Background: Traumatic brain injury (TBI) can induce long-term severe disorders of consciousness. Evidence suggests an underlying dopaminergic deficit. Dopamine agonists may therefore play an important role in recovery of consciousness.
Objective: To explore the response to continuous subcutaneous administration of apomorphine in a patient who had remained in minimally conscious state for 104 days and to evaluate the anatomical substrate of the effect.
Design: A prospective, open-label, daily treatment, dose-escalation single case clinical study, with retrospective diffusion tensor image (DTI) evaluation.
Results: On the fist day of treatment, the patient was able to move his limbs on command and answer yes/no questions which had not been the case prior to apomorphine administration. Subsequently there was a full recovery of consciousness and substantial functional recovery that was sustained even after apomorphine discontinuation. At the highest dose, mild dyskinesias were observed. These resolved with a lowering of the dose. DTI demonstrated a decrease of thalamocortical and corticothalamic projections in this MCS patient compared to normal volunteers.
Conclusion: Although this is an open-label single-patient case report, the data are consistent with the theory that a dopaminergic deficit underlies MCS and that it may be overcome with apomorphine administration.