Noise-induced hearing loss and stress-prone behavior

Previous research found a relationship between stress-prone personality (pattern A) and noise-induced vasoconstriction in normal-hearing adult subjects. The present research sought evidence for a possible relationship between susceptibility to high-frequency noise-induced permanent threshold shift (NIPTS) found among industrial workers and the vasoconstrictive behavior of the same workers when they were exposed to high-intensity noise. It was hypothesized that pattern A workers would show more vasoconstriction in the presence of high-intensity noise, and hence more susceptibility to NIPTS, than pattern B (non-stress-prone) workers. The 35 male subjects tested were divided into two groups. Group 1 contained 16 subjects who showed significant vasoconstriction in noise; group I subjects were clearly pattern A types. Group II contained 19 subjects who did not show significant vasoconstriction in noise; Group II contained mostly pattern B but a few pattern A subjects. Unexpectedly, it was the group II subjects who showed the most susceptibility to NIPTS; the difference between the means of the two groups was statistically significant (p greater than or equal to 0.001). The explanation for this unexpected finding is obscure.