جستجوی مقالات مرتبط با کلیدواژه "کاهش شنوایی ناشی از سر و صدا" در نشریات گروه "پزشکی"

Choosing the suitable hearing protection for workers as part of the Hearing Conservation Program was introduced as a final measure. This study aimed to investigate the absorption and transmission loss of common earmuffs at one third octave band frequencies using the impedance tube method.

An analytical-experimental study was carried out on absorbers of four earmuff models. The transmission loss of the absorbers was measured using the impedance tube by the transfer function method, in accordance with the ISO 10534-2 standard. Data analysis was conducted using the paired-samples t-test and analysis of variance (ANOVA) with SPSS software.

The highest and lowest mean transmission losses measured in absorbers were 27.5 dB and 0.3 dB, respectively. The results showed a significant difference in the mean transmission loss between absorber A and absorbers B, C, and D, as well as between absorber B with absorbers A and D, across all measured frequencies (P < 0.05). Moreover, the results showed a significant difference in all frequencies before and after in absorbers A, B, and C (P < 0.05).

When comparing earmuff absorbers, it is evident that their performance in transmission loss and efficiency varies across different frequencies. In addition, most of the earmuffs examined in the study showed a decrease in transmission loss at low frequencies as the frequency increased. However, above2 kHz, an increasing trend in transmission loss was observed. These results need to be noted when choosing suitable hearing protection for workers in industries.

Noise-induced hearing loss is a sensorineural hearing loss، which is associated with exposure to high levels of sound. Since train drivers exposed to high noise levels and the use of hearing protection devices is relatively difficult and they also need to hear the radio communications، this study examines the hearing status of train drivers of Yazd Railway Company.

This is a descriptive - analytical cross sectional study، which was performed on 153 train drivers. The results were compared with a control group of 148 office workers. After examination and blood tests، audiometry was performed for each subject by an audiologist and the data was analysis with SPSS software (ver. 19).

The mean age of the train drivers and control group were 35. 8±8. 3 and 35. 3±6. 3 years respectively. Prevalence of high frequency sensorineural hearing loss among train drivers was 21. 3% (29 patients)، that was significantly higher than the control group. Prevalence of high frequency notch in the right ear in train drivers was 9. 6% (13 patients) and 2. 9% (4 patients) in the control group (p-value <0. 02) and prevalence of notch in left ear was 14% (19 patients) and، 3. 7% (5 persons) in train drivers and control group respectively (p-value<0. 003). In train drivers average hearing thresholds of high frequencies was higher in the left ear than the right ear (p-value=0. 02).

The high level of noise in the train drivers'' cabin increases average hearing thresholds at high frequencies especially at 6000 Hz. The results also show that in noisy environment، left ear is more sensitive than the right ear.

Hearing is one the most important senses of human. Hearing loss is one of the greatest chronic disabilities. Noise induced hearing loss (NIHL) is a common occupational disorder and several factors affect its intensity. One of these factors is individual differences. The aim of present study is the assessment of dyslipidemia’s effect on NIHL. This study was conducted to evaluate association between dyslipidemia and noise induced hearing loss.

This was an analytic-descriptive study which was conducted in 2010. The factory workers of Rasht industrial city with the following inclusion criteria were selected: environmental noise above 85dB, age below 55 years, no otologic disease or surgery, and no history of usage of ototoxic drugs. A total of 298 workers were assessed. After physical examination and audiometry, we measured the level of serum cholesterol, triglyceride, high and low density lipoprotein of participants. The results were analyzed with the SPSS version 17.0. The p value < 0.05 is considered significant statistically.

In this study, 250 men and 48 women were assessed. The mean age of participants was 35.8 years. The participants had high noise exposure of 11 years on average (1-26years). Ninty five of them had NIHL (31.8%). The frequency of serum cholesterol, triglyceride, high and low density of this group were 31.5%, 10.8%, 53.2% and 14.3%, respectively. These levels in the group without NIHL (203 workers) were 38.9%, 12.6%, 58.9% and 21.1%, respectively. There was no statistical significance between these levels in the two groups. By backward logistic regression method, we observed that the duration of employment and gender increased the hearing threshold of 4 KHz frequency in the NIHL group. The odd ratio of hearing loss in male gender was 3.36 (95% confidence interval: 1.61-8.95, p= 0.004). The other effective factors on the hearing threshold of 4 KHz frequency had statistical, but no clinical significant difference in two groups.

We observed no statistical significance of dyslipidemia frequency between two groups. In addition to duration of employment, male gender was the other observed related factor with hearing loss in the two groups. This effect may be due to protective effect of estrogen on the hearing level. Studies with more sensitive approaches on a larger sample is advised.

Aluminum Phosphide or rice tablet is a solid fumigant pesticide widely used in the Iran especially in north of Iran as a grain preservative. Recent researches show dramatic increase in number of cases and deaths due to aluminum phosphide poisoning in Iran. The aim of this study is evaluation of electrolytes and blood glucose level in this poisoning as a prognostic factor. This is a case-control study. Forty-five patients with aluminum phosphide poisoning due to ingestion were studied in Loghman-Hakim hospital poisoning management center from 14 March 2006 to May 2007. Patients were divided to survived and non-survived groups and statistical comparisons were made in various parameters including demographic, electrolytes and blood glucose level. Between March 2006 and May 2007, 45 patients with aluminum phosphide poisoning of these 21(47%) were females and 24(53%) males. The mean ages of cases were 27.29 (+/-11.58) with a range of 14-62. Form all of the cases, 32 were died and 13 were alive. All of them were hospitalized in ICU. The route of exposure to aluminum phosphide was deliberate ingestion in all patients. The mean of Sodium and potassium level in non-survived were140.38 ± 1.1 and 3.95 ±0.14. And in survived were139.69 ± 4.9 and 3.86± 0.11. the mean of Bicarbonate level in non-survived was11.25 ± 0.9 and in survived was 12.3 ± 1.08. hypokalemia and hyperkalemia were seen in 17.79% and 4.4% respectively. Hypo and hypernaturemia were seen in 6.6% and 15.5% respectively. The mean of blood glucose level was 222.59 ± 20.18 mg/dL and 143.4 ± 13.7 mg/dL in survived and expired groups respectively. Two patients (4.4%) had hypoglycemia and 57.7% of patients had hyperglycemia. Aluminum phosphide can cause either elevation, decrease or no change in electrolytes, bicarbonate and blood glucose level. These factors may have a good role for assessment the severity of poisoning.