Article

There is now sufficient evidence that using a rehabilitation protocol
involving motor imagery (MI) practice in conjunction with physical practice (PP)
of goal-directed rehabilitation tasks leads to enhanced functional recovery of
paralyzed limbs among stroke sufferers. It is however difficult to confirm
patient engagement during an MI in the absence of any on-line measure.
Fortunately an EEG-based brain-computer interface (BCI) can provide an on-line
measure of MI activity as a neurofeedback for the BCI user to help him/her focus
better on the MI task. However initial performance of novice BCI users may be
quite moderate and may cause frustration. This paper reports a pilot study in
which a BCI system is used to provide a computer game-based neurofeedback to
stroke participants during the MI part of a protocol. METHODS: The participants
included five chronic hemiplegic stroke sufferers. Participants received up to
twelve 30-minute MI practice sessions (in conjunction with PP sessions of the
same duration) on 2 days a week for 6 weeks. The BCI neurofeedback performance
was evaluated based on the MI task classification accuracy (CA) rate. A set of
outcome measures including action research arm test (ARAT) and grip strength
(GS), was made use of in assessing the upper limb functional recovery. In
addition, since stroke sufferers often experience physical tiredness, which may
influence the protocol effectiveness, their fatigue and mood levels were assessed
regularly. RESULTS: Positive improvement in at least one of the outcome measures
was observed in all the participants, while improvements approached a minimal
clinically important difference (MCID) for the ARAT. The on-line CA of MI induced
sensorimotor rhythm (SMR) modulation patterns in the form of lateralized
event-related desynchronization (ERD) and event-related synchronization (ERS)
effects, for novice participants was in a moderate range of 60-75% within the
limited 12 training sessions. The ERD/ERS change from the first to the last
session was statistically significant for only two participants. CONCLUSIONS:
Overall the crucial observation is that the moderate BCI classification
performance did not impede the positive rehabilitation trends as quantified with
the rehabilitation outcome measures adopted in this study. Therefore it can be
concluded that the BCI supported MI is a feasible intervention as part of a
post-stroke rehabilitation protocol combining both PP and MI practice of
rehabilitation tasks. Although these findings are promising, the scope of the
final conclusions is limited by the small sample size and the lack of a control
group.

Langue : ANGLAIS