NEW YORK (Reuters Health) - Brain lesions known as neurofibrillary tangles, such as those seen in Alzheimer's disease, are also associated with impaired gait in older subjects with or without dementia, according to a postmortem study.
"The more tangles an older person had in the substantia nigra" - an area of the brain associated with Parkinson's disease -- "the more problems there were with gait," lead author Dr. Julie A. Schneider told Reuters Health. Results were not altered by dementia.
"The spectrum of Alzheimer's disease is wide and poses a greater public health concern than previously recognized," Schneider said. "These data suggest that in addition to, or even instead of, problems with memory, persons with Alzheimer's disease may have problems with walking and balance."
In the study, Schneider and colleagues, from Rush University Medical Center in Chicago, investigated Parkinson-like signs and brain tangles in the substantia nigra in 86 deceased subjects without idiopathic Parkinson's disease. They used a modified Unified Parkinson's Disease Rating Scale to assess signs of gait and movement disturbance, rigidity, and tremor proximate to death.
According to a report in the Annals of Neurology, substantia nigra tangles were present in 78 percent of study subjects. The average number of tangles was more than 1500. In analyses taking into account multiple factors, the team found a strong link between the presence of these brain tangles and impaired gait.
Gait problems without an established cause, like arthritis or stroke, Schneider said, "may be a harbinger of future dementia including Alzheimer's disease. Our data suggest that these gait problems may indicate that there is already Alzheimer's disease pathology in the brain."
The investigators plan to study the functional status of the substantia nigra by measuring levels of certain brain enzymes in the substantia nigra. "If these substances are depleted it may suggest that agents that increase them may be helpful to older persons with gait problems," Schneider offered.
"In addition, our team is looking at other regions of the brain and how Alzheimer's disease pathology in these other regions may be causing symptoms not traditionally thought of as Alzheimer's disease," she added.
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