Mobile phones: influence on auditory and vestibular systems

Effect of 2.45 GHz Microwave Radiation on the Inner Ear: A Histopathological Study on 2.45 GHz Microwave Radiation and Cochlea

BACKGROUND

The present study aims to determine the possible low dose-dependent adverse effects of 2.45 GHz microwave exposure and Wi-Fi frequency on the cochlea.

METHODS

Twelve pregnant female rats (n=12) and their male newborns were exposed to Wi-Fi frequencies with varying electric field values of 0.6, 1.9, 5, 10 V/m, and 15 V/m during the 21-day gestation period and 45 days after birth, except for the control group. Auditory brainstem response testing was performed before exposure and sacrification. After removal of the cochlea, histopathological examination was conducted by immunohistochemistry methods using caspase (cysteine-aspartic proteases, cysteine aspartates, or cysteine-dependent aspartate-directed proteases)-3, -9, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). Kruskal-Wallis and Wilcoxon tests and multivariate analysis of variance were used.

RESULTS

Auditory brainstem response thresholds in postexposure tests increased statistically significantly at 5 V/m and above doses. When the number of apoptotic cells was compared in immunohistochemistry examination, significant differences were found at 10 V/m and 15 V/m doses (F(5,15)=23.203, P=.001; Pillai's trace=1.912, η2=0.637). As the magnitude of the electric field increased, all histopathological indicators of apoptosis increased. The most significant effect was noted on caspase-9 staining (η2 c9=0.996), followed by caspase-3 (η2 c3=0.991), and TUNEL staining (η2 t=0.801). Caspase-3, caspase-9, and TUNEL-stained cell densities increased directly by increasing the electric field and power values.

CONCLUSION

Apoptosis and immune activity in the cochlea depend on the electric field and power value. Even at low doses, the electromagnetic field in Wi-Fi frequency damages the inner ear and causes apoptosis.

The potential protective effects of melatonin and omega-3 on the male rat optic nerve exposed to 900 MHz electromagnetic radiation during the prenatal period

BACKGROUND

Due to children and adolescents' widespread use of electronic devices, researchers have focused on pre-and early postnatal electromagnetic field (EMF) exposure. However, little is known about the effects of EMF exposure on the optic nerve. The aim of study was to investigate the changes occurring in the optic nerve and the protective effects of melatonin (mel) and omega 3 (ω-3) in rats.

METHODS

Thirty-five pregnant rats were divided into seven groups, Cont, Sham, EMF, EMF + melatonin (EMF + Mel), EMF + ω3, Mel, and ω3. The EMF groups were exposed to 900 megahertz (MHz) EMF daily for two hours during pregnancy. After the experiment, the right optic nerve of each offspring rat was removed and fixed in glutaraldehyde. Thin and semi-thin sections were taken for electron microscopic and stereological analyses. Myelinated axon numbers, myelin sheath thicknesses, and axonal areas were estimated using stereological methods.

RESULTS

The groups had no significant differences regarding mean numbers of axons, mean axonal areas, or mean myelin sheath thicknesses (p > 0.05). Histological observations revealed impaired lamellae in the myelin sheath of most axons, and vacuolization was frequently observed between the myelin sheath and axon in the EMF-exposed group. The Mel and ω-3-treated EMF groups exhibited well-preserved myelinated nerve fibers and intact astrocytes and oligodendrocytes.

CONCLUSIONS

At the ultrastructural level, Mel and ω3 exhibits a neuroprotective effect on the optic nerve exposed to prenatal EMF. The protective effects of these antioxidants on oligodendrocytes, which play an essential role in myelin formation in the central nervous system, now require detailed investigation.

