©December 2007

New brain imaging discoveries are surfacing each day, providing us with astonishing new insights into our thinking machines.  One of those insights has to do with how we communicate.  It turns out that many of our perceptions are constructed automatically from data that is collected and analyzed even before we realize that our brains have actively participated in the act of interpretation.  Creatures have an uncanny capacity to interpret body posture and facial expressions as an integral part of our communication skills, even before we realize that we have drawn conclusions from our observations of each other.  It might be worthwhile to consider this compulsion for practicing amateur sociology as we prepare to join our family members over the holidays to share meals and revelry.

As is often the case, our understanding of our capacity for communication has been boosted by our observations of individuals in whom this capacity has malfunctioned or been delayed.  Recent attention has been focused upon the condition of autism, in which there is a deficiency in the ability to interpret social cues from the faces of other people.  In severely autistic patients, the ability to recognize a human face is diminished even in infancy.  While the cause of autism remains a mystery, brain imaging has clarified that autistic patients have abnormalities in how social information is physically processed by the brain.

If any doubt exists about the magnitude of our drive for gathering social signals, consider the success of televised game and reality shows.  The camera seems to linger for entire seasons on the magnified faces of preoccupied game show participants to satisfy our voyeuristic interests.  While maintaining vigilance in our interpersonal data-gathering can be exhausting, ratings for televised international poker championships remain high.

Consider the mind boggling success of Facebook, YouTube and the multitudes of other social media networks.  The notion of employing electrons to facilitate interactive written communication was agonizingly simple.  However, our hard-wired compulsion to communicate has required the remodeling of a bewildering network of satellites and the commitment of some of our most sophisticated technology.  It is perhaps a positive commentary on humanity when we do so for the sake of communication rather than for other less constructive purposes.

Even the smorgasbord of downloadable music on the internet is further evidence of our insatiable appetite for communication.  As musical tastes become increasingly intercultural and international in scope, boundaries between peoples stand to be blurred and mutual understandings at least potentially facilitated.  The biological roots and community benefits of rhythm and music are undeniable, even among species other than humans.

And so it seems that given such an innate ability to communicate, and with such a demonstrated devotion to facilitating conversation, we ought to attempt to make our interactions worthwhile.  While some degree of our ability to communicate effectively across the dinner table is learned and some inherited, maximizing our enjoyment takes some effort – sometimes considerable effort.  A secret among clinicians is to verbally acknowledge perceived social cues, so that misinterpretations have an opportunity to be corrected.  Ultimately, holiday gatherings provide one of our greatest opportunities to exercise our talents for listening, singing, laughing, asking questions, challenging, debating, and simply expressing ourselves.  Here is to hoping we all do so with joy.

©December 2008

Reading “Batteries Not Included” when one is preparing to bring a device to life can inspire disappointment.  On Christmas morning, surrounded by children with giddy expectations, a battery deficiency can lead to downright panic.  Nevertheless, we have a pretty clear understanding that most hi-tech devices these days require some source of electricity to do their magic.  It may not be as clear that our own nervous systems are equally as dependent upon electricity.  In an organism, the electrical charges are generated by the elegant movement of salts across membranes, but the principles otherwise follow the same rules as the electrical systems in our homes and appliances.  Therefore, many of the nervous system diseases would make perfect sense to an electrician.

In the 1800s, Lord Kelvin conducted experiments to describe how electrical signals decayed as they were conducted through transatlantic underwater telegraph cables.  In the early 1900s, the same formulas were found to accurately describe the way signals were transmitted through our nerve fibers.  It was determined that many of our nerves, much like the electrical cords on a T.V., are covered with insulation in order to increase the speed of conduction and diminish the loss of electrical energy as the signals travel to our muscles or sensory machinery.  Once an electrical signal comes to the end of a fiber in a particular nerve cell, the signal is passed on to the next nerve or muscle cell across a microscopic gap via chemicals that act like an elbow in the ribs.  Thus, the signal travels on throughout the system to have its intended effect, whether to raise a cup of coffee to the lips or remember a figure for your checkbook.

The disease “Multiple Sclerosis” results from the loss of insulation from nerve fibers scattered throughout the central nervous system (the brain or spinal cord).  As a result, various malfunctions begin to occur in different locations controlled by the affected areas of the brain, or less frequently the spinal cord.  Typical early symptoms can be perplexing, with difficulty speaking, problems with vision, loss of coordination, muscle spasms, numbness, tremors (fine shaking) or even personality changes.  This condition may be progressive, or it may progress to a point and become relatively quiescent.  Newer treatments promise to benefit some patients with this disorder.

Another similar condition known as “Amytrophic Lateral Sclerosis” (also known as ALS or Lou Gehrig’s disease) occurs in the spinal cord or brain stem and typically first involves the arms, legs or speech and swallowing functions.  This condition is also slowly progressive and not yet well understood.

