Subclinical behavior

Stice, E., Ziemba, C., Margolis, ]., Flick, P. (1996). The dual pathway model differentiates bulimics, subclinical bulimics, and controls Testing the continuity hypothesis. Behavior Therapy, 27, 531-550. 

What are these subclinical effects Very simply, they are effects that occur at blood lead levels below those that produce clinically measurable effects - they occur in the absence of any sign of overt lead poisoning. These effects can be detected only by studying various forms of behavior, such as degree of hyperactivity and classroom attention span, and performance on various tests of intelligence and mental development. Deficits in neurobehavioral development, as measured by two widely used tests - the Bayley and McCarthy Scales - have been reported in children exposed prenatally (via maternal blood) to blood... 

Recently, Olson et al. (2000) and Benschop et al. (1998) have provided reports of animal studies of effects of repeated low-level exposure to nerve CWA. In rats, Olson et al. determined the LOAEL and NOEL of subacute dosages of sarin, administered, i.m. They found that the dose of sarin (GB) needed to produce a low but measurable blood ChE inhibition was 0.75 p-g/kg once a day for 4 days. Thus, the exposure in Olson s study would be described as subclinical. GB was paired with a variety of other chemicals to include chlorpyrifos, DEET (A,A-diethyl-m-toluamide), carbaryl, and PB. No neurobehavioral or neuropathologic effects could be attributable to dosing with GB alone or in any combination with the other chemicals. Rats were also evaluated using a functional observational battery (EOB) and a Eigure 8 Activity Monitor with no significant behavioral effects reported. Benschop et al. (1998) reported on the toxicokinetics of low-level inhalation exposure to soman in... 

Unfortunately, for the development of the human brain, this question can be addressed only indirectly—from animal experiments and by deduction. But even animal experiments are problematic because it s not always clear how measurements of animal behavior have any serious meaning for measurements of human behavior. An animal, even a chimpanzee, is not just a simplified human being exhibiting simplified human behavior. Deduction, on the other hand, gives us a clearer answer It stands to reason that clinical observations of the effects of brain-development aberrations are the proverbial tip of the iceberg—with an entire universe of subclinical differences, variations, and developmental aberrations that we have no means yet to measure. 

Wiimeke G. 1990. Neurobehavioral toxicity of selected environmental chemicals Clinical and subclinical aspects. In Russell RW, Flattau PE, Pope AM, eds. Behavioral Measures of Neurotoxicity Report of a Symposium. Washington, DC National Academy Press. Pp. 226-242. 

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