Thinner abuse alters optokinetic nystagmus parameters.
BACKGROUND
Deliberate self-inhalation of solvents such as thinner is a recognized problem in underdeveloped countries, with chronic abuse resulting in neurological impairment. In this article, we use electronystagmography (ENG) to study optokinetic nystagmus abnormalities (OKN) that may be induced by thinner consumption.


METHODS
Twenty-five patients exposed to thinner for 5-20 years, in an irregular fashion of consumption, were recruited from a toxicologic center. Twenty-five control subjects were invited to participate as volunteers matched by age (+/-2 years) and gender. At the time of evaluation, all had abstained from intoxicants for at least 4 weeks. ENG recordings were performed by clinicians masked to the patient's group. Clockwise and counterclockwise stimulation were performed at 20 and 40 degrees /sec.


RESULTS
None of the patients showed spontaneous nystagmus during the test period. Differences between thinner abusers and controls on clockwise and counterclockwise OKN on number of beats of nystagmus elicited on the 40 degrees /sec velocity were identified. The thinner abusers group showed a lesser number of nystagmus (p level was 0.02 and 0.005, respectively).


CONCLUSIONS
The present results confirm the sensibility of OKN as an early marker of solvent abuse. These results were obtained in middle-term chronic exposure to solvent mixtures and are in favor of both cortical and brainstem dysfunction.
Poblano
A
A
Laboratorio de Fisiología, Instituto Nacional de Comunicación Humana, México, D.F., Mexico. apoblano@df1.telmex.net.mx
Ishiwara
K
K
Ortega
P
P
Mora
L
L
Pineda
G
G
Arriaga
E
E
D000293:Adolescent; D000328:Adult; D001933:Brain Stem / Q000503:physiopathology; D002540:Cerebral Cortex / Q000503:physiopathology; D004584:Electronystagmography; D005260:Female; D006801:Humans; D008297:Male; D017120:Nystagmus, Optokinetic / Q000187:drug effects*; D012680:Sensitivity and Specificity; D012997:Solvents / Q000009:adverse effects / Q000494:pharmacology*; D019966:Substance-Related Disorders / Q000503:physiopathology*
D012997:Solvents