A more common slightly different condition is called “peripheral neuropathy,” and involves damage to the nerves that travel throughout our bodies outside of the central nervous system.  Most people with peripheral neuropathy find that the earliest symptoms occur in the feet or legs because the longest nerves in our bodies provide service to those locations, and the longer the nerve the greater is the amount of nerve tissue available to be targeted by the malady.  This is the type of neuropathy that people with diabetes may experience, and usually causes symptoms of numbness or tingling.  Other people develop neuropathy with no other underlying illness.  Special testing, called a “nerve conduction test,” by a neurologist can usually detect abnormalities in peripheral nerves at an early point.

Other people with peripheral neuropathy may have symptoms that result from repeated injury to the nerve due to physical work.  There is a place in the wrist called the “carpal tunnel’ through which a nerve passes that supplies sensation and some muscle function to the thumb and first two fingers.  Some people who use power tools or use their wrists for much of their work day may develop pressure on the nerve in this tunnel, leading to weakness, numbness and tingling in the hand affecting those three fingers, called “carpal tunnel syndrome.”

Perhaps the most well known neurologic disorder is the seizure disorder.  This is a condition in which electrical activity in the brain produces a discharge of a large number of the nerve cells. In some patients the brain electrical activity may simply travel to limited areas causing symptoms of eye-blinking, temporary inattention or limited movements of a hand or limb.  In other patients the electrical discharge may travel throughout a large portion of the brain, causing loss of consciousness, loss of urine and/or an alarming shaking movement of the arms and legs (a generalized seizure).  While frightening to witness, if you should see a person having this type of seizure, simply keep the person from falling or hurting themselves on surrounding objects and call for help if the patient fails to recover after 4 or 5 minutes.  Virtually any person can be induced to have a seizure if the nerve cells are irritated enough by a high fever, a toxin, an electrical shock or even by temporary loss of circulation.  People with a seizure disorder simply possess an area in the brain with a greater than usual amount of irritability.   To control seizures, therefore, these people often take medications which diminish the irritability of those nerve cells.

When we think about how quickly we respond to setting our fingers on the stove burner, we can be grateful that our nervous systems work with the assistance and speed of electricity.  Now if we could just reboot ourselves on a day when the old mother board is not up to speed…

©July 2008

In 1927, Dr. William Mayo, of Mayo Clinic fame, wrote an article in the Annals of Surgery about the relative importance of the various “five special senses” to a surgeon.  He expressed the opinion that sight was the most important, followed by touch, then hearing, smell and finally, taste.  He points out that even the sense of taste could be recruited as a tool for health care, having been incorporated in the first detection of “sugar in the urine of the patient with diabetes.”  While vision remains the sense that most sighted people prefer to exercise as they pursue their daily responsibilities, an understanding of our visual apparatus and the diseases that affect it deserves special attention.

The eye is constructed very much like a camera, with a lens which allows us to focus an image onto the back of the eye (the retina) so that one group of photo sensors are able to pick up color and other photo receptors are able to perceive light intensity.  With apologies to endless generations of romantic prose depicting the eye as a “window on the soul,” light energy is translated by the retina into electrical signals which are in turn interpreted by the back of the brain to reconstruct an image based upon our scrapbook of prior images.  This process occurs instantaneously, and can be used to illustrate two interesting phenomena about perception.

First, we can be misled.  Optical illusions are fun because they expose our propensity to make assumptions based upon our prior experience.  When the magician causes the maiden to emerge unscathed from the flaming telephone booth, this is beyond the understanding of our visual memory banks, at least from our available angle of observation.

Second, recent research has found that certain individuals with blindness utilize the part of the brain which normally processes visual information to process sound and other sensory signals in order to create a perception of the physical world.  Our brain’s ability to seek sensory data from the ears or from touch when it is not provided by the eyes is a tribute to our machinery’s appetite for information about the environment.

The most common causes of blindness develop over years.  Macular degeneration is the most common cause of blindness over age 65.  It is caused by a breakdown of a part of the retina but the reasons it occurs are not understood.  Diabetes is a common cause of blindness, as are cataracts (loss of clarity of the lens) and glaucoma (increased pressure in the eye).  Careful control of diabetes can protect significantly against blindness.  While Macular Degeneration typically causes a loss of vision in the center of our visual field, glaucoma causes an early loss in the peripheral, or outside edges, of what we observe.

The most common cause of one-sided blindness is direct eye injury.  To prevent this common cause of visual loss, it is important to remember eye protection while operating machinery or participating in other high-risk activities.

An eye exam should be done at the time of routine physical examination.  Particularly for people with a family history or personal history that puts them at risk for vision loss, a formal eye examination should be sought.  Vision loss can be prevented if conditions such as glaucoma are detected early.

Perhaps most overlooked in operating our visual apparatus is the fact that the owner/operator is ultimately responsible for awareness.  While beyond the scope of these shared thoughts, it is a puzzle that the ability to see perfectly well does not always coincide with the willingness to look.