H.M. case study

Henry Gustav Molaison (February 26, 1926 – December 2, 2008), famously known as HM or H.M., was an American memory disorder patient who was widely studied from late 1957 until his death. His case played a very important role in the development of theories that explain the link between brain function and memory, and in the development of cognitive neuropsychology,  branch of psychology that aims to understand how the structure and function of the brain relates to specific psychological processes. Before his death, he resided in a care institute located in Windsor Locks, Connecticut,  he was the subject of ongoing investigation. His brain now resides at UC San Diego where it was sliced into histological sections on December 4, 2009.

The most famous case study in the history of neuropsychology is that of an anonymous memory-impaired man usually referred to only by the initials H.M. This patient has one of the most severe cases of amnesia ever observed; he has been followed for over 40 years by more than 100 researchers, and is the subject of dozens of research papers and book chapters. The early studies of H.M. provide a basis for modern neuropsychology, and the findings of those who have studied him are today a cornerstone in memory research.

H.M. had brain surgery in 1953 when he was 27 yrs old. The surgery involved removal of part of the brain known as the hippocampus to alleviate the severe symptoms of epilepsy. Although the surgery controlled the epileptic seizures H.M. suffered serious and debilitating memory impairment as a side effect. His short-term memory was normal but he was completely unable to transfer any new information into his long-term memory.