Parkinsonism Dementia Complex on Guam: Current Status of the Problem

On the island of Guam, parkinsonism dementia (PD) complex accounts for a significant number of the adult deaths among the indigenous Chamorro population. It affects middle aged individuals who show parkinsonian features accompanied by a progressive dementia and death results in 3-5 yr. Pathological alterations involve the usual areas of classical parkinsonism but, in addition, the cerebrum is severely atrophic and the degree of involvement is much more profound. The most striking alterations are the intraneuronal fibrillary tangles found throughout the affected areas. These tangles are indistinguishable by either light or electron microscopy from those seen in Alzheimer's disease. The etiology of PD complex is unknown. No toxic agent has yet been found to be directly responsible. Attempts to demonstrate the presence of a slow virus by the inoculation of brain tissue from PD patients into chimpanzees have not yet been successful. Finally, the possibility of a genetic transmission of the disease is being studied by the examination of an emigrant Chamorro population on the W. coast of the USA. One autopsy confirmed case of PD complex has so far been discovered among this population. This is, to the author's knowledge, the first case of PD complex demonstrated outside of Guam.