Inclusion Criteria:

1. Patient is between 18 and 50 years of age, inclusive.
2. Male or non-pregnant female (females of child-bearing potential will be required to have undergone a pregnancy test with negative results prior to entry to the study).
3. Patients will have sustained a severe closed head injury within one to four months.
4. Patients will have remained in a vegetative or minimally conscious state between one and four months after injury.
5. Patients will have reached a stabilized clinical state prior to admission to the study (e.g. afebrile, haemodynamic and electrolyte stability).
6. Patients will have a mean DRS score between 17 and 29, when measured twice a day over two consecutive days.
7. Informed consent from a legal representative will have been obtained, according to the procedures outlined in Section 8.1.2.
8. Patients who, according to the investigator's opinion, are likely to be available for the required 180-day follow up evaluation.

Exclusion Criteria:

1. Patients who are not clinically stable at the time of entry into the study (infections, cardiovascular decompensation, etc.)
2. Patients who require mechanical respiratory assistance.
3. Patients who show signs of progressive neurological deterioration post-TBI.
4. Patients with a known history of medically relevant substance abuse.
5. Patients with history of cardiac disease.
6. Patients who suffered an anoxic event.
7. Patients who have received an investigational drug within 30 days of the study.
8. Patients who have previously used NH001, other dopaminergic agent (e.g. levodopa, amantadine, domperidone) or any known neurostimulant (e.g. methylphenidate, amphetamines, atomoxetine, modafinil) within the last 7 days days.
9. Patients who are receiving dopamine blockers (e.g. risperidone, haloperidol, chlorpromazine, flupenthixole, clozapine, olanzapine, quetapine)
10. Patients who are receiving drugs of the 5HT3 antagonist class, including, for example, ondansetron, granisetron, dolasetron, palonosetron and alosetron.
11. Patients who are receiving tricyclic antidepressants drugs
12. Patients who are receiving type I antiarrhythmics (i.e. quinidine).
13. Patients who have a known history of cardiac arrhythmias or congenital QTc prolongation.
14. Patients who have a known history of previous neurological functional impairment (e.g. stroke, spinal cord injury, dementia, epilepsy, psychiatric diseases).
15. Patients who experienced seizures within the first week post injury or have ongoing seizures.
16. Patients receiving prophylactic anti-convulsive medications.
17. Patients with known allergies to apomorphine, morphine, sulfites or trimethobenzamide.
18. Patients who are receiving nitrates or other vasodilators.
19. Patients receiving CNS acting agents such as barbiturates, morphine, belladonna, opiates.
20. For male patients, patients who are receiving trazadone or any other drug that is known to produce priapism.
21. Patients without a relative or legal guardian to consent to the study.
22. Patients who, according to the investigator's opinion, are unlikely to be available for the required 180-day follow up evaluation.