Induced Gamma-Band Activity During Voluntary Movement: EEG Analysis for Clinical Purposes

OBJECTIVE: Propose a simplified method applicable in routine clinical practice that uses EEG to assess induced gamma-band activity (GBA) in the 30-90 Hz frequency range in cerebral motor areas. DESIGN: EEG recordings (25 healthy subjects) of cerebral activity (at rest, motor task). GBA was obtained as power spectral density (PSD). GBA - defined as the gamma index (Iγ) - was calculated using the basal GBA (γB) and motor GBA (γMOV) PSD values. RESULTS: The mean values of Iγ were (IγR (right hand) = 1.30, IγL (left hand) = 1.22). Manual laterality showed a correlation with Iγ. CONCLUSIONS: Iγ may provide a useful way of indirectly assessing operation of activated motor neuronal circuits. It could be applied to diagnosis of motor area pathologies and as follow up in rehabilitation processes. Likewise, Iγ could enable the assessment of motor capacity, physical training and manual laterality in sport medicine.