Behavioral recovery from tetraparesis in a captive chimpanzee.

An adult male chimpanzee living in a captive social group at the Primate Research Institute of Kyoto University developed acute tetraparesis. He was paralyzed and received intensive care and veterinary treatment as previously reported in Miyabe-Nishiwaki et al. (J Med Primatol 39:336-346, 2010). The behavioral recovery of the chimpanzee was longitudinally monitored using an index of upright posture between 0 and 41 months after the onset of tetraparesis. Four phases were identified during the course of behavioral recovery. During Phase 0 (0-13 months), the chimpanzee remained lying on his back during the absence of human caretakers. An increase in upright posture occurred in Phase I (14-17 months), then remained at a stable level of around 50-70 % in Phase II (18-29 months). During Phases I and II, the subject's small treatment cage represented a spatial limitation. Thus, behavioral recovery was mainly mediated by arm muscle strengthening caused by raising the body trunk with the aid of materials attached to the cage walls as environmental enrichment. When the chimpanzee was moved to a larger rehabilitation room in Phase III (30-41 months), the percentage of upright posture constantly exceeded 80 %, except in the 40th month when he injured his ankle and was inactive for several days. The enlargement of the living space had a positive effect on behavioral recovery by increasing the types of locomotion exhibited by the subject, including the use of legs during walking. Rehabilitation works were applied in face-to-face situations which enabled the use of rehabilitation methods used in humans. The process of behavioral recovery reported in this study provides a basic data set for planning future rehabilitation programs and for comparisons with further cases of physical disability in non-human primates.