Are deficits in the equilibrium system relevant to the clinical investigation of solvent-induced neurotoxicity?
OBJECTIVE
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.


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.


CONCLUSIONS
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.
Niklasson
M
M
Department of Otorhinolaryngology, Head and Neck Surgery, Faculty of Health Sciences, University Hospital, Linköping, Sweden.
Möller
C
C
Odkvist
L M
LM
Ekberg
K
K
Flodin
U
U
Dige
N
N
Sköldestig
A
A
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001927:Brain Diseases / Q000139:chemically induced* / Q000175:diagnosis / Q000503:physiopathology; D016022:Case-Control Studies; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D005133:Eye Movements / Q000187:drug effects / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000139:chemically induced* / Q000175:diagnosis / Q000503:physiopathology; D016273:Occupational Exposure / Q000009:adverse effects*; D004856:Postural Balance / Q000187:drug effects* / Q000502:physiology; D011187:Posture / Q000502:physiology; D012678:Sensation Disorders / Q000139:chemically induced / Q000175:diagnosis / Q000503:physiopathology; D012997:Solvents / Q000506:poisoning*; D014724:Vestibular Function Tests
D012997:Solvents