Familial occurrence of the mu rhythm

EEGs of the close relatives of patients and normal volunteers with the mu rhythm were investigated. EEGs were recorded from 14 families which included 12 fathers, 14 mothers and 9 siblings. In nine families, at least one nonproband family member had the mu rhythm. The mu rhythm was found in 13 (37.1%) of the 35 relatives. This incidence is much higher than that in a general population. These data suggest that the mu rhythm is genetically determined in most cases. The mode of inheritance might be autosomal dominant.