Autism: A Unique Type of Mercury Poisoning

..b. Language and Hearing
The third diagnostic criterion for autism is a qualitative impairment in communication (APA, 1994), and such impairment is a primary feature of mercury poisoning. Delayed language onset is often among the first overt signs of ASD (Eisenmajer et al, 1998). Historically, half of those with classic autism failed to develop meaningful speech (Gillberg & Coleman, 1992; Prizant, 1996); and oral-motor deficits (e.g. chewing, swallowing) are often present (Filipek et al, 1999). When speech develops, there may be “specific neuromotor speech disorders,” including verbal dyspraxia, a dysfunction in the ability to plan the coordinated movements to produce intelligible sequences of speech sounds, or dysarthria, a weakness or lack of control of the oral musculature” leading to articulation problems (Filipek et al, 1999)…

In regard to language and auditory phenomena, autism’s parallels to mercurialism are striking. Emerging signs of mercury poisoning are dysarthria (defective articulation in speech due to CNS dysfunction) and then auditory disturbance, leading to deafness in very high doses (Clarkson, 1992). In some cases, hearing impairment manifests as an inability to comprehend speech rather than an inability to hear sound (Dales, 1972). Hg poisoning can also result in aphasia, the inability to understand and/or physically express words (Kark et al, 1971). Speech difficulties may arise from “intention tremor, which can be noticeable about the mouth, tongue, face, and head, as well as in the extremities” (Adams et al, 1983).

Mercury-exposed children especially show a marked difficulty with speech (Pierce et al, 1972; Snyder, 1972; Kark et al, 1971). Even children exposed prenatally to “safe” levels of methylmercury performed less well on standardized language tests than did unexposed controls (Grandjean et al, 1998). Iraqi babies exposed prenatally either failed to develop language or presented with severe language deficits in childhood. They exhibited “exaggerated reaction” to sudden noise and some had reduced hearing (Amin-Zaki, 1974 and 1979). Iraqi children who were postnatally poisoned from bread containing either methyl or ethylmercury developed articulation problems, from slow, slurred word production to the inability to generate meaningful speech. Most had impaired hearing and a few became deaf (Amin-Zaki, 1978). In acrodynia, symptoms of sufferers (vs. controls) include noise sensitivity and hearing problems (Farnesworth, 1997). ..

Table III: Summary of Speech, Language
& Hearing Deficits in Autism & Mercury Poisoning


Complete loss
of speech in adults or children; failure to develop speech in infants

Delayed language
onset; failure to develop speech
speech difficulties from intention tremor; slow and slurred speech

dyspraxia and oral-motor planning difficulties; unintelligible speech
Aphasia, the
inability to use or understand words, inability to comprehend speech
although ability to hear sound is intact

Speech comprehension
deficits, although ability to hear sound is intact
verbalizing; word retrieval problems

Echolalia; pronoun
reversals, word meaning and pragmatic errors; limited speech production
Auditory disturbance;
difficulties differentiating voices in a crowd

following conversational speech with background noise
Sound sensitivity

Sound sensitivity
Hearing loss;
deafness in very high doses

Mild to profound
hearing loss
Poor performance
on standardized language tests

Poor performance
on verbal IQ tests

c. Sensory Perception
Sensory impairment is considered by many researchers to be a defining characteristic of autism (Gillberg and Coleman, 1992; Williams, 1996). Baranek (1999) detected sensory-motor problems – touch aversion, poor non-social visual attention, excessive mouthing of objects, and delayed response to name – in 9-12 month old infants later diagnosed with autism, and suggests that these impairments both underlie later social deficits and serve to differentiate ASD from mental retardation and typical controls. Besides sensitivity to sound, as previously noted, ASD often involves insensitivity to pain, even to a burning stove (Gillberg & Coleman, 1992), while on the other hand there may be an overreaction to stimuli, so that even light to moderate touches are painful. Pinprick tests are usually normal. Children with autism have been described as “stiff to hold,” and one of the earliest signs reported by mothers is an aversion to being touched (Gillberg & Coleman, 1992). Abnormal sensation in the extremities and mouth are common. Toe-walking is frequently seen. Oral sensitivity often results in feeding difficulties (Gillberg & Coleman, 1992, p.31). Autistic children frequently have vestibular impairments and difficulty orienting themselves in space (Grandin, 1996; Ornitz, 1987).

As in ASD, sensory issues are reported in nearly all cases of mercury toxicity, and serve to demonstrate the similarities between the two conditions. Paresthesia, or abnormal sensation, tingling, and numbness around the mouth and in the extremities, is the most common sensory disturbance in Hg poisoning, and is usually the first sign of toxicity (Fagala and Wigg, 1992; Joselow et al, 1972; Matheson et al, 1980; Amin-Zaki, 1979). In Japanese who ate contaminated fish, there was numbness in the extremities, face and tongue (Snyder, 1972; Tokuomi et al, 1982). Iraqi children who ate bread experienced sensory changes including numbness in the mouth, hands and feet, and a feeling that there were “ants crawling under the skin.” These children could still feel a pinprick (Amin-Zaki, 1978). Loss of position in space has also been noted (Dales, 1972). Acrodynia sufferers describe excessive pain when bumping limbs, numbness, and poor circulation (Farnesworth, 1997). One adult acrodynia victim described himself as a boy as “shying away from people wanting to touch me” due to extreme touch sensitivity (Neville Recollection, Pink Disease Support Group). Iraqi babies exposed to mercury prenatally showed excessive crying, irritability, and exaggerated reaction to stimulation such as sudden noise or when touched (Amin-Zaki et al, 1974 and 1979).

