Clinical application of magnetoencephalography in a patient with corticobasal degeneration

Previous neuroimaging studies in corticobasal degeneration (CBD), such as M RI and positron emission tomography, showed lateralized cortical atrophy an d a decrease in cortical oxygen metabolism, respectively. The advantage of magnetoencephalography in the research of the auditory system is that activ ity of both hemispheres can be detected separately. Auditory-evoked magneti c fields (AEFs) were then applied to a patient with corticobasal degenerati on. The strength of N100m equivalent current dipoles (ECD) in left hemisphe re was extremely smaller (20 nAm) than that in right hemisphere (48 nAm). T his results implies that CBD patient might have a decrease in the number of neurons in the primary auditory cortex. This study suggests that AEF measu rement is one of the most powerful tools for detecting latent impairment of auditory function in patients with corticobasal degeneration.