Electrohypersensitivity as a Newly Identified and Characterized Neurologic Pathological Disorder: How to Diagnose, Treat, and Prevent It.

Since 2009, we built up a database which presently includes more than 2000 electrohypersensitivity (EHS) and/or multiple chemical sensitivity (MCS) self-reported cases. This database shows that EHS is associated in 30% of the cases with MCS, and that MCS precedes the occurrence of EHS in 37% of these EHS/MCS-associated cases. EHS and MCS can be characterized clinically by a similar symptomatic picture, and biologically by low-grade inflammation and an autoimmune response involving autoantibodies against O-myelin. Moreover, 80% of the patients with EHS present with one, two, or three detectable oxidative stress biomarkers in their peripheral blood, meaning that overall these patients present with a true objective somatic disorder. Moreover, by using ultrasonic cerebral tomosphygmography and transcranial Doppler ultrasonography, we showed that cases have a defect in the middle cerebral artery hemodynamics, and we localized a tissue pulsometric index deficiency in the capsulo-thalamic area of the temporal lobes, suggesting the involvement of the limbic system and the thalamus. Altogether, these data strongly suggest that EHS is a neurologic pathological disorder which can be diagnosed, treated, and prevented. Because EHS is becoming a new insidious worldwide plague involving millions of people, we ask the World Health Organization (WHO) to include EHS as a neurologic disorder in the international classification of diseases.

Chemical intolerance: involvement of brain function and networks after exposure to extrinsic stimuli perceived as hazardous.

BACKGROUND: Chemical intolerance (CI) is a chronic condition characterized by recurring and severe symptoms triggered by exposure to low levels of odorous or pungent substances. The etiology of CI has been a controversial subject for a long time. The aim of this review is to summarize findings on the neurological processing of sensory information during and after exposure to low levels of odorous or pungent substances in individuals with CI, focusing on the brain function and networks. METHODS: Scientific studies on CI published between 2000 and 2019 in academic peer-reviewed journals were systematically searched using medical and scientific literature databases. Only peer-reviewed articles reporting original research from experimental human studies directly associated with CI, and involving related neurological responses or brain imaging after exposure to odorous or pungent substances (i.e., in chemical provocation tests), were considered. RESULTS: Forty-seven studies were found to be eligible for a full-text review. Twenty-three studies met the selection criteria and were included in this review. Evidence indicated that differences between subjects with CI and healthy controls were observed by brain imaging during and after exposure to odorous or pungent substances. Differences in brain imaging were also observed between initial exposure and after exposure to these substances. Neurological processing of sensory information after exposure to extrinsic stimuli in the limbic system and related cortices were altered in subjects with CI. A previous documentable exposure event was likely to be involved in this alteration. CONCLUSIONS: This review documents consistent evidence for the altered neurological processing of sensory information in individuals with CI. Further neurophysiological research exploring the processing of extrinsic stimuli and cognition of sensation through the limbic system and related cortices in CI, and the appearance of symptoms in individuals with CI, are required.

Neuropsychological and positron emission tomography correlates in idiopathic environmental intolerances.

OBJECTIVES: It has been hypothesized that people with subjective hypersensitivity to chemicals may indeed suffer from neuronal damage due to widely distributed environmental toxins and that such deficits of diagnostic importance can be demonstrated with the help of functional neuroimaging even in single cases. In this study, a small group of well-characterized patients with idiopathic environmental intolerance were examined in order to identify such changes. METHODS: Twelve patients with idiopathic environmental intolerance were investigated neuropsychologically and underwent cerebral F-18 fluorodeoxyglucose (F-18 FDG) positron emission tomography (PET). The imaging results were compared with findings from 17 healthy controls. RESULTS: Six patients showed deficits in verbal learning and memory, three of them also had a reduced information processing speed. In the individual analyses, 11 patients showed normal cerebral glucose metabolism. In the group analysis of the patients, no areas with significantly reduced glucose metabolism could be found. CONCLUSIONS: No consistent pathological cognitive performance and functional imaging pattern was found. It appears premature to claim specific neuropsychological or neuroimaging findings characteristic of idiopathic environmental intolerance. Therefore cerebral F-18 FDG PET should not be used to corroborate or rule out suspected idiopathic environmental intolerance, a syndrome whose potential biological underpinnings still need to be clarified.

PET in patients with clear-cut multiple chemical sensitivity (MCS).

