title: Automatic learning algorithm for the MD-logic artificial pancreas system.
abstract: BACKGROUND
  Applying real-time learning into an artificial pancreas system could effectively track the unpredictable behavior of glucose-insulin dynamics and adjust insulin treatment accordingly. We describe a novel learning algorithm and its performance when integrated into the MD-Logic Artificial Pancreas (MDLAP) system developed by the Diabetes Technology Center, Schneider Children's Medical Center of Israel, Petah Tikva, Israel.
  
  
  METHODS
  The algorithm was designed to establish an initial patient profile using open-loop data (Initial Learning Algorithm component) and then make periodic adjustments during closed-loop operation (Runtime Learning Algorithm component). The MDLAP system, integrated with the learning algorithm, was tested in seven different experiments using the University of Virginia/Padova simulator, comprising adults, adolescents, and children. The experiments included simulations using the open-loop and closed-loop control strategy under nominal and varying insulin sensitivity conditions. The learning algorithm was automatically activated at the end of the open-loop segment and after every day of the closed-loop operation. Metabolic control parameters achieved at selected time points were compared.
  
  
  RESULTS
  The percentage of time glucose levels were maintained within 70-180 mg/dL for children and adolescents significantly improved when open-loop was compared with day 6 of closed-loop control (P<0.0001) and remained unaltered for the adult group (P=0.11) during nominal conditions. In varying insulin sensitivity conditions, the percentage of time glucose levels were below 70 mg/dL was significantly reduced by approximately sevenfold (P<0.001). These observations were correlated with significant reduction in the Low Blood Glucose Index (P<0.001).
  
  
  CONCLUSIONS
  The new algorithm was effective in characterizing the patient profiles from open-loop data and in adjusting treatment to provide better glycemic control during closed-loop control in both conditions. These findings warrant corroboratory clinical trials.
authors.affiliation: The Jesse Z. and Sara Lea Shafer Institute for Endocrinology and Diabetes, The National Center for Childhood Diabetes, Schneider Children's Medical Center of Israel, Petah Tikva, Israel.
authors.forename: Shahar
authors.initials: S
authors.lastname: Miller
authors.forename: Revital
authors.initials: R
authors.lastname: Nimri
authors.forename: Eran
authors.initials: E
authors.lastname: Atlas
authors.forename: Eli A
authors.initials: EA
authors.lastname: Grunberg
authors.forename: Moshe
authors.initials: M
authors.lastname: Phillip
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D001786:Blood Glucose / Q000378:metabolism*; D002648:Child; D015331:Cohort Studies; D003198:Computer Simulation; D003920:Diabetes Mellitus / Q000097:blood / Q000188:drug therapy*; D006801:Humans; D007328:Insulin / Q000008:administration & dosage*; D019397:Pancreas, Artificial
chemical_list: D001786:Blood Glucose; D007328:Insulin