Comparing MEG and EEG in detecting the ~20-Hz rhythm modulation to tactile and proprioceptive stimulation
Mia Illman,
Kristina Laaksonen,
Mia Liljeström,
Veikko Jousmäki,
Harri Piitulainen,
Nina Forss
Affiliations
Mia Illman
Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, P.O.BOX 12200, 00760 AALTO, Espoo, Finland; Aalto NeuroImaging, Aalto University School of Science, P.O.BOX 12200, 00760 AALTO, Espoo, Finland; Faculty of Sport and Health Sciences, University of Jyväskylä, P.O. BOX 35, FI-40014, Jyväskylä, Finland; Corresponding author. Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, P.O.BOX 12200, 00760 AALTO, Espoo, Finland.
Kristina Laaksonen
Department of Neurology, Helsinki University Hospital and Clinical Neurosciences, Neurology, University of Helsinki, P.O. Box 340, 00029 HUS, Helsinki, Finland
Mia Liljeström
Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, P.O.BOX 12200, 00760 AALTO, Espoo, Finland
Veikko Jousmäki
Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, P.O.BOX 12200, 00760 AALTO, Espoo, Finland; Aalto NeuroImaging, Aalto University School of Science, P.O.BOX 12200, 00760 AALTO, Espoo, Finland
Harri Piitulainen
Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, P.O.BOX 12200, 00760 AALTO, Espoo, Finland; Faculty of Sport and Health Sciences, University of Jyväskylä, P.O. BOX 35, FI-40014, Jyväskylä, Finland
Nina Forss
Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, P.O.BOX 12200, 00760 AALTO, Espoo, Finland; Department of Neurology, Helsinki University Hospital and Clinical Neurosciences, Neurology, University of Helsinki, P.O. Box 340, 00029 HUS, Helsinki, Finland
Modulation of the ~20-Hz brain rhythm has been used to evaluate the functional state of the sensorimotor cortex both in healthy subjects and patients, such as stroke patients. The ~20-Hz brain rhythm can be detected by both magnetoencephalography (MEG) and electroencephalography (EEG), but the comparability of these methods has not been evaluated. Here, we compare these two methods in the evaluating of ~20-Hz activity modulation to somatosensory stimuli.Rhythmic ~20-Hz activity during separate tactile and proprioceptive stimulation of the right and left index finger was recorded simultaneously with MEG and EEG in twenty-four healthy participants.Both tactile and proprioceptive stimulus produced a clear suppression at 300–350 ms followed by a subsequent rebound at 700–900 ms after stimulus onset, detected at similar latencies both with MEG and EEG. The relative amplitudes of suppression and rebound correlated strongly between MEG and EEG recordings. However, the relative strength of suppression and rebound in the contralateral hemisphere (with respect to the stimulated hand) was significantly stronger in MEG than in EEG recordings.Our results indicate that MEG recordings produced signals with higher signal-to-noise ratio than EEG, favoring MEG as an optimal tool for studies evaluating sensorimotor cortical functions. However, the strong correlation between MEG and EEG results encourages the use of EEG when translating studies to clinical practice. The clear advantage of EEG is the availability of the method in hospitals and bed-side measurements at the acute phase.
