Nocebo as headache trigger: evidence from a sham-controlled provocation study with RF fields.

BACKGROUND: A large proportion of the population in Norway has experienced headache in connection with mobile phone use, but several double-blind provocation studies with radiofrequency (RF) and sham exposures have shown no relation between headache and mobile phone RF fields. AIMS: To investigate the type and location of headache experienced by participants in one provocation study in order to gain insight into possible causes and mechanisms of the headaches. METHOD: Questionnaire about headache, indication on figure of location of headache after exposure, interview with neurologist about headache features to make headache diagnoses. RESULTS: The 17 participants went through 130 trials (sham or RF exposure). No significant difference existed in headache type, laterality or location between the headaches experienced with the two exposures types. In most participants, the headache was compatible with tension-type headache. DISCUSSION: As participants experienced their typical 'mobile phone headache' both with and without RF exposure, and since the experiment did not involve the stress or the arm/head position of mobile phone use, the most likely explanation is that the headache in this situation is caused by negative expectations (nocebo). CONCLUSION: This and other similar studies indicate that headache occurring in connection with mobile phone use is not related to RF fields, and that a nocebo effect is important for this and possibly other headache triggers.

Mobile phone headache: a double blind, sham-controlled provocation study.

The objective was to test whether exposure to radio frequency (RF) fields from mobile phones may cause head pain or discomfort and whether it may influence physiological variables in individuals attributing symptoms to mobile phones, but not to electromagnetic fields in general. Seventeen eligible individuals, who experienced these symptoms in an open provocation test, took part in a double-blind, randomized provocation study with cross-over design. Sixty-five pairs of sham and mobile phone RF exposures were conducted. The increase in pain or discomfort (visual analogue scales) in RF sessions was 10.1 and in sham sessions 12.6 (P=0.30). Changes in heart rate or blood pressure were not related to the type of exposure (P: 0.30-0.88). The study gave no evidence that RF fields from mobile phones may cause head pain or discomfort or influence physiological variables. The most likely reason for the symptoms is a nocebo effect.

Multiple doses of secretin in the treatment of autism: a controlled study.

UNLABELLED: Dramatic effects on autistic behaviour after repeated injections of the gastrointestinal hormone secretin have been referred in a number of case reports. In the absence of curative and effective treatments for this disabling condition, this information has created new hope among parents. Although controlled studies on the effect of mainly one single dose have not documented any effect, many children still continue to receive secretin. Six children enrolled in a double-blind, placebo-controlled crossover study in which each child was its own control. Human synthetic secretin, mean dose 3.4 clinical units, and placebo were administered intravenously in randomized order every 4th wk, on three occasions each. The measurement instruments were the visual analogue scale (VAS) and the aberrant behaviour checklist (ABC). Statistically significant differences were found for placebo in 3 out of 6 children and for secretin in one child, using parental ratings only (VAS scores). Differences were small and lacked clinical significance, which was in accordance with the overall impression of the parents and teachers and visual inspection of graphs. CONCLUSION: In this placebo-controlled study, multiple doses of secretin did not produce any symptomatic improvement.

Mobile phone use and subjective symptoms. Comparison of symptoms experienced by users of analogue and digital mobile phones.

In 1995 many people reported symptoms such as headaches, feelings of discomfort, warmth behind/around or on the ear and difficulties concentrating while using mobile phones. The number of complaints was higher for people using the digital (GSM) system, i.e. with pulse modulated fields, than for those using the analogue (NMT) system. Our main hypothesis was that GSM users experience more symptoms than NMT users. An epidemiological investigation was initiated including 6379 GSM users and 5613 NMT 900 users in Sweden, and 2500 from each category in Norway. The adjusted odds ratio did not indicate any increased risk for symptoms for GSM users compared with NMT 900 users. Our hypothesis was therefore disproved. However, we observed a statistically significant lower risk for sensations of warmth on the ear for GSM users compared with NMT 900 users. The same trend was seen in Norway for sensations of warmth behind/around the ear and in Sweden for headaches and fatigue. Factors distinguishing the two systems (radio frequency emission, phone temperatures and various ergonomic factors) may be responsible for these results, as well as for a secondary finding: a statistically significant association between calling time/number of calls per day and the prevalence of warmth behind/around or on the ear, headaches and fatigue.

Symptoms experienced in connection with mobile phone use.

Many people in Norway and Sweden reported headaches, fatigue, and other symptoms experienced in connection with the use of a mobile phone (MP). Therefore, we initiated a cross-sectional epidemiological study among 17,000 people, all using an MP in their job. Thirty-one percent of the respondents in Norway and 13% of those in Sweden had experienced at least one symptom in connection with MP use. Next to the sensations of warmth on the ear and behind/around the ear, burning sensations in the facial skin and headaches were most commonly reported. Most symptoms usually began during or within half an hour after the call and lasted for up to 2 h. Relatively few had consulted a physician or been on sick leave because of the symptoms, but about 45% among those with an MP attributed symptom had taken steps to reduce the symptom. These results suggest an awareness of the symptoms, but not necessarily a serious health problem.