Approaches for the Elimination of Microbial Contaminants from Lippia multiflora Mold. Leaves Intended for Tea Bagging and Evaluation of Formulation

Elimination of microorganisms from herbal products has been a major concern due to its implicated health risk to consumers. Drying of herbal materials has been employed for centuries to reduce the risk of contamination and spoilage. The present study adopted three drying approaches in an attempt to eliminate microorganisms from Lippia multiflora tea bag formulation. This study also evaluated the tea bags and optimized the extraction procedure. The L. multiflora leaves for tea bagging were air-dried and milled (A), oven-dried and milled (B), and microwaved (the milled air-dried leaves) (C). The moisture contents were determined at 105°C ± 2°C for 2 hours to constant weight. Phytochemical parameters such as phytochemical constituents, total water extractive, and pH were assessed. The microbial safety and quality of the L. multiflora tea bags were evaluated using the British Pharmacopoeia 2019 specifications. The uniformity of the mass of the formulated tea bags was also determined. Extraction from the Lippia tea bags was optimized. The results showed that using the approaches (A, B, and C) adopted for drying and processing, the moisture contents of the formulated tea bags were in the range of 9.75–10.71% ^w/_w. All the formulated tea bags contained reducing sugars, phenolic compounds, polyuronides, flavonoids, anthracenosides, alkaloids, saponins, and phytosterols. The pH range of the formulations was 7.11–7.54, whereas the total water extractive values were in the range of 19.12–20.41% ^w/_w. The one-way analysis of variance demonstrated no significant difference in the data obtained from the results from A, B, and C. The formulation from A was found to be unsafe for consumption due to unacceptable microbial contamination limits. Microbial load of the formulations from B and C were within the BP specifications. All the batches of the formulations passed the uniformity of mass test. An optimized extraction procedure was obtained when one tea bag was extracted in 250 mL of hot water within the specified time. L. multiflora leaves meant for tea bagging should be oven-dried or microwaved before tea bagging for safe consumption.

The Impact of Mobile Phone Use on Tinnitus: A Systematic Review and Meta-Analysis

Tinnitus is a perception of sound in the absence of an external source. The aim of our study was to investigate with a meta-analytical approach, whether mobile phone (MP) use increases the risk of tinnitus. Eight studies reporting the risk of tinnitus in relation to MP use were identified, and six high-quality studies (two cohort studies, one case-control study, and three cross-sectional ones) were included in the meta-analysis. The quality assessment was performed using the Newcastle-Ottawa scale. The risk of tinnitus was analyzed depending on the exposure to MPs in subgroups according to the study design and method of exposure assessment. Two cohort studies, which assessed the exposure to MPs using network operator data, indicated no significantly increased risk of tinnitus among highly exposed MP users in comparison to lightly exposed individuals (odds ratio [OR]: 1.03 [95% confidence interval [CI]: 0.93-1.15]). Likewise, the self-reported exposure data from two cohorts/case-control and four cross-sectional studies did not find an association between exposure to MPs and tinnitus (OR: 1.20 [95% CI: 0.40-3.61] and OR: 1.73 [95% CI: 0.67-4.49], respectively). Current scientific knowledge, including high-quality studies with a reliable exposure assessment based on network operator data, does not support the hypothesis that MP use is associated with tinnitus. © 2020 Bioelectromagnetics Society.

Does the short-term exposure to radiofrequency electromagnetic field originating from mobile phone affect auditory functions as measured by Acoustic Admittance and Evoked Otoacoustic Emission tests?

BACKGROUND

Mobile phones constitute an important source of radiofrequency electromagnetic field (RF-EMF) for humans. Taking into account high sensitivity of sensory hair cells of the inner ear to endogenous and exogenous agents, the potential impact of mobile phone usage on auditory organs is of particular interest.

AIM

The aim of the study was to evaluate the impact of short-term exposure to RF-EMF generated by a mobile phone during 15-minute simulated phone call on human hearing as measured by Transient Evoked Otoacoustic Emission (TEOAE) and Acoustic Admittance Testing (AAT).

MATERIAL AND METHODS

Within-subject study was performed on 23 healthy volunteers. All of the participants underwent TEOAE and AAT before and immediately after 15-minute simulated phone call with the use of a standard, modern smartphone. Analyzed parameters included: static compliance of tympanic membrane, middle ear pressure, ipsi- and contralateral acoustic reflex thresholds and percentage of signal reproducibility in TEOAE for exposed and non-exposed ear. Additionally, the results were compared in subgroups distinguished basing on self-reported sensitivity to RF-EMF originating from mobile phones.

RESULTS

No statistically significant differences were identified between results of TEOAE and AAT before and after exposure, both in exposed and non-exposed ear. The results of EMF sensitive and non-sensitive subjects were comparable in all performed tests.

