Incidence of amyotrophic lateral sclerosis and of the parkinsonism-dementia complex of Guam, 1950-1989.

Studies representing the accumulated information from the first 30 years of research effort on Guam (1950-1979) have demonstrated a varying degree of decline in the incidence of amyotrophic lateral sclerosis (ALS) and the parkinsonism-dementia complex (PDC) of Guam. Analysis with more complete information for the period 1980-1989 provides more valid estimates of the later patterns in the incidence of ALS and PDC and affords a more extensive assessment of trends over a 40-year period. The annual age-adjusted incidence of ALS was 7/100,000 and the annual age-adjusted incidence of PDC was 22/100,000 in 1989.

Amyotrophic lateral sclerosis in Olmsted County, Minnesota, 1925 to 1998.

The authors sought to determine trends in the incidence of ALS in Olmsted County from 1925 to 1998. Seventy-seven cases of ALS were identified during the period studied. The incidence rate remained stable at 1.

Behavioral and neurological correlates of ALS-parkinsonism dementia complex in adult mice fed washed cycad flour.

Consumption of cycad seed products (Cycas circinalis) is one of the strongest epidemiological links to the Guamian neurological disorder amyotrophic lateral sclerosis-parkinsonism-dementia complex (ALS-PDC), however, the putative toxin which causes neurodegeneration has never been identified definitively. To reexamine this issue, 6-7-mo-old, male CD-1 mice were assessed for motor and cognitive behaviours during and following feeding with pellets made from washed cycad flour. Cycad-fed animals showed early evidence of progressive motor and cognitive dysfunctions.