2007, Piran, Slovenia

Occupational Thermal Problems
temperatures were the same across conditions. These results suggest that core cooling
potentiates the deteriorating effects of hand cooling on manual performance.
That the synchronous coupling of grip and load forces was remarkably well-preserved in the
absence of sensory (tactile, visual) feedback signifies the importance of central motor
processing in regulating grip control. Moreover, the large time delays associated with nerve
conduction mean that the feedforward specification of grip and load forces cannot possibly be
guided solely via afferent feedback. Our findings indicate that small core temperature
fluctuations do not influence the good overall temporal co-ordination of grip and load forces.
That core temperature alterations did not induce measurable changes in grasping efficiency
and temporal synchronicity signifies the sizeable contribution of internal models to accurate
object manipulation. As well, it suggests that the neural control of grasping is not only
resistive to thermal changes in the periphery, but also to changes in the central milieu.
Given the relationship we observed between the cooler core temperature and reduced manual
dexterity and tactile sensitivity, it is interesting that core cooling did not influence any of the
measured manipulation dynamics in the cyclical load-lifting task. The impairments seen in
manual dexterity as a function of core temperature demonstrate that some aspects of
sensorimotor control are influenced by thermal alterations. However, the fact that
manipulation dynamics and timing were insensitive to the same thermal alterations implies
that these sensorimotor parameters are controlled, at least in part, by different neural
mechanisms. It is not yet clear what those mechanisms might be, and why some are sensitive
to core temperature whereas others are not.
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