Wednesday, June 4, 2014

The Science Behind Autism - As This Parent Understands It

As a parent of spectrum children, I can attest to the peer pressure we feel when raising our children. The constant questions or words of advice we often face… Have you tried changing her diet this way? Have you thought about increasing his vitamin intake that way? Maybe if you took away that pink polka-dotted cup… Trust me, I’ve heard it all and equally guilty of pushing my own advice, which one should certainly take for what it’s worth.   I am definitely no Autism expert.   I’m just your average mom who has done a ton of reading.  However, one thing I know for certain is this… To make the best decisions for one’s children, one can’t go along with the crowd, because the needs of each child are completely individual.  What works for one may not work for another, and having two on the spectrum, I can proclaim with the utmost of certainty the bitter-sweet truth behind this sentiment.

Most websites define Autism Spectrum Disorder, or ASD, as a life-long neuro-developmental disability with an onset before 36 months of age and characterized by impairments in social interactions, verbal and non-verbal communication skills. It also encompasses repetitive/stereotypical behavior, interests and activities. Although the cause(s) are not known, autism is likely to have multiple aetiologies, including genetic factors.

Okay, well then what the heck does this mean??

In my opinion, it really means nothing.  Currently, Autism Spectrum Disorder is just a convenient label without a clear definition.  It covers a vast number of disabilities as well as level of affectation.  There are literally hundreds of books written on the subject.  However, the nature and severity of the symptoms described in most books weren’t anything I could personally relate to at all.  It wasn’t until I delved further in and came across another term before I felt like I was getting anywhere.

Sensory Integration Dysfunction, defined by Wikipedia as a neurological disorder that causes difficulties with processing information from the five senses (vision, auditory, touch, olfaction, and taste), the sense of movement (vestibular system), and/or the positional sense (proprioception). For those with SID, sensory information is sensed, but perceived abnormally. Unlike blindness or deafness, sensory information is received by people with SID; the difference is that information is processed by the brain in an unusual way that may cause distress or confusion. SID is its own diagnosis, but it can be linked to other neurological conditions, including autism spectrum disorders, attention deficit disorder, dyslexia, Developmental Dyspraxia, Tourette syndrome, multiple sclerosis, and speech delays, among many others.  From here, I took a peek beneath the skull by stumbling through as many scientific research articles that I could.

The brain is an elegant piece of organic machinery.  To work well, it requires a lot of coordination in the transfer and processing of sensory information.  The carriers of the information are called neurons, and whenever we receive input through our senses, these little guys go to work.  For example, a person places a cup of hot tea in front of you and says, “Here is your tea.” – this being the visual and auditory sensory input. Your brain processes this information and determines all of the social, physical and emotional necessities involved before sending a signal to our body for a response … thanking the person who made the tea for you, how to position your fingers around the handle of the cup, the amount of pressure you need to apply to the handle to pick it up and the anticipation of hot liquid as it reaches your mouth, including an emotional response if the liquid is too hot.  It is theorized that the majority of spectrum cases result from an anomaly in this neurological process, the connection – or synapses – between nerve cells and the brain.

Here’s what we know through scientific study…. It all began several years ago when a set of scientists performed a study using a machine that measures MU waves in the brain; the firing of neurons.  Using this device, they studied the responses in both typical and spectrum children.  First, they measured the brain responses in typical children as they went about executing a task; such as drinking from a cup.  As expected, when a typical child picked up the cup drank from it, a set of neurons fired off in the brain to promote the completion of the task.  They repeated the same test for the spectrum children and pretty much found the same result.  When the spectrum child drank from the cup, the neurons usually fired as they should.

Next, they completed the same test, only this time, they measured the brain’s response in typical children as they watched another child drink from a cup. Interestingly, in the typical children, the neurons fired off again as if they were performing the task themselves.  However, when the spectrum children watched another child complete the task, the neurons did not fire at all.

This particular movement in neurons is referred to as mirroring neurons, which are believed to be instrumental in a child’s early learning and development.  Their existence was discovered a few decades ago by scientists who conducted a study on monkeys.  Mirroring neurons are thought to be key in adaptive learning, essentially enabling us to mimic another in order to learn things, such as waving, walking, eating, communicating and many other skills.  They are also thought to have a role in enabling us to empathize and maintain eye contact. This is why you often see therapists working “hand-over-hand” with children — placing their hand over the child’s and repetitively having them complete a certain task.

You see, the neurons are actually firing off when the child is doing the task themselves, and with enough repeat in this action, the so-called “memory chip” will be stored away for later retrieval

In 2008, scientists honed in on six genes within the chromosomal helix that were consistently “switched off” in children falling within the spectrum.  These six genes are thought to be involved in the synapses between nerve cells and the brain.  Science posits that a child’s brain is in a rampant mode of development up until around the age of eight, upon which time its development slows considerably.  This is why early diagnosis is thought to be key.  The brain of a young child still in the stages of development is thought to be more malleable for “retraining”, thus a much higher chance of success in intervening and essentially “switching on” those six genes in the helix.  But what about these cases where you hear of a child developing in a typical fashion, when suddenly, their learned skills begin to regress or disappear? My child was smiling, talking and playing just fine, then suddenly, he reached the age of 18 months and everything changed.

The Salience Landscape resides deep within the part of the brain known as the Amygdala, dead center of one’s head (behind the eyes and nose and in between the ears). This is where a memory bank of learned information is stored, resulting from all memories of processed input taken in through our senses.  When we are newborns, the Salience Landscape is much like a large field full of rich soil, and as we grow, the resulting seeds from our experiences are planted in this landscape.  Over time, it takes shape, starting off extremely slow and adding momentum until it takes off like kudzu during our preschool years.

As it pertains to ASD, if something external triggers a disruption in sensory processing into memory, at any point during development, it stands to reason it could easily disrupt prior learned memory stored inside the Salience Landscape.

No comments:

Post a Comment