Artikel
Rapid cortical reorganization following traumatic spinal shock: a well-documented case
Suche in Medline nach
Autoren
Veröffentlicht: | 9. Juni 2017 |
---|
Gliederung
Text
Objective: Damage to the spinal cord is known to be associated with a posterior shift of the cortical upper limb representation, i.e. to the sensorimotor cortex. Due to missing pre-traumatic data, knowledge is acquired by comparing findings between patients and healthy subjects. Here, we present an exceptional case of traumatic spinal shock resulting in acute 5-hours tetraparesis followed by a left-sided hemiparesis lasting for 4 weeks. By chance, this patient had a pre-trauma (PT) navigated transcranial magnetic stimulation (nTMS) motor mapping 2 years before. Hence, nTMS mapping was repeated during the acute (after 1 day), sub-acute (after 10 days) and chronic (after 1.5 years) phase in order to trace the cortical reorganization following this incident.
Methods: Clinical work-up included magnetic resonance imaging (MRI) of the spine and brain as well as electroencephalography (EEG) and navigated transcranial magnetic stimulation (nTMS). Motor mapping was performed with 110% of the abductor pollicis brevis muscle (APB) resting motor threshold (rMT). Amplitudes and latencies of the motor-evoked potential (MEPs) were recorded and analyzed. In addition, motor performance was evaluated by the Medical Research Council (MRC) scale and by a reaction time (RT) task.
Results: MRI and EEG revealed no aberrant findings. nTMS mapping, however, showed a posterior shift of the APB representation from the anatomical hand knob to the sensorimotor cortex in the acute in comparison to the PT phase. Concomitantly, there was an increase of rMT (approx. 10%) and APB MEP latencies (2-3 ms). Within 10 days, there was an incomplete reversal of the posterior shift in parallel with the improvement of the clinical motor performance. MRC increased from 3/5 to 4/5 while RTs improved from 0.78±0.21 s to 0.61± 0.11 s (Student’s t-Test, p<0.001). However, long-term follow-up revealed a complete restitution of nTMS cortical mapping and behavioral measures.
Conclusion: The present case report well documents a rapid cortical reorganization within a few days after a transient spinal shock. Our data adds further evidence to the literature suggesting a posterior shift of cortical representation following spinal cord injury. For the first time, cortical reorganization was shown idiosyncratically in a single patient arising from the fortuitous fact of having a pre-shock nTMS map.