February 1, 2006

Brain tangles linked to gait impairment in elderly

By Michelle Rizzo

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

"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

"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.

SOURCE: Annals of Neurology January 2006.