Long-term effects on symptoms by reducing electric fields from visual display units.

OBJECTIVES: The purpose of the study was to see whether the results of an earlier study [ie, that skin symptoms were reduced by reducing electric fields from visual display units (VDU)] could be reproduced or not. In addition, an attempt was made to determine whether eye symptoms and symptoms from the nervous system could be reduced by reducing VDU electric fields. METHODS: The study was designed as a controlled double-blind intervention. The electric fields were reduced by using electric-conducting screen filters. Forty-two persons completed the study while working at their ordinary job, first 1 week with no filter, then 3 months with an inactive filter and then 3 months with an active filter (or in reverse order). The inactive filters were identical to the active ones, except that their ground cables were replaced by empty plastic insulation. The inactive filters did not reduce the fields from the VDU. The fields were significantly lower with active filters than with inactive filters. RESULTS: Most of the symptoms were statistically significantly less pronounced in the periods with the filters when compared with the period with no filter. This finding can be explained by visual effects and psychological effects. No statistically significant difference in symptom severeness was observed between the period with an inactive filter and the one with an active filter. CONCLUSIONS: The study does not support the hypothesis that skin, eye, or nervous system symptoms can be reduced by reducing VDU electric fields.

Skin symptoms after the reduction of electric fields from visual display units.

OBJECTIVES: The objective of this work was to determine whether facial skin symptoms are reduced by decreasing static and low-frequency electric fields produced by visual display units. METHODS: The electric fields were reduced by electric-conducting screen filters. Twenty subjects took part in the study while working at their ordinary jobs, first two weeks without any filter, then two weeks with an inactive filter and two weeks with an active filter (or in reversed order). The inasctive filters were identical to the active ones except that the ground cable was cut. Measurements showed that the inactive filters reduced the static electric fields nonsignificantly less than the active filters. For extremely low-frequency fields the difference was greater, and the active filters reduced the very low-frequency fields significantly more than the inactive ones. RESULTS: Most symptoms were less pronounced with active filters than with inactive filters. The differences were small, and for one symptom only, tingling, pricking or itching, the result was statistically significant. The recorded physical and psychosocial factors did not explain the reduction with the use of active filters. Days with a long period spent near a visual display unit resulted in significantly more pronounced symptoms than days with short time. The findings registered by a dermatologist did not reveal any consistent difference between the two periods with filters. CONCLUSION: The results weakly support the hypothesis that skin symptoms can be reduced by a reduction of electric fields.

Noise-induced hearing damage caused by metabolic exhaustion: a mathematical model.

A mathematical model for noise-induced hearing loss is based on the assumption that hair cells are damaged, temporarily or permanently, by metabolic exhaustion, and that the number of damaged hair cells and the hearing loss are monotonically increasing functions of an energy deficiency. The purpose of the model is to focus on the influence of sound intensity, exposure duration, and temporal pattern of the sound exposure on the noise-induced hearing loss from long-duration exposures. The model is restricted to the range of sound levels where metabolic exhaustion probably is the main reason for the hair cell damage. Only exposures with similar frequency spectra and producing moderate hearing losses are considered; frequency dependence is not discussed.

Intensity-time tradeoff for constant hearing loss with high sound levels.

The tradeoff relation between exposure intensity and duration for constant hearing loss was investigated in two series of experiments using Mongolian gerbils. The gerbils were exposed to a 1/3 octave band of noise at 2.5 kHz. In the first series animals were exposed to 120 dB SPL for 1 h, to 126 dB SPL for 15 min, and to 126 dB SPL for 3.75 min. In the second series, shorter durations were used: 120 dB SPL for 15 min, 126 dB SPL for 3.75 min, and 126 dB SPL for 56 s. The hearing thresholds were determined behaviorally immediately before exposure and 6 weeks after exposure. The results suggest that the intensity-time tradeoff for the investigated intensity interval is between 1.5 and 3 dB per halving of the duration.

Perinatal retinal haemorrhages and development. Follow-up in seven year olds.

Depending on methods of delivery, 7-50% of all children are born with retinal haemorrhages (RH). To assess the prognostic value of extensive RH for the future development of the child, the ophthalmological, neurological and psychological status of 52 children, 26 born with RH and 26 controls, were examined at the age of seven years. There were significant differences between the two groups using only psychological measures. Children with RH performed poorer than the control group, but the results did not point to any particular cerebral areas being affected. However, children with both RH and low socio-economic status were significantly less emotionally stable than the controls. Socio-economic factors also seem to be more highly correlated with later performance than do RH.

Familial dysautonomia in a non-Jewish child.

Few documented cases of Riley-Day syndrome fulfilling current diagnostic criteria have been recognized in non-Jews. In our case the diagnosis was established in a Norwegian child despite the absence of Jewish origin. It represents a report of this syndrome with bilateral pathological changes in the hypothalamus in addition to extensive abnormal findings in the spinal cord and the autonomic ganglia. These findings may have significance with regard to the pathogenesis of the disease.