Knowing the Difference: Alzheimer’s Disease vs. Other Types of Dementia
Alzheimer’s disease (AD) is the most common type of dementia, but there are many other kinds of dementia, including Lewy body dementia, Huntington’s disease and non-Alzheimer’s dementias. Not a normal part of aging, dementia is caused by damage to brain cells that affects an individual’s ability to communicate, which can affect thinking, behavior and feelings. AD accounts for 60-80% of dementia cases and afflicts an estimated 5.8 million Americans aged 65 and older.
An early diagnosis of AD can help determine if a patient’s symptoms are truly due to AD or some other conditions that can be curable, such as infections, emotional distress or nutritional deficiencies, such as a vitamin B12 deficiency. What’s more, a definitive AD diagnosis allows patients to start clinical interventions sooner, providing a cost savings for payers, as well as saving time, money and the despair of not knowing for those involved. It has been estimated that early diagnosis of AD could save the health system $7.9 trillion (present value of future costs). Unfortunately, early diagnosis of AD has been costly with poor accuracy.
What is Alzheimer’s Disease?
AD is a type of dementia that affects memory, thinking and behavior. Over time, symptoms tend to increase and start interfering with individuals’ ability to perform everyday activities. In the early stages of AD, memory loss is mild but gradually individuals lose the ability to respond to their environment.
AD is a complex disease with plaques and tau tangles–both abnormal clusters of protein fragments, which many experts believe play a critical role in the clinical symptoms of AD by blocking communication among nerve cells and disrupting processes that cells require. While these are clinical findings associated with AD, there are other factors at work. This is evidenced by a recent paper that demonstrated centenarians with little or no cognitive decline were found to have high levels of plaque and tau at death, while another paper suggested that more than one-third of people studied with mild to moderate AD had minimal levels of plaque accumulation in the cerebral cortex.
Unfortunately, most patients with AD are diagnosed in the late stages of the disease, with very few being diagnosed in the preclinical stages when treatment can be the most effective.
Rather than focusing on clinical findings associated with AD, there is a new approach that assesses neural and synaptic loss to diagnose AD in people diagnosed with dementia. DISCERN™, the first autopsy-validated, highly accurate, minimally invasive test for the definitive diagnosis of AD versus other forms of non-AD dementias and those with AD and other degenerative pathologies, gives patients and families the answers they need, enables providers to make a conclusive diagnosis, and allows payers to establish protocols and prior authorizations for prescribing and reimbursing treatment. It also helps pharmaceutical companies identify appropriate clinical trial participants.
DISCERN™ can be utilized as a tool to manage appropriate patient access to therapies approved in the future, in addition to the clinical and economic benefits of improved early, accurate diagnosis.