Brain activation in the chronic phase of traumatic spinal cord injury

Study design: Cross-sectional clinical study. Objectives: Plastic changes within cortical areas occur after traumatic spinal cord injury (TSCI). The aim of the study was to assess cortical activation in the chronic phase of TSCI using functional magnetic resonance imaging (fMRI). Setting: Tartu University Hospital, Tartu, Estonia. Methods: Ten right-handed patients with paraplegia and 18 healthy controls were studied by fMRI. Individuals performed simple flexion/extension of the right hand fingers and the right ankle during fMRI. The activation volumes, maximum t values (T max) and centres of gravity (COG) were calculated. Results: The mean time since trauma was 1848 +/- 1046 days (range 388-4459). During hand movements, the volume of activation (VOA) in the contralateral primary motor cortex was significantly larger among the TSCI patients who did not recover compared with the controls (4112 vs 2777, P=0.02). The VOA did not enlarge during the ankle movements (2420 vs 1114, P=0.08). There was a significant relationship between the VOA in Brodmann area 4 (BA4) and American Spinal Injury Association motor score during hand movements (r=-0.67, P=0.03). A positive correlation was found during hand movements in the VOA of BA4 and time since injury (r=0.62, P=0.05). Conclusions: We found increased cortical activation in the chronic phase of thoraco-lumbar TSCI that may be caused by increased use of upper limbs.