Movement dysfunction following repetitive hand opening and closing: Anatomical analysis in owl monkeys

Work-Related Musculoskeletal Disorders of the Hand and Wrist: Epidemiology, Pathophysiology, and Sensorimotor Changes

“…the potential for increased peripheral tissue injury due to imprecisely controlled and inefficient movements. These behavioral consequences have been observed in both animals 12,13,15,23,26,28,33,111 and humans. 22,24,27,43,110 Failure by health care providers to recognize such central phenomena in patients could lead to poor treatment outcomes and contribute to long-term disability and loss of income.…”

“…There is strong evidence that repetitive tasks alone can lead to degradation of the somatosensory cortex in monkeys, 25,26,28,111 rats, 91 and humans (Table 4). 22,24,27 In the primate model of repetitive grasping, electrophysiological mapping of the primar y somatosensory cortex (the region of the dorsal parietal cortex designated as area SI) reveals a dedifferentiation of the hand region with shifted or degraded digit-receptive fields.…”

“…22,24,27 In the primate model of repetitive grasping, electrophysiological mapping of the primar y somatosensory cortex (the region of the dorsal parietal cortex designated as area SI) reveals a dedifferentiation of the hand region with shifted or degraded digit-receptive fields. [23][24][25]111 These changes are associated with movement dysfunctions. However, use of proximal muscles and variable strategies result in less SI degradation and improved motor control.…”

“…However, use of proximal muscles and variable strategies result in less SI degradation and improved motor control. 111 In humans, degradation of hand representations also occurs with focal hand dystonia. 22,24,27 The severity of focal hand dystonia positively correlates with the ratio of the mean amplitude to latency of the somatosensory evoked potential (SEP) in the SI cortex.…”

Dystonia Pathophysiology: A Critical Review

“…So far, the only phenotypic model of primary dystonia in the primate was that obtained in monkeys trained to perform repetitive movements (60)(61)(62). The animals performed the same movement of grasping 2 hours a day 5 days a week for 12 to 25 weeks and experienced difficulties removing their hands from the handpiece after 5-8 weeks of training, associated with a reduction in the number of trials correctly performed (60).…”