Posts from — November 2004

Neuroscientists now generally agree that the brain is always changing and reorganizing (neuroplasticity). Equally important is the realization that the brain’s actual fundamental architecture is subject to change in relation to internal and external challenge or stimulation. This includes the brain’s wiring or neural connections, even its shape, and size.

It was believed in the recent past that our genetic makeup was the only factor in determining how our brain develops and forms its neural connections. We now know that brain development relies on a complex interplay of nature (genetic endowment) and nurture (environmental challenges)]. The formation of neural networks can be affected by good social interactions and even good exercise. Conversely, just as the brain responds favorably to good stimulation, it can also respond unfavorably to negative stimulation.

Lack of stimulation affects the architecture of the brain

Romanian orphans offer a primary example of pernicious effects due to lack of stimulation. Studies on human children demonstrating the impact of stimuli deprivation on brain function are scarce. Many stimuli deprivation studies have been performed on animal populations resulting in deleterious brain function. Romania does not adequately fund staffing for its orphanages as is the case for many of its bureaucratic institutions. Thus, there is a shortage of staff to nurture and stimulate the great number of orphans in their care. Infant stimulation is restricted to changing and feeding. However, even the feeding process is automated; the infant is turned on its side, a bottle is placed on a towel, and the child is left to suckle. The bottle is removed when empty. A study performed on these infants performed by Wayne State University, Detroit, found that Romanian orphans had dysfunction in a number of brain regions that caused both short-term and long-term detriments. It clearly demonstrates that nature and nurture play significant roles in brain development. Lack of stimulation actually affects the architecture of the brain – its fundamental wiring does not develop appropriately.

Appropriate stimulation affects the brain positively

Recent research suggests that appropriate stimulation affects the brain positively. In a study performed by psychology professor, Frances Kuo of the University of Illinois, and reported in the American Journal of Public Health children with ADHD were placed in an outdoor ‘green’ environment. Researchers wanted to explore the possibility that exposure to nature and challenges presented by being outdoors could mitigate attention deficit/hyperactivity disorder symptoms. The results, reported by parents, showed that children who spent a few hours playing outside in green, natural settings showed a significant reduction of symptoms compared with children who had spent time indoors or surrounded by asphalt and pavement. These results were reported regardless of whether the children in the study were on medication. The study did not indicate the degree by which symptoms were reduced; it reported only that the symptoms were reduced. The author of the study, Dr. Kuo, says, “Unfortunately, all we can say is that (the effect of nature) is a real effect that is big enough that parents were noticing it, and they were not looking for it.”

Taxi drivers’ brains ‘grow’ on the job

Another noteworthy study performed by University College, London and reported by BBC News, compared the brains of London taxi cab drivers with non-taxi drivers. London is a very old city. Its buildings were built around very old streets and closes. Thus, navigation in London is more challenging than a city like New York whose streets have been laid out in a grid or matrix. London taxi drivers must apprentice for at least two years and then pass rigorous police examinations before they can be licensed. This period is colloquially termed ‘Being on the Knowledge.’ The driver must develop extraordinary spatial navigational skills to be able to accommodate his passenger’s requests. Most drivers can not only find the most arcane location, but can describe the scenery and history of the sites en route. Brain scans of the taxi drivers pre and post apprenticeship and over long terms of duty revealed that their brains had changed from their peers. A region of the hippocampus, center of memory, emotion, and learning, had nearly doubled in size compared to others who had not undergone training. As I’ve noted previously, the constant reorganization and changes in the connections between linked neurons in the brain is termed neuroplasticity. New neural connections are actually made through the mechanism of axonal sprouting where axons grow new nerve endings to reconnect the neurons. Particular to the hippocampus, the center of memory, emotion, and learning in the brain, axons can also sprout nerve endings and connect with other neurons to form new neural pathways. While new connections can form quickly, the process must be initiated by appropriate challenge/stimulation. The extraordinary challenge provided to the taxi drivers during their apprenticeships resulted in the increased development of posterior sections of their hippocampi. The study suggests that the growth became greater in correlation to the time spent on the job or ‘On the Knowledge.”

Rethinking ADHD

Two significant conclusions can be drawn from this research. The first is that the brain is always changing and reorganizing (neuroplasticity), and due to this, it can actually change its fundamental architecture. Secondly, such fundamental changes come from external challenges and can result in behavioral changes like finding one’s way through a city or mitigating ADHD symptoms. The ramifications of this are significant because at this time ADHD is considered to be a neurobiological disorder. If mitigation of ADHD symptoms can be induced by external challenges, we may very well have to rethink its etiology or concede that it a normal characteristic on the spectrum of human traits which can be dealt with, at least in part, by external challenges.

Attention-deficit hyperactivity disorder (ADHD) is currently defined as a neurological disorder (brain disorder) that affects both children and adults. It is characterized by symptoms of inattention, impulsivity, and hyperactivity.

According to the National Mental Health Association, “ADHD is the most common psychiatric condition affecting children, estimates in prevalence in childhood range from 5 – 10%.” The ratio of ADHD boys to girls treated in clinical settings is 3:1.

Attention Deficit/Hyperactivity Disorder in Girls May Often Go Undiagnosed

Girls are often overlooked as they do not frequently display hyperactivity or behavioral problems. Girls are 2.5 times more likely to be diagnosed with a learning disability, more than 16 times more likely to have repeated a grade in school, and almost 10 times as likely to have been placed in a special class at school (Joseph Biederman, M.D., “Clinical Correlates of Attention Deficit Hyperactivity Disorder in Females: Findings from a Large Group of Pediatrically and Psychiatrically Referred Girls,” Journal of the American Academy of Child and Adolescent Psychiatry, August 1999, p. 966-975).

U.S. Is The World Leader In ADHD Drug Consumption

Most estimates indicate the United States has less than fifty percent of the ADHD population in the developed world. Yet, the US is the world leader in ADHD drug consumption at 90%. Conversely, Europe, which does not readily accept ADHD as a true disorder, labels only 1% of its child population as ‘hyperkinetic.’

Diffused Attention vs Attention Deficit

The mystery of AD/HD begins because the label, attention-deficit/hyperactivity disorder, is a misnomer of sorts. People with the disorder do not have a deficit of attention, but they do have diffused attention; attention that is fleeting and can be sustained only for short periods before moving to another stimulus.

A Difficult Diagnosis

ADHD is an umbrella category that frequently engenders controversy. This may be attributable to the fact that everyone periodically exhibits the characteristics used to diagnose ADHD. These may include general problems with attention such as frequent distractibility, difficultly being organized or keeping track of things, making careless mistakes, and failing to complete tasks, etc. Common characteristics of hyperactivity can include excessive talking, constant fidgeting, or constantly being on the go as if driven by a motor. Since most everyone exhibits these characteristics, the ADHD diagnosis is dependent upon the frequency that the characteristics are exhibited. Typically the diagnosis is determined by analysis of parent and teacher rating scales (behavioral checklists) and a patient interview.

ADHD Can Be Easily Mistaken For Other Problems

Thus, the diagnosis is quite subjective (Bird 2002) and can be easily mistaken for other problems like learning disabilities, unidentified mood disorders, or parenting problems. By labeling such problems as due to ADHD, many children are given a quick fix via medication.