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.