Fresh
evidence provided by Canadian researchers points to the nose and odor
identification as a possible conduit for understanding when people first are afflicted
by Alzheimer’s disease (AD), according to a study in Neurology, the journal of the American Academy of Neurology.
Researchers
at McGill University in Montreal studied 274 healthy aging people with a parental
or multiple-sibling history of AD dementia who donated cerebrospinal fluid
(CSF) to be studied in conjunction with odor identification testing protocols.
Using
established measurement guides for odor identification and cognitive
performance, such as the University of Pennsylvania Smell Identification Test
and the Repeatable Battery for Assessment of Neuropsychological Status,
researchers gathered evidence that showed a reduced ability to identify odors was associated with lower
cognitive score and older age.
“These
findings from healthy high-risk older individuals suggest that odor
identification reflects a degree of preclinical AD pathology, while its
relationships with age and cognition result from the association of these
latter variables with such pathology,” researchers said. “Diminished odor
identification may be a practical and affordable biomarker of AD pathology.”
Catching
the disease early is thought to be vital for preventing full-onset, they said.
According to the Alzheimer’s Association, those with AD live an average of
eight years after their symptoms become noticeable to others, but survival can
range from four to 20 years, depending on age and other health conditions.
The
study highlighted the fact that prevention of AD can be accomplished “by
retarding the progression of the disease in its pre-symptomatic stages, thus
postponing the onset of clinical symptoms.”
This
makes research on the identification and development of AD preventive steps
even more important. Researchers said their hope is to make it easier for
physicians to find more accessible markers of these earliest stages of AD
through the odor tests.
The
study did note that their work contradicted that of other recent research. The
previous study, however, attempted to control for known detriments to odor
identification, excluding people from their test group, which the Canadian
study did not.
In
addition, the earlier research was characterized by intervals ranging up to
five years between tests of odor identification and PET scans, “whereas our
work consistently tested odor identification within three months of [cerebrospinal
fluid] collection,” the study said.
Read the
study at http://tinyurl.com/yb4jvwug.