Limbs; D003199:Computer Systems; D004576:Electromyography; D006801:Humans; D007091:Image Processing, Computer-Assisted; D009068:Movement; D014463:Ultrasonography / Q000379:methods*