The scientific evidence of magnetoencephalography (MEG) is not necessarily clear except for a diagnosis of epilepsy. In this study, we reviewed clinical MEG studies regarding neurological diseases or neurorehabilitation based on a website bibliographic survey. We searched MEG papers on neurological diseases or neurorehabilitation before November 2011 using MEDLINE by keywords: (a representative diagnosis such as amyotrophic lateral sclerosis, ALS) AND (MEG OR magnetoencephalography). Among many papers retrieved, we further narrowed the search to 27 papers based on levels of evidence and abstract contents; as to neurological diseases, 3 papers on ALS, 8 papers on Parkinson disease and 4 papers on multiple sclerosis were reviewed: and as to neurorehabilitation, 9 papers on recovery from sensorimotor deficits and 3 papers on recovery from aphasia due to an ischemic stroke. The levels of evidence were classified as grade 1: no paper, 2: 18 papers, 3: 3 papers, 4: 6 papers, 5: no paper, 6: no paper, respectively. Most studies were confined to small number of patients. However, MEG has an advantage of detecting spontaneous activity in a small brain region and providing functional network activity between multiple brain areas or coherent activity between deep brain nuclei and distinct cortical areas. Therefore, the MEG tells us functional changes in a certain disease or a recovery phase from an ischemic stroke, and gives a novel insight into disease-specific pathophysiology such as Parkinson disease.

View full abstract

Somatosensory evoked magnetic fields (SEFs) are the most commonly used clinical testing among various stimulus-evoked or event-related magentoencephalogram (MEG). The standardization of stimulus methods for evoked MEG is one of necessary conditions for determining diagnostic protocols in the future. In this study, we reviewed clinical SEF studies regarding stimulus methods or conditions based on a website bibliographic survey. We searched original clinical papers published in English on SEF before July 2012 using MEDLINE by keywords: (magnetoencephalography OR MEG OR magnetic source imaging) AND (presurgical or pathophysiology). Among many papers retrieved, we further narrowed the search to 49 papers based on medical subject headings such as presurgical or pathophysiology: Stimulus methods comprise electrical stimulation in 30 papers, mechanical stimulation in 17 papers, and both electrical and mechanical stimulation in 2 papers. As to parameters in electrical stimulation, many papers followed the recommendations of somatosensory evoked potentials proposed by the International Federation of Clinical Neurophysiology (2008). With regards to mechanical stimulation, a method to produce indentation of the skin as wide as a 10 mm diameter was commonly used but the latency of the cortical response it evokes is markedly long compared to that evoked by the electrical stimulation. Therefore, it is hoped that a novel mechanical stimulation technique which can be used in a magnetically shielded room is available in the near future to quickly indent the skin area as narrow as a 1–2 mm diameter that enables us to effectively stimulate RA1 and RA2 fibers projecting to area 3b.

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract