Abstracts:
Neurological Damage Due to Exposure
to Neurotoxic Solvents
| 1)
Audiological
disturbances caused by long-term exposure to industrial solvents. 2) Long-term follow up of workers exposed to solvents. 3) Are deficits in the equilibrium system relevant to the clinical investigation of solvent-induced neurotoxicity? 4) Otoneurological findings in psycho-organic syndrome caused by industrial solvent exposure. 5) Neurospect in neurotoxic chemical exposure demonstration of long-term functional abnormalities. 6) Neurotoxicity in single photon emission computed toomography brain scans of patients reporting chemical sensitivities. |
| 1) Audiological
disturbances caused by long-term exposure to industrial solvents. Relation to the diagnosis of toxic encephalopathy. Scand Audiol 1998;27(3):131-6 Niklasson M, Arlinger S, Ledin T, Moller C, Odkvist L, Flodin U, Tham R Department of Otorhinolaryngology, Head and Neck Surgery, Faculty of Health Sciences, University Hospital, Linkoping, Sweden. Sixty workers, consecutively admitted due to suspicion of solvent-induced chronic toxic encephalopathy (CTE), were investigated with pure-tone audiometry, determination of speech recognition of monosyllabic words and distorted speech and cortical response audiometry (CRA). Eighteen workers not exposed to occupational solvents and noise were also investigated. The scores in the distorted speech test were significantly lower and the CRA latencies were significantly longer in the solvent group than in the control group. There was no difference between the groups in the pure-tone and monosyllabic speech recognition tests. In the solvent group, 19 subjects had one or several pathological audiological test results (values exceeding the mean result of the control group by 2 SD). Independently of the audiological examination all the workers in the solvent group underwent the traditional clinical assessment of CTE, which is based on symptoms, history of exposure, clinical neurological examination and a neuropsychological investigation. They were classified in three groups -- CTE, incipient CTE and non-CTE. There was no correlation between these groups and the audiological test results. A previous report on vestibular pathology in the same group of subjects and the present investigation on hearing deficits suggest that long- term exposure to solvents causes disturbances of the central pathways in the otovestibular system. Hitherto, no attention has been paid to these disturbances in the definition of the CTE syndrome. E-mail: Magnus.Niklasson@oto.us.lio.se PMID: 9728772, UI: 98396973 |
| 2) Long-term follow
up of workers exposed to solvents. Br J Ind Med 1990 Feb;47(2):75-82 Edling C, Ekberg K, Ahlborg G Jr, Alexandersson R, Barregard L, Ekenvall L, Nilsson L, Svensson BG Department of Occupational Medicine, University Hospital, Uppsala, Sweden. Long term occupational exposure to organic solvents may cause adverse effects to the central nervous system. This collaborative study between six Swedish departments of occupational medicine examines the overall prognosis in terms of working capacity, symptoms, and psychometric test performance for individuals occupationally exposed to organic solvents. After re-analyses of the data from an initial clinical investigation of 111 men, the subjects were divided into two subgroups: one group of 65 with symptoms but no impairment on the tests and one group of 46 with toxic encephalopathy (symptoms and test impairment). At least five years after the initial examination the subjects were asked to attend a re-examination that included a structured medical interview and a psychometric investigation. The results indicate that effects on the central nervous system persist even when exposure has ceased. In the group of 46 more men had stopped working and were receiving sickness or early retirement pensions. This group also had reduced activity levels with regard to everyday life, leisure activities, and education or training and more neuropsychiatric symptoms. There was no support for the view that a solvent induced toxic encephalopathy is a progressive disease comparable with presenile dementia such as Alzheimer's disease or Pick's disease. If a worker was removed from exposure when he presented symptoms without signs of impairment in intellectual function, recovery was seen in most cases. |
