Browsing by Author "Lindholm, Harri"
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- ItemCellular phone use does not acutely affect blood pressure or heart rate of humans.(2004-01-21) Tahvanainen, Kari; Niño, Juanita; Halonen, Pirjo; Kuusela, Tom; Laitinen, Tomi; Länsimies, Esko; Hartikainen, Juha; Hietanen, Maila; Lindholm, HarriA recent study raised concern about increase of resting blood pressure after a 35 min exposure to the radiofrequency RF field emitted by a 900 MHz cellular phone In this randomized double blind placebo controlled crossover trial 32 healthy subjects were submitted to 900 MHz 2 W 1800 MHz 1 W cellular phone exposure and to sham exposure in separate sessions Arterial blood pressure arm cuff method and heart rate were measured during and after the 35 min RF and sham exposure sessions We evaluated cardiovascular responses in terms of blood pressure and heart rate during controlled breathing spontaneous breathing head up tilt table test Valsalva manoeuvre and deep breathing test Arterial blood pressure and heart rate did not change significantly during or after the 35 min RF exposures at 900 MHz or 1800 MHz compared to sham exposure The results of this study indicate that exposure to a cellular phone using 900 MHz or 1800 MHz with maximal allowed antenna powers does not acutely change arterial blood pressure and heart rate
- ItemEffects of cellular phone use on ear canal temperature measured by NTC thermistors.(2007-04-20) Tahvanainen, Kari; Niño, Juanita; Halonen, Pirjo; Kuusela, Tom; Alanko, Tommi; Laitinen, Tomi; Länsimies, Esko; Hietanen, Maila; Lindholm, HarriThe earlier studies using phantom models and human subjects concerning warming effects during cellular phone use have been controversial partly because radiofrequency RF exposures have been variable In this randomized double blind placebo controlled crossover trial 30 healthy subjects were submitted to 900 MHz 2W and 1800 MHz 1W cellular phone RF exposure and to sham exposure in separate study sessions Temperature signals were recorded continuously in both ear canals before during and after the 35 min RF exposure and the 35 min sham exposure sessions Temperature was measured by using small sized NTC thermistors placed in the ear canals through disposable ear plugs The mean temperature changes were determined during a set cardiovascular autonomic function studies during a 5 min controlled breathing test during a 5 min spontaneous breathing test during 7 min head up tilting 1 min before during and after two consecutive Valsalva manoeuvres and during a deep breathing test Temperatures in the exposed ear were significantly higher during RF exposures compared with sham exposure in both 900 and 1800 MHz studies with maximum differences of 1 x 2 0 x 5 degrees C 900 MHz exposure and 1 x 3 0 x 7 degrees C 1800 MHz exposure Temperatures in the RF exposed ear were also significantly higher during the postexposure period compared with post sham exposure period with maximum differences of 0 x 6 0 x 3 degrees C for 900 MHz and 0 x 5 0 x 5 degrees C for 1800 MHz The results of this study suggest that RF exposure to a cellular phone either using 900 or 1800 MHz with their maximal allowed antenna powers increases the temperature in the ear canal The reason for the ear canal temperature rising is a consequence of mobile phone battery warming during maximal antenna power use The earlier published articles do not indicate that temperature rising in the ear canal has any significant contribution from the RF fields emitted from mobile phones
- ItemGSM mobile phone radiation suppresses brain glucose metabolism.(2011-12-01) Kwon, Myoung Soo; Vorobyev, Victor; Kännälä, Sami; Laine, Matti; Rinne, Juha O; Toivonen, Tommi; Johansson, Jarkko; Teräs, Mika; Lindholm, Harri; Alanko, Tommi; Hämäläinen, HeikkiWe investigated the effects of mobile phone radiation on cerebral glucose metabolism using high resolution positron emission tomography PET with the 18 F deoxyglucose FDG tracer A long half life 109 minutes of the 18 F isotope allowed a long natural exposure condition outside the PET scanner Thirteen young right handed male subjects were exposed to a pulse modulated 902 4 MHz Global System for Mobile Communications signal for 33 minutes while performing a simple visual vigilance task Temperature was also measured in the head region forehead eyes cheeks ear canals during exposure 18 F deoxyglucose PET images acquired after the exposure showed that relative cerebral metabolic rate of glucose was significantly reduced in the temporoparietal junction and anterior temporal lobe of the right hemisphere ipsilateral to the exposure Temperature rise was also observed on the exposed side of the head but the magnitude was very small The exposure did not affect task performance reaction time error rate Our results show that short term mobile phone exposure can locally suppress brain energy metabolism in humans
