title: Evidence of significant central fatigue in patients with cancer-related fatigue during repetitive elbow flexions till perceived exhaustion.
abstract: OBJECTIVE
  To investigate whether fatigue induced by an intermittent motor task in patients with cancer-related fatigue (CRF) is more central or peripheral.
  
  
  METHODS
  Ten patients with CRF who were off chemo and radiation therapies and 14 age-matched healthy controls were enrolled. Participants completed a Brief Fatigue Inventory (BFI) and performed a fatigue task consisting of intermittent elbow-flexion contractions at submaximal (40% maximal voluntary contraction) intensity till self-perceived exhaustion. Twitch force was elicited by an electrical stimulation applied to the biceps brachii muscle. The relative degree of peripheral (muscle) vs. central contribution to fatigue induced by the intermittent motor task (IMT) was assessed using twitch force ratio (TF ratio) defined as post IMT twitch force to pre IMT twitch force. The total number of trials (intermittent contractions) and total duration of all trials performed by each subject were also quantified.
  
  
  RESULTS
  BFI scores were higher (p < 0.001) in CRF than controls, indicating greater feeling of fatigue in CRF patients than controls. A significantly smaller number of trials and shorter total duration of the trials (p < 0.05) were observed in CRF than control participants. The TF ratio (0.81 ± 0.05) in CRF was higher (p < 0.05) compared with that of controls (0.62 ± 0.05), suggesting CRF patients experienced a significantly lower degree of muscle (peripheral) fatigue at the time of perceived exhaustion.
  
  
  CONCLUSIONS
  Consistent with prior findings for fatigue under submaximal sustained contraction, our results indicate that motor fatigue in CRF is more of central than peripheral origin during IMT. Significant central fatigue in CRF patients limits their ability to prolong motor performance.
authors.affiliation: Department of Rehabilitation Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Road, Shanghai 200011, China; Institute of Rehabilitation Engineering, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Cai
authors.affiliation: Human Performance & Engineering Laboratory, Kessler Foundation Research Center, 1199 Pleasant Valley Way, West Orange, New Jersey 07052, United States of America.
authors.forename: Didier
authors.initials: D
authors.lastname: Allexandre
authors.affiliation: Human Performance & Engineering Laboratory, Kessler Foundation Research Center, 1199 Pleasant Valley Way, West Orange, New Jersey 07052, United States of America.
authors.forename: Venkateswaran
authors.initials: V
authors.lastname: Rajagopalan
authors.affiliation: Human Performance & Engineering Laboratory, Kessler Foundation Research Center, 1199 Pleasant Valley Way, West Orange, New Jersey 07052, United States of America.
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Jiang
authors.affiliation: Department of Biomedical Engineering, Cleveland Clinic, Cleveland, Ohio 44195, United States of America.
authors.forename: Vlodek
authors.initials: V
authors.lastname: Siemionow
authors.affiliation: Department of Physical Medicine & Rehabilitation, Cleveland Clinic, Cleveland, Ohio 44195, United States of America.
authors.forename: Vinoth K
authors.initials: VK
authors.lastname: Ranganathan
authors.affiliation: The Harry R. Horvitz Center for Palliative Medicine, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio 44195, United States of America.
authors.forename: Mellar P
authors.initials: MP
authors.lastname: Davis
authors.affiliation: The Harry R. Horvitz Center for Palliative Medicine, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio 44195, United States of America.
authors.forename: Declan
authors.initials: D
authors.lastname: Walsh
authors.affiliation: Department of Orthopaedics, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Road, Shanghai 200011, China; Engineering Research Center of Digital Medicine and Clinical Translation, Ministry of Education, PRC, 1954 Huashan Road, Shanghai 200030, China.
authors.forename: Kerong
authors.initials: K
authors.lastname: Dai
authors.affiliation: Human Performance & Engineering Laboratory, Kessler Foundation Research Center, 1199 Pleasant Valley Way, West Orange, New Jersey 07052, United States of America; Department of Biomedical Engineering, Cleveland Clinic, Cleveland, Ohio 44195, United States of America; Department of Physical Medicine & Rehabilitation, Cleveland Clinic, Cleveland, Ohio 44195, United States of America.
authors.forename: Guang H
authors.initials: GH
authors.lastname: Yue
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use; D004551:Elbow Joint / Q000502:physiology*; D004558:Electric Stimulation; D005221:Fatigue / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology; D009369:Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000532:radiotherapy
chemical_list: D000970:Antineoplastic Agents