| 3) Are deficits in
the equilibrium system relevant to the clinical investigation of solvent-induced neurotoxicity? Scand J Work Environ Health 1997 Jun;23(3):206-13 Niklasson M, Moller C, Odkvist LM, Ekberg K, Flodin U, Dige N, Skoldestig Department of Otorhinolaryngology, Head and Neck Surgery, Faculty of Health Sciences, University Hospital, Linkoping, Sweden. OBJECTIVES: The diagnosis of solvent-induced chronic toxic encephalopathy is commonly based on case histories of exposure to solvents, symptoms, and deficits on psychometric tests. It has previously been demonstrated that long-term solvent-exposed workers have disturbances of the equilibrium system. The correlation between these disturbances and the diagnosis of chronic toxic encephalopathy has been analyzed in the present study. MATERIAL AND METHODS: Sixty men, consecutively admitted due to the suspicion of this syndrome, were investigated and classified into 3 groups -- solvent-induced chronic toxic encephalopathy, incipient chronic toxic encephalopathy and nonchronic toxic encephalopathy. They were all examined using an otoneurological test battery, including analysis of saccades, smooth pursuit, visual suppression of the vestibular ocular reflex, and dynamic posturography. RESULTS: Compared with healthy referents several of the subjects, even in the nonchronic toxic encephalopathy group, showed a reduced visual suppression ability, a prolonged latency of saccades, and pathological posturographic results. Some otoneurological tests correlated with the duration of exposure and the results of psychometric tests representing memory and perceptual skills. Nevertheless, there was no significant group correlation between the otoneurological findings and the diagnosis of chronic toxic encephalopathy. CONCLUSION: Disturbances revealed by an otoneurological investigation have so far not been considered in the diagnosis of chronic toxic encephalopathy. Our results indicate that an otoneurological test battery adds worthwhile information about lesions within the brainstem-cerebellar complex not revealed by a psychometric investigation. |
| 4)
Otoneurological findings in psycho-organic syndrome caused by industrial solvent exposure. Acta Otolaryngol (Stockh) 1989 Jan-Feb;107(1-2):5-12 Moller C, Odkvist LM, Thell J, Larsby B, Hyden D, Bergholtz LM, Tham R Department of Otolaryngolgy and Head and Neck Surgery, University Hospital, Linkoping, Sweden. Nine subjects with long-term (8-30 years) occupational exposure to industrial solvents and a confirmed diagnosis of psycho-organic syndrome (POS) have been studied with audiological and otoneurological test batteries. The results were compared to a matched control group of nine industrial workers not exposed to solvents and to normal data from healthy volunteers. In the clinical examination, the Romberg test identified 5/9 workers as pathologic and concurrently the stabilometry showed significantly larger sway areas in the POS-group. In the audiological test battery, the significantly pathologic tests were discrimination of interrupted speech and evoked cortical responses to frequency glides (CRA-delta-f). The saccade test disclosed abnormal findings in 5/9 workers. In the smooth pursuit test, abnormality was found at some test frequencies using pseudorandomized stimulus. The VOR-suppression test was significantly abnormal at all test frequencies. The test battery used strongly indicates CNS lesions due to industrial solvents. |
| 5) Neurospect in neurotoxic chemical exposure
demonstration of long-term functional abnormalities. Toxicol Ind Health 1998 Nov-Dec;14(6):813-27 Heuser G, Mena I
Department of Radiology, UCLA-Harbor Medical Center,
Patients who had experienced well-documented neurotoxic
Seventy-two right-handed adults who claimed continuing
Bilateral, often asymmetrical, impairment of perfusion
Abnormalities were found months and years after neurotoxic |
| 6) Neurotoxicity in single photon emission
computed toomography brain scans of patients reporting chemical sensitivities. 1: Toxicol Ind Health 1999 Apr-Jun;15 (3-4):415-20
Ross GH, Rea WJ, Johnson AR, Hickey DC, Simon TR
The subset of patients reporting chemical sensitivity with
Controlled challenges to ambient chemicals can induce
profound ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
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