New Blood Test Detects Early Brain Damage in Pre-Symptomatic Alzheimer’s Disease

Introduction to the Research

An international research team has assessed a novel blood test capable of identifying early brain damage associated with pre-symptomatic Alzheimer’s disease. In degenerative brain disorders like Alzheimer’s and multiple sclerosis, brain damage and structural alterations can occur much earlier than the onset of symptoms. Currently, these changes are detectable through brain scans or analysis of cerebrospinal fluid samples; however, such methods are often costly and uncomfortable for patients.

Limitations of Existing Tests

Present diagnostic tests for early signs of Alzheimer’s disease are invasive and expensive. Consequently, medical professionals are seeking simpler and more affordable alternatives that can effectively detect early brain damage and anticipate the progression of the illness.

Study Overview and Findings

The international research team evaluated a new blood test involving patients with a rare genetic variant of Alzheimer’s disease. Their findings were recently published in *Nature Medicine*. The study focused on individuals with this genetic form of Alzheimer’s, which typically manifests in their 30s, 40s, or 50s. Parents carrying the gene mutation have a 50% likelihood of passing it to their children, leading to dementia symptoms appearing at the same age as the affected parent. This inheritance pattern enables researchers to observe the effects in gene carriers long before symptoms materialize.

Research Methodology

The research involved 247 gene carriers and 162 unaffected relatives. Participants received evaluations at neurology clinics every two to three years, which included brain scans, cerebrospinal fluid tests, and memory assessments. Additionally, blood samples were collected to analyze levels of neurofilament light chains (NfL), proteins integral to nerve cell structure. When nerve cells suffer damage or begin to die, NfLs leak into the spinal fluid and subsequently into the bloodstream.

Key Results

In individuals carrying the faulty gene, NfL blood levels were elevated at the study’s outset and increased over time. In contrast, non-carriers displayed consistently low NfL levels. Notably, this distinction was detectable 16 years prior to the expected onset of dementia symptoms. Furthermore, the rate of increase in NfL correlated with changes observed in brain scans of the memory area, as well as alterations in brain function assessed through memory and mental state evaluations.

Conclusion and Future Directions

The researchers concluded that the NfL blood test effectively identifies brain damage and forecasts disease progression during the early pre-symptomatic stages of genetic Alzheimer’s disease. This test may prove beneficial for diagnosing and monitoring other forms of Alzheimer’s and various neurological disorders, although additional research is necessary. Dr. Brian Gordon from the Washington University School of Medicine, a lead author of the study, expressed optimism about the test’s future clinical application, stating, “I could see this being used in the clinic in a few years to identify signs of brain damage in individual patients.”

References

Preische O, Schultz SA, Apel A, et al. Serum neurofilament dynamics predicts neurodegeneration and clinical progression in presymptomatic Alzheimer’s disease. *Nature Medicine* (Letters) doi:10.1038/s41591-018-0304-3.
Press release. Washington University School of Medicine 21 Jan 2019. “Blood test detects Alzheimer’s damage before symptoms” https://www.eurekalert.org/pub_releases/2019-01/wuso-btd011719.php