A man charged in the murder of an 82-year old Middleton woman has changed his plea to not guilty by reason of mental disease or defect. 53 year old Jack Hamann was in Dane County Court on Monday. A hearing has been set for next month. Hamann was renting a room in the home of Agnes Bram in April, when Hamann hit the elderly woman at least eight times over the head with an object. Hamann has a previous felony conviction for hitting a neighbor over the head with a baseball bat.