We all have expectations of what it will be like as we age. Our hair may thin and become gray, our eyesight may worsen, or our hearing may change, prompting us to ask people to repeat themselves.  These changes are considered normal aging.

But what about abnormal aging? Are there warning signs that could show us when Mom or Dad's health isn't what it should be at their age?

There are some changes that can be signs that something else may be happening.  In fact, we have a guide all about positive aging for seniors. In it, you'll learn about:

• the stages of aging;
• differences between normal and abnormal aging;
• implications of aging on overall wellness; and
• strategies, tips and local resources for positive aging.

Here are some warning signs of abnormal aging, so you'll know what to look for, and when to intervene.

Eyesight

Signs that your older loved one might be having difficulty seeing include squinting while reading or asking others to read things out loud to him or her, slow driving, clumsiness, and trips and falls.

One of the most common sight-related problems in the elderly is the development of cataracts, which cloud the vision and render an older person nearly blind. At first, a cataract isn't obvious, but if it isn't treated, it will become visible to others as a milky area in the eye.

The good news is they're curable, thanks to cataract surgeries, which are among the most common operations in the country. During cataract surgery, a doctor removes the clouded lens and replaces it with a new, artificial lens.

Other eye changes, though, like glaucoma or macular degeneration, aren't curable. They require ongoing, close monitoring by an ophthalmologist (eye doctor).

Glaucoma is an abnormal increase in the eyeball's internal fluid pressure, and is the leading cause of blindness in people 60 and older. But if it's caught and treated early, blindness can be prevented.

Age-related macular degeneration is another leading cause of blindness for older adults, affecting an estimated 20 million Americans. It's caused by deterioration of the central part of the retina and causes "holes," or dark areas, that obstruct a person's vision. One out of three people 75 or older are at risk of it.

Macular degeneration is currently considered incurable, but it is treatable. Therefore, older adults need to receive yearly eye exams to detect problems early.

Related blog/video: Vision problems can lead to dementia, study finds

Touch

Many older adults begin to experience decreased sensitivity to hot and cold, or to touch. That's normal. But numbness isn't. And it can be a sign of a serious neurological problem.

Sudden loss of sensation in an extremity, or along one side of the body, can indicate a stroke. When someone reports a sudden loss of sensation or quick-developing numbness, they should be seen immediately in the emergency room.

Numbness that comes on slowly and continues to worsen might also be an indication of a neurological problem; it might be caused by a problem with one of the cushioning spinal discs in the neck or back, by a pinched nerve, or even by a growing tumor.

Diabetes is another potential cause of numbness — particularly in the hands and feet because it causes decreased blood circulation. If your older loved one consistently complains of worsening numbness in the extremities, he or she should be seen by the doctor.

Numbness also can be caused by an adverse medication reaction. Many American seniors take multiple medications, vitamins or supplements to treat chronic ailments; occasionally, these medications can react with each other in unintended ways. Sometimes, that can cause a medical emergency.

The good news is that, when identified early, medication reactions often are fully reversible by a change in medication or a different dosage.

Related blog/video: Hearing aids can slow memory loss in those at high risk for dementia

Behavioral changes

Uncharacteristic behaviors and instances of severe mood swings can be a sign your loved one is depressed. They could also be a warning sign of new-onset Alzheimer's or other dementia disorders.

In dementia cases, one of the most common things people notice is their loved one becomes easily tired in the afternoon and early evening, and they may have behavioral outbursts. This is known as "sundowning."

Inappropriate behaviors — laughing at odd moments, sudden bursts into tears or hysterics, or irrational anger — also can be a sign someone may be developing dementia. If you notice these in your loved one, encourage him or her to schedule a doctor's appointment.

Memory loss and confusion

The classic sign of Alzheimer's disease, or dementia disorders in general, of course is profound memory loss.

Some memory loss is a normal part of aging. Forgetting an anniversary, for example, or not remembering to meet a friend for coffee, can easily be chalked up to momentary forgetfulness.

But when someone has forgotten something profoundly personal and important, such as their own address, a loved one's name or birthday, or the year they graduated from high school, that may be a sign of dementia.

Watch for these warning signs ... and others.

These are some of the most reported signs of abnormal aging, but there are many more. Click here for a checklist of signs your older loved one's health might not be optimal. Also, for more information, visit this web page that describes normal memory loss versus dementia, and how to maintain brain health. 

If you suspect your loved one is showing signs of failing health, encourage them to see a family doctor or geriatrician right away, and offer to take them there. Early action can save your loved one's life, or improve their quality of life.