Normal Aging

Adam Gazzaley, MD, PhD's research on the way the normal aging brain is challenged in its ability to remember was featured on NBC Nightly News. Dr. Gazzaley is a member of the UCSF Memory and Aging Center and director of the UCSF Neuroscience Imaging Center.

Introduction
Human development is an ongoing process. Normal aging or “healthy aging” is a term that is widely used to describe the natural changes that occur in the absence of any disease. Many people older than age 65 live happy and healthy independent lives. In this section, we discuss the typical changes that may be expected as people grow older.

Some changes in the ability to think are considered a normal part of the aging process. Researchers have found that healthy older adults experience mild decline in some areas of cognition. These changes may occur in the areas of visual and verbal memory, visuospatial abilities, immediate memory, or the ability to name objects.

Symptoms and Anatomy
Research indicates that age related changes in the brain such as decreased hippocampal, frontal, and temporal lobe volumes can occur. However, the extent to which these age-related changes contribute to cognitive decline has yet to be determined. Non-verbal memory impairments are also considered to be a common cognitive deficit associated with aging. Control and maintenance of attention and immediate memory can be affected in normal aging individuals. With regards to the language abilities associated with normal aging, it has been found that vocabulary and verbal reasoning remain unchanged or may improve during the aging process. However, the ability to generate words declines at a faster rate than confrontation naming which is the ability to name objects. This is particularly true with advancing age beginning in the 70s.

• Notice how both sides of the brain look symmetrical to each other
• There is no discernable atrophy as there is very little space between the cortex and skull.
• No visible indication of significant atrophy in the hippocampii, which are thought to be responsible for consolidating memory.

Normal Aging vs. Senility
“Senility” or “senile” is an out-date term that has been replaced with “dementia” in recent years. Dementia is characterized by multiple cognitive deficits with memory impairments as an early symptom.

These cognitive deficits include:

• Executive Functioning
• Language
• Working (immediate) Memory
• Spatial Memory
• Verbal Memory

Symptoms to watch for:

• Getting lost in familiar places
• Repetitive questioning
• Odd or inappropriate behaviors
• Forgetfulness of recent events
• Repeated falls or loss of balance
• Personality changes
• Decline in planning and organization
• Changes in diet/eating habits
• Changes in hygiene
• Increased apathy
• Changes in language abilities, including comprehension

 However, a diagnosis of dementia is not generally given if there is no impairment in social functioning and independent living. Independent living describes the ability to shop alone, manage finances, perform basic household duties, and monitor appropriate social behaviors. Often it is difficult to determine exactly when a person should be concerned with cognitive changes they may be experiencing. Symptoms vary from person to person, what is normal for someone, may not be normal for someone else. This contributes to the challenges clinicians may face when determining whether or not cognitive decline is due to a physiological or psychological (excessive worry, depression, anxiety, etc.) condition.

The progression of cognitive deficits observed in conditions such as Alzheimer’s disease, may be accelerated in the few years immediately preceding the diagnosis. Accelerated cognitive decline may not occur until certain events, such as a stroke, reach a threshold where the brain can no longer compensate for damage. Thus, it is important to receive longitudinal examinations in order to monitor the extent and severity to which someone may be experiencing cognitive decline. These changes are limited in nature and independent living should not be compromised during normal aging, compared to those that occur during the transition to a neurodegenerative condition.

Risk factors for cognitive decline:

• High blood pressure, diabetes, poor nutrition, and social isolation are associated with a higher probability of developing a neurodegenerative condition
• Heart disease
• Family history of dementia
• Psychological factors such as stress and depression also negatively affect the healthy aging process

How Can the Aging Process be Slowed Down?
Although we have yet to discover the fountain of youth, there are many ways individuals can increase their life expectancy.

Important factors that contribute to healthy aging:

• Stay away from smoking and limit alcohol consumption.
• It is important to maintain a high level of physical activity through exercise. Exercise facilitates the maintenance of muscle flexibility, strength, and mood.
• Routine medical care is also essential in maintaining good health.
• Always keep in mind that excellent cardiovascular health is very important. What's good for the heart is good for the brain!
• Extensive social support networks provide a good mechanism for sharing the aging process with other people who are experiencing the same challenges and joys of entering into the latter years of life.

While it is important to remain vigilant about maintaining good health, it is equally important to acknowledge that there are individual differences during the aging process. You should discuss any concerns you may have with a health care professional.

References

• Braver TS, Barch DM, Keys BA., Carter CS, Cohen JD, Kaye JA, et al. Context processing in older adults: Evidence for a theory relating cognitive control to neurobiology in healthy aging. Journal of Experimental Psychology: General. 2001;130:746-63.
• Burke GL, Arnold AM, Bild DE, Cushman M, Fried LP, Newman A, Nunn C, Robbins J. Factors associated with healthy aging: the cardiovascular health study. Journal of the American Geriatric Society. 2001;49:254-62.
• Christensen H. What cognitive changes can be expected with normal ageing? Australian and New Zealand Journal of Psychiatry. 2001;35:768-75.
• Hickman SE, Howieson DB, Dame A, Sexton G, Kaye J. Longitudinal analysis of the effects of the aging process on neuropsychological test performance on the healthy young-old and oldest-old. Developmental Neuropsychology. 2000;17:323-37.
• Aging: The Health Care Challenge, 3rd ed. by Carol Bernstein Lewis
• Neuropsychological Assessment, 4th ed. by Muriel Lezak, Diane Howison and David Loring.
• Barnes DE, Yaffe K, Satariano WA, Tager IB. A longitudinal study of cardiorespiratory fitness and cognitive function in healthy older adults. J Am Geriatr Soc. 2003;51:459-65.

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