Studies of mercury
related to ataxia, balance, tremor :
There was a strong
association between learning disability* and autism spectrum disorder (often
combined with hyperactivity disorder) on the one hand, and both simple and
borderline 'ataxia' on the other
Ataxia,
autism, and the cerebellum: a clinical study of 32 individuals with congenital
ataxia. Ahsgren I, Baldwin I, Goetzinger-Falk C, Erikson A, Flodmark O, Gillberg C. Dev Med Child Neurol. 2005 Mar;47(3):193-8.
Those with autism and
ataxia usually improve after metals detoxification. Likewise is true for MS patients. www.flcv.com/ms.html
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(Mercury causes
ataxia) NIH Medline Items 1 - 20 of 80
Mercury
as a serious health hazard for children in gold mining areas (ataxia,etc.)
Bose-O'Reilly S, Lettmeier B, Gothe RM, Beinhoff C, Siebert U, Drasch G. Environ Res. 2008 May;107(1):89-97.
Epub 2008 Mar 5
Long-term exposure to methylmercury
and neurologic signs in Minamata
and neighboring communities. Yorifuji T, Tsuda T, Takao S, Harada M. Epidemiology.
2008 Jan;19(1):3-9
Somatosensory disturbance by methylmercury exposure
Takaoka S, Kawakami Y, Fujino T, Oh-ishi F,
Motokura F, Kumagai Y, Miyaoka T. Environ Res. 2008 May;107(1):6-19.
Epub 2007 Jul 20
High
prevalence of extrapyramidal signs and symptoms in a
group of Italian dental technicians
Fabrizio E, Vanacore N, Valente M, Rubino A, Meco G. BMC Neurol. 2007 Aug 8;
Elemental mercury
poisoning probably causes cortical myoclonus.
Mov Disord. 2007 Oct 15;22(13):1964-8. Ragothaman M et al
Coordination deficits
induced in young adult mice treated with methylmercury.
Int J Toxicol. 2007 Mar-Apr;26(2):115-21.
Bellum S, Thuett KA, Grajeda R, Abbott LC.
A meta-analysis
epidemiological assessment of neurodevelopmental
disorders following vaccines administered from 1994 through 2000 in the
Neuro Endocrinol Lett. 2006
Aug;27(4):401-13. Geier DA, Geier
MR.
Toxic
effects seen in a herd of beef cattle following exposure to ash residues
contaminated by lead and mercury.
Vet J. 2007 Jul;174(1):99-105. Epub 2006 Jun 5. Krametter-Froetscher R et al
Dose-dependent effects of methylmercury administered during neonatal brain spurt in
rats. Brain Res
Dev Brain Res. 2004 Sep 17;152(2):171-6. Sakamoto M, et al
Etc.
The Institute for Chronic Illnesses, Inc.,
BACKGROUND:
Thimerosal is an ethylmercury-containing compound
(49.6% mercury by weight) used as at the preservative level in vaccines (0.005%
to 0.01%). METHODS: Statistical modeling in a meta-analysis epidemiological
assessment of the Vaccine Adverse Event Reporting System (VAERS) for
neurodevelopment disorders (NDs) reported following
Diphtheria-Tetanus-whole-cell-Pertussis (DTP)
vaccines in comparison to Diphtheria-Tetanus-whole-cell-Pertussis-Haemophilus
Influenzae Type b (DTPH) vaccines (administered:
1994-1997) and following Thimerosal-containing Diphtheria-Tetanus-acellular-Pertussis (DTaP),
vaccines in comparison to Thimerosal-free DTaP
vaccines (administered: 1997-2000), was undertaken. RESULTS: Significantly
increased adjusted (sex, age, vaccine type, vaccine manufacturer) risks of
autism, speech disorders, mental retardation, personality disorders, thinking
abnormalities, ataxia, and NDs in general, with
minimal systematic error or confounding, were associated with TCV exposure.
