Subtle Neurological Abnormalities Predict Early Mortality in Older Adults

By Michael Jahn
FLORENCE, Italy, 24 june 2008-- Otherwise healthy septuagenarians who have three or more subtle neurological abnormalities, such as difficulty maintaining balance, are at an increased risk for cognitive decline and early death, researchers here reported.
In a study of 506 men and women, average age 73, at least three of these abnormalities were associated with a 77% increase in risk of death over eight years compared with same-age adults who had fewer than three, reported Marco Inzitari, M.D., of the University of Florence, and colleagues in the June 23 issue of Archives of Internal Medicine.
The mortality rates were 22.6% per 1,000 person years for those with no abnormalities versus 58.6% for those with three and 91.9% per 1,000 person years for people with four or more subtle deficits.
In an accompanying editorial, Malaz Boustani M.D., M.P.H., and Michael Justiss, Ph.D., of the Regenstrief Institute Inc., in Indianapolis, said that meant that a 65-year-old American who visited a senior care center clinic and who had no overt neurological disease but had three or more abnormalities would have a life expectancy of about seven years. A same-age person with no evidence of neurological abnormalities could expect to live another 14 years.
The participants all lived in Dicomano, a small rural town near Florence, and 58% were women.
A neurological examination to assess cognitive status and disability was conducted at baseline and repeated four years later. Deaths and cerebrovascular events were documented over eight years. Expert geriatricians conducted the baseline examination, which required no more than 15 minutes and included a traditional neurological examination plus two additional simple tests.
The parameters measured included muscle strength on physical examination (reduced shoulder elevation, reduced or absent foot extension, pronator drift or shift, and shift of one leg) and as determined by dynamometry (handgrip and hip flexion). Sensitivity on physical examination was determined by reduced foot-plant sensitivity. Deep tendon reflexes were assessed by absent or reduced patellar and achilles reflexes.
At baseline 59% of participants had at least one abnormality (average per patient, 1.1).
When adjusted for age, sex, comorbidity, cognitive, and physical functions, and functional status, the increased number of abnormalities predicted mortality with a statistical significance of P=0.006 for the likelihood ratio test. But the risk of stroke did not track the number of neurological abnormalities.
According to Dr. Inzitari and colleagues, theirs is the first study showing the association between subtle neurological changes and functional and cognitive decline, death, and stroke prospectively in a relatively large sample of unselected older persons.
They concluded, "a simple neurological examination seems to be an additional prognosticator of hard outcomes, particularly death, above and beyond other measures used in clinical practice."
Moreover, they said the data "support the hypothesis that subtle neurological abnormalities in elderly individuals are a manifestation of early brain damage, a finding that may have important implications in research studies on the prevention of age-related cognitive and functional decline."
Drs. Boustani and Justiss wrote that the data suggested that clinicians could use a simple neurological assessment "to identify at-risk older adults and enroll them in research studies of interventions to prevent disability and eventually increase the active life expectancy of the aging population."
The study was support by the Italian Ministry of Scientific and Technological Research, by the government of Tuscany, and by the Azienda Osperdaliero-Universitaria Careggi-Firenze, Italy. Dr. Inzitari reported no financial disclosures, nor did Drs. Boustani and Justiss.
Primary source: Archives of Internal MedicineSource reference:Inzitari M, et al. "Subtle Neurological Abnormalities as Risk Factors for Cognitive and Functional Decline, Cerebrovascular Events, and Mortality in Older Community-Dwelling Adults" Arch Intern Med 2008; 168(12): 1270-1276.