Currently, there is no physical method of monitoring progression of Alzheimer’s dementia (AD). While several biomarkers and scans have been advocated, none of them is 100 percent sensitive or reliable. Now, a study by Amanda Khan from Canada (1) indicates that measuring temporal horn volume may be a sensitive biomarker for AD. This study revealed that only individuals with cognitive impairment and AD had evidence of significant enlargement in the temporal horn of the brain.
Patients underwent MRIs over a two-year span, and the data revealed that overall, patients with AD had much larger volume expansions in a particular location of their brains. The researchers speculated that the reason for the volume expansions includes the fact that as the brain gets smaller in patients with AD, it is replaced with a large volume of brain fluid. This leads to an increase in volume of the temporal horn, which serves as a measure of brain atrophy.
The researchers indicate that this finding may help with early diagnosis of AD and monitoring effects of treatment. While this all sounds great, one should remember that even if the diagnosis of AD is made much earlier, there are no “good” treatments.
Most of the available drugs have many side effects that are sometimes worse than the actual disorder (e.g., donezepil, memantine). Secondly, MRI scans are prohibitively expensive, and they are not covered by any health plan as a screening test for AD. Experts in the field of mental health indicate that most patients with early AD do not require any drug treatment, and even the progression of the disease is unpredictable (2,3). Therefore, for now, use of biomarkers for diagnosis of this disease is only of an academic interest.
Sources
1. Biomarker Sensitive Predictor of Alzheimer's Progression http://www.medscape.com/viewarticle/739939
2. National Institute of Aging http://www.nia.nih.gov/Alzheimers/Publications/adfact.htm
3. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/alzheimersdisease/alzheimersdisease.htm
Reviewed June 29, 2011
Edited by Kate Kunkel