CONCLUSION: It is clear from the results of the present epidemiological study
and other recently published data associating mercury exposure with childhood NDs, additional ND research should be undertaken in the
context of evaluating mercury-associated exposures, especially from
Thimerosal-containing vaccines.
Autopsy case of acute
encephalopathy linked to familial hemiplegic migraine
with cerebellar atrophy and mental retardation. Neuropathology. 2005
Sep;25(3):228 (causes of such include mercury toxicity)
Retrospective
and current risks of mercury to panthers in the Florida Everglades.
Ecotoxicology.
2004 Apr;13(3):223 (clinical symptoms,
including ataxia and convulsions)
Brain sites of movement
disorder: genetic and environmental agents in neurodevelopmental
perturbations. Neurotox
Res. 2003;5(1-2):1-26
(mercury
can be a factor in ataxia disorders including autism, ADHD, parkinson’s,
Frederrich’s ataxia, etc.)
The
Sci Total Environ. 2003 May 20;307(1-3):71-82.
(mercury
causes neurological problems including ataxia, which improve after mercury
detoxification)
Clinical
investigation of the lesions responsible for sensory disturbance in Minamata disease.
Tohoku J Exp Med. 2001 Nov;195(3):181-9 (mercury posioning)
Chronic neurobehavioural effects of mercury poisoning on a group of
Zulu chemical workers.
Brain Inj.
2000 Sep;14(9):797-814. (mercury causes
ataxia/impaired motor function)
Effects
of protein-deficient nutrition during rat pregnancy and development on
developmental hindlimb crossing due to methylmercury intoxication. Arch Toxicol. 2000 Jul;74(4-5):196-202
(offspring
from mothers on the protein-deficient diet were found to be more sensitive to MeHg-induced ataxia than those on the protein-sufficient
diet)
The
toxicology of mercury. Crit Rev Clin Lab Sci. 1997 Aug, Clarkson TW. (merucy
vapor and organic mercury cause neurological problems including ataxia)
The
major physical forms of mercury to which humans are exposed are mercury vapor,
Hg0, and methylmercury compounds, Ch3HgX. Mercury
vapor emitted from both natural and anthropogenic sources is globally
distributed in the atmosphere. It is returned as a water-soluble form in
precipitation and finds its way into bodies of fresh and ocean water. Land
run-off also accounts for further input into lakes and oceans. Inorganic
mercury, present in water sediments, is subject to bacterial conversion to methylmercury compounds that are bioaccumulated
in the aquatic food chain to reach the highest concentration in predatory fish.
Human exposure to mercury vapor is from dental amalgam and industries using
mercury. Methylmercury compounds are found
exclusively in seafood and freshwater fish. The health effects of mercury vapor
have been known since ancient times. Severe exposure results in a triad of
symptoms, erethism, tremor, and gingivitis. Today, we are concerned with more subtle effects such as
preclinical changes in kidney function and behavioral and cognitive changes
associated with effects on the central nervous system. Methylmercury
is a neurological poison affecting primarily brain tissue. In adults, brain
damage is focal affecting the function of such areas as the cerebellum (ataxia)
and the visual cortex (constricted visual fields). Methylmercury
also at high doses can cause severe damage to the developing brain. Today the chief concern is with the more subtle effects
arising from prenatal exposure such as delayed development and cognitive
changes in children.
[Trace elements in spinocerebellar degeneration]
Usually Parkinsonism was
observed in manganese intoxication in man.
Parkinsonism in chronic
occupational metallic mercury intoxication]
[Article in Polish] Neurol
Neurochir Pol. 2003;37 Suppl
Miller K, Ochudło S, Opala G, Smolicha W, Siuda J.
Poradnia Chorób Zawodowych, Szpital, Instytut Medycyny Pracy i Zdrowia Srodowiskowego
w Sosnowcu.
