Dreyer NA, Loughlin JE, Rothman KJ · 1999
Researchers attempted to track cause-specific mortality (death rates from specific diseases) among cellular phone users in 1994, focusing on brain-related deaths. However, the study was cut short when a class-action lawsuit blocked access to the mortality data after just one year of surveillance. This prevented the researchers from completing their investigation into whether cell phone use was associated with increased death rates from brain tumors or other causes.
de Seze R, Ayoub J, Peray P, Miro L, Touitou Y · 1999
French researchers exposed 38 young men to cell phone radiation (GSM 900 MHz and DCS 1800 MHz) for 2 hours daily over 4 weeks to test whether it would disrupt melatonin, the hormone that regulates sleep cycles. They found no changes in melatonin patterns during or after exposure. This suggests that typical cell phone use may not directly interfere with the body's natural sleep hormone production.
Belousova TE, Kargina-Terent'eva RA · 1999
Russian researchers exposed hypertensive rats to millimeter wave radiation at frequencies used in medical therapy devices (42,194 MHz and 53,534 MHz). They found the radiation reduced nerve density in heart tissue and decreased stress hormone production in both the heart and adrenal glands. This suggests millimeter wave exposure can suppress the sympathetic nervous system that controls heart rate and blood pressure responses.
Adey WR et al. · 1999
Researchers exposed pregnant rats and their offspring to cell phone radiation (836 MHz) for 24 months to study brain tumor development. Surprisingly, the radiation-exposed animals showed fewer brain tumors than unexposed controls, both naturally occurring tumors and those induced by a cancer-causing chemical. This unexpected protective effect was most pronounced in rats that died early in the study, where radiation exposure reduced chemically-induced brain tumors by a statistically significant amount.
Van Leeuwen GM et al. · 1999
Computer modeling showed mobile phone radiation heats brain tissue by only 0.11 degrees Celsius during continuous use. While radiation levels exceeded some proposed safety standards, researchers concluded these tiny temperature increases are far too small to cause lasting biological harm.
Seaman RL, Belt ML, Doyle JM, Mathur SP · 1999
Researchers exposed mice to ultra-wideband electromagnetic pulses at extremely high field strength (102,000 volts per meter) to see if it could counteract the hyperactive behavior caused by blocking nitric oxide production in the brain. The electromagnetic exposure successfully eliminated the drug-induced hyperactivity, suggesting the pulses somehow restored normal nitric oxide function. This demonstrates that pulsed electromagnetic fields can directly influence brain chemistry and behavior in laboratory animals.
Paul Raj R, Behari J, Rao AR · 1999
Researchers exposed young rats to radiofrequency radiation at cell phone-like levels for 35 days and found significant changes in brain chemistry, including increased calcium movement and enzyme activity. These cellular changes in developing brains suggest RF exposure during growth may disrupt normal brain function.
Kemerov, S, Marinkev, M, Getova, D · 1999
Researchers exposed rats to electromagnetic fields at different frequencies and tested their learning abilities. EMF exposure at 10 mW/cm² impaired the rats' ability to learn new behaviors, with different frequencies affecting brain function differently, even at low power levels that don't cause tissue heating.
Borbely et al. · 1999
Researchers exposed healthy adults to cell phone radiation (900 MHz) during sleep using 15-minute cycles. The radiation reduced nighttime awakenings and changed brain wave patterns during deep sleep, showing that phone signals can directly affect brain function even at supposedly safe levels.
Wagner, P, Roschke, J, Mann, K, Hiller, W, Frank, C · 1998
German researchers monitored the sleep patterns of 24 healthy men using brain wave measurements while exposing them to cell phone-like radiofrequency signals (900 MHz GSM signals). The study found no statistically significant changes in sleep quality, REM sleep duration, or brain wave patterns during EMF exposure. The researchers noted their failure to replicate previous findings might indicate that EMF effects on sleep depend on the specific exposure dose.
Urban, P, Lukas, E, Roth, Z · 1998
Researchers exposed 20 healthy volunteers to electromagnetic fields from a Motorola mobile phone for 5 minutes and measured visual evoked potentials (electrical brain responses to visual stimuli) to see if phone radiation affected brain function. They found no changes in brain activity after the exposure. This small pilot study suggests short-term mobile phone use may not immediately disrupt this particular aspect of brain function.
Seaman RL, Belt ML, Doyle JM, Mathur SP · 1998
Researchers exposed mice to extremely high-intensity ultra-wideband electromagnetic pulses (99-105 kV/m) for up to 45 minutes and tested whether this affected their pain sensitivity and movement, including when combined with morphine. The study found no changes in pain response or activity levels in either normal mice or those given morphine. This suggests these particular electromagnetic pulses did not interfere with the nervous system pathways that control pain and movement.
Schonborn F, Burkhardt M, Kuster N · 1998
Researchers used computer simulations to compare how much cell phone radiation is absorbed by children's heads versus adults' heads at 900 MHz and 1,800 MHz frequencies. They found no significant differences in radiation absorption between children and adults, contradicting earlier studies that suggested children absorb more radiation. This finding has important implications for safety standards, which are currently based only on adult head models.
