The definition of ME can be found in Hyde, 1992 as chapter 4: 
 * Ramsay AM, Dowsett EG, "Myalgic Encephalomyelitis  Then and Now: An Epidemiological Introduction". 

 Definition of ME 
 # Generalized or localised muscle fatigue after minimal exercise with prolonged recovery time. 
 # Neurological disturbance, especially of cognitive, autonomic and sensory functions, often accompanied by marked emotional lability and sleep reversal. 
 # Variable involvement of cardiac and other bodily systems. 
 # An extended relapsing course with a tendency to chronicity. 
 # Marked variability of symptoms both within and between episodes. 
 of course in addition to the meaning of the term.  , )