Alterations in spontaneous brain oscillations during stroke recovery

Area of Science:

• Neuroscience
• Biophysics
• Medical Imaging

Background:

• Spontaneous brain oscillations' role in pathology and recovery is unclear.
• Temporal dynamics and functional significance of altered brain oscillations post-stroke require investigation.

Purpose of the Study:

• To investigate the temporal evolution of spontaneous brain oscillations after stroke.
• To correlate changes in brain oscillations with clinical recovery and lesion characteristics.

Main Methods:

• Whole-head magnetoencephalography (MEG) recordings in 16 stroke patients at 1-7 days (T0), 1 month (T1), and 3 months (T2) post-stroke.
• Clinical examinations were performed concurrently with MEG recordings.
• Analysis focused on temporo-parietal oscillations (≈10 Hz) and abnormal low-frequency magnetic activity (ALFMA, ≈1 Hz) in the affected hemisphere.

Main Results:

• Significant clinical improvement observed from T0 to T1/T2.
• Increased temporo-parietal ≈10-Hz oscillations in the affected hemisphere during recovery (T1, T2).
• Abnormal low-frequency magnetic activity (ALFMA) detected in the perilesional cortex in 7/16 patients at T0, persisting in 4/7 at T2.
• Larger lesion size and worse clinical outcome associated with ALFMA, particularly persisting ALFMA.

Conclusions:

• Temporo-parietal ≈10-Hz oscillations are enhanced in the affected hemisphere during stroke recovery.
• Stroke induces ALFMA, which may serve as a biomarker for predicting poorer clinical outcomes.