title: Phantom motor execution facilitated by machine learning and augmented reality as treatment for phantom limb pain: a single group, clinical trial in patients with chronic intractable phantom limb pain.
abstract: Phantom limb pain is a debilitating condition for which no effective treatment has been found. We hypothesised that re-engagement of central and peripheral circuitry involved in motor execution could reduce phantom limb pain via competitive plasticity and reversal of cortical reorganisation.
  
  
  
  Patients with upper limb amputation and known chronic intractable phantom limb pain were recruited at three clinics in Sweden and one in Slovenia. Patients received 12 sessions of phantom motor execution using machine learning, augmented and virtual reality, and serious gaming. Changes in intensity, frequency, duration, quality, and intrusion of phantom limb pain were assessed by the use of the numeric rating scale, the pain rating index, the weighted pain distribution scale, and a study-specific frequency scale before each session and at follow-up interviews 1, 3, and 6 months after the last session. Changes in medication and prostheses were also monitored. Results are reported using descriptive statistics and analysed by non-parametric tests. The trial is registered at ClinicalTrials.gov, number NCT02281539.
  
  
  
  Between Sept 15, 2014, and April 10, 2015, 14 patients with intractable chronic phantom limb pain, for whom conventional treatments failed, were enrolled. After 12 sessions, patients showed statistically and clinically significant improvements in all metrics of phantom limb pain. Phantom limb pain decreased from pre-treatment to the last treatment session by 47% (SD 39; absolute mean change 1·0 [0·8]; p=0·001) for weighted pain distribution, 32% (38; absolute mean change 1·6 [1·8]; p=0·007) for the numeric rating scale, and 51% (33; absolute mean change 9·6 [8·1]; p=0·0001) for the pain rating index. The numeric rating scale score for intrusion of phantom limb pain in activities of daily living and sleep was reduced by 43% (SD 37; absolute mean change 2·4 [2·3]; p=0·004) and 61% (39; absolute mean change 2·3 [1·8]; p=0·001), respectively. Two of four patients who were on medication reduced their intake by 81% (absolute reduction 1300 mg, gabapentin) and 33% (absolute reduction 75 mg, pregabalin). Improvements remained 6 months after the last treatment.
  
  
  
  Our findings suggest potential value in motor execution of the phantom limb as a treatment for phantom limb pain. Promotion of phantom motor execution aided by machine learning, augmented and virtual reality, and gaming is a non-invasive, non-pharmacological, and engaging treatment with no identified side-effects at present.
  
  
  
  Promobilia Foundation, VINNOVA, Jimmy Dahlstens Fond, PicoSolve, and Innovationskontor Väst.
authors.affiliation: Department of Signals and Systems, Chalmers University of Technology, Gothenburg, Sweden; Centre for Advanced Reconstruction of Extremities, Sahlgrenska University Hospital, Mölndal, Sweden; Integrum AB, Mölndal, Sweden. Electronic address: maxo@chalmers.se.
authors.forename: Max
authors.initials: M
authors.lastname: Ortiz-Catalan
authors.affiliation: Department of Signals and Systems, Chalmers University of Technology, Gothenburg, Sweden; Integrum AB, Mölndal, Sweden.
authors.forename: Rannveig A
authors.initials: RA
authors.lastname: Guðmundsdóttir
authors.affiliation: Department of Signals and Systems, Chalmers University of Technology, Gothenburg, Sweden; Integrum AB, Mölndal, Sweden.
authors.forename: Morten B
authors.initials: MB
authors.lastname: Kristoffersen
authors.affiliation: Department of Signals and Systems, Chalmers University of Technology, Gothenburg, Sweden; Integrum AB, Mölndal, Sweden.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Zepeda-Echavarria
authors.affiliation: Centre for Advanced Reconstruction of Extremities, Sahlgrenska University Hospital, Mölndal, Sweden.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Caine-Winterberger
authors.affiliation: Centre for Advanced Reconstruction of Extremities, Sahlgrenska University Hospital, Mölndal, Sweden.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Kulbacka-Ortiz
authors.affiliation: University Health Care Research Centre, Faculty of Medicine and Health, Örebro University, Örebro, Sweden; Department of Pediatrics, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
authors.forename: Cathrine
authors.initials: C
authors.lastname: Widehammar
authors.affiliation: Department of Pediatrics, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
authors.forename: Karin
authors.initials: K
authors.lastname: Eriksson
authors.affiliation: BräckeDiakoni Rehabcenter Sfären, Solna, Sweden.
authors.forename: Anita
authors.initials: A
authors.lastname: Stockselius
authors.affiliation: BräckeDiakoni Rehabcenter Sfären, Solna, Sweden.
authors.forename: Christina
authors.initials: C
authors.lastname: Ragnö
authors.affiliation: University Rehabilitation Institute, Ljubljana, Slovenia.
authors.forename: Zdenka
authors.initials: Z
authors.lastname: Pihlar
authors.affiliation: University Rehabilitation Institute, Ljubljana, Slovenia.
authors.forename: Helena
authors.initials: H
authors.lastname: Burger
authors.affiliation: University Health Care Research Centre, Faculty of Medicine and Health, Örebro University, Örebro, Sweden; Department of Prosthetics and Orthotics, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
authors.forename: Liselotte
authors.initials: L
authors.lastname: Hermansson
mesh_terms: D000328:Adult; D000368:Aged; D000588:Amines; D000671:Amputation, Surgical / Q000534:rehabilitation; D059350:Chronic Pain / Q000188:drug therapy / Q000628:therapy*; D003509:Cyclohexanecarboxylic Acids; D005081:Exercise Therapy / Q000379:methods; D000077206:Gabapentin; D000068957:Games, Recreational; D006801:Humans; D000069550:Machine Learning; D008875:Middle Aged; D010147:Pain Measurement / Q000706:statistics & numerical data; D010591:Phantom Limb / Q000628:therapy*; D017524:Slovenia; D013548:Sweden; D016896:Treatment Outcome; D034941:Upper Extremity / Q000503:physiopathology / Q000601:surgery; D063367:Virtual Reality Exposure Therapy; D005680:gamma-Aminobutyric Acid
chemical_list: D000588:Amines; D003509:Cyclohexanecarboxylic Acids; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin