Neurodegenerative disorders

Abstract

Scientific evidence of the efficacy of magnetoencephalography (MEG) is currently lacking except in diagnosing epilepsy. In the present study, we performed a review of clinical MEG studies on neurodegenerative disorders using a website bibliographic survey. We searched MEDLINE for MEG papers on neurodegenerative disorders published before December 2014 using the following keywords: a representative diagnosis such as amyotrophic lateral sclerosis (ALS) and magnetoencephalography or MEG. We further narrowed the search to 30 papers based on the levels of evidence and abstract contents; 3 papers on ALS, 18 papers on Parkinson disease, and 9 papers on multiple sclerosis were included in the final review. Levels of evidence were classified as follows: grade I, no paper; grade II, 19 papers; grade III, 2 papers; and grade IV, 9 papers. The majority of studies were conducted with a small number of patients. However, MEG has the advantage of being able to detect spontaneous activity in small brain regions and to measure functional network activity between multiple brain areas or coherent activity between deep brain nuclei and distinct cortical areas. Accordingly, MEG allows the assessment of functional changes in certain diseases and provides novel insights into disease-specific pathophysiology, such as in Parkinson disease.