During the first half of the day, Bernard Martin, Ph.D., from University of Michigan, Center for Ergonomics, presented "Human Vibration: Understanding the Effects and Using Appropriate Methods to Prevent Disorders". He gave an overview of human vibration, starting with Ramazzini, who was the first occupational physician who pointed out the harmful effects of vibration that emerged with industrialization. He discussed the harmful effects of vibration from biomechanics, physiology and pathology. He described how vibration affects motor skills and performance, and other disorders ranging from vascular disorders ("white finger" and Raynaud's syndrome), to bone and joint disorders, to neurological and muscular disorders. He described preventative measures, both administrative and technical, and presented design examples for handles, tools, gloves and seats to reduce the effects of vibration. Since Dr. Martin is originally from France, he was happy to point out the accomplishments of French scientists in the field of vibration. It was a fascinating presentation.

After a delicious Bavarian Inn chicken dinner, the second half of the day was divided into two sections.

The first section, presented by Mr. Lee Hager of Sonomax Great Lakes, was "What's New With Noise? Hearing Conservation Updates and Changes To The Noise Reduction Rating". He discussed recordkeeping, hearing protection issues, and new technology for hearing protection including noise-canceling devices. He also presented an interesting emerging issue of research findings from NIHL, which discusses free radicals in the cochlear fluid that may contribute to hearing loss. Also, he discussed gene therapy findings in which hair cells may be regenerated subsequent to injection of viruses. Very interesting!

The final speaker of the day was Thais C. Morata, Ph.D., from NIOSH, who presented on "Toluene, Styrene, Carbon Monoxide: Risk Factors for Hearing Loss". She described in detail the synergistic effects of noise combined with chemical exposures to toluene, styrene and carbon monoxide. She also predicted that the majority of neurotoxic chemicals are also ototoxic, affecting the auditory nerve. She explained the "Response Level", an Action Level-like criterion developed by NIOSH. It is the level of chemical exposure (alone or with noise), at which employees should be enrolled in hearing loss prevention programs. A very note-worthy presentation!

Many thanks to Lisa Quiggle, MIHS President-Elect, and Gerry Plattenberg, MIHS President, for putting together this interesting PDC.