The following is an abstract of a paper presented
by RAYMOND SINGER, PH.D.:<br><br>Singer, R. (1995).
Neuropsychological assessment of a practicing dentist with elevated
urinary mercury. Fundamental and Applied Toxicology,
Supplement:The Toxicologist, 15, 1, March,
1995.<br><br><br>Website: www.neurotox.com<br>E-mail:
raysinger@...<br><br><br>NEUROPSYCHOLOGICAL ASSESSMENT OF A PRACTICING
DENTIST WITH ELEVATED
URINARY MERCURY. R. Singer. Santa Fe, New Mexico,
USA<br><br>Dentists are exposed to mercury from amalgam (composed of
52% mercury, 8% copper, 37% silver) used as implants
for dental restoration. A recent study of 32% of
Singapore's dentists found mercury dose-related
neuropsychological deficits when compared with controls. <br><br>The
current subject, a dentist practicing for 14 years in the
USA, was referred by his physician for neurobehavioral
examination. The subject presented with symptoms including
fatigue, GI problems, sweats, tremors, rashes, bowel
dyscontrol, and heart arrhythmia. Tremors of the hand and
eyelid affect the subject's hand stability while
working. <br><br>Results of the Neurotoxicity Screening
Survey showed a profile of symptoms consistent with
neurotoxicity. Urine sampling (24 h) over the past year found
2.1 - 99 ppb mercury, averaging 35 ppb (expected
range &lt; 2 ppb; atomic fluorescence spectrometry).
High readings may be related with chelation therapy.
<br><br>Current IQ was at the 87% (% = percentile; 91-96% or
greater estimated pre-morbidly), consistent with his
presentation as an intelligent, competent dentist. In contrast
to a relatively high IQ, appropriate
neuropsychological testing revealed that the subject has deficits in
immediate memory (16%); visuospatial perception (50%);
visual memory; visual figure-ground perception (50%);
verbal learning (2-5%); mental flexibility (12%);
attentional processes (19%); logical memory (p &lt; .004);
and non-verbal recognition memory (50%).
Neuropsychological testing helped confirm mercury toxicity affecting
multiple organ systems. Such deficits impact the subject's
ability to practice dentistry, and raises questions as to
effects of mercury in other dentists, as well as possible
subclinical or clinical effects among the estimated 80-90% of
Americans with mercury amalgam implants.