Parkinson syndrome occurs in the course of chemical
intoxication, especially Mn, CS2, CO. We present the
case of 55 year old man who was exposed to metallic mercury vapor during 33
years of working in the chemical plant at the production of chlorine. On
several occasions patient was removed from contact with Hg because of the
symptoms of increased Hg absorption. At the age of 52 he developed hand tremor,
balance and gait disturbance with bradykinesia, paresthesias of the upper extremities, neurobehavioral
abnormalities, slight memory loss, and spatial disorientation. Psychoneurological examination revealed dementia,
Parkinson's syndrome and ataxia of the lower limbs. Mercury excretion in the
urine, which equaled 18.3 mu\g creatinine, confirmed exposure to Hg. MRI of the
head revealed cortical and cerebellar atrophy. Electroneurography examination found features of subclinical peripheral sensory axonopathy
of the upper limbs. Despite atypical clinical course (parkinsonismus)
chronic mercury encephalopathy was diagnosed based on documented occupational
exposure and diagnostic test results.
Coordination deficits induced in
young adult mice treated with methylmercury.
Bellum S, Thuett KA, Grajeda R, Abbott LC. Int J
Toxicol. 2007 Mar-Apr;26(2):115-21
Safety Assessment, Merck Research
Laboratories,
Male and female C57BL/6J mice starting at postnatal (P)
day 34 were exposed orally to five divided doses totaling 1.0 or 5.0 mg/kg of methylmercury (MeHg; given as methylmercuric chloride) or sterile deionized
water in moistened rodent chow. After a 5-day waiting period, control and MeHg-treated mice were subjected to a standard battery of
behavior tests for balance and motor coordination. Latency to falling on the
accelerating rota-rod was significantly decreased in
5.0 mg/kg MeHg-exposed mice when compared to control
mice. In the open field, horizontal exploration with respect to total distance
traveled during the first 5 min on the first test day was significantly reduced
in 1.0 mg/kg MeHg-exposed mice when compared to
control mice. Rearing activity was not affected by MeHg
treatment. In the footprint analysis, angle of foot placement measured in 1.0
mg/kg MeHg-treated mice was significantly greater
compared to control mice. Base stance and stride length were unaffected by MeHg treatment. On the vertical pole test, 10 mice from
each treatment group fell off the pole during the time the pole was shifted
from a horizontal position to a vertical position, whereas none of the control
mice fell. These results indicate that short-term, low to moderate doses of MeHg in young adult mice can be detrimental to motor
coordination and balance.
Tremor in workers with
low exposure to metallic mercury.
Verberk MM, Sallé HJ, Kemper CH. Am
In a fluorescent lamp production factory, a newly
developed lightweight balance-tremormeter was used to
measure postural tremor of the finger in 21 workers (ages 28 to 61) exposed for
0.5-19 yr to metallic mercury. In addition, tremor was measured in an indirect
way by means of a "hole-tremormeter." The
excretion of mercury in urine was 9-53 (average 20) mumol/mol
creatinine. With increasing
mercury excretion, the following parameters increased: the acceleration of the
tremor, the contribution of the neuromuscular component (8-12 Hz) to the power
spectrum of the acceleration, the width of the power-spectrum and the score on
the hole-tremormeter. The study indicates that
exposure to metallic mercury below the current TLV (50 micrograms/m3) may
increase the tremor of the finger.
Mercury as a serious
health hazard for children in gold mining areas.
Bose-O'Reilly S, Lettmeier B, Gothe RM, Beinhoff C, Siebert U, Drasch G. Environ Res. 2008 May;107(1):89-97.
Epub 2008 Mar 5
In many developing countries, mercury is used to extract
gold from ore in small-scale mining areas. Exposure through mercury in these
small-scale mining communities is a serious health hazard, especially to the
children living and working there. Many children begin working with immediate
contact to mercury from the very early age of seven. In
Long-term exposure to methylmercury and neurologic
signs in Minamata and neighboring communities.
