1) An impairment of memory 
An obsolete term for a naturally poor or an impaired memory. ... Origin: dys-+ G. Mneme, mnesi-, memory ... (05 Mar 2000) ... 
(dis-ne´zhә) disordered memory; as in the amnestic syndrome. adj. dysmnes´tic., adj.
dysmnesia, dysmnesic Any impairment of memory, as in amnestic syndrome; a bad memory.
an impairment of memory.