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Disorder of neural development that is characterized by impaired social interaction and communication , and by restricted and repetitive behavior . One of the components of Autism spectrum disorder (ASD) increased dramatically since the 1980s
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Disorder of neural development that is characterized by impaired social interaction and communication, and by restricted and repetitive behavior. • One of the components of Autism spectrum disorder (ASD) • increased dramatically since the 1980s • Four times more common in men than women because of testosterone level. • Prevalence of autism is 1–2/1,000 people the prevalence of ASD is about 6/1,000
ETIOLOGY OF
Multifactorial (genetic and environmental) GENETIC • Complex genetic basis because scientist couldn’t determine whether ASD is explained more by rare mutations, or by rare multigene interactions of common genetic variants. • Autism cannot be traced to a Mendelian (single-gene) mutation or to a single chromosome abnormality
Some autism cases traceable to genetic causes, but the mutation that causes the autism is not present in the parental genome. • Most of autistic individuals with unaffected family members result from copy number variations—spontaneous deletions or duplications in genetic material during meiosis. • Rare mutations may lead to autism by disrupting some synaptic pathways.
ENVIRONMENT • Teratogens (agents that cause birth defects) act during the first eight weeks from conception. • Certain foods • Infectious disease • Heavy metals • Chemicals (solvents, diesel exhaust, PCBs, phthalates and phenols used in plastic products, pesticides, brominated flame retardants) • Alcohol • Smoking • Illicit drugs • Vaccines • Prenatal stress
Divided into two areas : • The pathophysiology of brain structures and processes associated with autism • Neuropsychological linkages between brain structures and behaviors
PATHOPHYSIOLOGY • Alteration of brain development soon after conception. This anomaly starts a cascade of pathological events in the brain which influenced by environmental factors. • After birth, the brain of an autistic child grows faster than usual, followed by normal or relatively slower growth in childhood. • The early overgrowth is prominent in areas underlying the development of higher cognitive specialization. • CT and MRI scans of autistic savants’ brain suggest that the damage to the left CNS and higher memory structures, hence the right brain and lower ("habit") memory structures must compensate.
Other abnormalities have been found in the brains of autistics : • Hypoplasia, where the VII and VI lobules of the cerebellum are significantly reduced in size. • Neuron immaturities and error in migration within hippocampus and amygdala (Limbic System) • Loss of Purkinje cells and their synaptic connections to neurons in the cerebellum
ABILITIES • According to Dr. Stephen Edelson, Ph.D, the director of the Autism Research Institute, 10 per cent of people with autism show special and remarkable skills. The skills includes: • Splinter skills - most common type. The person, like an obsessive hobbyist, commits certain things to memory, such as sports trivia. • Talented skills - highly developed and specialized skill. For example, artistic and paint beautiful pictures, or have a memory work out difficult mathematical calculations in their head. • Prodigious skills - the rarest type. There are only 25 autistic savants in the world who show prodigious skills. These skills include, for example, the ability to play an entire concerto on the piano after hearing it only once.
Specialised skill - specific, limited and most often reliant on memory, includes : • Music - piano is the most popular instrument. The skill may be the ability to play the piano without being taught. • Art - ability to draw, paint or sculpt to high standards. For example, Richard Wawro is an autistic savant who is also blind, but his crayon drawings command up to $10,000 each. • Mathematics - ability to work out complicated sums in their head, or calendar calculation (for example, what day it was on 1 June 1732?). • Language - in rare cases, the person may be gifted in languages. • Other skills - such as knowing the time without seeing a clock, untaught mechanical skills, having an unfailing sense of direction or the ability to commit maps to memory.
Does Autistic Skills Could Be Triggered In Normal Human? • The cause of increased memory of autistic savant is related to the role of the hippocampus in autism. Even with a better memory, autistic savant would still be incapable of performing certain types of task. • The reason for this problem is related to the way by which the brain perceives the outer stimuli. For example, when an image falls on the retina, much of the information is screened out (examined). Before this happens, all sorts of details are identified by various parts of the brain in ways that are eventually reconciled to assemble patterns. • In savants, this reconciliation does not occur in the same way, and thus they "identify the picture in fantastically detailed components, like individual pixels in a photograph". • If the speed of reconciliation is the largest issue, then it follows that within every human, the possibility of savant abilities is present.
Evidence to support this fact : • As babies, all humans possess savant abilities, as can be seen in the rapid language acquisition at that age as well as the fact that absolute pitch and eidetic memory are much more present in children. • Newborns are neurologically limited to parts of the brain that eventually, become a part of the unconscious. This theory supported by the fact that children often lose their abilities once their social interactions improve, much as children's savant skills deteriorate once they obtain a strong command of language.
Every Brain May Have Untapped Savant Skills • San Franciscan neurologist, Dr Bruce Miller recently discovered new savant skills in some of his patients who were undergoing a certain type of dementia. These patients had a type of dementia that affected the left temporal region of their brains (located over the left ear). When the patients were given brain function tests, their results were similar to those of a young autistic savant. • Researchers from Flinders University in Adelaide were able to provoke new savant skills in volunteers by using transcranial magnetic stimulation to temporarily 'disable' the frontal temporal lobe of the brain. (Transcranial magnetic stimulation is a type of treatment for depression.) During the test, five of the 17 volunteers showed new and remarkable skills like calendar calculation. These studies suggest that amazing savant abilities may be lying dormant in all of us.
References • http://www.autism.com/ari/edelson.htm • http://en.wikipedia.org/wiki/Autism • http://encyclopedia.farlex.com/Autistic+savant • http://www.youtube.com/watch?v=dhcQG_KItZM
