“It (hearing loss) not only increases age-related memory loss, it increases the incidents of Alzheimer’s disease, so if you can prevent the onset of Alzheimer’s disease or delay it with good hearing devices, that’s a major public health advance.” -Erik Kandel, Recipient of the Nobel Prize in Physiology or Medicine
What is the Relationship? And is Dementia Avoidable?
Hearing loss impacts over 48 million people in the U.S. and is listed by the Department of Health and Human Services as the 3rd most common chronic disorder affecting today’s older adults. Unfortunately for most of us, hearing loss as we get older is inevitable; impacting nearly 50% of seniors between the ages of 60-70, almost 2/3rd of people between the ages of 70-80 and nearly 80% of individuals over the age of 80.This hearing loss is characterized by the progressive loss of receptor cells in the ear that consequently reduces the quantity and quality of neural connections from ear to brain. This slow-onset disease can have a significant impact on several key brain areas including the memory, hearing, speech and language portions of cognition.
Several key research studies have pointed to the potential links of hearing loss and Dementia, including the groundbreaking work from Dr. Lin and his colleagues at Johns Hopkins Medical Center which indicates that hearing loss can increase the risk of Dementia and cognitive decline in Worcester, MA, by 200-500% (depending on degree of hearing loss).
Every 3-4 seconds another patient is diagnosed with Dementia, and rates of Dementia are estimated to triple in the next 30 years. Unlike some other diseases, with Dementia the physical body is estimated to outlive the individual’s mental capabilities by 10 or more years. There is no cure for this catastrophic disease, and there is no F.D.A. approved treatment; but new studies indicate that as many as 35% of cases of Dementia are considered preventable. Three risk factors associated with hearing loss and Dementia include social isolation, cerebral atrophy and cognitive overload.
Social Isolation: The impact of reduced social and physical activity. Withdrawal from social situations is common in individuals with hearing loss. Many studies cite feelings of embarrassment, fear of making mistakes in conversations and feeling like you are not part of the conversation as the common rational for individuals with hearing impairment to separate themselves from family, friends and community. This retreat from social activity has even been found in individuals with a mild degree of hearing loss. In addition, individuals with hearing loss are less likely to engage in physical activity. Both increased social isolation and reduced physical activity are strong risk factors for the development of Dementia.
Cerebral Atrophy: The association of a shrinking brain, resulting from the loss of neurons, with Dementia has been long documented. Even people with MCI (Mild Cognitive Impairment) show signs of cerebral atrophy. In recent years, scientific studies using advanced brain imaging techniques (including fMRI-Functional Magnetic Resonance Imaging) have demonstrated that hearing impairment is associated with accelerated brain atrophy in both the overall brain as well as even more advanced reductions in volume associated with the memory, hearing, speech and language portions of the brain.
Cognitive Overload: Hearing loss is not normal, and neither is the excess strain that is puts on your brain. While hearing loss may be more common as we age, it is critical that it be treated. With hearing loss, the brain is constantly on ‘overload’ trying to fill in the missing pieces and follow the conversation. Increased cognitive decline in Worcester, MA, is considered a risk factor for developing Dementia. Cognitive load, as measured by pupillometry, is a measurement of how hard your brain is working to follow a conversation. Recent research has found that individuals who treat their hearing loss do not work as hard to listen (i.e. have a reduced cognitive load) and have as much as a 20% increase in memory recall when following a conversation.