Yorifuji T, Tsuda T, Takao S, Harada M. Epidemiology.
2008 Jan;19(1):3-9
Department of Hygiene and
Preventive Medicine,
BACKGROUND: It is well known that large-scale poisonings
caused by methylmercury occurred in
Somatosensory disturbance by methylmercury
exposure.
Takaoka S, Kawakami Y, Fujino T, Oh-ishi F,
Motokura F, Kumagai Y, Miyaoka T. Environ Res. 2008 May;107(1):6-19.
Epub 2007 Jul 20
Minamata disease is methylmercury
poisoning from consuming fish and shellfish contaminated by industrial waste.
The polluted seafood was widely consumed in the area around Minamata,
but many individuals were never examined for or classified as having Minamata disease. Following the determination of the
Supreme Court of Japan in October 2004 that the Japanese Government was
responsible for spreading Minamata disease, over
13,000 residents came forward to be examined for Minamata
disease. We studied 197 residents from the Minamata
area who had a history of fish consumption during the polluted period to
determine the importance of sensory symptoms and findings in making a diagnosis
of Minamata disease. We divided the exposed subjects
into non-complicated (E) and complicated (E+N) groups based on the absence or
presence of other neurological or neurologically related disorders and compared
them to residents in control area (C) after matching for age and sex. We
quantitatively measured four somatosensory modalities
(minimal tactile sense by Semmes-Weinstein monofilaments, vibration sense,
position sense, and two-point discrimination) and did psychophysical tests of
fine-surface-texture discrimination. Subjective complaints were higher in
groups E and E+N than C. Over 90% of E+N and E subjects displayed a sensory
disturbance on conventional neurological examination and 28% had visual
constriction. About 50% of the E and E +N groups had upper and lower extremity
ataxia and about 70% had truncal ataxia. The prevalence
of these neurological findings was significantly higher in exposed subjects
than controls. All sensory modalities were impaired in the E and E+N groups.
All four quantitatively measured sensory modalities were correlated. The
prevalence of complaints, neurological findings, and sensory impairment was
similar or a little worse in group E+N than in group E. We conclude that
sensory symptoms and findings are important in making the diagnosis of Minamata disease and that they can be determined even in
the presence of neurological or neurologically related diseases.
High prevalence of extrapyramidal signs and symptoms in a group of Italian
dental technicians.
Fabrizio E, Vanacore N, Valente M, Rubino A, Meco G. BMC Neurol. 2007 Aug 8;
Department of Neurological
Sciences, La
BACKGROUND: Occupational and chronic exposure to solvents
and metals is considered a possible risk factor for Parkinson's disease and
essential tremor. While manufacturing dental prostheses, dental technicians are
exposed to numerous chemicals that contain toxins known to affect the central
nervous system, such as solvents (which contain n-hexane in particular) and
metals (which contain mercury, iron, chromium, cobalt and nickel). METHODS: We
performed an epidemiological and clinical study on all 27 dental technicians
working in a school for dental technicians. We asked all the technicians to
fill in a self-administered questionnaire on extrapyramidal
symptoms, and the General Health Questionnaire (GHQ), a self-administered
screening instrument, to detect any psychiatric disorders. Moreover, we invited
all 27 dental technicians to undergo a neurological examination and provide a
detailed occupational history in our clinic. RESULTS: Of the 14 subjects who underwent the neurological examination, four
had postural tremor and one had a diagnosis of Parkinson's disease. CONCLUSION:
We found a high prevalence of extrapyramidal signs
and symptoms in this group of male dental technicians working in a state
technical high school in
Effects of mercury vapor exposure
on neuromotor function in Chinese miners and
smelters.