AIM: Multiple chemical sensitivity (MCS) is a controversially discussed symptom complex. Patients afflicted by MCS react to very low and generally non-toxic concentrations of environmental chemicals. It has been suggested that MCS leads to neurotoxic damage or neuroimmunological alteration in the brain detectable by position emission tomography (PET) and single photon emission computer tomography (SPECT). These methods are often applied to MCS patients for diagnosis, although they never proved appropriate. METHOD: We scanned 12 MCS patients with PET, hypothesizing that it would reveal abnormal findings. RESULTS: Mild glucose hypometabolism was present in one patient. In comparison with normal controls, the patient group showed no significant functional brain changes. CONCLUSION: This first systematic PET study in MCS patients revealed no hint of neurotoxic or neuroimmunological brain changes of functional significance.

Functional brain imaging in the assessment of multiple chemical sensitivities.

The author provides a brief overview of single photon emission computed tomography in the assessment of multiple chemical sensitivities.

[Role of positron emission tomography (PET) and single photon emission tomography (SPECT) in so-called "multiple chemical sensitivity"]. / Rolle der Positronen-Emissions-Tomographie (PET) und Single-Photon-Emissions-Tomographie (SPECT) bei der sogenannten "Multiple Chemical Sensitivity" (MCS).

Functional imaging with SPECT and PET is increasingly used to prove evidence for the existence of a syndrome "Multiple Chemical Sensitivity" (MCS) and plays a major role in legal trials to justify compensation for the exposure to solvents. This paper critically reviews the literature on the use of SPECT and PET for the determination of MCS. The authors come to the conclusion that the current data are not sufficient to justify the claim of the existence of such a syndrome. The low specificity of the observed PET and especially SPECT-findings makes it very difficult to establish a cause-result relationship and therefore makes the use of these methods in legal trials on this issue doubtful.

Neurotoxicity in single photon emission computed tomography brain scans of patients reporting chemical sensitivities.

The subset of patients reporting chemical sensitivity with neurocognitive complaints usually exhibits specific abnormalities of brain metabolism consistent with neurotoxicity, on imaging with single photon emission computed tomography (SPECT). These recurrent neurotoxic patterns are characterized by a mismatch in tracer uptake between early- and late-phase imaging, multiple hot and cold foci throughout the cortex, temporal asymmetry and increased tracer uptake into the soft tissues and, sometimes, the basal ganglia. Previous studies confirm these neurotoxic findings in patients with neurotoxic chemical exposures and breast implants. Affective processes such as depression do not, alone, show this pattern. These abnormalities in SPECT images correlate with documented neurocognitive impairment. Controlled challenges to ambient chemicals can induce profound neurotoxic changes seen on SPECT imaging in chemically sensitive patients. Detoxification treatment techniques frequently produce significant improvement on brain SPECT brain imaging in these patients. Neurotoxicity appears to be characteristic in many cases of chemical sensitivity.

Single photon emission computed tomography of the brain in patients with chemical sensitivities.

Chemical sensitivities display a recurrent pattern on scintigraphic examinations of the brain. The pattern can include mismatching between early and late imaging, multiple hot and cold foci distributed throughout the cortex without regard to lobar distribution (salt and pepper pattern), temporal asymmetries, and sometimes increased activity in the basal ganglia. This study used Desert Shield/Desert Storm veterans who present with abnormal neurological and psychological symptoms as a model to exhibit abnormalities by brain scintigraphy. These are typical of those seen in patients with documented exposure to neurotoxic compounds who develop a clinical syndrome that has been termed "chemical sensitivity." Exposure to cocaine, alcohol, and other substances of abuse can result in abnormal scintigrams of the brain using tracers such as [technetium-99m]hexamethylpropyleneoxime. This study used techniques combining regional cerebral blood flow data with delayed distributional data after the intracellular conversion of the tracer into a hydrophilic molecule. In addition to delayed image abnormalities, a mismatch occurs in the regional activity between the two image sets of the veterans. This degree of mismatch was not seen in control subjects who were screened for avoidance of neurotoxic agents. Patterns identified from examinations performed on patients with known exposure to petroleum distillates, pesticides and other materials linked with neurotoxicity were identified in some veterans of the Desert Shield/Desert Storm operation. A single case of repeated examinations on a veteran showed a reversion of these patterns toward normal after therapy. This reversion followed independent assessments of clinical improvement.