Enabling motor control in chronic spinal cord injury: found in translation.

Abstract

Chronic spinal cord injury affects between 440 and 681 people in every million, depending on country (Bickenbach, 2013), and remains an unmet medical need. While there has been an exponential increase in our molecular and cellular understanding of spinal cord injury over the last three decades, with a considerable number of interventions producing functional neurological recovery in experimental models, not one has been translated into an FDA-approved treatment available in the clinic. Translating neurobiological concepts from basic neuroscience to clinical treatments is one of the toughest challenges and its success depends on a bidirectional dialogue (Curt, 2012). In the current issue of Brain , Susan Harkema and Victor Edgerton scale up the results of an earlier case report (Harkema et al. , 2011) to demonstrate that epidural stimulation, beginning >2 years after spinal cord injury, can restore voluntary movement in a select group of patients (Angeli et al. , 2014). Epidural stimulation (25 or 30 Hz, 1.5–2.5 V) was applied to the index patient from the initial case report and to three additional patients (neurological lesion level C7–T5), via an implanted device at spinal cord level L1-S1 as previously described (Harkema et al. , 2011). Two of the patients had lesions classified as grade A according to the American Spinal Injury Association Impairment Scale (AIS) (sensory and motor complete), while two had lesions classified as AIS B (sensory incomplete). The concept of lumbar stimulation to treat spinal injury is derived from research in the ‘spinal cat’ that revealed the presence of a locomotor centre in the lumbar spinal cord (Grillner et al. , 1969), a discovery that was further advanced in human patients by Milan Dimitrijevic. It was subsequently confirmed that both propriospinal and supraspinal afferents to spinal locomotor centres could facilitate motor output in patients with complete spinal …