Iwata T, Sakamoto M, Feng X, Yoshida M, Liu XJ, Dakeishi M, Li P, Qiu G, Jiang H, Nakamura M, Murata K. Int
Arch Occup Environ Health. 2007 Apr;80(5):381-7. Epub 2006 Sep 22
Department of Environmental Health
Sciences,
OBJECTIVES: Current risk assessment of elemental mercury
vapor is based on the tremor toxicity. To clarify the neuromotor
effects of occupational exposure to mercury vapor, hand tremor and postural
sway were measured in 27 miners and smelters (i.e., exposed workers) and 52
unexposed subjects. METHODS: Urine samples were collected and total mercury and
creatinine concentrations were determined. Data of
the tremor and postural sway were analyzed using the fast Fourier
transformation. RESULTS: The geometric means of the urinary mercury level (UHg) were 228 (range 22.6-4,577) microg/g creatinine for the
exposed workers and 2.6 (1.0-17.4) microg/g creatinine for the unexposed subjects. Total tremor
intensity and frequency-specific tremor intensities at 1-6 and 10-14 Hz were
significantly larger in the exposed workers than in the unexposed subjects (P
< 0.05), but they were not significantly related to the UHg
among the exposed workers (P > 0.05). In contrast,
there were no significant differences in any postural sway parameters between
the above two groups (P > 0.05), but the transversal sway with eyes open was
positively related to the UHg among the exposed
workers in using multiple regression analysis (P < 0.05). CONCLUSIONS: These
findings suggest that postural sway, as well as hand tremor, may be affected by
elemental mercury vapor exposure, but the former test seems to be less
sensitive to mercury than the latter one.
Neuromotor functions in Inuit preschool children exposed to Pb,
PCBs, and Hg.
Després C, Beuter A, Richer F, Poitras K, Veilleux A, Ayotte P, Dewailly E, Saint-Amour D, Muckle G. Neurotoxicol Teratol.
2005 Mar-Apr;27(2):245-57. Epub
2005 Jan 11
Cognitive
The aim of this study was to examine the effects of
prenatal and postnatal chronic exposure to mercury (Hg), polychlorinated
biphenyls (PCBs) and lead (Pb) on the neuromotor development of preschool children. The study
population consisted of 110 preschool Inuit children from Nunavik
(
Low-level methylmercury exposure as a risk factor for neurologic abnormalities in adults.
Auger N, Kofman O, Kosatsky T, Armstrong B. Neurotoxicology.
2005 Mar;26(2):149-57.
Department of Epidemiology,
Biostatistics, and Occupational Health,
Methylmercury is a neurotoxicant
that bio-accumulates in the aquatic food chain and is present in all fish.
Little is known about the effects of long-term low-dose exposure to methylmercury in adults. The aim of this study was to
determine whether a dose-response relationship exists between long-term methylmercury exposure and neurological abnormalities in
aboriginal Quebec Cree adults for whom fish is a dietary staple. We re-analysed data from a 1977 cross-sectional study conducted
by Kofman and collaborators on a group of Quebec Cree
individuals claiming ill health from local fish consumption. In the original
1977 study, 306 adult participants aged 18-82 years were assessed for methylmercury exposure. Tremor and other neurologic outcomes were assessed with a clinical
examination. The investigators did not find clinical evidence of methylmercury intoxication based on an analysis of
covariance. We used ordinal regression to obtain odds ratios for the
relationship between total hair mercury levels and neurologic
abnormalities. Hair mercury concentrations ranged from 0.5 to 46 ppm (parts per million). A 6 ppm
increase in hair mercury was associated with increasing levels of tremor (OR,
2.22; 95% CI, 1.15-4.26) in adults under 40 years of age. There was no
association with nine other outcomes considered, nor
with tremor among older persons. Odds ratios were not influenced by gender,
smoking, alcohol use, or co-morbidity. CONCLUSION::
Dose-dependent effects of methylmercury on tremor may
occur below the commonly accepted 50 ppm threshold,
particularly in young adults. These effects may be detectable by clinical
examination. However, the results should be interpreted with caution given that
alcohol use was probably under-reported and that multiple outcomes were
studied.