The aim of this study is to determine effect of proprioceptive stimulation with passive gait training on the cortical activity in patients with severe brain injury, demonstrated as changes in EEG (electroencephalogram)and ERP (Event Related Potentials).

Hypotheses: 1) Proprioceptive stimulation increases EEG-frequency in patients with impaired consciousness due to severe brain injury.

2) Proprioceptive stimulation increases conductivity speed of the cognitive P300-component of ERP in patients with impaired consciousness due to severe brain injury.

Design: Prospective controlled non-randomized study. Materials and methods: 45 patients with severe brain injury and 15 healthy volunteers will be included in this study.

The study design is illustrated below:

1. Baseline measurement of electroencephalography (EEG) and event related potentials (ERP)
2. Gait training in the tilt table with integrated stepping system(20 min).
3. Control measurement of EEG and ERP Effect parameters: se outcome measures. Statistical evaluation: All collected data will be tested with reference to normal distribution. If the data is not distributed normally, then we will use either a logarithmic transformation before we use parametric statistics, or we will use non-parametric statistics for further calculations.

Further analysis of the data will be done with the help of variance analysis with an inter-individually factor as a group (patients vs control persons) and intra-individually factors as: 1) experimental condition (before vs after training), 2) topographic distribution (anterior vs central vs posterior).

Significance level is set to 0.05 for all effect parameters.

Inclusion Criteria:

Patient Goup:

1. Severe Brain Injury
2. Ongoing Impaired State of Consciousness (RLAS<4)
3. Stable Vital Functions
4. Written Consent from Relatives/Legal Guardian

Control Group:

1. No History of Neurological Diseases in the Past
2. Age over 18 years
3. Written Consent -

Exclusion Criteria:

Patient and Control Goup:

1. Age older than 80 years
2. Other Neurological Diseases
3. Lack of BAEP
4. Severe Co-morbidity
5. Pregnancy
6. Tilt table contraindications: orthostatic circulatory problems, unstable fractures, severe osteoporosis, sken problems, joint problems, severe asymmetry (major difference in leg length over 2 cm), co-operation problems (psychotic illnesses or neurotic disturbances), adjustment problems (i.e. integrated stepping system cannot be safely adjusted to the patient)