- ItemInappropriate implantable cardioverter-defibrillator magnet-mode switch induced by a laptop computer.(2012-06-07) Tiikkaja, Maria; Aro, Aapo; Alanko, Tommi; Lindholm, Harri; Hietanen, MailaAn implantable cardioverter defibrillator ICD experienced electromagnetic interference from a laptop computer s hard disk The patient with the ICD was using his laptop computer at home while lying on his bed The laptop was positioned on his chest when he heard a beeping sound from the ICD indicating magnet mode conversion This situation was replicated in a controlled environment and the conversion was found to be due to the static magnetic field produced by the laptop s hard disk The ICD s conversion to magnet mode can be dangerous because it ends all tachyarrhythmia detections and therapies
- ItemNo effects of short-term GSM mobile phone radiation on cerebral blood flow measured using positron emission tomography.(2012-03-05) Kwon, Myoung Soo; Vorobyev, Victor; Kännälä, Sami; Laine, Matti; Rinne, Juha O; Toivonen, Tommi; Johansson, Jarkko; Teräs, Mika; Joutsa, Juho; Tuominen, Lauri; Lindholm, Harri; Alanko, Tommi; Hämäläinen, HeikkiThe present study investigated the effects of 902 4 MHz global system for mobile communications GSM mobile phone radiation on cerebral blood flow using positron emission tomography PET with the 15 O water tracer Fifteen young healthy right handed male subjects were exposed to phone radiation from three different locations left ear right ear forehead and to sham exposure to test for possible exposure effects on brain regions close to the exposure source Whole brain O H O PET images were acquired 12 times 3 for each condition in a counterbalanced order Subjects were exposed for 5 min in each scan while performing a simple visual vigilance task Temperature was also measured in the head region forehead eyes cheeks ear canals during exposure The exposure induced a slight temperature rise in the ear canals but did not affect brain hemodynamics and task performance The results provided no evidence for acute effects of short term mobile phone radiation on cerebral blood flow
- ItemTesting of common electromagnetic environments for risk of interference with cardiac pacemaker function.(2013-10-09) Tiikkaja, Maria; Aro, Aapo L; Alanko, Tommi; Lindholm, Harri; Sistonen, Heli; Hartikainen, Juha E K; Toivonen, Lauri; Juutilainen, Jukka; Hietanen, MailaCardiac pacemakers are known to be susceptible to strong electromagnetic fields EMFs This in vivo study investigated occurrence of electromagnetic interference with pacemakers caused by common environmental sources of EMFs
- ItemThermal effects of mobile phone RF fields on children: a provocation study.(2011-11-29) Lindholm, Harri; Alanko, Tommi; Rintamäki, Hannu; Kännälä, Sami; Toivonen, Tommi; Sistonen, Heli; Tiikkaja, Maria; Halonen, Janne; Mäkinen, Tero; Hietanen, MailaThe aim of this study was to examine thermal and local blood flow responses in the head area of the preadolescent boys during exposure to radiofrequency RF electromagnetic fields produced by a GSM mobile phone The design was a double blinded sham controlled study of 26 boys aged 14 15 years The SAR distribution was calculated and modelled in detail The duration of the sham periods and exposures with GSM 900 phone was 15 min each and the tests were carried out in a climatic chamber in controlled thermoneutral conditions The ear canal temperatures were registered from both ear canals and the skin temperatures at several sites of the head trunk and extremities The local cerebral blood flow was monitored by a near infrared spectroscopy NIRS and the autonomic nervous system function by recordings of ECG and continuous blood pressure During the short term RF exposure local cerebral blood flow did not change the ear canal temperature did not increase significantly and autonomic nervous system was not interfered The strengths of this study were the age of the population multifactorial physiological monitoring and strictly controlled thermal environment The limitations of the study were large inter individual variation in the physiological responses and short duration of the exposure Longer provocation protocols however might cause in children distress related confounding physiological responses