Partial recovery of hemiparesis following hemispherectomy in infant monkeys.
Hemiparesis, unilateral weakness or partial paralysis, is a common outcome following hemispherectomy in humans. We use the non-human primate as an invaluable translational model for our understanding of developmental plasticity in response to hemispherectomy. Three infant vervet monkeys (Chlorocebus sabeus) underwent hemispherectomy at a median age of 9 weeks and two additional monkeys at 48 months. Gross motor assessment was conducted in a large open field that contained a horizontal bar spanning the width of the cage. Subjects were assessed yearly following surgery in infantile lesions for a period of 3 years. Adult-lesioned subjects were assessed 40 months following surgery. Shortly after surgery both infant and adult-lesioned subjects were unable to move the contralateral side of their body, but all subjects were able to walk within 6 months following surgery. At each time point the lower limb gait was normal in infant-lesioned subjects with no apparent limp or dragging, however the upper limb demonstrated significant impairment. Horizontal bar crossing was significantly impaired during the first 24 months following surgery. Adult-lesioned subjects also displayed upper limb movement impairments similar to infant-lesioned subjects. In addition the adult-lesioned subjects displayed a noticeable lower limb limp, which was not observed in the infant-lesioned group. Both groups at each time point showed a propensity for ipsiversive turning. The upper limb gait impairment and horizontal bar crossing of lesioned subjects are reminiscent of hemiparesis seen in hemisperectomized humans with the young-lesioned subjects showing a greater propensity for recovery.
Burke
Mark W
MW
School of Optometry, University of Montreal, Montreal, QC, Canada. mark.burke@umontreal.ca
Zangenehpour
Shahin
S
Ptito
Maurice
M
D000375:Aging; D000818:Animals; D001132:Arm; D001921:Brain / Q000254:growth & development* / Q000503:physiopathology* / Q000601:surgery; D002522:Chlorocebus aethiops; D020820:Dyskinesias / Q000209:etiology / Q000503:physiopathology*; D005684:Gait / Q000502:physiology; D038421:Hemispherectomy; D007866:Leg; D009043:Motor Activity / Q000502:physiology; D009473:Neuronal Plasticity; D010291:Paresis / Q000209:etiology / Q000503:physiopathology*; D020127:Recovery of Function / Q000502:physiology*