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, Sm, 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 Sm; and a decreasing trend in contralesional Sm. In the only non-recovery patient, absence of ipsilesional modulation was observed, while his contralesional Sm 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 Sm in patients with a good recovery suggests an important role of this hemisphere during recovery