ABSTRACT
The argument of a gradual decline with aging is buttressed by research on the interaction of aging with neurological disease. This was evidenced in a study of a cognitive change associated with Parkinson's disease called "bradyphrenia,w or increased mental slowing (Lafleche, Stuss, Nelson, & Picton, 1990). When patients with Parkinson's disease were studied on the Sternberg memory search task, a general slowing was noted, but there was no significant difference from a control group in the slope of the memory retrieval function related to the number of items in memory storage. That is, there was no "mentalw slowing; the results could be explained by motor dysfunction. However, when patients with similar levels of severity of Parkinson's disease were divided according to their chronological age, bradyphrenia was more notable in the older patients. Age appeared to interact with the neurological disease.
