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Background: We investigated the effect of age on nerve conduction parameters with special reference to the compound muscle action potential (CMAP) duration and duration ratio.Method: We examined 295 subjects (aged 15-85 years old) with no previous history or present signs of peripheral neuropathy. The subjects were divided into 3 groups: young (15-34 years old); intermediate (35-64 years old), and old (65-85 years old).Results: CMAP amplitude was lower in the old group than in the young group; however, the CMAP ratio (proximal CMAP/distal CMAP) did not change with age. The CMAP duration and duration ratio did not differ among the 3 groups. The CMAP area was smaller in the old group, but the area ratio was almost constant among the 3 groups.Conclusion: We suggest that age-related changes in CMAP amplitude, duration or area may occur uniformly, at least in the forearm and the calf segment, in routine nerve conduction studies. The present findings also provide useful and reliable information, regardless of age, in diagnosing peripheral neuropathy. [ABSTRACT FROM AUTHOR]

Background: Although dementia is rarely listed on death certificates, it does contribute to mortality. The predominant immediate causes of death coincident with dementia are pneumonia and cardiovascular diseases., Objective: To estimate the impact of dementia on specific mortality risks., Methods: We applied DSM-III/R criteria for Alzheimer's disease (AD) and vascular dementia (VaD) to 2,172 subjects of the Adult Health Study of the Radiation Effects Research Foundation who were 60 or more years old when examined from 1992 to 1996. The underlying causes of death were compiled from death certificates. We performed a Poisson regression analysis to evaluate specific causes of mortality for which AD or VaD was a significant risk factor., Results: The relative risk of mortality was 2.2 for AD and 2.4 for VaD. Mortality from pneumonia and stroke was elevated for both types of dementia, independent of other medical conditions. AD was also associated with death from trauma., Conclusion: Dementia was a predictor of death due to pneumonia, stroke, and trauma among the Japanese elderly. The prevention and early detection of those conditions are important in the medical care and treatment of dementia cases., (Copyright 2004 S. Karger AG, Basel)