Temporal evolution of event-related desynchronization in acute stroke: A pilot study
OBJECTIVE
Assessment of event-related desynchronization (ERD) may assist in predicting recovery from stroke and rehabilitation, for instance in BCI applications. Here, we explore the temporal evolution of ERD during stroke recovery.


METHODS
Ten stroke patients and eleven healthy controls were recruited to participate in a hand movement task while EEG was being recorded. Four measurements were conducted in eight patients within four months. We quantified changes of ERD using a modulation strength measure, S(m), which represents an area and amplitude of ERD.


RESULTS
7/8 patients showed good recovery. Absence-or-reduction of ipsilesional modulation was initially found in stroke patients but not in the healthy controls. In the patient group, two evolutions were found in 6/8 patients: a significant increase in ipsilesional S(m); and a decreasing trend in contralesional S(m). In the only non-recovery patient, absence of ipsilesional modulation was observed, while his contralesional S(m) increased with time after stroke.


CONCLUSION
The two evolutions presumably reflect the reorganization of brain networks and functional recovery after acute stroke. The significant increase of ipsilesional S(m) in patients with a good recovery suggests an important role of this hemisphere during recovery.


SIGNIFICANCE
Improved understanding of ERD in acute stroke may assist in prognostication and rehabilitation.