Neurophysiological changes

Mild neurophysiological changes, including reductions in motor and sensory nerve conduction velocities (sometimes still within the normal range), have been documented in lead-exposed workers compared with control groups, with blood lead levels less than 40p,g/ 100 ml blood. A prospective follow-up study of workers with blood lead levels of 30-50p,g/ 100 ml blood demonstrated mild slowing of conduction velocities. "... 

Another method of classification has been based on such criteria as their subjective effects, the neurophysiological changes they produce, and their ability to cause cross-tolerance with members of the same or different chemical series. This has led to the classification into ... 

Toxicity and health effects Exposure to high concentrations of carbon disulfide causes deleterious effects that include headaches, nausea, vomiting, dizziness, fatigue, chest pains, blurred vision, delirium, neurophysiological changes, reduced nerve condnetion velocity, peripheral neuropathy, polyneuropathy, convulsions, and problems with brain, liver, heart. After pregnant rats breathed carbon disnlfide in the air, some of the newborn rats died or had birth defects. High concentrations of carbon disnlfide have caused skin bnrns when the chemical accidentally tonched people s skin. - ... 

Long-term exposure to carbon disulfide via inhalation has been reported to result in neurological effects such as polyneuropathy, neurophysiologic changes, and general depression of nerve conduction velocities in humans. Cardiovascular effects that have been observed following chronic inhalation of carbon disulfide vapors by workers include generalized symptoms of heart disease, vascular... 

Neurophysiological changes have also been reported during acute inhalation exposure to... 

CHRONIC HEALTH RISKS angina coronary heart disease neurophysiological changes behavioral changes muscle pain ocular effects anorexia decreased sperm count in men menstrual disturbances in women. 

The adult nervous system is a critical target for the toxic effects of lead. Effects on the central nervous system of lead workers include dose-related changes in cognitive and psychomotor performance and mood, neurodegenera-tive diseases, and neurophysiologic changes in the auditory, visual, and balance systems. Effects of occupational lead exposure on the peripheral nervous system at BLLs of 60-70 pg/dL are manifested as motor weakness with abnormahties in motor and sensory nerve conduction. No peripheral motor or sensory symptoms are known to occur at BLLs imder 40 pg/dL, but sensory nerve function is associated with lead dose. 

Several factors have been reported to account for age-related changes in olfaction, such as the drying out of the mucous layer, and reduction of the production of new sensory cells (Boyce and Shone, 2006 Schiffman and Graham, 2000). In addition to these neurophysiological changes associated with the normal ageing process, extrinsic factors may also impact on the chemosensory decline, such as the number of diseases, medication, prior upper respiratory tract infection, prior exposure to certain air-bone chemicals known to affect odour sensitivity adversely (Murphy et al 2002). These factors, closely related to the life story of each individual, probably account for a large part of the variabihty observed in the elderly population. 

In the Soviet Union as opposed to the United States greater emphasis is put on neurophysiological changes in experimental animals as well as behavioural effects in human beings. It should be noted that although low levels may be embodied in national regulations this does not mean they are achieved in practice. In the past this has been acknowledged by Russian spokesmen. 

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