title: A longitudinal study of pain, personality, and brain plasticity following peripheral nerve injury.
abstract: We do not know precisely why pain develops and becomes chronic after peripheral nerve injury (PNI), but it is likely due to biological and psychological factors. Here, we tested the hypotheses that (1) high Pain Catastrophizing Scale (PCS) scores at the time of injury and repair are associated with pain and cold sensitivity after 1-year recovery and (2) insula gray matter changes reflect the course of injury and improvements over time. Ten patients with complete median and/or ulnar nerve transections and surgical repair were tested ∼3 weeks after surgical nerve repair (time 1) and ∼1 year later for 6 of the 10 patients (time 2). Patients and 10 age-/sex-matched healthy controls completed questionnaires that assessed pain (patients) and personality and underwent quantitative sensory testing and 3T MRI to assess cortical thickness. In patients, pain intensity and neuropathic pain correlated with pain catastrophizing. Time 1 pain catastrophizing trended toward predicting cold pain thresholds at time 2, and at time 1 cortical thickness of the right insula was reduced. At time 2, chronic pain was related to the time 1 pain-PCS relationship and cold sensitivity, pain catastrophizing correlated with cold pain threshold, and insula thickness reversed to control levels. This study highlights the interplay between personality, sensory function, and pain in patients following PNI and repair. The PCS-pain association suggests that a focus on affective or negative components of pain could render patients vulnerable to chronic pain. Cold sensitivity and structural insula changes may reflect altered thermosensory or sensorimotor awareness representations.
authors.affiliation: Division of Brain, Imaging, and Behaviour, Systems Neuroscience, Krembil Research Institute, Toronto Western Hospital, University Health Network, Toronto, ON, Canada Institute of Medical Science, University of Toronto, Toronto, ON, Canada Department of Surgery, University of Toronto, Toronto, ON, Canada Department of Psychology, York University, Toronto, ON, Canada Department of Anesthesia, University of Toronto, Toronto, ON, Canada Department of Anesthesia and Pain Management, Toronto General Hospital, University Health Network, Toronto, ON, Canada.
authors.forename: Ruma
authors.initials: R
authors.lastname: Goswami
authors.forename: Dimitri J
authors.initials: DJ
authors.lastname: Anastakis
authors.forename: Joel
authors.initials: J
authors.lastname: Katz
authors.forename: Karen D
authors.initials: KD
authors.lastname: Davis
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology; D058443:Catastrophization / Q000175:diagnosis / Q000523:psychology*; D003080:Cold Temperature / Q000009:adverse effects; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009473:Neuronal Plasticity / Q000502:physiology; D010147:Pain Measurement / Q000523:psychology* / Q000639:trends; D017288:Pain Threshold / Q000502:physiology / Q000523:psychology*; D059348:Peripheral Nerve Injuries / Q000175:diagnosis / Q000523:psychology*; D010551:Personality / Q000502:physiology; D055815:Young Adult