Min ST, Redelmeier DA · 1998
Researchers analyzed car accident data from Toronto between 1984-1993 to see if cellular phone use correlated with increased crashes. They found that areas with the biggest increases in collision rates actually had the smallest increases in phone usage. The study concluded that cellular phones' effects on driving safety are too small to detect using this type of population-level analysis.
Mann et al. · 1998
Researchers exposed healthy volunteers to 900 MHz electromagnetic fields (similar to older cell phones) while they slept and measured hormone levels throughout the night. They found a small, temporary increase in cortisol (stress hormone) right after exposure began, but no effects on growth hormone, reproductive hormones, or melatonin. The study suggests our bodies may quickly adapt to this type of EMF exposure.
Mann, K, Roschke, J, Connemann, B, Beta, H · 1998
Researchers monitored heart rate patterns during sleep in healthy adults exposed to radiofrequency fields from digital mobile phones. They found no changes in heart rate variability or the balance between the sympathetic and parasympathetic nervous systems (the body's automatic stress and rest responses) during EMF exposure compared to placebo conditions. The study suggests that weak pulsed RF fields from mobile phones don't disrupt the heart's natural rhythm control during sleep.
Malyapa RS et al. · 1998
Researchers exposed rats to 2450 MHz microwave radiation (the same frequency used in microwave ovens and some WiFi devices) for 2 hours to see if it would damage DNA in brain cells, as a previous study had suggested. They found no DNA damage in either the brain's cortex or hippocampus regions, contradicting the earlier research. This study suggests that short-term exposure to this type of radiation at moderate levels may not cause immediate genetic damage to brain cells.
Malyapa RS et al. · 1998
Researchers exposed rats to microwave radiation at 2450 MHz (the same frequency used in microwave ovens) for 2 hours to test whether it causes DNA breaks in brain cells. They found no DNA damage in either the brain's cortex or hippocampus regions, contradicting an earlier study that reported such damage. This suggests that short-term exposure to this type of microwave radiation at moderate levels may not harm brain cell DNA.
Szmigielski et al. · 1998
Polish researchers studied 61 workers exposed to radiofrequency EMF at radio stations and compared their daily blood pressure and heart rate patterns to 42 unexposed workers. They found that EMF exposure disrupted the natural daily rhythms of both blood pressure and heart rate, with higher exposure levels causing more pronounced effects. This suggests that radiofrequency radiation may interfere with the body's autonomic nervous system, which controls these vital functions.
Hocking, B · 1998
Researchers surveyed 40 mobile phone users who experienced unusual symptoms like burning sensations and dull aches in their head and ears during or after phone calls. These symptoms typically started within minutes of use and lasted up to an hour afterward, with 75% of cases linked to digital phones. The study found that most people got relief by changing how they used their phones or switching to different devices.
Hanson Mild et al. · 1998
Swedish and Norwegian researchers compared symptoms between users of older analog mobile phones (NMT) and newer digital phones (GSM) in a large study of over 17,000 people. Surprisingly, they found that digital phone users actually reported fewer symptoms like warmth sensations around the ear compared to analog users, contradicting their initial hypothesis. However, both phone types showed a clear pattern: the more people talked on their phones, the more they experienced symptoms like headaches, fatigue, and ear warmth.
Grisanti G et al. · 1998
Italian researchers studied how cellular phone radiation affects the inner ear by measuring otoacoustic emissions (tiny sounds the ear produces naturally). They found that the electromagnetic fields from phones altered these natural ear responses in nearly all test subjects. This suggests that phone radiation can interfere with normal inner ear function, potentially affecting hearing.
Freude, G, Ullsperger, P, Eggert ,S, Ruppe, I · 1998
German researchers studied how cell phone radiation affects brain wave patterns by having men perform simple finger movements and complex visual tasks while exposed to phone emissions. They found that radiation significantly altered slow brain potentials (electrical patterns that prepare the brain for action) during the demanding cognitive task, but not during simple movements. This suggests cell phone radiation can interfere with brain electrical activity during mentally challenging activities, even when performance appears normal.
Eulitz, C, Ullsperger, P, Freude, G, Elbert ,T · 1998
German researchers examined how mobile phone radiation affects brain activity by measuring electrical responses while people listened to sounds. They found that phone radiation altered specific patterns of brain activity, particularly in higher frequency brain waves when people were actively processing important sounds. This suggests mobile phones can directly change how our brains process information.
Duan L, Shan Y, Yu X · 1998
Chinese researchers tested brain function in workers exposed to high-frequency electromagnetic radiation using standardized tests recommended by the World Health Organization. They found that exposed workers scored significantly lower on multiple brain performance measures compared to unexposed controls, and these changes correlated with symptoms of neurasthenia (a condition involving mental fatigue and cognitive difficulties). This suggests that occupational exposure to high-frequency EMF can measurably impair cognitive function.
