Leukoaraiosis linked to motor deficits in elderly

Last Updated: 2008-03-17 16:00:05 -0400 (Reuters Health)

NEW YORK (Reuters Health) – Age-related cerebral white matter changes (ARWMC) are associated with gait and balance disturbances in nondisabled elderly individuals, according to data from the Leukoaraiosis and Disability Study ongoing in Europe.

"Neurologists, geriatricians and family doctors frequently send patients for brain MRIs to rule out severe atrophy, a tumor, stroke or encephalitis because of mild cognitive problems, gait unsteadiness or depressed mood, and get back ‘ARWMCs’ (or ‘leukoaraiosis’) as the main finding," Dr. Hansjoerg Baezner told Reuters Health.

"The Leukoaraiosis and Disability Study primarily aims to assess ARWMCs as a determinant of global functional decline in the elderly population," he added.

The study participants were 639 independently functioning individuals between 65 and 84 years of age with evidence of ARWMC on brain MRI. Dr. Baezner, at the University of Heidelberg in Mannheim, Germany, and his co-investigators assessed gait and balance with the Short Physical Performance Battery (range: 0=poor to 12=normal), a timed 8-meter walk test, and a timed single leg stance test. ARWMCs were classified as mild, moderate, or severe.

Their findings, reported in the March 18th issue of Neurology, indicate that "the condition is absolutely worth monitoring closely, especially in cases with severe ARWMC," Dr. Baezner said.

Mean Short Physical Performance Battery scores correlated with the severity of white matter changes (mild, 10.2; moderate, 9.9; or severe, 8.9; p < 0.001).

Similar associations were observed for single leg stance time (18.9, 16.4, and 13.6 seconds, respectively) and for walking speed (1.24, 1.18, and 1.09 m/sec, respectively).

Subjects who exercised regularly performed better on the Short Physical Performance Battery and on the timed single leg stance test in each grade of leukoaraiosis, suggesting that "exercise could have a protective effect in delaying transition to disability," the authors note.

In contrast, "walking speed seems to be a robust and early indicator of motor compromise in association with ARWMC, because physical exercise did not alter this effect."

"Although ARWMCs may be diffusely scattered in the brain white matter, they are often concentrated in areas known to be involved in motor function such as the region around the frontal horns of the brain ventricles," Dr. Baezner noted. He theorizes that ARWMCs represent a "motor network disturbance."

"The ‘motor network’ consists of cortical neurons in primary and supplementary motor cortices and their associated fibers connecting them to basal ganglia neurons, and from there to the brain stem and spinal neuronal structures," he explained. "When ARWMCs are severe enough, the network will break down and symptoms become visible."

Risk factors for ARWMC are the same as those for other vascular diseases, he said. "Physicians treating patients with ARWMC on MRI should treat arterial hypertension and diabetes very strictly."

"The longitudinal results will be analyzed soon and should be the basis for interventional studies," he added. "The most important future goal will be to find therapeutic strategies – both preventive and symptom-oriented."

Neurology 2008;70:935-942.