title: Residual central nervous system damage due to organoarsenic poisoning.
abstract: BACKGROUND
  Drinking well water contaminated with the organoarsenic compound diphenylarsinic acid (DPAA) causes central nervous system (CNS) disorders that improve within several years after last drinking such water. Subjective symptoms such as lightheadedness and dizziness appear to persist, however, suggesting CNS damage. We evaluated CNS damage due to DPAA by detecting abnormal eye movements.
  
  
  METHODS
  Subjects comprised 29 victims of exposure to DPAA in whom this substance had been detected in the nails. Investigations were performed more than 3years following cessation of DPAA exposure. Abnormal eye movements were monitored using electronystagmography. We analysed unpaired t-test between exposure subjects who exhibited upbeat nystagmus and those who did not. Upbeat nystagmus parameters were measured, and mean values were calculated. Associations between the properties of upbeat nystagmus and maximum concentrations of DPAA among DPAA exposure were also investigated.
  
  
  RESULTS
  Upbeat nystagmus was common among exposure victims, occurring in 23 of 29 subjects (79.0%). The subjects with upbeat nystagmus had significantly higher ratio than those without upbeat nystagmus in the points of subjective symptoms and DPAA concentration of drinking water (p<0.01). The slow-phase amplitude of upbeat nystagmus enlarged with increasing DPAA concentrations, showing a significant positive correlation (p<0.05). These findings suggest that the level of exposure to DPAA affects the properties of nystagmus. High-frequency pathological square-wave jerks (SWJ) were seen in 14 of 29 patients (48.0%), and mean SWJ frequency was 112.4±16.7/min.
  
  
  CONCLUSIONS
  Detection of abnormal ocular movements may be useful in evaluating residual/persistent/chronic CNS damage due to organoarsenic poisoning.
authors: Department of Neurology, Institute of Clinical Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan. Nakamagoek@md.tsukuba.ac.jp
authors: Kiyotaka
authors: K
authors: Nakamagoe
authors: Natsu
authors: N
authors: Fujizuka
authors: Tadachika
authors: T
authors: Koganezawa
authors: Kotone
authors: K
authors: Shimizu
authors: Shino
authors: S
authors: Takiguchi
authors: Takahiro
authors: T
authors: Horaguchi
authors: Kazuhiro
authors: K
authors: Ishii
authors: Akira
authors: A
authors: Tamaoka
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D020261:Arsenic Poisoning / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D001152:Arsenicals / Q000493:pharmacokinetics; D016022:Case-Control Studies; D002490:Central Nervous System / Q000187:drug effects* / Q000473:pathology; D004584:Electronystagmography; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D009262:Nails / Q000737:chemistry; D009759:Nystagmus, Pathologic / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D014018:Tissue Distribution; D014874:Water Pollutants, Chemical / Q000493:pharmacokinetics / Q000633:toxicity*; D055815:Young Adult
chemical_list: D001152:Arsenicals; D014874:Water Pollutants, Chemical; C493087:diphenylarsinic acid