Do radiofrequency radiation affect the auditory system of people with occupational exposure?

The present study intended to investigate whether radiofrequency (RF) affects auditory system of people who are occupationally exposed to RF in terms of noise-induced hearing loss (NIHL) or not. The study was carried out on 31 men from 26 to 53 years of age. All of them have been working in the Diyarbakir Radio Broadcasting Station. On the other hand, the control group was based on 30 unexposed voluntary and healthy men. The range of age for control group was the same as in the exposed group (experimental group). The results of the present study showed that the incidence of NIHL in the exposed group is more and more than that of the unexposed (control) group. The incidence of NIHL was approximately found 70 % for exposed group and 6% for unexposed group. The difference of the incidence of NIHL between exposed and unexposed groups were statistically found significant for right and left ears at “4 kHz notch” (p < 0.001). Hearing loss was not observed below 1 kHz. The percentage difference in the incidence of hearing loss (decibel) between control and experimental group was found insignificant for frequency below 1 kHz (p > 0.05). The experimental group was also divided to three subgroups of technicians, officers and men staying in the quarters of radio broadcasting station. Three subgroups were compared with one another statistically. The incidence of NIHL for the right ears of technicians was found higher than the officer (p < 0.05). The incidence of NIHL for the left ears of men staying in quarters was found higher than officers (p < 0.05). The other results of comparison were found insignificant (p > 0.05). In conclusion, the incidence of NIHL at “4 kHz Notch” in the experimental group was found more common than the control group

Reward-dependent plasticity in the primary auditory cortex of adult monkeys trained to discriminate temporally modulated signals

Adult owl monkeys were trained to detect an increase in the envelope frequency of a sinusoidally modulated 1-kHz tone. Detection was positively correlated with the magnitude of the change in the envelope frequency. Surprisingly, neuronal responses recorded in the primary auditory cortex of trained monkeys were globally suppressed by the modulated tone. However, the contrast in neuronal responsiveness to small increases versus large increases in envelope frequencies was actually enhanced in the trained animals. The results suggest behaviorally contingent inhibitory and excitatory processes that are modulated by the probability that a particular signal predicts a reward