Study links gait problems to dementia

The investigation included 86 autopsied subjects from the aptly named “Religious Orders Study”. Participants in the study were older Catholic clergy who enrolled without known dementia and agreed to annual neurological assessmetns and brain donation at death.

The researchers were interested in investigating changes to the substantia nigra, a part of the brain that is subject to cell loss in Parkinson’s disease and is associated with gait impairment in older persons with and without dementia.

Though less than half of the subjects had dementia, the study found nearly 78% of test subjects had neurofibrillary tangles (a classic brain abnormality seen in Alzheimer’s disease), in the substantia nigra. All 86 persons had at least some evidence of parkinsonian signs before death. Gait was the most severely affected domain followed by bradykinesia (slowness in movement), rigidity, and tremor.

The study looked at the relationship between nigra tangles and each parkinsonian sign. It found that every 1,000 nigra tangles increased the gait score of subjects, measured using a standardized assessment, by more than three points. In contrast, nigra tangles were not related to bradykinesia, rigidity, or tremor. The relationship between substantia nigra tangles and gait impairment was found in persons with and without dementia.

“This study shows that the spectrum of Alzheimer’s disease is broader than we thought and may be more common than previously recognized. Alzheimer’s disease doesn’t just cause memory and cognitive problems, it is also causing motor problems in aging,” said Dr Julie Schneider study investigator at the Rush Alzheimer’s disease Center.