Cognitive Changes, Lifespan, and Healthy Aging
Murman (2015) notes that “cognitive abilities often decline with age,” and structural and functional changes occur in tandem with declining cognitive abilities. The most important changes are “declines in performance on cognitive tasks (which) require one to quickly process or transform information…” which are related to processing speed, working memory, and executive function.
Murman reports that “cumulative knowledge and experiential skills” and speech and language skills are typically well maintained with advanced age. In 1910, the average lifespan for men and women were 48 and 52 years (respectively); in 2010, lifespans are 76 and 81 years (respectively) and the number of Americans over age 65 is expected to more than double in the next 40 years, from 40 million (2010) to 89 million (in 2050).
Murman states that “crystallized abilities” are “the cumulative skills and memories that result from cognitive processing that occurred in the past…” which might be thought of as acquired knowledge. These abilities are tested through tests of general knowledge (science, math, reading comprehension, historical knowledge, vocabulary etc.). With regard to crystallized abilities, the good news is multiple studies have shown an improvement in crystallized abilities through age 60 years, then a plateau till age 80 years. “Fluid abilities” are those which require cognitive processing at the same moment as assessment (of new information) and reflects the manipulation and transformation of new information. That is, fluid abilities are dependent on the ability to attend to the environment while processing new information to assess the immediate situation and arrive at a solution or conclusion.
Murman reports that there is a steady decline in fluid abilities from ages 20 years to 80 years. He states that “there is a nearly linear decline in processing speed, a fluid ability, with a -0.02 standard deviation” decrease annually. He reports “the most noticeable changes in attention that occur with age are declines in performance on complex attentional tasks such as selective or divided attention…” Alzheimer’s Disease (AD) is the “most common cause of cognitive decline in older adults…” Murman reports at age 65, fewer than 5 percent of adults have AD, but by age 85, 40 percent have AD.
However, he states “there is emerging evidence that healthy lifestyles may decrease the rate of cognitive decline…” associated with aging. Healthy lifestyles include a healthy diet, avoiding excessive alcohol consumption, regular exercise, participation in cognitively stimulating events, managing and minimizing stress, managing hypertension, diabetes, depression, obstructive sleep apnea and more. He reports (through healthy lifestyles) we may already “hold the keys” with regard to how to minimize the detrimental impact of age on cognition and how to delay the onset of dementia in the elderly.
For More Information, References, and Recommendations
Beck DL. (2015) The state of the art: hearing impairment, cognitive decline, and amplification. Hearing Review 22(9):14.
Murman DL. (2015) The impact of age on cognition. Seminars in Hearing 36(3):111-121.