Amyotrophic lateral sclerosis, Parkinson's disease, and the amyotrophic lateral sclerosis-Parkinsonism-dementia complex on Guam: a review and summary of attempts to demonstrate infection as the aetiology.

In a series of lectures delivered in 1874, Charcot described a new syndrome which he termed amyo-trophlc lateral sclerosis (ALS). At that time he presented the essential pathological and classical characteristics of the disease which, although later modified and refined by himself and subsequent workers, have remained remarkedly classical for ALS during the almost 100 years since they were published. Recently, Goldblatt (1968) has extensively reviewed the literature on motor neurone disease. Most investigators now recognize three forms of ALS: (1) the sporadic or classic, (2) the familial and presumably hereditary, and (3) the Mariana Islands form or the western Pacific islands form which is the major cause of death among the Chamorro Indians, an indigenous population on the island of Guam (Table I). Indeed, the highest incidence of ALS in the world occurs in the Chamorro population coincident with an unusual form of dementia with Parkinsonian features and upper motor neurone changes referred to as the Parkinsonism-dementia complex, which may be a classical variant of the Guam type (Brody and Chen, 1968). It is of interest that this rather isolated population in the Pacific Ocean manifests the presenile dementia of Parkin-sonism while the best known of the world's presenile dementias, ie, Alzheimer's disease, Pick's disease, and Creutzfeldt-Jakob disease, have not been clinically recognized as occurring. We have recently had a case of 'Parkinsonism-dementia' which histo-logically was diagnosed by Hirano as a possible case of Creutzfeldt-Jakob disease with spongiform changes. This patient was a Filipino not born on Guam. The Parkinsonism-dementia complex, although more recently characterized and less well known than ALS, actually accounts for an equal number of adult deaths among the Chamorro population (Brody and Chen, 1968).