CONCLUSIONS

Short-term exposure to mobile phone electromagnetic field did not influence auditory functions as measured by Evoked Otoacoustic Emission test and Acoustic Admittance Testing.

Adverse Effect of Mobile Phone on Hearing in Healthy Individuals: A Clinical Study

The mobile phone is a ubiquitous piece in this modern world. An estimated 85% of Americans, 80% of the British, and perhaps 75% of Indians use it, as of today. Mobile phones communicate by transmitting radio waves through a network of fixed antennas called base stations. Radio frequency waves are electromagnetic fields, and unlike ionizing radiation such as X-rays or gamma rays, can neither break chemical bonds nor cause ionization in the human body. 1000 participants from outpatient department of a tertiary care center over a period of one and a half years, were included in the study and were divided equally into case (> 1 year use) and control (< 1 year use) groups. Out of 500 cases, maximum 233(46.6%) subjects were using mobile since last 4-6 year and 134(26.8%) were using mobile since last 7-9 year and maximum 344(68.8%) subjects were using mobile 1-3 h/day and 145(29.0%) were using mobile 4-6 h/day.

A study on the effect of prolonged mobile phone use on pure tone audiometry thresholds of medical students of Sikkim

Introduction:

Mobile phones have become indispensable for daily activities, and people are exposed to them from an early age. There is, however, concern about the harmful effect of the electromagnetic radiation emitted from the mobile phones.

Objective:

The objective of the study was to study the effect of mobile phone on average pure tone audiometry (PTA) threshold of the person and to study the changes in the pure tone threshold at high frequencies such as 2 kHz, 4 kHz, and 8 kHz among the students with prolonged exposure to mobile phones.

Methodology:

A cross-sectional study was conducted among the medical students who have been using mobile phones for the past 5 years. The effect of mobile phones on the PTA threshold in the exposed ear and the nonexposed ear was assessed.

Results:

The study shows that there is a significant difference in average air conduction (AC) and bone conduction (BC) hearing threshold among the exposed and the nonexposed ears (P < 0.05). A significant rise of both AC and BC threshold at individual frequencies between the exposed and the nonexposed ear is also noted in this study.

Conclusion:

The study conducted shows changes in the hearing threshold of the exposed ear when compared with the nonexposed ear. There are however lot of unanswered questions which provide an interesting avenue for further research. Till concrete evidence is available the only feasible way to control its exposure is to limit the duration of usage of mobile phones.

Does chronic exposure to mobile phones affect cognition?

Mobile phones form an integral part of our modern lifestyle. Following the drastic rise in mobile phone use in recent years, it has become important to study its potential public health impact. Amongst the various mobile phone health hazards, the most alarming is the possible effect on the brain. The aim of the present study was to explore whether chronic exposure to mobile phones affects cognition. Ninety subjects aged 17-25 years with normal hearing were recruited for the study and divided into three groups according to their duration of mobile phone use. No significant differences in N100, P200, N200, P300 latencies or N2-P300 amplitude were observed. Our results suggest that chronic mobile phone exposure does not have detrimental effects on cognition.

EFFECTS OF MOBILE PHONE RADIATION ON CARDIAC HEALTH

Mobile phones (MPs) progressed from a tool of the privileged few to a gadget for the masses. However, the physical effects, which enable wireless information transmission, did not change; MP technology still relies on pulsed high-frequency electromagnetic (EM) fields. Therefore, the health risks, associated with EM fields, remain. Studies that investigated these health risks have reported dizziness, numbness in the thigh, and heaviness in the chest. This study investigates neurological effects that are caused by EM fields radiated from MPs. The heart rate variability (HRV) can be used as a measure for these neurological effects, because the automated nervous system modulates the HRV. We measured the HRV of 14 healthy male volunteers. We used the following nonlinear parameters to quantify the MP radiation effects on HRV: approximate entropy (ApEn), capacity dimension (CaD), correlation dimension (CD), fractal dimension (FD), Hurst exponent (H), and the largest Lyapunov exponent (LLE). The results indicate that there is a measurable difference in the parameter values when the MP is kept close to the chest and when it is kept close to the head. However, these differences are very small and statistical analysis showed that they have no clinical significance. Furthermore, the result analysis does not show a consistent trend, which indicates that there is no underlying pathological effect.