Table IV: Summary of Sensory Abnormalities
in Mercury Poisoning & Autism


Abnormal sensation
or numbness around mouth and extremities (paresthesia); burning feet

Abnormal sensation
in mouth and extremities; excessive mouthing of objects (infants);
toe walking; difficulty grasping objects
Sound sensitivity

Sound sensitivity
Excessive pain
when bumping; abnormal touch sensations; touch aversion

or overreaction to pain and touch; touch aversion; stiff to hold
Loss of position
in space

Vestibular system
abnormalities; difficulty orienting self in space
Normal pinprick

Normal pinprick

Copyright (c) 2000 by ARC Research
14 Commerce Drive
Cranford, NJ 07016

April 3, 2000
Revision of April 21, 2000

Sallie Bernard

Autism is a syndrome characterized by impairments in social relatedness, language and communication, a need for routine and sameness, abnormal movements, and sensory dysfunction. Mercury (Hg) is a toxic metal that can exist as a pure element or in a variety of inorganic and organic forms and can cause immune, sensory, neurological, motor, and behavioral dysfunctions similar to traits defining or associated with autism. Thimerosal, a preservative frequently added to childhood vaccines, has become a major source of Hg in human infants and toddlers. According to the FDA and the American Academy of Pediatricians, fully vaccinated children now receive, within their first two years, Hg levels that exceed safety limits established by the FDA and other supervisory agencies. A thorough review of medical literature and U.S. government data indicates (i) that many and perhaps most cases of idiopathic autism, in which an extended period of developmental normalcy is followed by an emergence of symptoms, are induced by early exposure to Hg; (ii) that this type of autism represents a unique form of Hg poisoning (HgP); (iii) that excessive Hg exposure from thimerosal in vaccine injections is an etiological mechanism for causing the traits of autism; (iv) that certain genetic and non-genetic factors establish a predisposition whereby thimerosal’s adverse effects occur only in some children; and (v) that vaccinal Hg in thimerosal is causing a heretofore unrecognized mercurial syndrome.

A review of medical literature indicates that the characteristics of autism and of mercury poisoning (HgP) are strikingly similar. Traits defining or associated with both disorders are summarized in Table A immediately following the Table of Contents and are discussed and cited in the body of this document. The parallels between the two diseases are so thorough as to suggest, based on total Hg injected into U.S. children, that many cases of autism are a form of mercury poisoning.

For these children, the exposure route is childhood vaccines, most of which contain thimerosal, a preservative which is 49.6% ethylmercury by weight. The amount of mercury a typical child under two years receives from vaccinations equates to 237.5 micrograms, or 3.53 x 1017 molecules (353,000,000,000,000,000 molecules). Most such vaccinal Hg may not be excreted and instead migrates to the brain.

The total amount injected into infants and toddlers (i) is known to exceed Federal safety standards, (ii) is officially considered to be a low level; whereby (iii) only a small percentage of exposed individuals exhibit symptoms of toxicity. In fact, children who develop Hg-related autism are likely to have had a predisposition derived from genetic and non-genetic factors.

Importantly, the timings of vaccinal Hg-exposure and its latency period coincide with the emergence of autistic-symptoms in specific children. Moreover, excessive mercury has been detected in urine, hair, and blood samples from autistic children; and parental reports, though limited at this date, indicate significant improvement in symptoms subsequent to heavy-metal chelation therapy.

The HgP phenotype is diverse and depends upon a number of factors – including type of Hg, route of entry into the body, rate and level of dose, individual genotype, and the age and immune status of the patient. Historically, variation among these factors has caused slightly different manifestations of mercurialism; Mad Hatters disease, Minamata disease, acrodynia, and industrial exposures provide examples.

The pathology arising from the mercury-related variables involved in autism – intermittent bolus doses of ethylmercury injected into susceptible infants and toddlers – is heretofore undescribed in medical literature. Therefore, in accord with existing HgP data and HgPs ability to induce virtually all the traits defining or associated with autism spectrum disorders, we hypothesize that many and perhaps most cases of autism represent a unique form of mercury poisoning.

This conclusion and its supporting data have important implications for the affected population of autistic individuals and their families, for other unexplained disorders with symptoms similar to those of heavy metal intoxication, for vaccine content, and for childhood vaccination programs. Due to its high potential for neurotoxicity, thimerosal should be removed immediately from all vaccine products designated for infants and toddlers.

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