Aging is not a linear process, and different causes and consequences of aging run at different paces at different times in later life. In most cases, the rate of decline accelerates. All of our biological support systems, large-scale and small-scale, interact with one another. Damage and dysfunction in one speeds up the progression of damage and dysfunction in others. Just look at failure of cellular maintenance operations, degrading the effectiveness of all tissues, or the decline of the immune system, which is responsible for culling dangerous cells, assisting in healing, and numerous other jobs beyond the better known function of defense against invading pathogens. Here, researchers provide one example among many of the way in which specific manifestations of aging speed up as the years pass:
Presbycusis, or age-related hearing loss (ARHL), affects approximately two-thirds of adults older than 70 years and four-fifths of adults older than 85. It is a major public health concern that is associated with numerous deleterious effects. Currently, there is a global demographic change that has resulted in an increase in the number of older adults. In the United States, the population of individuals older than 80 years is expected to double in the next 40 years. The majority of research in ARHL, however, groups participants older than 70 years into a single category, thus obscuring changes in the severity of hearing loss as individuals live to 80 years or older.
This study included 647 patients 80 to 106 years of age who had audiometric evaluations at an academic medical center (141 had multiple audiograms). The degree of hearing loss was compared across the following age brackets: 80 to 84 years, 85 to 89 years, 90 to 94 years, and 95 years and older. From an individual perspective, the rate of hearing decrease between 2 audiograms was compared with age. The researchers found that changes in hearing among age brackets were higher during the 10th decade of life than the 9th decade at all frequencies for all the patients (average age, 90 years). Correspondingly, the annual rate of low-frequency hearing loss was faster during the 10th decade. Despite the universal presence of hearing loss in this sample, 382 patients (59 percent) used hearing aids. "More attention should be on counseling patients on accepting hearing aids in a longitudinal primary care setting, especially in the population living to 80 years or older."
The scientists here urge greater use of existing compensatory mechanisms, but should also be urging greater funding for work on regenerative medicine for the causes of age-related deafness. There are a number of promising lines of research focused on neurodegeneration in the connections between ear and brain on the one hand and regrowth of hair cells in the ear on the other, for example.