title: Robotic Rehabilitator of the Rodent Upper Extremity: A System and Method for Assessing and Training Forelimb Force Production after Neurological Injury.
abstract: Rodent models of spinal cord injury are critical for the development of treatments for upper limb motor impairment in humans, but there are few methods for measuring forelimb strength of rodents, an important outcome measure. We developed a novel robotic device--the Robotic Rehabilitator of the Rodent Upper Extremity (RUE)--that requires rats to voluntarily reach for and pull a bar to retrieve a food reward; the resistance of the bar can be programmed. We used RUE to train forelimb strength of 16 rats three times per week for 23 weeks before and 38 weeks after a mild (100 kdyne) unilateral contusion at the cervical level 5 (C5). We measured maximum force produced when RUE movement was unexpectedly blocked. We compared this blocked pulling force (BPF) to weekly measures of forelimb strength obtained with a previous, well-established method: the grip strength meter (GSM). Before injury, BPF was 2.6 times higher (BPF, 444.6 ± 19.1 g; GSM, 168.4 ± 3.1 g) and 4.9 times more variable (p < 0.001) than pulling force measured with the GSM; the two measurement methods were uncorrelated (R(2) = 0.03; p = 0.84). After injury, there was a significant decrease in BPF of 134.35 g ± 14.71 g (p < 0.001). Together, our findings document BPF as a repeatable measure of forelimb force production, sensitive to a mild spinal cord injury, which comes closer to measuring maximum force than the GSM and thus may provide a useful measure for quantifying the effects of treatment in rodent models of SCI.
authors.affiliation: 1 Department of Dance, University of California at Irvine , Irvine, California.|2 Reeve-Irvine Research Center, University of California at Irvine , Irvine, California.
authors.forename: Kelli G
authors.initials: KG
authors.lastname: Sharp
authors.affiliation: 3 Department of Mechanical and Aerospace Engineering, University of California at Irvine , Irvine, California.
authors.forename: Jaime E
authors.initials: JE
authors.lastname: Duarte
authors.affiliation: 2 Reeve-Irvine Research Center, University of California at Irvine , Irvine, California.
authors.forename: Berkenesh
authors.initials: B
authors.lastname: Gebrekristos
authors.affiliation: 3 Department of Mechanical and Aerospace Engineering, University of California at Irvine , Irvine, California.
authors.forename: Sergi
authors.initials: S
authors.lastname: Perez
authors.affiliation: 2 Reeve-Irvine Research Center, University of California at Irvine , Irvine, California.|4 Department of Anatomy and Neurobiology, University of California at Irvine , Irvine, California.|5 Department of Neurobiology and Behavior, University of California at Irvine , Irvine, California.|6 Department of Neurosurgery, University of California at Irvine , Irvine, California.
authors.forename: Oswald
authors.initials: O
authors.lastname: Steward
authors.affiliation: 2 Reeve-Irvine Research Center, University of California at Irvine , Irvine, California.|3 Department of Mechanical and Aerospace Engineering, University of California at Irvine , Irvine, California.|4 Department of Anatomy and Neurobiology, University of California at Irvine , Irvine, California.
authors.forename: David J
authors.initials: DJ
authors.lastname: Reinkensmeyer
mesh_terms: D000818:Animals; D002574:Cervical Vertebrae; D005260:Female; D005552:Forelimb / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012371:Robotics / Q000295:instrumentation / Q000379:methods*; D013119:Spinal Cord Injuries / Q000473:pathology* / Q000534:rehabilitation*
keywords: grip strength; motor learning; motor system; rat; recovery of function; rehabilitation; robotics; spinal cord injury